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1

The vascular system of human fetal long bones: a scanning electron microscope study of corrosion casts.  

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The vascular system of the femur and humerus was investigated in 17-24 wk human fetuses by scanning electron microscopy of corrosion casts. The number of nutrient foramina present in both bones ranged from 1 to 3 and the number of nutrient vessels associated with individual foramina also varied. The medullary arteries supplied both the bone cortex and marrow. There was no arterial supply to the shaft cortex from the periosteal side, where only capillaries were found to enter the bone. The met...

Skawina, A.; Litwin, J. A.; Gorczyca, J.; Miodon?ski, A. J.

1994-01-01

2

The vascular system of human fetal long bones: a scanning electron microscope study of corrosion casts.  

Science.gov (United States)

The vascular system of the femur and humerus was investigated in 17-24 wk human fetuses by scanning electron microscopy of corrosion casts. The number of nutrient foramina present in both bones ranged from 1 to 3 and the number of nutrient vessels associated with individual foramina also varied. The medullary arteries supplied both the bone cortex and marrow. There was no arterial supply to the shaft cortex from the periosteal side, where only capillaries were found to enter the bone. The metaphyses were supplied and drained by conspicuous vascular triads composed of an artery and 2 veins. In the marrow cavity, 2 morphologically different areas of the fine vascular network could be distinguished: diaphyseal sinusoids and metaphyseal capillaries forming a 'vascular besom' which was abruptly demarcated by the growth plate cartilage. The cortical microvascular bed was composed of capillaries and more numerous irregular sinusoids. The 2 main vascular systems, nutrient and periosteal, were interconnected not only via the network of cortical capillaries/sinusoids, but also by larger arteries and veins traversing the cortex. The features of the vascular system of human fetal long bones suggest its considerable functional flexibility and its capacity to modify blood flow patterns depending on circumstances. PMID:7961142

Skawina, A; Litwin, J A; Gorczyca, J; Miodo?ski, A J

1994-10-01

3

The venous system of the human foetal spinal cord. Scanning electron microscope of vascular corrosion casts.  

Science.gov (United States)

The investigation was carried out on 16 human foetal cadavers at the age of 17-23 weeks from the time of conception. The foetal vascular system was injected with the synthetic resin MERCOX CL-2R and analysed in scanning electron microscope.The vascular system of the foetal spinal cord was studied. The foetal vascular system was characterised by high variability concerning the number, course and localisation of blood vessels. It contained numerous anastomoses with the internal spinal venous plexuses, which included anterior and posterior radicular veins. Large arteries running on the surface of the spinal cord are accompanied by the homoname veins. The venous system of the investigated foetuses was divided into 2 categories of veins: internal veins responsible for the drainage of blood from the central area, that is central and peripheral veins coming radially to the surface of the spinal cord and external veins, which form the venous system of the surface of the spinal cord. The venous system of the foetal spinal cord was also examined as to the presence of the valves. PMID:24902090

Zawili?ski, J; Zagórska-?wie?y, K; Sk?adzie?, J

2014-05-01

4

Microangioarchitecture of the guinea pig gallbladder and bile duct as studied by scanning electron microscopy of vascular corrosion casts.  

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The microvasculature of the gallbladder, the common bile duct, and the duodenal papilla was investigated in 20 albino guinea pigs (Cavia porcellus) using microvascular corrosion casting and scanning electron microscopy (SEM). Main supplying and draining vessels (first-order vessels) approach the gallbladder along the cystic duct. From the latter, penetrating vessels (second-order vessels) arise which pierce the muscular coat of the gallbladder body to form the plexus of third-order vessels be...

Aharinejad, S.; Lametschwandtner, A.

1992-01-01

5

Design of Cerebellar and Nontegmental Rhombencephalic Microvascular Bed in the Sterlet, Acipenser ruthenus: A Scanning Electron Microscope and 3D Morphometry Study of Vascular Corrosion Casts  

Science.gov (United States)

The design of the microvasculature of cerebellum and nontegmental rhombencephalic areas was studied in eight adult Acipenser ruthenus L. by scanning electron microscopy of vascular corrosion casts and three-dimensional morphometry. Gross vascularization was described and diameters and total branching angles of parent and daughter vessels of randomly selected arterial and capillary bifurcations (respectively, venous mergings) were measured. With diameters ranging from 15.9 ± 1.9 [mu]m (cerebellum; mean ± S.D.) to 15.9 ± 1.7 mm (nontegmental rhombencephalon; mean ± S.D.) capillaries in Acipenser were significantly (p [greater-than-or-equal] .05) smaller than in cyclostomes (18 20 [mu]m) but significantly thicker than in higher vertebrates and men (6 8 [mu]m). With the exception of the area ratio [beta] (i.e., sum of squared daugther diameters divided by squared diameter of parent vessel) of the venular mergings in the nontegmental rhombencephalon, no significant differences (p [greater-than-or-equal] .05) existed between the two brain areas. Data showed that arteriolar and capillary bifurcations and venular mergings are optimally designed in respect to diameters of parent vessel to daughter vessels and to branching (merging) angles. Quantitative data are discussed both in respect to methodical pitfalls and the optimality principles possibly underlying the design of vascular bifurcations/mergings in selected brain areas of a nonteleost primitive actinopterygian fish.

Stöttinger, Bernhard; Klein, Martin; Minnich, Bernd; Lametschwandtner, Alois

2006-07-01

6

Fasudil, a Rho-kinase inhibitor, attenuates induction and progression of cerebral aneurysms: experimental study in rats using vascular corrosion casts.  

Science.gov (United States)

Fasudil (a Rho-kinase inhibitor) has been shown to attenuate abdominal aortic aneurysm development, but any preventive effect against development of cerebral aneurysms is unclear. The effect of fasudil on the development of cerebral aneurysms was investigated in 55 female Sprague-Dawley rats divided into 4 groups: Group 1 (n=10) was the control group without treatment. Groups 2-4 (n=15 each) were subjected to cerebral aneurysm induction procedures plus 1% NaCl in the drinking water. Groups 3 and 4 were also treated with 0.5 or 1.0mg/mL of fasudil in the drinking water, respectively. Vascular corrosion casts of the cerebral arteries were prepared and examined using a scanning electron microscope after 2 months. No significant differences were observed in the degree of induced hypertension between Groups 2, 3 and 4. No aneurysms were found in Group 1. Examination of the left anterior cerebral-olfactory artery junction, which is the most susceptible site for aneurysm development, found significantly fewer aneurysmal lesions in Groups 3 (60%) and 4 (53%) compared to Group 2 (100%) (P<0.02). This study suggests that fasudil attenuated induction of cerebral aneurysms in the rat model. PMID:20043978

Eldawoody, Hany; Shimizu, Hiroaki; Kimura, Naoto; Saito, Atsushi; Nakayama, Toshio; Takahashi, Akira; Tominaga, Teiji

2010-02-01

7

Evaluation of Accelerated Graphitic Corrosion Test of Gray Cast Iron  

International Nuclear Information System (INIS)

In operating nuclear power plants, gray cast iron is commonly used as materials for various non-safety system components including pipes in fire water system, valve bodies, bonnets, and pump castings. In such locations, operating condition does not require alloy steels with excellent mechanical properties. But, a few corrosion related degradation, or graphitic corrosion is frequently occurred to gray cast iron during the long-term operation in nuclear power plant. Graphitic corrosion is selective leaching of iron from gray cast iron, where iron gets removed and graphite grains remain intact. In U.S.A., one-time visual inspection and hardness measurement are required from regulatory body to detect the graphitic corrosion for the life extension evaluation of the operating nuclear power plant. In this study, experiments were conducted to make accelerated graphitic corrosion of gray cast iron using electrochemical method, and hardness was measured for the specimens to establish the correlation between degree of graphitic corrosion and surface hardness of gray cast iron

2011-05-01

8

Vascular corrosion casting of human heart  

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Variation in the morphological pattern of coronary arteries and their major branches is an important factor in the assessment and treatment of coronary heart disease. Detailed knowledge of the blood supply of the heart is necessary today because of the wider practice of cardiac surgery, and also for better understanding of the anomalous branches, anastomosis and dominance pattern in circulation caused by coronary vasculature. We utilized 80 human heart specimens and found right dominance in 6...

Vasudeva Reddy, J.; Lokanadham, S.

2013-01-01

9

Surgical Importance of Arterial Segments of Human Kidneys: An Angiography and Corrosion Cast Study  

Science.gov (United States)

Objective: Variations in the arterial supply of human kidney have been observed frequently, either in routine dissections or surgical practice. The main objective of the present study was to describe the arterial segmental pattern of human kidneys and its variation by angiography and corrosion cast techniques. Materials and Methods: Forty kidneys were washed and a plastic cannula was inserted into renal artery and the omnipaque dye was injected into it and X-ray was taken. The corrosion casts were prepared by injecting coloured acetate butyrate (CAB) granules solution. Results: Five vascular segments of kidney were seen based on the branching pattern of the renal artery by angiography and corrosion cast techniques. The renal artery was divided into anterior and posterior branches. The anterior branch further divided into four branches viz. apical segmental artery (ASA), Upper segmental artery (USA), middle segmental artery (MSA), lower segmental artery (LSA) while the posterior branch continue as posterior segmental artery. The origins of segmental arteries were variable. In 60% cases apical segmental artery (ASA) had common origin with upper segmental artery (USA) while in 40% cases it took origin directly from the main renal artery. Similarly the variations in the origin of the other branches of anterior division of renal artery were observed. The posterior segmental artery (PSA) however was single and comparatively small and supplied the posterior surface of the kidney. Conclusion: The knowledge of the vascular pattern of the kidney is thus important for the purpose of angiography and surgical procedures especially for nephrectomy and kidney transplantation.

Rani, Neerja; Singh, Seema; Dhar, Pushpa; Kumar, Rani

2014-01-01

10

Corrosion fatigue of cast aluminium- and cast magnesium alloys; Korrosionsermuedung von Aluminium- und Magnesium-Gusslegierungen  

Energy Technology Data Exchange (ETDEWEB)

The fatigue properties of the aluminium cast alloys AlSi7Mg and AlSi10Mg, magnesium high pressure die-cast AZ91 hp and AM60 hp, as well as low-pressure permanent mould casting AZ91 hp were determined at numbers of cycles to failure between 10{sup 5} and 10{sup 9} in ambient air and in saltwater spray. The investigations were performed at constant amplitudes and in addition at varying load amplitudes for aluminium cast alloy AlSi10Mg and low-pressure permanent mould casting AZ91 hp with a high-frequency testing facility (20 kHz ultrasound). The SN-curves of the aluminium cast alloys and of the magnesium low-pressure permanent mould casting are steeper in corrosive environment than in laboratory air. No endurance limit could be detected up to 10{sup 9} cycles in both environments. The magnesium high pressure die-cast alloys do not have an endurance limit in saltwater spray, whereas an endurance limit could be detected in laboratory air. The life time curves for in-service loading conditions are about parallel to the SN-curves for ambient air, but steeper for corrosive environment. The reason for the reduced fatigue properties in corrosive environment are accelerated crack initiation and higher crack propagation rates. Material defects may lead to a large scatter of the fatigue data for testing in air as well as in saltwater spray. Corrosion pits are formed on the surface of both light-weight alloys at higher number of cycles. They become crack initiation sites. (orig.) 10 refs.

Mayer, H.; Papakyriacou, M.; Stanzl-Tschegg, S.; Zettl, B. [Univ. fuer Bodenkultur, Vienna (Austria). Inst. fuer Meteorol. und Phys.; Tschegg, E. [Technische Univ., Vienna (Austria). Inst. fuer Angewandte und Technische Physik; Lipowsky, H.; Roesch, R.; Stich, A. [Audi AG, Ingolstadt (Germany)

1999-02-01

11

Corrosion resistant high silicon cast iron  

International Nuclear Information System (INIS)

Abstract: In domestic foundries production of acid resistance high silicon cast iron quite defined and because of that is with small productivity and many defect products. Process monitoring is with problems, because of that material is hard and brittle so sampling for characterisation is difficult, except of chemical analysis. That is reason for non destructive testing application, mainly ultrasonic. (Original)

2003-09-24

12

Galvanic corrosion of copper-cast iron couples  

Energy Technology Data Exchange (ETDEWEB)

To ensure the safe encapsulation of spent nuclear fuel rods for geological disposal, SKB are considering using the Copper-Cast Iron Canister, which consists of an outer copper canister and an inner cast iron container. The canister will be placed into boreholes in the bedrock of a geologic repository and surrounded by bentonite clay. In the unlikely event of the outer copper canister being breached, water would enter the annulus between the inner and outer canister and at points of contact between the two metals there would be the possibility of galvanic interactions. Although this subject has been considered previously from both a theoretical standpoint and by experimental investigations there was a need for further experimental studies in support of information provided by SKB to the Swedish regulators (SKI). In the work reported here copper-cast iron galvanic couples were set up in a number of different environments representing possible conditions in the SKB repository. The tests investigated two artificial porewaters at 30 deg C and 50 deg C, under aerated and deaerated conditions. Tests were also carried out in a 30 wt% bentonite slurry made up in artificial groundwater. The potential of the couples and the currents passing between the coupled electrodes were monitored for several months. The effect of growing an oxide film on the surface of the cast iron prior to coupling it with copper was investigated. In addition, some crevice specimens based on the multi-crevice assembly (MCA) design were used to simulate the situation where the copper canister will be in direct contact with the cast iron inner vessel. The electrochemical results are presented graphically in the form of electrode potentials and galvanic corrosion currents as a function of time. The galvanic currents in aerated conditions were much higher than in deaerated conditions. For example, at 30 deg C, galvanic corrosion rates as low as 0.02 {mu}m/year for iron were observed after deaeration, but the corrosion rates were near 100 {mu}m/year for the cast iron at 50 deg C in the presence of oxygen. There was evidence of temporary polarity reversal at very low levels of current (i.e. the copper became the anode). The galvanic corrosion rates of iron coupled to copper at low groundwater oxygen concentrations were close to the values measured for anaerobic corrosion rates of uncoupled iron. Under deaerated conditions a black film was formed on the surface of the cast iron, which was consistent with the formation of magnetite. The electrochemical potentials of the cast iron-copper couples in deaerated conditions were in the thermodynamically stable regions for magnetite and metallic copper. The galvanic currents under deaerated conditions were higher at 50 deg C than at 30 deg C, by a factor of up to 10. This can be attributed to an increase in the exchange current density for the water reduction reaction on the copper cathode and to an increase in the rate of diffusion processes in the oxide film on cast iron. There was some evidence for an increase in the galvanic corrosion rate in the presence of bentonite slurry compared to fully aqueous artificial groundwaters. Pre-grown corrosion films on cast iron did not have a significant effect on subsequent measured galvanic corrosion rates when coupled to copper in deaerated conditions. None of the MCA specimens exhibited any signs of galvanically enhanced crevice corrosion under deaerated conditions. In terms of application of the results to the evolution of the environment within the annulus of the canister the following scenario is envisaged. If water penetrates the annulus through a hole in the outer copper container a galvanic couple will be set up between the copper and the cast iron insert. The current passing between the copper and the cast iron will be concentrated at the contact points. If any residual air is present in the annulus the corrosion rate of the cast iron will be enhanced (i.e. the iron will be the anode and copper the cathode). In the absence of oxygen in the annulus, as a result of oxygen c

Smart, N.R.; Rance, A.P.; Fennell, P.A.H. [Serco Assurance, Risley (United Kingdom)

2005-01-01

13

Surgical importance of arterial segments of human kidneys: an angiography and corrosion cast study.  

Science.gov (United States)

Objective: Variations in the arterial supply of human kidney have been observed frequently, either in routine dissections or surgical practice. The main objective of the present study was to describe the arterial segmental pattern of human kidneys and its variation by angiography and corrosion cast techniques. Materials and Methods: Forty kidneys were washed and a plastic cannula was inserted into renal artery and the omnipaque dye was injected into it and X-ray was taken. The corrosion casts were prepared by injecting coloured acetate butyrate (CAB) granules solution. Results: Five vascular segments of kidney were seen based on the branching pattern of the renal artery by angiography and corrosion cast techniques. The renal artery was divided into anterior and posterior branches. The anterior branch further divided into four branches viz. apical segmental artery (ASA), Upper segmental artery (USA), middle segmental artery (MSA), lower segmental artery (LSA) while the posterior branch continue as posterior segmental artery. The origins of segmental arteries were variable. In 60% cases apical segmental artery (ASA) had common origin with upper segmental artery (USA) while in 40% cases it took origin directly from the main renal artery. Similarly the variations in the origin of the other branches of anterior division of renal artery were observed. The posterior segmental artery (PSA) however was single and comparatively small and supplied the posterior surface of the kidney. Conclusion: The knowledge of the vascular pattern of the kidney is thus important for the purpose of angiography and surgical procedures especially for nephrectomy and kidney transplantation. PMID:24783063

Rani, Neerja; Singh, Seema; Dhar, Pushpa; Kumar, Rani

2014-03-01

14

Effect of alloy purity and surface treatment on corrosion of AZ91 castings  

Energy Technology Data Exchange (ETDEWEB)

Magnesium casting alloys represent one of the most significant growth potential for magnesium. Among the various types of cast alloys the AZ91 alloy represents 90% of the total shipments. Further improvements in the corrosion resistance of the alloys are expected to play a key role in new applications. In the present work the corrosion behaviour of an ultra high purity AZ91 casting alloy has been investigated. Casting plates and parts were produced and salt spray corrosion tests were carried out on an ultra high purity AZ91 UX alloy and a typical commercial AZ91 high purity alloy. (orig.)

Closset, B. [Timminco SA, Geneva (Switzerland); Dimayuga, F. [Timminco Metals, Haley (Canada)

1992-12-31

15

Corrosion of two kinds of cast steels containing chromium in hot concentrated alkaline  

Directory of Open Access Journals (Sweden)

Full Text Available A typical hot concentrated alkaline corrosion environment exists in alumina metallurgical industry, so that steel materials with outstanding alkaline corrosion resistance are strongly demanded for its processing equipment. In this paper, the corrosion resistance of two kinds of martensitic cast steels containing chromium in static 303g/L NaOH alkaline solution at 85? was studied through polarization and potential-time curves, corrosion weight loss and corrosion morphology analysis. Experimental results showed that protection effect by passive film of cast steel containing Cr was temporary. The low carbon steel without Cr content also exhibited chemical passivity in the same solution. The corrosion mode of the tested Cr-containing cast steel was composed of active dissolving corrosion and caustic embrittlement cracking. Dissolving corrosion was the primary mechanism for the induced weight loss, while severe caustic embrittlement cracking was secondary. With the increase of chromium content in the cast steel, the tendency of the caustic embrittlement cracking decreased, while the active dissolving corrosion increased.

LI Wei

2007-02-01

16

A Moessbauer spectroscopy study of the corrosion of nodular cast iron in mine waters  

International Nuclear Information System (INIS)

The corrosion of ductile cast iron in water containing different amounts of chloride ions was investigated under both static and dynamic conditions. Corrosion/time relationships were established for exposure times of up to 30 days. Post-corrosion investigations were performed, employing Moessbauer spectroscopy, optical microscopy and electrochemical techniques. It was found that the nature of the surface corrosion product formed under static conditions differed morphologically and chemically from that formed under dynamic conditions. The latter was a hard layer consisting of a mixture of ?- and ?-FeOOH (situated on an underlying cementite layer), whereas the static tests resulted in a soft, spongy corrosion product, identified as ?-FeOOH. (orig.)

1994-11-01

17

Microvascular changes during the development of follicles in bovine ovaries: a study of corrosion casts by scanning electron microscopy.  

Science.gov (United States)

Microvascular changes during the development of follicles in bovine ovaries were studied by scanning electron microscopy of corrosion casts. A clear vascular plexus of ovarian follicles appeared at the stage when secondary follicles were 200-400 microns in diameter. The plexus consisted initially of a thin, roughly structured and single-layered capillary network. During follicular development, the microvascular architecture of antral follicles was arranged as two independent vascular plexuses. The inner plexus, which received a spiral arteriole, consisted of a dense sinusoidal capillary network with an arterial and a venous layer; it functioned as an independent microcirculatory unit. The inner plexus developed from the capillary plexus of the theca interna of the secondary follicles. The outer plexus, which anastomosed with several stromal capillaries, consisted of a thin, coarse and basket-like capillary plexus. The outer plexus was formed from the stromal capillary plexus as a consequence of the rapid enlargement of developing antral follicles. PMID:8845238

Yamada, O; Abe, M; Takehana, K; Hiraga, T; Iwasa, K; Hiratsuka, T

1995-12-01

18

The anaerobic corrosion of carbon steel and cast iron in artificial groundwaters  

International Nuclear Information System (INIS)

In Sweden, high level radioactive waste will be disposed of in a canister with a copper outer and a cast iron or carbon steel inner. If the iron insert comes into contact with anoxic geological water, anaerobic corrosion leading to the generation of hydrogen will occur. This paper presents a study of the anaerobic corrosion of carbon steel and cast iron in artificial Swedish granitic groundwaters. Electrochemical methods and gas collection techniques were used to assess the mechanisms and rates of corrosion and the associated hydrogen gas production over a range of conditions. The corrosion rate is high initially but is anodically limited by the slow formation of a duplex magnetite film. The effects of key environmental parameters such as temperature and ionic strength on the anaerobic corrosion rate are discussed

2001-01-01

19

The anaerobic corrosion of carbon steel and cast iron in artificial groundwaters  

Energy Technology Data Exchange (ETDEWEB)

In Sweden, high level radioactive waste will be disposed of in a canister with a copper outer and a cast iron or carbon steel inner. If the iron insert comes into contact with anoxic geological water, anaerobic corrosion leading to the generation of hydrogen will occur. This paper presents a study of the anaerobic corrosion of carbon steel and cast iron in artificial Swedish granitic groundwaters. Electrochemical methods and gas collection techniques were used to assess the mechanisms and rates of corrosion and the associated hydrogen gas production over a range of conditions. The corrosion rate is high initially but is anodically limited by the slow formation of a duplex magnetite film. The effects of key environmental parameters such as temperature and ionic strength on the anaerobic corrosion rate are discussed.

Smart, N.R. [AEA Technology plc, Culham Science Centre (United Kingdom); Blackwood, D.J. [National Univ. of Singapore (Singapore); Werme, L. [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)

2001-07-01

20

Corrosion behaviour of unalloyed steel and cast iron in groundwaters of the bedrock of Northern Switzerland  

International Nuclear Information System (INIS)

The corrosion behaviour of both materials is essentially the same in the two water compositions investigated. No significant effect of the bentonite on the corrosion behaviour could be detected. The corrosion rate decreases rapidly over the first 500 hours; after that time the corrosion rate settles to values difficult to determine accurately, but estimated to be less than 10 ?m/a both at 80"0C and 140"0C. Localized attack was not observed. It is concluded that a corrosion allowance of 20 mm is adequate to ensure a life of 1'000 years for cast steel and cast iron under repository conditions close to the test conditions. (orig./PW)

1985-06-01

 
 
 
 
21

Corrosion resistance of various bio-films deposited on austenitic cast steel casted by lost-wax process and in gypsum mould  

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This work is the next of a series concerning the improvement of austenitic cast steel utility predicted for use in implantology for complicated long term implants casted by lost-wax process and in gypsum mould. Austenitic cast steel possess chemical composition of AISI 316L medical steel used for implants. In further part of present work investigated cast steel indicated as AISI 316L medical steel. Below a results of electrochemical corrosion resistance of carbon layer and bi-layer of carbon/...

2010-01-01

22

Corrosion Behavior of the As-cast and Heat-treated ZA27 Alloy  

Directory of Open Access Journals (Sweden)

Full Text Available Corrosion behaviour of the as-cast and heat-treated ZA27 alloy was examined. The alloy was prepared by conventional melting and casting route and then thermally processed by applying T4 heat treatment regime (solutionizing at 370 °C for 3 hours followed by water quenching and natural aging. Corrosion rate of the as-cast and heat-treated ZA27 alloy was determined in 3.5 wt. % NaCl solution through immersion test using both weight loss method and polarization resistance measurements. It was shown that applied thermal treatment resulted in increased ductility of the heat-treated alloy and had a small beneficial effect on the corrosion resistance of ZA27 alloy.

B. Bobic

2011-06-01

23

Corrosion behavior of nodular cast iron casks for low and intermediate level wastes  

International Nuclear Information System (INIS)

In applying new conditioning methods dehydrated wastes (e.g. concentrates, ion exchange resins) from operation of nuclear power plants and wastes from decommissioning (e.g., highly-activated core components) are conditioned using high integrity nodular cast iron casks without further solidification. Therefore more stringent requirements have to be made for the packaging material. The objective of the investigations was to evaluate the corrosion resistance of the cask material. For this purpose chemical corrosion tests were made applying corrosion media actually considered or postulated in accident scenarios during interim storage or after disposal in the abandoned iron ore mine Konrad or in a salt formation. The conclusion from the corrosion experiments, which have been performed up to now for the basic packaging material, indicates that nodular cast iron casks with wall thicknesses about 200 mm seem to ensure good protection for wastes especially from nuclear power plants with relatively short-lived radionuclides

1985-09-09

24

Effect of Tempering on Corrosion Resistance of Cast Aluminium Bronzes.  

Science.gov (United States)

The subject of this study is corrosion resistance of aluminium bronzes, which are copper base alloys containing aluminium up to 12% with additions of nickel, iron and manganese. The main conclutions that can be drawn are: (1) The dealloying corrosion resi...

P. Aaltonen K. Klemetti H. Haenninen

1985-01-01

25

Calculated phase diagrams and the corrosion of die-cast Mg-Al alloys  

International Nuclear Information System (INIS)

The corrosion of commercial die-cast Mg-Al alloys was elucidated by a study, of the corrosion in 3% NaCl, of (i) high-pressure die-cast (HPDC) model Mg-Al alloys, (ii) low-purity Mg, (iii) high-purity (HP) Mg and (iv) HP Mg heat treated at 550 deg. C. HPDC is the most important route for the production of Mg components. The corrosion of the model alloys was dominated by the Fe impurity element. The present research identified the appearance of the Fe-rich particles in the microstructure. In high magnification (?1000x to 5000x) secondary electron images, they appear as small white features, typically less than 1 ?m in diameter. In order to understand the impurity tolerance limits, (i) the appropriate corrosion literature was summarised and reviewed and (ii) Mg phase diagrams were calculated using the Pandat software package. Calculated phase diagrams can explain (i) the tolerance levels for Fe and Cu and (ii) the production of high-purity castings by means of control of melt conditions; this has high significance for the production of quality castings from recycled Mg. A full analysis requires that the Mg database be extended to include Ni, Co and some RE. The Fe tolerance limit is ?5-10 ppm for cast HP Mg heat treated at 550 deg. C. Analysis of the Mg corrosion literature indicates that several studies have been dominated by the Fe impurity content and have not dealt with the stated aims; it means that the full chemical composition should be reported in all studies of the corrosion of Mg alloys

2009-03-01

26

Calculated phase diagrams and the corrosion of die-cast Mg-Al alloys  

Energy Technology Data Exchange (ETDEWEB)

The corrosion of commercial die-cast Mg-Al alloys was elucidated by a study, of the corrosion in 3% NaCl, of (i) high-pressure die-cast (HPDC) model Mg-Al alloys, (ii) low-purity Mg, (iii) high-purity (HP) Mg and (iv) HP Mg heat treated at 550 deg. C. HPDC is the most important route for the production of Mg components. The corrosion of the model alloys was dominated by the Fe impurity element. The present research identified the appearance of the Fe-rich particles in the microstructure. In high magnification ({approx}1000x to 5000x) secondary electron images, they appear as small white features, typically less than 1 {mu}m in diameter. In order to understand the impurity tolerance limits, (i) the appropriate corrosion literature was summarised and reviewed and (ii) Mg phase diagrams were calculated using the Pandat software package. Calculated phase diagrams can explain (i) the tolerance levels for Fe and Cu and (ii) the production of high-purity castings by means of control of melt conditions; this has high significance for the production of quality castings from recycled Mg. A full analysis requires that the Mg database be extended to include Ni, Co and some RE. The Fe tolerance limit is {approx}5-10 ppm for cast HP Mg heat treated at 550 deg. C. Analysis of the Mg corrosion literature indicates that several studies have been dominated by the Fe impurity content and have not dealt with the stated aims; it means that the full chemical composition should be reported in all studies of the corrosion of Mg alloys.

Liu Ming [University of Queensland, Division of Materials, ARC CoE for Design in Light Metals, St. Lucia, Brisbane, Qld 4072 (Australia); Swiss Federal Laboratories for Materials Science and Technology, Uberlandstrasse 129, CH-8600 Dubendorf (Switzerland); Uggowitzer, Peter J. [ETH Zuerich, Department of Materials, CH-8093 Zurich (Switzerland); Nagasekhar, A.V. [University of Queensland, Division of Materials, ARC CoE for Design in Light Metals, St. Lucia, Brisbane, Qld 4072 (Australia); Schmutz, Patrik [Swiss Federal Laboratories for Materials Science and Technology, Uberlandstrasse 129, CH-8600 Dubendorf (Switzerland); Easton, Mark [Monash University, Department of Materials Engineering, CAST Co-operative Research Centre, Melbourne, Vic. 3800 (Australia); Song Guangling [University of Queensland, Division of Materials, ARC CoE for Design in Light Metals, St. Lucia, Brisbane, Qld 4072 (Australia); Atrens, Andrej [University of Queensland, Division of Materials, ARC CoE for Design in Light Metals, St. Lucia, Brisbane, Qld 4072 (Australia); Swiss Federal Laboratories for Materials Science and Technology, Uberlandstrasse 129, CH-8600 Dubendorf (Switzerland)], E-mail: andrejs.atrens@uq.edu.au

2009-03-15

27

A modified method for vascular casting and scanning electron microscopy: its utility in the demonstration of rat pancreatic insulo-acinar and other blood vascular systems.  

Science.gov (United States)

Monomeric methyl methacrylate resin, supplemented with 1.0% benzoyl peroxide and 1.0% N, N-dimethyaniline, enables good vascular casts useful for scanning electron microscopy when the injected organs or tissues are promptly heated in a microwave processor. The details of this vascular casting and scanning method are described with a clear demonstration of the rat pancreatic blood vascular bed, in particular, its intralobular, extralobular and translobular insulo-acinar portal systems and other vascular routes, including the insulo-venous vessels, which are sinusoidal in nature. PMID:1290672

Murakami, T; Fujita, T; Hinenoya, H

1992-01-01

28

Corrosion of Cast Iron Mill Plates in Wet Grinding  

Directory of Open Access Journals (Sweden)

Full Text Available Corrosion studies were carried out on two different maize grinding plates. Maize was soaked in water for three days and the water decanted and used as electrolyte. Mass loss and pH measurements were carried out every 3 days for 15-day period. Results show that, for each plate, mass loss and pH increased with exposure time. Corrosion rates determined from mass loss data was found to be strongly dependent on pH. The observed behaviour may be explained in terms of the chemical composition and/or microstructures of the plates. Results are briefly discussed in terms of the contribution of corrosion to wear.

Anthony ANDREWS

2010-12-01

29

A new corrosion protection coating system for pressure-cast aluminium automotive parts  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A simple to employ corrosion protecting coating based on sol-gel derived new nanocomposites for Al alloys has been developed. This composite coating reacts to the Al surface by formation of a thermodynamically stabilized interface. Moreover, for pressure cast Al, the coating process can be used for sealing the pores at the same time.

Schmidt, Helmut K.; Langenfeld, Stefan; Nass, Ru?diger

1997-01-01

30

Effect of tempering on corrosion resistance of cast aluminium bronzes  

International Nuclear Information System (INIS)

The subject of this study is corrosion resistance of aluminium bronzes, which are copper base alloys containing aluminium up to 12% with additions of nickel, iron and manganese. The main conclutions that can be drawn are: (1) The dealloying corrosion resistance of nickel-aluminium bronze is much better than that of aluminium bronze with iron and manganese additions, but it is not immune; (2) The dealloying corrosion resistance of aluminium bronzes can be improved by appropiate heat treatments. The best properties were obtained by temperering between 600 and 800 deg C, depending on the initial microstructure; (3) In crevice conditions, where local acidification can occur, dealloying of aluminium bronzes is a consequence of the preferential attack of aluminium-rich phases. By appropriate tempering, a uniform distribution of aluminium-rich phases is obtained and the continous path for selective corrosion is not formed

1985-08-27

31

Improvement in corrosion resistance of a nodular cast iron surface modified by plasma beam treatment  

Science.gov (United States)

Nodular cast iron (NCI) specimens with corrosion-resistant surfaces were fabricated by plasma beam treatment and tempering (400 °C, 1 h), which consisted of plasma surface melting, plasma surface melting + tempering, plasma surface alloying and plasma surface alloying + tempering. In this manner, near-surface graphite nodules were eliminated, and inter-dendrites and eutectics with a hyper-eutectic structure appeared on the modified surfaces, as indicated by SEM. The corrosion behaviour of treated specimens in 3.5 wt% NaCl was characterised by electrochemical methods and compared with that of an untreated NCI specimen at 25 °C. The corrosion resistance ranked as follows: surface-alloyed and tempered specimen > surface-alloyed specimen ? surface-melted and tempered specimen > surface-melted specimen > the untreated NCI specimen. Metallographic as well as electrochemical corrosion studies illustrate the beneficial effects of surface modification in refining the microstructure and in enhancing the corrosion resistance of NCI.

Cheng, Xiu; Hu, Shubing; Song, Wulin; Xiong, Xuesong

2013-12-01

32

Study on the hot corrosion behavior of a cast Ni-base superalloy  

Energy Technology Data Exchange (ETDEWEB)

Hot corrosion behavior of Nickel-base cast superalloy K447 in 90% Na{sub 2}SO{sub 4} + 10% NaCl melting salt at 850 C and 900 C was studied. The hot corrosion kinetic of the alloy follows parabolic rate law under the experimental conditions. The external layer is mainly Cr{sub 2}O{sub 3} scale which is protective to the alloy, the intermediate layer is the Ti-rich phase, and the internal layer is mainly the international oxides and sulfides. With increased corrosion time and temperature, the oxide scales are gradually dissolved in the molten salt and then precipitate as a thick and non-protective scale. Chlorides cause the formation of volatile species, which makes the oxide scale disintegrate and break off. The corrosion kinetics and morphology examinations tend to support the basic dissolution model for hot corrosion mechanisms. (orig.)

Wang, W.; Guo, J.T.; Zhang, J.; Yuan, C.; Zhou, L.Z.; Hu, Z.Q. [Chinese Academy of Sciences, Shenyang (China). Inst. of Metal Research

2010-07-01

33

Microstructure and Corrosion Performance of Carbonitriding Layers on Cast Iron by Plasma Electrolytic Carbonitriding  

International Nuclear Information System (INIS)

The surface carbonitriding of cast iron is investigated in an aqueous solution of acetamide and glycerin. Microstructure, chemical and phase composition and corrosion performance of the carbonitriding layers are investigated by scanning electron microscopy, energy dispersive spectroscopy and x-ray diffraction, as well as potentiodynamic polarization testing. X-ray diffraction results show that the carbonitriding coatings are composed of martensite, austenite(?-Fe), Fe2C, Fe3C, Fe5C2, FeN and element of -Fe2?3N. After the plasma electrolytic carbonitriding treatment the corrosion resistance of cast iron is clearly improved compared to the substrate, and the coatings produced at 350 V for 30s give the best corrosion resistance. (condensed matter: structure, mechanical and thermal properties)

2009-08-01

34

Corrosion resistance of various bio-films deposited on austenitic cast steel casted by lost-wax process and in gypsum mould  

Directory of Open Access Journals (Sweden)

Full Text Available This work is the next of a series concerning the improvement of austenitic cast steel utility predicted for use in implantology for complicated long term implants casted by lost-wax process and in gypsum mould. Austenitic cast steel possess chemical composition of AISI 316L medical steel used for implants. In further part of present work investigated cast steel indicated as AISI 316L medical steel. Below a results of electrochemical corrosion resistance of carbon layer and bi-layer of carbon/HAp deposited on AISI 316L researches are presented. Coatings were manufactured by RF PACVD and PLD methods respectively. Obtained results, unequivocally indicates on the improvement of this type of corrosion resistance by substrate material with as deposited carbon layer. While bi-layer of carbon/HAp are characterized by very low corrosion resistance.

J. Gawro?ski

2010-01-01

35

Scanning electron microscopic study of rabbit ovarian follicle microvasculature using resin injection-corrosion casts.  

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The microvasculature of rabbit ovarian follicles was investigated three dimensionally with resin casting/SEM technique. Characteristic vascular patterns were revealed around the follicles of various developing stages. It is suggested that increased capillary permeability and congestion of the blood stream occurred just prior to ovulation.

Kanzaki, H.; Okamura, H.; Okuda, Y.; Takenaka, A.; Morimoto, K.; Nishimura, T.

1982-01-01

36

Characteristics of low nickel ferritic-austenitic corrosion resistant cast steel  

Directory of Open Access Journals (Sweden)

Full Text Available The article presents the results of microscopic examinations of corrosion resistant cast steel with reduced nickel content obtained in a test casting with varying wall thickness. Investigations were carried out in as-cast condition and after heat treatment. Regardless of the casting wall thickness, increasing the manganese and nitrogen content to about 5 % and 2 500 ppm, respectively, yields the material with a two-phase microstructure containing ferrite in an amount of 55,6 ÷ 57,2 % (magnetic method and 52,3 ÷ 55,2 % (analytical method. Based on the results of metallographic examinations, total elimination of the secondary austenite from the microstructure was observed. Microhardness measurements showed average values of 352,3 ?HV20 and 267 ?HV20 for the chromium ferrite and austenite, respectively.

B. Kalandyk

2014-10-01

37

Scanning electron microscopy study on corrosion cast of rat uterine vasculature during the first half of pregnancy.  

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Vascular changes in the rat uterus during the first half of pregnancy were studied by the microcorrosion casting/scanning electron microscope method. Arterioles supplying the endometrium were divided into two groups according to differences in their shape, distribution, and development. Circular impressions indicative of the presence of vascular sphincters were observed around the casts of each group of arterioles. Resin leakage, suggesting an increase in vascular permeability, was observed f...

Takemori, K.; Okamura, H.; Kanzaki, H.; Koshida, M.; Konishi, I.

1984-01-01

38

Corrosion of Cast Iron Mill Plates in Wet Grinding  

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Corrosion studies were carried out on two different maize grinding plates. Maize was soaked in water for three days and the water decanted and used as electrolyte. Mass loss and pH measurements were carried out every 3 days for 15-day period. Results show that, for each plate, mass loss and pH increased with exposure time. Corrosion rates determined from mass loss data was found to be strongly dependent on pH. The observed behaviour may be explained in terms of the chemical composition and/or...

Andrews, Anthony; Kwofie, Samuel

2010-01-01

39

Effects of tungsten on erosion-corrosion behavior of high chromium white cast iron  

Energy Technology Data Exchange (ETDEWEB)

In this study, effects of tungsten on wear resistance of high chromium white cast iron with and without tungsten in erosion-corrosion condition have been investigated. At the same time, the comparison between wear resistance of this grade of cast iron and low alloy steels with various contents of Cr which are used in industrial condition (in Sarcheshme Company, the greatest copper production company in the Middle East and with more than 4000 years historical cupper production background) was studied, while, copper concentrates have used for erosion particles. Results show that, because of higher hardness of matrix due to the tungsten, the wear resistance of high chromium cast iron increases. In addition to that, combine cutting and deformation wear mechanism and spalling mechanism were attributed in high chromium cast iron and low alloy steels, respectively. Subsequently, pitting mechanism in corrosion aspect was recognized because of inhomogeneity in chemical composition and sulfide inclusions content. Finally, the combine effects of erosion and corrosion (synergetic effect) were recognized in the high chromium white iron in industrial condition for the damaged samples.

Mousavi Anijdan, S.H. [Mining, Metals and Materials Engineering Department, McGill University, M.H. Wong Building, 3610 University Street, Montreal, H3A 2B2 (Canada); Materials Science and Engineering Department, Sharif University of Technology, P.O. Box 11365-9944, Tehran (Iran, Islamic Republic of)], E-mail: hashem.mousavi@mail.mcgill.ca; Bahrami, A. [Department of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft (Netherlands); Varahram, N. [Materials Science and Engineering Department, Sharif University of Technology, P.O. Box 11365-9944, Tehran (Iran, Islamic Republic of); Davami, P. [Materials Science and Engineering Department, Sharif University of Technology, P.O. Box 11365-9944, Tehran (Iran, Islamic Republic of)

2007-04-25

40

Effects of tungsten on erosion-corrosion behavior of high chromium white cast iron  

International Nuclear Information System (INIS)

In this study, effects of tungsten on wear resistance of high chromium white cast iron with and without tungsten in erosion-corrosion condition have been investigated. At the same time, the comparison between wear resistance of this grade of cast iron and low alloy steels with various contents of Cr which are used in industrial condition (in Sarcheshme Company, the greatest copper production company in the Middle East and with more than 4000 years historical cupper production background) was studied, while, copper concentrates have used for erosion particles. Results show that, because of higher hardness of matrix due to the tungsten, the wear resistance of high chromium cast iron increases. In addition to that, combine cutting and deformation wear mechanism and spalling mechanism were attributed in high chromium cast iron and low alloy steels, respectively. Subsequently, pitting mechanism in corrosion aspect was recognized because of inhomogeneity in chemical composition and sulfide inclusions content. Finally, the combine effects of erosion and corrosion (synergetic effect) were recognized in the high chromium white iron in industrial condition for the damaged samples

2007-04-25

 
 
 
 
41

Microstructure Aspects of a Newly Developed, Low Cost, Corrosion-Resistant White Cast Iron  

Science.gov (United States)

The purpose of this work is to study the influence of heat treatment on the corrosion resistance of a newly developed white cast iron, basically suitable for corrosion- and wear-resistant applications, and to attain a microstructure that is most suitable from the corrosion resistance point of view. The composition was selected with an aim to have austenitic matrix both in as-cast and heat-treated conditions. The difference in electrochemical potential between austenite and carbide is less in comparison to that between austenite and graphite. Additionally, graphitic corrosion which is frequently encountered in gray cast irons is absent in white cast irons. These basic facts encouraged us to undertake this work. Optical metallography, hardness testing, X-ray diffractometry, and SEM-EDX techniques were employed to identify the phases present in the as-cast and heat-treated specimens of the investigated alloy and to correlate microstructure with corrosion resistance and hardness. Corrosion testing was carried out in 5 pct NaCl solution (approximate chloride content of sea water) using the weight loss method. In the investigated alloy, austenite was retained the in as-cast and heat-treated conditions. The same was confirmed by X-ray and EDX analysis. The stability and volume fraction of austenite increased with an increase of heat-treated temperature/time with a simultaneous decrease in the volume fraction of massive carbides. The decrease in volume fraction of massive carbides resulted in the availability of alloying elements. These alloying elements, on increasing the heat treatment temperature or increasing the soaking period at certain temperatures, get dissolved in austenite. As a consequence, austenite gets enriched as well as becomes more stable. On cooling from lower soaking period/temperature, enriched austenite decomposes to lesser enriched austenite and to a dispersed phase due to decreasing solid solubility of alloying elements with decreasing temperature. The dispersed second phase precipitated from the austenite adversely influenced corrosion resistance due to unfavorable morphology and enhanced galvanic action. Corrosion rate and hardness were found to decrease with an increase in heat treatment temperatures/soaking periods. It was essentially due to the increase in the volume fraction and stability of the austenitic matrix and favorable morphology of the second phase (carbides). The corrosion resistance of the investigated alloy, heat treated at 1223 K (950 °C) for 8 hours, was comparable to that of Ni-Resist iron. Thus, a microstructure comprising austenite and nearly spherical and finer carbides is the most appropriate from a corrosion point of view. Fortunately, the literature reveals that the same microstructure is also well suited from a wear point of view. It confirms that this investigated alloy will be suitable for corrosive-wear applications.

Sain, P. K.; Sharma, C. P.; Bhargava, A. K.

2013-04-01

42

Physicochemical studies of glucose, gellan gum, and hydroxypropyl cellulose--inhibition of cast iron corrosion.  

Science.gov (United States)

Glucose, gellan gum, and hydroxypropyl cellulose were studied against the acid corrosion of cast iron by means of weight loss, potentiodynamic polarization, and AC impedance spectroscopy techniques. The inhibition efficiency was found to increase with increasing concentration of the inhibitors. The effect of immersion time and temperature were also studied. The addition of potassium iodide to the corrosion-inhibition system showed both antagonism and synergism toward inhibition efficiency. Polarization studies revealed the mixed-type inhibiting nature of the carbohydrates. The adsorption of inhibitors on the cast iron surface obeys Langmuir adsorption isotherm model, both in presence and absence of KI. Physical interaction between the inhibitor molecules and the iron surface was suggested by the thermochemical parameters, rather than chemical interaction. PMID:23618271

Rajeswari, Velayutham; Kesavan, Devarayan; Gopiraman, Mayakrishnan; Viswanathamurthi, Periasamy

2013-06-01

43

Effect of extracellular polymeric substances on corrosion of cast iron in the reclaimed wastewater.  

Science.gov (United States)

Microorganisms were cultured in the R2A medium with inoculum from biofilm in a reclaimed wastewater distribution system and then extracellular polymeric substances (EPS) were extracted from the culture. Characterization of EPS and their effects on the corrosion of cast iron were examined. EPS extracted from different culturing stages contained different proportions of protein and polysaccharide but with similar functional groups. All types of EPS could inhibit cast iron corrosion and the EPS from the stationary stage had the highest inhibition efficiency. The inhibition efficiency was increased with addition of a small amount of EPS while decreased with excessive amount of EPS. EPS formed a protective film on the metal surface, which retarded the cathodic reduction of oxygen. Excessive amount of EPS promoted anodic dissolution through EPS-Fe binding. The CO and C(O, N) in EPS could be the anodic electrochemical sites with possible products of C(C, H). PMID:24618284

Jin, Juntao; Wu, Guangxue; Zhang, Zhenhua; Guan, Yuntao

2014-08-01

44

Corrosion of copper, nickel, and gold dental casting alloys: an in vitro and in vivo study.  

Science.gov (United States)

The corrosion behavior of commercially available copper, nickel, and gold alloys for dental castings was investigated. The alloys investigated included: three copper alloys (76-87Cu, 6-11A1, 0-12Zn, 1-5Ni, 0-4Fe, 0.5-1.2Mn), two nickel alloys (68-78Ni, 12-16Cr, 4-14Mo, 0-1.7Be), and one gold alloy (77Au, 14Ag, 8Cu, 1Pd). Anodic and cathodic polarization curves, long-term immersion tests in saline and artificial saliva solutions, and dog crown studies were conducted to evaluate both the in vitro and in vivo corrosion characteristics of the alloys. All evaluations conducted demonstrated that the copper alloys were highly susceptible to corrosion attack. High corrosion currents were observed in the in vitro tests, and SEM of the alloys specimens showed significantly altered surfaces. The anodic polarization curves predicted that the beryllium-containing nickel alloy should be susceptible to localized corrosion and SEM revealed an etched surface with corrosion of certain microstructural features. No significant corrosion was predicted or observed for the non-beryllium nickel alloy and the gold alloy. The in vitro corrosion evaluations predicted the in vivo corrosion behavior for the alloys. Since the three copper alloys and the beryllium-containing nickel alloy demonstrated significant corrosion under the tested conditions, the use of these alloys for restorative procedures is questionable due to the release of significant levels of selected ions to the oral cavity. PMID:2613743

Johansson, B I; Lucas, L C; Lemons, J E

1989-12-01

45

Application of Continuous Cast Billet in Corrosion-Resistant Steel Tube Making  

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Large-scale experiments related to the tube making from high-alloy corrosion-resistant steel ?? 304L and ?? 316L continuous cast billets have been carried out for the first time in domestic practice. The tubes with a wide dimensional range are produced by means of hot pressing, warm and cold rolling under industrial conditions. The complex estimation of produced tube quality has shown their conformity with ASTM standards.

2010-01-01

46

Corrosion behaviour of unalloyed steel, cast steel and cast iron as final storage canister material in water-bearing granite rocks  

International Nuclear Information System (INIS)

During final storage of radioactive waste the corrosion behaviour of the canister materials is an important parameter. In this study the external corrosion behaviour of unalloyed steel, cast steel and cast iron in water-bearing granite rocks is discussed with a particular view to the conditions in Switzerland (temperature, pressure, water composition, etc.). The report is based on a critical literature review, on the author's own experience and on experience from other fields of technology. Furthermore, model calculations are made for corrosion rates to be expected in the presence of a mass transfer barrier. The most important results are as follows: -corrosion rates in waters and soils are low, provided oxygen is excluded or protective layers are formed, -under the expected conditions all of the relevant waters can produce significant corrosion, -the pressure dependence of the corrosion rate is small, while the temperature dependence is large, -in the presence of an effective convection and diffusion barrier (bentonite) the corrosion rate is very small (10"-"5 mm/year), -if such a barrier maintains its properties for the required lifetime of the final storage system the corrosion rate of the canister material can be neglected. (author)

1982-01-01

47

Blood vessel remodeling in pig ovarian follicles during the periovulatory period: an immunohistochemistry and SEM-corrosion casting study  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The present research aims to describe the process of vascular readjustment occurring in pig ovary during the periovulatory phase (from LH surge to ovulation that drives the transformation of the follicle, a limited blood supplied structure, into the corpus luteum, a highly vascularised endocrine gland required to maintain high levels of progesterone in pregnancy. The swine model was chosen because it is characterized by a long periovulatory window (about 40–44 hrs-similar to human that permits to recover follicles at a precise endocrinological timing. Methods By validated hormonal protocol (eCG+hCG, able to mimic the physiologic gonadotropin stimulation, preovulatory follicles (PreOFs, 60 h-eCG, follicles in the middle (early periovulatory follicles, EPerOFs, 18 h-hCG or late (LPerOFs, 36 h-hCG periovulatory phase were isolated from prepubertal gilts. To understand the angiogenic process, morphological/morphometrical analyses were performed by combining immunohistochemistry (IHC and SEM of vascular corrosion casts (VCC techniques. Results PreOFs showed a vascular plexus with proliferating endothelial cells (EPI. This plexus was characterized by a dense inner capillary network, with angiogenic figures, connected to the outer network by anastomotic vessels (arterioles and venules of the middle network. EPerOFs decreased their EPI, blood vessel extension in the outer network, and evidenced a reduced compactness of blood vessels. In LPerOFs, a rapid neovascularization was associated to an intensive tissue remodeling: the follicle acquired an undulated aspect presenting arterioles/venules near the basal membrane, increased vascular extension by EPI, sprouting and non-sprouting angiogenesis. The analysis of vascular geometric relations and branching angles evidenced similar values at all stages. Conclusion These data allow us to hypothesize that EPerOFs are in a quiescent status. LPerOFs represent the "metamorphic" follicles that rapidly turn-on angiogenesis to sustain a successful corpus luteum formation. Particularly, it is interesting to underlie that the non-sprouting angiogenesis, typical of structures in rapid neovascularization, occurred only in the LPerOFs. Moreover, vascular geometric relations showed as blood vessel remodeling occurs with the "maximum output and the minimum energetic expense". This knowledge will allow to better understand the mechanisms regulating the reproductive success and to clarify the complex physiological angiogenic process in adult tissues.

Berardinelli Paolo

2009-07-01

48

The development of high strength corrosion resistant precipitation hardening cast steels  

Science.gov (United States)

Precipitation Hardened Cast Stainless Steels (PHCSS) are a corrosion resistant class of materials which derive their properties from secondary aging after a normalizing heat treatment step. While PHCSS materials are available in austenitic and semi-austenitic forms, the martensitic PHCSS are most widely used due to a combination of high strength, good toughness, and corrosion resistance. If higher strength levels can be achieved in these alloys, these materials can be used as a lower-cost alternative to titanium for high specific strength applications where corrosion resistance is a factor. Although wrought precipitation hardened materials have been in use and specified for more than half a century, the specification and use of PHCSS has only been recent. The effects of composition and processing on performance have received little attention in the cast steel literature. The work presented in these investigations is concerned with the experimental study and modeling of microstructural development in cast martensitic precipitation hardened steels at high strength levels. Particular attention is focused on improving the performance of the high strength CB7Cu alloy by control of detrimental secondary phases, notably delta ferrite and retained austenite, which is detrimental to strength, but potentially beneficial in terms of fracture and impact toughness. The relationship between age processing and mechanical properties is also investigated, and a new age hardening model based on simultaneous precipitation hardening and tempering has been modified for use with these steels. Because the CB7Cu system has limited strength even with improved processing, a higher strength prototype Fe-Ni-Cr-Mo-Ti system has been designed and adapted for use in casting. This prototype is expected to develop high strengths matching or exceed that of cast Ti-6Al-4V alloys. Traditional multicomponent constitution phase diagrams widely used for phase estimation in conventional stainless steels, give poor estimates of secondary phases in PHCSS. No measureable retained austenite was observed in any of the CB7Cu-1 steels studied, in spite of the fact that austenite is predicted by the constitution diagrams. A designed experiment using computationally derived phase equilibrium diagrams and actual experimental tests on CB7Cu of different compositions suggests that the ferrite phase is less stable than the constitution diagrams for austenitic stainless steels suggest. Delta ferrite was also more stable in slower-cooled sand cast material as compared to thin, fast-cooled investment cast material. High temperature solutionizing treatments were effective in dissolving delta ferrite at temperatures above 1900°F (˜1040°C). Delta ferrite dissolution was found to proceed at high rates during initial dissolution, and then was found to slow after 1 hour. Diffusion during the later stages is well-predicted by classical diffusion models. Repeated solution treatments were found to modestly increase both ductility and strength, likely due to subgrain refinement through austenite regrowth. Multistaged aging provided superior strength and toughness increases over similarly peak-aged and near peak-aged material aged at a single temperature. Peak-aged material fractography suggested that low energy quasi-cleavage fracture was likely due to age precipitate embrittlement along with some nucleation of MnS particulates at prior austenite grain boundaries. Yield strengths approaching 190 ksi (1310MPa) can be achieved in CB7Cu-1 if appropriate best-practices "+" processing techniques are used. This includes hot isostatic processing to reduce solidification segregation and heal microporosity, high temperature homogenization for effective age hardening and ferrite reduction, double-cycle solutionizing for structure refinement, and multistaged age strengthening for finer precipitate control. The experimental prototype 11-11PH (Fe-Ni-Cr-Ti-Mo) casting alloys was cast and was found to be delta-ferrite free in the as-cast condition. In this material, proper quench process

Abrahams, Rachel A.

49

Corrosion resistances and passivation of powder metallurgical and conventionally cast 316L and 2205 stainless steels  

International Nuclear Information System (INIS)

Highlights: ? Corrosion of powder metallurgical (P/M) and conventional steels has been compared. ? P/M 316L steel has higher pitting corrosion resistance than conventional 316L steel. ? Differences in the passivation process were found for the steels in 0.5 M HCl. ? The presence of three mixed potentials is explained using the mixed potential theory. ? XPS results show differences in the composition and thickness of the passive films. - Abstract: The corrosion resistances and passivation of austenitic 316L and duplex 2205 powder metallurgical (P/M) steels, produced by gas atomizing and hot isostatic pressing (HIP), have been compared with those of their conventional cast counterparts. P/M 316L steel is shown to have significantly higher pitting corrosion resistance than conventional 316L steel in 0.5 M HCl. This effect is ascribed to the fine grained microstructure of the P/M 316L steel yielding an improved passive layer. The latter hypothesis is supported by photoelectron spectroscopy data demonstrating differences between the thickness and composition of the passive layers for the 316L steels.

2013-02-01

50

Interfacial morphology and corrosion resistance of Fe-B cast steel containing chromium and nickel in liquid zinc  

International Nuclear Information System (INIS)

Highlights: ? Fe-B steels containing Cr and Ni exhibit the best corrosion resistance in liquid zinc. ? Surface layers show gamma-Fe3Zn10, delta-FeZn10, zeta-FeZn13 and eta-Zn. ? Cr and Ni can enrich at the interface during the corrosion process. ? Corrosion processes include leaching, formation of compounds and spalling of borides. - Abstract: The interfacial morphology and corrosion resistance of low carbon Fe-B cast steels in zinc bath at 520 deg. C were investigated. The results show Fe-B cast steel containing high Cr and Ni exhibits the best corrosion resistance to liquid zinc. The corrosion layers are composed of ?-Fe3Zn10, ?-FeZn10, ?-FeZn13 and ?-Zn. The corrosion behaviour of Fe-B cast steels includes the following processes: the preferential leach and dissolution of Cr and Ni, the formation of Fe-Zn compounds controlled by zinc atom diffusion, and the spalling of borides without the supporting role of ?-(Fe, Cr) matrix corroded by liquid zinc.

2011-09-01

51

Corrosion behaviour of chemical conversion treatments on as-cast Mg-Al alloys: Electrochemical and non-electrochemical methods  

International Nuclear Information System (INIS)

Magnesium alloys are often used in as-cast conditions. So, the aim of this work is to characterize the corrosion protection of as-cast AZ91D alloys coated with simple chemical conversion (phosphate-permanganate, and cerium-based coatings). With the two coatings, the electrochemical measurements show that the corrosion protection is due to both the inhibition of cathodic and anodic reactions, because of the presence of stable CeO2 or manganese oxides in basic pH. Nevertheless, the non-electrochemical tests of corrosion are required to bring to light the healing effect of phosphate-permanganate coating compared to Ce-coating and to describe the corrosion behaviour completely. Finally phosphoric and soda pickling associated to phosphate-permanganate conversion treatment or cerium coating are ecologically efficient alternatives to fluoride-based pickling and the chromating treatment.

2010-06-01

52

Corrosion behaviour of chemical conversion treatments on as-cast Mg-Al alloys: Electrochemical and non-electrochemical methods  

Energy Technology Data Exchange (ETDEWEB)

Magnesium alloys are often used in as-cast conditions. So, the aim of this work is to characterize the corrosion protection of as-cast AZ91D alloys coated with simple chemical conversion (phosphate-permanganate, and cerium-based coatings). With the two coatings, the electrochemical measurements show that the corrosion protection is due to both the inhibition of cathodic and anodic reactions, because of the presence of stable CeO{sub 2} or manganese oxides in basic pH. Nevertheless, the non-electrochemical tests of corrosion are required to bring to light the healing effect of phosphate-permanganate coating compared to Ce-coating and to describe the corrosion behaviour completely. Finally phosphoric and soda pickling associated to phosphate-permanganate conversion treatment or cerium coating are ecologically efficient alternatives to fluoride-based pickling and the chromating treatment.

Rocca, E. [Institut Jean Lamour UMR CNRS 7198, Nancy Universite - Corrosion Group, B.P. 70239, 54506 Vandoeuvre-Les-Nancy (France)], E-mail: emmanuel.rocca@lcsm.uhp-nancy.fr; Juers, C.; Steinmetz, J. [Institut Jean Lamour UMR CNRS 7198, Nancy Universite - Corrosion Group, B.P. 70239, 54506 Vandoeuvre-Les-Nancy (France)

2010-06-15

53

Effects of disinfectant and biofilm on the corrosion of cast iron pipes in a reclaimed water distribution system.  

Science.gov (United States)

The effects of disinfection and biofilm on the corrosion of cast iron pipe in a model reclaimed water distribution system were studied using annular reactors (ARs). The corrosion scales formed under different conditions were characterized by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), and scanning electron microscopy (SEM), while the bacterial characteristics of biofilm on the surface were determined using several molecular methods. The corrosion scales from the ARs with chlorine included predominantly ?-FeOOH and Fe2O3, while CaPO3(OH)·2H2O and ?-FeOOH were the predominant phases after chloramines replaced chlorine. Studies of the consumption of chlorine and iron release indicated that the formation of dense oxide layers and biofilm inhibited iron corrosion, causing stable lower chlorine decay. It was verified that iron-oxidizing bacteria (IOB) such as Sediminibacterium sp., and iron-reducing bacteria (IRB) such as Shewanella sp., synergistically interacted with the corrosion product to prevent further corrosion. For the ARs without disinfection, ?-FeOOH was the predominant phase at the primary stage, while CaCO3 and ?-FeOOH were predominant with increasing time. The mixed corrosion-inducing bacteria, including the IRB Shewanella sp., the IOB Sediminibacterium sp., and the sulfur-oxidizing bacteria (SOB) Limnobacter thioxidans strain, promoted iron corrosion by synergistic interactions in the primary period, while anaerobic IRB became the predominant corrosion bacteria, preventing further corrosion via the formation of protective layers. PMID:22209261

Wang, Haibo; Hu, Chun; Hu, Xuexiang; Yang, Min; Qu, Jiuhui

2012-03-15

54

Moessbauer studies of the corrosion products of cast iron in aqueous ammonium nitrate solution  

International Nuclear Information System (INIS)

The corrosion products of cast iron in 45% NH4NO3 solution at different temperatures have been studied using mainly Moessbauer spectroscopy. Ferrihydrite (Fe5HO8x4H2O or 5Fe2O3x9H2O) is found along with ?-FeOOH in the initial stages of the reaction at room temperature. At a later stage, partial dissolution of ?-FeOOH takes place and magnetite is precipitated. Above 80 deg C either Fesub(3-x)Osub(4) or Fe5HO8x4H2O or ?-Fe2O3 is formed as the major product depending on the ratio of the reactants. (author)

1982-07-09

55

Influence of Thermal Aging on Primary Water Stress Corrosion Cracking of Cast Duplex Stainless Steels  

International Nuclear Information System (INIS)

In order to evaluate the SCC (stress corrosion cracking) susceptibility of cast duplex stainless steels which are used for the main coolant piping material of pressurized water reactors (PWRs), the slow strain rate test (SSRT) and the constant load test (CLT) were performed in simulated PWR primary water at 360 C. The main coolant piping materials contain ferrite phase with ranging from 8 to 23 % and its mechanical properties are affected by long time thermal aging. The 23% ferrite material was prepared for test as the maximum ferrite content of main coolant pipes in Japanese PWRs. The brittle fracture in the non-aged materials after SSRT is mainly caused by quasi-cleavage fracture in austenitic phase. On the other hand, a mixture of quasi-cleavage fracture in austenite and ferrite phases was observed on long time aged material. Also on CLT, (2 times ?y), after 3,000 hours exposure, microcracks were observed on the surface of non-aged and aged for 10,000 hours at 400 C materials. The crack initiation site of CLT is similar to that of SSRT. The SCC susceptibility of the materials increases with aging time. It is suggested that the ferrite hardening with aging affect SCC susceptibility of cast duplex stainless steels. (authors)

2002-09-23

56

Influence of Thermal Aging on Primary Water Stress Corrosion Cracking of Cast Duplex Stainless Steels  

Energy Technology Data Exchange (ETDEWEB)

In order to evaluate the SCC (stress corrosion cracking) susceptibility of cast duplex stainless steels which are used for the main coolant piping material of pressurized water reactors (PWRs), the slow strain rate test (SSRT) and the constant load test (CLT) were performed in simulated PWR primary water at 360 C. The main coolant piping materials contain ferrite phase with ranging from 8 to 23 % and its mechanical properties are affected by long time thermal aging. The 23% ferrite material was prepared for test as the maximum ferrite content of main coolant pipes in Japanese PWRs. The brittle fracture in the non-aged materials after SSRT is mainly caused by quasi-cleavage fracture in austenitic phase. On the other hand, a mixture of quasi-cleavage fracture in austenite and ferrite phases was observed on long time aged material. Also on CLT, (2 times {sigma}{sub y}), after 3,000 hours exposure, microcracks were observed on the surface of non-aged and aged for 10,000 hours at 400 C materials. The crack initiation site of CLT is similar to that of SSRT. The SCC susceptibility of the materials increases with aging time. It is suggested that the ferrite hardening with aging affect SCC susceptibility of cast duplex stainless steels. (authors)

Yamada, T.; Totsuka, N.; Nakajima, N.; Arioka, K. [Institute of Nuclear Safety System, Inc., Mikata-gun, Fukui (Japan); Negishi, K. [Aomori Gennen Technology Center, Touhoku-cho, Kamikita-gun, Aomori (Japan)

2002-07-01

57

CAST  

Science.gov (United States)

The Council for Agricultural Science and Technology (CAST) was formed in 1972 as a result of a meeting sponsored by the National Academy of Sciences' National Research Council. CAST's mission is to "assemble, interpret, and communicate credible science-based information regionally, nationally, and internationally to legislators, regulators, policymakers, the media, the private sector and the public." Visitors will find the Education tab near the top of the page to be particularly helpful for those who want to pursue agricultural careers or learn about agricultural education, such as 4-H or Future Farmers of America. The CAST Videos section has a number of PowerPoint presentations on current topics of importance in agriculture, such as "The Science and Regulation of Food from Genetically Engineered Animals," "Food Safety and Fresh Produce," and "Probiotics in Human Health." A number of the papers that accompany the PowerPoint presentations are available for free.

2012-02-03

58

Eddy current measurement system evaluation for corrosion depth determination on cast aluminum aircraft structure  

Science.gov (United States)

An eddy current (EC) technique was developed to determine the corrosion depth on a bare flange face of a cast aluminum A356-T6 aircraft engine structure. The EC response and the corrosion depths determined through metallurgical cross sections were used to develop an empirical relation between EC response and depth. The EC technique and depth determination are used to inspect the engine structures during overhaul to determine if they are fit for continued service. An accurate and reliable Non-Destructive Inspection is required to ensure that structures returned to service are safe for continued operation. NDE system reliability demonstrations of the eddy current technique are traditionally reported in terms of Probability of Detection (POD) data using MIL-HDBK-1823A. However, the calculation of POD data is based on a simple linear predictive model that is valid only if certain criteria are met. These are: 1) NDE system response is measurable (i.e. continuous data), 2) Flaw size is known and measurable (i.e. continuous data), 3) relationship between the NDE system response and flaw size is linear (or linear on a log scale), 4) variation in measured responseresponse around a predicted response for a given flaw size is normally distributed, 5) the variation around the predicted response is constant (i.e. variation does not change with flaw size), and 6) inherent variability in the NDE system is known and fully understood. In this work, a Measurement System Evaluation (MSE) of the Eddy Current System was used to address some of these concerns. This work was completed on two aircraft structures having varying corrosion depths. The data were acquired in a random manner at fifty regions of interests (ROIs). Three operators participated in this study, and each operator measured Eddy Current response three times in each ROI. In total, there were four hundred and fifty data points collected. Following this, the two structures were sectioned for measuring corrosion depth. The obtained EC response and depth data were used for quantifying the EC System inherent variability by determining Analysis Of Variance (ANOVA), Gage R&R, control charts, Gage run charts, and regression curve. Initial results from this study show that the Eddy Current System is capable for determining corrosion depths on the structures as well as for discriminating good parts from bad.

Singh, Surendra; Greving, Dan; Kinney, Andy; Vensel, Fred; Ohm, Jim; Peeler, Mike

2013-01-01

59

Corrosion resistance of cast irons and titanium alloys as reference engineered metal barriers for use in basalt geologic storage: a literature assessment  

International Nuclear Information System (INIS)

A survey and assessment of the literature on the corrosion resistance of cast irons and low-alloy titanium are presented. Selected engineering properties of cast iron and titanium are briefly described; however, the corrosion resistance of cast iron and titanium in aqueous solutions or in soils and their use in a basalt repository are emphasized. In evaluating the potential use of cast iron and titanium as structural barrier materials for long-lived nuclear waste packages, it is assumed that titanium has the general corrosion resistance to be used in relatively thin cross sections whereas the cost and availability of cast iron allows its use even in very thick cross sections. Based on this assumption, the survey showed that: The uniform corrosion of low-alloy titanium in a basalt environment is expected to be extremely low. A linear extrapolation of general corrosion rates with an added corrosion allowance suggests that a 3.2- to 6.4-mm-thick wall may have a life of 1000 yr. Pitting and crevice corrosion are not likely corrosion modes in basalt ground waters. It is also unlikely that stress corrosion cracking (SCC) will occur in the commercially pure (CP) titanium alloy or in palladiumor molybdenum-alloyed titanium materials. Low-alloy cast irons may be used as barrier metals if the environment surrounding the metal keeps the alloy in the passive range. The solubility of the corrosion product and the semipermeable nature of the oxide film allow significant uniform corrosion over long time periods. A linear extrapolation of high-temperature corrosion rates on carbon steels and corrosion rates of cast irons in soils gives an estimated metal penetration of 51 to 64 mm after 1000 yr. A corrosion allowance of 3 to 5 times that suggests that an acceptable cast iron wall may be from 178 to 305 mm thick. Although they cannot be fully assessed, pitting and crevice corrosion should not affect cast iron due to the ground-water chemistry of basalt

1981-01-01

60

Corrosion resistance of cast irons and titanium alloys as reference engineered metal barriers for use in basalt geologic storage: a literature assessment  

Energy Technology Data Exchange (ETDEWEB)

A survey and assessment of the literature on the corrosion resistance of cast irons and low-alloy titanium are presented. Selected engineering properties of cast iron and titanium are briefly described; however, the corrosion resistance of cast iron and titanium in aqueous solutions or in soils and their use in a basalt repository are emphasized. In evaluating the potential use of cast iron and titanium as structural barrier materials for long-lived nuclear waste packages, it is assumed that titanium has the general corrosion resistance to be used in relatively thin cross sections whereas the cost and availability of cast iron allows its use even in very thick cross sections. Based on this assumption, the survey showed that: The uniform corrosion of low-alloy titanium in a basalt environment is expected to be extremely low. A linear extrapolation of general corrosion rates with an added corrosion allowance suggests that a 3.2- to 6.4-mm-thick wall may have a life of 1000 yr. Pitting and crevice corrosion are not likely corrosion modes in basalt ground waters. It is also unlikely that stress corrosion cracking (SCC) will occur in the commercially pure (CP) titanium alloy or in palladiumor molybdenum-alloyed titanium materials. Low-alloy cast irons may be used as barrier metals if the environment surrounding the metal keeps the alloy in the passive range. The solubility of the corrosion product and the semipermeable nature of the oxide film allow significant uniform corrosion over long time periods. A linear extrapolation of high-temperature corrosion rates on carbon steels and corrosion rates of cast irons in soils gives an estimated metal penetration of 51 to 64 mm after 1000 yr. A corrosion allowance of 3 to 5 times that suggests that an acceptable cast iron wall may be from 178 to 305 mm thick. Although they cannot be fully assessed, pitting and crevice corrosion should not affect cast iron due to the ground-water chemistry of basalt.

Charlot, L.A.; Westerman, R.E.

1981-07-01

 
 
 
 
61

Systematic Microstructural and Corrosion Performance Evaluation of CK-3MCuN and CN-3MN High Molybdenum Stainless Steel Castings  

Energy Technology Data Exchange (ETDEWEB)

High molybdenum austenitic stainless steel castings are widely accepted for their high strength, excellent weldability, and good corrosion resistance over a wide range of temperatures in highly oxidizing aqueous and gaseous media in chemical processing and other environments. With their desirable performance, high molybdenum austenitic stainless steel castings are increasingly applied in industry in a similar manner as wrought materials. In general, cast and wrought stainless and high alloy steels are anticipated to possess equivalent resistance to corrosive media, and they are frequently used in conjunction with each other. However, alloying element segregation usually is more evident in castings than in wrought counterparts. Segregation of alloying elements can lead to the formation of secondary phases, such as sigma. Mechanical properties and especially the corrosion resistance of castings may be affected by the secondary phases. In addition, improper heat treatment procedures c an also lead to the formation of carbides and secondary phases in high alloy and austenitic stainless steels.

C.D. Lundin; S. Wen; W. Liu; G. Zhou

2001-10-01

62

Characterization of biofilm and corrosion of cast iron pipes in drinking water distribution system with UV/Cl2 disinfection.  

Science.gov (United States)

The effect of UV/Cl2 disinfection on the biofilm and corrosion of cast iron pipes in drinking water distribution system were studied using annular reactors (ARs). Passivation occurred more rapidly in the AR with UV/Cl2 than in the one with Cl2 alone, decreasing iron release for higher corrosivity of water. Based on functional gene, pyrosequencing assays and principal component analysis, UV disinfection not only reduced the required initial chlorine dose, but also enhanced denitrifying functional bacteria advantage in the biofilm of corrosion scales. The nitrate-reducing bacteria (NRB) Dechloromonas exhibited the greatest corrosion inhibition by inducing the redox cycling of iron to enhance the precipitation of iron oxides and formation of Fe3O4 in the AR with UV/Cl2, while the rhizobia Bradyrhizobium and Rhizobium, and the NRB Sphingomonas, Brucella producing siderophores had weaker corrosion-inhibition effect by capturing iron in the AR with Cl2. These results indicated that the microbial redox cycling of iron was possibly responsible for higher corrosion inhibition and lower effect of water Larson-Skold Index (LI) changes on corrosion. This finding could be applied toward the control of water quality in drinking water distribution systems. PMID:24859195

Zhu, Ying; Wang, Haibo; Li, Xiaoxiao; Hu, Chun; Yang, Min; Qu, Jiuhui

2014-09-01

63

Effect of sulfate on the transformation of corrosion scale composition and bacterial community in cast iron water distribution pipes.  

Science.gov (United States)

The chemical stability of iron corrosion scales and the microbial community of biofilm in drinking water distribution system (DWDS) can have great impact on the iron corrosion and corrosion product release, which may result in "red water" issues, particularly under the situation of source water switch. In this work, experimental pipe loops were set up to investigate the effect of sulfate on the dynamical transformation characteristics of iron corrosion products and bacterial community in old cast iron distribution pipes. All the test pipes were excavated from existing DWDS with different source water supply histories, and the test water sulfate concentration was in the range of 50-350 mg/L. Pyrosequencing of 16S rRNA was used for bacterial community analysis. The results showed that iron release increased markedly and even "red water" occurred for pipes with groundwater supply history when feed water sulfate elevated abruptly. However, the iron release of pipes with only surface water supply history changed slightly without noticeable color even the feed water sulfate increased multiply. The thick-layered corrosion scales (or densely distributed tubercles) on pipes with surface water supply history possessed much higher stability due to the larger proportion of stable constituents (mainly Fe3O4) in their top shell layer; instead, the rather thin and uniform non-layered corrosion scales on pipes with groundwater supply history contained relatively higher proportion of less stable iron oxides (e.g. ?-FeOOH, FeCO3 and green rust). The less stable corrosion scales tended to be more stable with sulfate increase, which was evidenced by the gradually decreased iron release and the increased stable iron oxides. Bacterial community analysis indicated that when switching to high sulfate water, iron reducing bacteria (IRB) maintained dominant for pipes with stable corrosion scales, while significant increase of sulfur oxidizing bacteria (SOB), sulfate reducing bacteria (SRB) and iron oxidizing bacteria (IOB) was observed for pipes with less stable corrosion scales. PMID:24784453

Yang, Fan; Shi, Baoyou; Bai, Yaohui; Sun, Huifang; Lytle, Darren A; Wang, Dongsheng

2014-08-01

64

Corrosion behaviour of the AlSi6Cu4 alloy and cast AlSi6Cu4-graphite particles composite  

Directory of Open Access Journals (Sweden)

Full Text Available The corrosion behaviour of the AlSi6Cu4 alloy as a composite matrix and of composites with 8% vol. of graphite particles was investigated. The corrosion experiments were performed over a range of elevated temperatures and were carried out in sea water (3.5%NaCl solution. We have focused our attention to the determination of the mode of corrosion attack and to the determination of the rate ofcorrosion and other corrosion characteristics. Both as-cast and annealed matrix and composite specimens were tested, as well as the99.9% as-cast aluminium for comparison. Corrosion behaviour of the materials was assessed by the corrosion potential (Ec and bypotentiodynamic (polarization curves. As expected, composite is less corrosion resistant than the matrix alloy. In addition to pitting,a severe galvanic corrosion occurs as a result of galvanic couple aluminium/graphite formation. Corrosion potentials imply that examinedmaterials would be sufficiently resistant in non or slightly oxidizing solutions without dissolved oxygen. All studied materials corrode very slowly at potentials negative to corrosion potential, while at potentials positive to corrosion potential the corrosion rate goes up by 1 or 2 orders.

S. Holecek

2009-04-01

65

Galvanic corrosion of copper-cast iron couples in relation to the Swedish radioactive waste canister concept  

Energy Technology Data Exchange (ETDEWEB)

To ensure the safe encapsulation of spent nuclear fuel rods for geological disposal, SKB are considering using the Copper-Iron Canister, which consists of an outer copper canister and an inner cast iron container. The canister will be placed into boreholes in the bedrock of a geologic repository and surrounded by bentonite clay. In the unlikely event of the outer copper canister being breached, water could enter the annulus between the inner and outer canister and at points of contact between the two metals there would be a possibility of galvanic interactions. To study this effect, copper-cast iron galvanic couples were set up in a number of different environments representing possible conditions in the SKB repository. The tests investigated two artificial pore-waters and a bentonite slurry, under aerated and deaerated conditions, at 30 deg. C and 50 deg. C. The currents passing between the coupled electrodes and the potential of the couples were monitored for several months. In addition, some bimetallic crevice specimens based on the multi-crevice assembly (MCA) design were used to simulate the situation where the copper canister will be in direct contact with the cast iron inner vessel. The effect of growing an oxide film on the surface of the cast iron prior to coupling it with copper was also investigated. The electrochemical results are presented graphically in the form of electrode potentials and galvanic corrosion currents as a function of time. The galvanic currents in aerated conditions were much higher than in deaerated conditions. For example, at 30 deg. C, galvanic corrosion rates as low as 0.02 {mu}m/year were observed for iron in groundwater after de-aeration, but of the order of 100 {mu}m/year for the cast iron at 50 deg. C in the presence of oxygen. The galvanic currents were generally higher at 50 deg. C than at 30 deg. C. None of the MCA specimens exhibited any signs of crevice corrosion under deaerated conditions. It will be shown that in deaerated conditions the galvanic corrosion rates of iron coupled to copper are close to the values observed for anaerobic corrosion rates of uncoupled iron. The results from the work presented in the paper will be discussed in relation to understanding the evolution of the environment within the annulus of the SKB canister if premature failure of the outer copper canister were to occur. (authors)

Smart, N.R.; Fennell, P.A.H.; Rance, A.P. [Serco Assurance, Culham Science Centre, Abingdon, Oxfordshire, OX14 3ED (United Kingdom); Werme, L.O. [SKB, Box 5864, SE-10240, Stockholm (Sweden)

2004-07-01

66

Galvanic corrosion of copper-cast iron couples in relation to the Swedish radioactive waste canister concept  

International Nuclear Information System (INIS)

To ensure the safe encapsulation of spent nuclear fuel rods for geological disposal, SKB are considering using the Copper-Iron Canister, which consists of an outer copper canister and an inner cast iron container. The canister will be placed into boreholes in the bedrock of a geologic repository and surrounded by bentonite clay. In the unlikely event of the outer copper canister being breached, water could enter the annulus between the inner and outer canister and at points of contact between the two metals there would be a possibility of galvanic interactions. To study this effect, copper-cast iron galvanic couples were set up in a number of different environments representing possible conditions in the SKB repository. The tests investigated two artificial pore-waters and a bentonite slurry, under aerated and deaerated conditions, at 30 deg. C and 50 deg. C. The currents passing between the coupled electrodes and the potential of the couples were monitored for several months. In addition, some bimetallic crevice specimens based on the multi-crevice assembly (MCA) design were used to simulate the situation where the copper canister will be in direct contact with the cast iron inner vessel. The effect of growing an oxide film on the surface of the cast iron prior to coupling it with copper was also investigated. The electrochemical results are presented graphically in the form of electrode potentials and galvanic corrosion currents as a function of time. The galvanic currents in aerated conditions were much higher than in deaerated conditions. For example, at 30 deg. C, galvanic corrosion rates as low as 0.02 ?m/year were observed for iron in groundwater after de-aeration, but of the order of 100 ?m/year for the cast iron at 50 deg. C in the presence of oxygen. The galvanic currents were generally higher at 50 deg. C than at 30 deg. C. None of the MCA specimens exhibited any signs of crevice corrosion under deaerated conditions. It will be shown that in deaerated conditions the galvanic corrosion rates of iron coupled to copper are close to the values observed for anaerobic corrosion rates of uncoupled iron. The results from the work presented in the paper will be discussed in relation to understanding the evolution of the environment within the annulus of the SKB canister if premature failure of the outer copper canister were to occur. (authors)

2004-09-12

67

Influence of cyclic strain on the corrosion rate of cast steels in aqueous inhibitor solutions. Fushoku yokuseizaichu no chuko fushoku ni oyobosu kurikaeshi hizumi no eikyo  

Energy Technology Data Exchange (ETDEWEB)

Influence of surface properties and cyclic strain on the corrosion of cast steels in the corrosion inhibitors, potassium chromate (A) and sodium nitrite (B) solutions were discussed. Unstrained specimens were nearly protected from corrosion in both solutions (A) and (B). However, heavy corrosion was found at the stress concentrated area of (A) in tests where a cyclic strain was imposed. Negative current loops in anodic polarization curves were observed in (A) for specimens finished with empty cloth. No negative current loops were observed for the rusted specimens. In (B), no negative current loops in anodic polarization curves were observed either in finished or rusted surfaces. From these results, it was clarified that cast steels were initially in an unstable passive state in the (B) solutions, and the formation of a passive film was obstructed under the low cyclic strain, moreover, corrosion was heavily progressed. 5 refs., 10 figs., 2 tabs.

Yamamoto, S. (Mitsubishi Heavy Industries Ltd., Tokyo (Japan). Yokohama R and D); Ueda, K. (Mitsubishi Heavy Industries Ltd., Tokyo (Japan). Nagasaki R and D)

1993-11-15

68

Effect of N addition on tensile and corrosion behaviors of CD4MCU cast duplex stainless steels  

Science.gov (United States)

The effect of N addition on the microstructure, tensile, and corrosion behaviors of CD4MCU (Fe-25Cr-5Ni-2.8Cu-2Mo) cast duplex stainless steel was examined in the present study. The slow strain rate tests were also conducted at a nominal strain rate of 1 × 10-6/s in air and 3.5 pct NaCl+5 pct H2SO4 solution for studying the stress corrosion cracking (SCC) behavior. It was observed that the volume fraction of austenitic phase in CD4MCU alloy varied from 38 to 59 pct with increasing nitrogen content from 0 to 0.27 wt. pct. The tensile behavior of CD4MCU cast duplex stainless steels, which tended to vary significantly with different N contents, appeared to be strongly related to the volume changes in ferritic and austenitic phases, rather than the intrinsic N effect. The improvement in the resistance to general corrosion in 3.5 pct NaCl+5 pct H2SO4 aqueous solution was notable with 0.13 pct N addition. The further improvement was not significant with further N addition. The resistance to SCC of CD4MCU cast duplex stainless steels in 3.5 pct NaCl+5 pct H2SO4 aqueous solution, however, increased continuously with increasing N content. The enhancement in the SCC resistance was believed to be related to the volume fraction of globular austenitic colonies, which tended to act as barriers for the development of initial pitting cracks in the ferritic phase into the sharp ones.

Son, Jinil; Kim, Sangshik; Lee, Jehyun; Choi, Byunghak

2003-08-01

69

Corrosion resistance of Al-Li-Cu-Mg and Al-Li-Mg alloy castings; Al-Li kei imono gokin no taishokusei  

Energy Technology Data Exchange (ETDEWEB)

Corrosion resistance of step castings of Al-2.5%Li-1.2%Cu-0.7%Mg alloys and Al-2.5%Li-2%Mg alloys with or without 0.15% Zr and 0.12% Ti were examined using salt spray tests. Corrosion resistance of the as-cast materials in the middle part and near surface part was almost same as that of the Al-7%Si-0.4%Mg alloy (AC4C). The corrosion resistance was good in spite of existence of unstable non-equilibrium crystal phase {delta}. This is due to formation of Na(ClCN), Cu3(CO3)2(OH)2 and Al(OH)3 on the surface of castings in the initial stage of corrosion, which work as a barrier over a corrosive environment. After T6 heat treatment of the alloys at 453 K and 36 ks, corrosion resistance of the near surface part of the casting was better than that of the middle part, and was almost equal to that of AC4C. This is considered due to more precipitation of the metastable phases:{delta}prime, Sprime and T1 in the middle part. 8 refs., 11 figs., 1 tab.

Saikawa, S.; Nakai, K.; Sugiura, Y.; Kamio, A. [Tokyo Univ. (Japan)

1997-07-25

70

Investigations of high-temperature corrosion of Cr-Ni cast steel  

Directory of Open Access Journals (Sweden)

Full Text Available Austenitic cast steels of Cr25-Ni32-Nb grade have found wide application in chemical and petrochemical industries. This study discusses the problem of the kinetics of oxidation of these materials in the atmosphere of laboratory air at temperatures of 930 and 1000 °C. Considering the operating conditions of castings (centrifugally cast reformer tubes, the results of the oxidation test of specimens taken from the zone of columnar crystals and equiaxial grains were presented.

R. Zapa?a

2009-07-01

71

Influence of microstructure on corrosion of as-cast ZE41  

Energy Technology Data Exchange (ETDEWEB)

Corrosion of ZE41 initiated in the {alpha}-Mg matrix adjacent to the eutectic micro-constituent and was attributed to micro-galvanic corrosion of the {alpha}-Mg matrix coupled to the eutectic micro-constituent. The eutectic micro-constituent did not act as a corrosion barrier and did not stop the advance of the corrosion. As a consequence, the {alpha}-Mg matrix corroded over the whole surface with little corrosion of the inter-connected eutectic micro-constituent. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

Zhao, M.C.; Liu, M. [Division of Materials, The University of Queensland, Brisbane, Qld 4072 (Australia); Swiss Federal Laboratories for Materials Science and Technology, EMPA, Dept 136, Ueberlandstrasse 129, CH-8600 Dubendorf (Switzerland); Song, G.L. [Division of Materials, The University of Queensland, Brisbane, Qld 4072 (Australia); Atrens, A.

2008-02-15

72

Penile vascular system of the dog. An injection-corrosion and histological study.  

Science.gov (United States)

The vascular architecture of the dog penis was studied by resin casts and histological preparations. Morphological evidence was found for penile engorgement. The crus and the bulb were compressed by the ischiocavernosus and the bulbospongiosus muscles, respectively, indicating that these muscles act as a booster pump. The distal part of the bulb was also strangulated by the external anal sphincter, indicating that this muscle prevents blood in the corpus spongiosum penis from going back into the bulb. The common trunk of the dorsal vein of the penis was significantly occluded by the ischiourethralis muscle. The internal pudendal vein was also throttled by the levator ani, the coccygeus, and the internal obturator muscles. The extremely narrow diameter of each vein draining the erectile body was insufficient to drain the increased blood flow and, therefore, formed a sluice channel. It is inferred that these muscle activities and sluice channels facilitate the erection of the penis. PMID:2685437

Ninomiya, H; Nakamura, T; Niizuma, I; Tsuchiya, T

1989-08-01

73

Microstructure, mechanical property and corrosion behavior of interpenetrating (HA+?-TCP)/MgCa composite fabricated by suction casting.  

Science.gov (United States)

The novel interpenetrating (HA+?-TCP)/MgCa composites were fabricated by infiltrating MgCa alloy into porous HA+?-TCP using suction casting technique. The microstructure, mechanical properties and corrosion behaviors of the composites have been evaluated by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), mechanical testing, electrochemical and immersion tests. It was shown that the composites had compact structure and the interfacial bonding between MgCa alloy and HA+?-TCP scaffolds was very well. The ultimate compressive strength of the composites was about 500-1000 fold higher than that of the original porous scaffolds, and it still retained quarter-half of the strength of the bulk MgCa alloy. The electrochemical and immersion tests indicated that the corrosion resistance of the composites was better than that of the MgCa matrix alloy, and the corrosion products of the composite surface were mainly Mg(OH)2, HA and Ca3(PO4)2. Meanwhile, the mechanical and corrosive properties of the (HA+?-TCP)/MgCa composites were adjustable by the choice of HA content. PMID:23910342

Wang, X; Dong, L H; Li, J T; Li, X L; Ma, X L; Zheng, Y F

2013-10-01

74

Energy Saving Melting and Revert Reduction (E-SMARRT): Optimization of Heat Treatments on Stainless Steel Castings for Improved Corrosion Resistance and Mechanical Properties  

Energy Technology Data Exchange (ETDEWEB)

It is commonly believed that high alloy steel castings have inferior corrosion resistance to their wrought counterparts as a result of the increased amount of microsegregation remaining in the as-cast structure. Homogenization and dissolution heat treatments are often utilized to reduce or eliminate the residual microsegregation and dissolve the secondary phases. Detailed electron probe microanalysis (EPMA) and light optical microscopy (LOM) were utilized to correlate the amount of homogenization and dissolution present after various thermal treatments with calculated values and with the resultant corrosion resistance of the alloys.The influence of heat treatment time and temperature on the homogenization and dissolution kinetics were investigated using stainless steel alloys CN3MN and CK3MCuN. The influence of heat treatment time and temperature on the impact toughness and corrosion reistance of cast stainless steel alloys CF-3, CF-3M, CF-8, and CF-8M was also investigated.

John N. DuPont; Jeffrey D. Farren; Andrew W. Stockdale; Brett M. Leister

2012-06-30

75

APPLIED 3-DANATOMY OF LIVER BILE DUCTS IN INJECTION CORROSION CASTS  

Directory of Open Access Journals (Sweden)

Full Text Available On the 20 post-autopsy adult isolated liver specimens of patients of both sexes (17 male and 3female aged 29–88, the injection-corrosion method was used. Colored acrylate was injected into the biliary system, and uncolored acrylate into the portal vein. A total of 17 acrylate casts were of proper quality.Within the 9 portal segments, both the anatomical determination and quantity and the mode of confluence of intrahepatic bile ducts were established. Different modes of biliary tract confluence up to the sectors and hepatics were found. Besides the most frequent findings of conventionally confluence bile ducts, there were aberrant modalities of biliary drainage in eight cases. Among them 5 cases had confluence of posterior and anterior sector ducts in the left hepatic duct and 1 case had confluence at first of anterior and then posterior sector ducts in the left hepatic duct. Also, extrahilar connection of the right posterior with left lateral into common hepatic duct, where the latter entered themedial and anterior sectors ducts in1 case was found. There was a subsequent confluence of ducts from the 8th and 5th segments in 1 case, and from the lateral andmedial sectorswith or without caudate lobe in 3 cases. A common (4 or separate (2 confluence of left and right portions ducts in the left drainage system were in 6 cases, whereas in both, the left and right drainage system in 7 cases was found. Rare, there wasan aberrant single channel from the right portion in 1 case, as well as the presence and biliary drainage only of the left portion of 1st segment was found. Segment 9 bile ducts drained all three subsegments (b, c and d in 10 cases, and only two (c and d in 3 cases, as well as only two (c and b of present three subsegments in 3 cases. Also, there was even one case with present 9d subsegment and without 9th segment duct. Those modalities are of interest in an applying and accurate interpretation and performance of diagnostic and interventional procedures, as well as in segmental, sectoral or hemihepatic resection in liver surgery.

Jurkovikj Dragica M.

2013-01-01

76

Microstructure and corrosion behavior of die-cast AM60B magnesium alloys in a complex salt solution: A slow positron beam study  

Energy Technology Data Exchange (ETDEWEB)

The microstructure and corrosion behavior of high pressure die-cast (HPDC) and super vacuum die-cast (SVDC) AM60B magnesium alloys were investigated in a complex salt solution using slow positron beam technique and potentiodynamic polarization tests. The experiments revealed that a CaCO3 film was formed on the surface of the alloys and that the rate of CaCO3 formation for the SVDC alloy with immersion time was slower than that of the HPDC alloy. The larger volume fraction of b-phase in the skin layer of the SVDC alloy than that of the HPDC alloy was responsible for the better corrosion resistance.

Liu, Y.F. [Wuhan University; Qin, Q.L. [Wuhan University; Yang, W. [Wuhan University; Wen, W. [University of Kentucky; Zhai, T. [University of Kentucky; Yu, B. [University of Alberta; Liu, D.Y. [University of Alberta; Luo, A. [GM Research and Development Center; Song, GuangLing [ORNL

2014-01-01

77

Effects of Ce addition on microstructure, mechanical properties and corrosion resistance of as-cast AZ80 magnesium alloy  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, Ce was introduced into the AZ80 alloy and the effects of Ce addition on the microstructure, mechanical properties and corrosion resistance of the as-cast AZ80 magnesium alloy were investigated. The results show that the addition of Ce into the AZ80 alloy can not only refine the microstructure, but also result in the formation of the needle-like Al4Ce phase. These tiny Al4Ce phases are homogeneously distributed at grain boundaries and within grains. An appropriate Ce addition can also change the ?-Mg17Al12 phase at the grain boundaries from continuous network to small island-like. At the same time, with the increase of Ce content from 0 to 2.0wt.%, the macro-hardness of the as-cast alloy is enhanced linearly, while impact toughness, tensile strength and elongation all firstly increase and then decrease. The AZ80 alloy containing 1.0wt.% Ce exhibits the optimal properties. Its macro-hardness, impact toughness, tensile strength and elongation are 61.90 HB, 15.50 J·cm-2, 171.80 MPa and 3.35%, increase by 9.95%, 63%, 13.3% and 36.7%, respectively compared with the base alloy. In addition, Ce can enhance the corrosion resistance of the AZ80 magnesium alloy.

Wang Wei

2014-05-01

78

Effects of the Exposure to Corrosive Salts on the Frictional Behavior of Gray Cast Iron and a Titanium-Based Metal Matrix Composite  

Energy Technology Data Exchange (ETDEWEB)

The introduction of increasingly aggressive road-deicing chemicals has created significant and costly corrosion problems for the trucking industry. From a tribological perspective, corrosion of the sliding surfaces of brakes after exposure to road salts can create oxide scales on the surfaces that affect friction. This paper describes experiments on the effects of exposure to sodium chloride and magnesium chloride sprays on the transient frictional behavior of cast iron and a titanium-based composite sliding against a commercial brake lining material. Corrosion scales on cast iron initially act as abrasive third-bodies, then they become crushed, spread out, and behave as a solid lubricant. The composition and subsurface microstructures of the corrosion products on the cast iron were analyzed. Owing to its greater corrosion resistance, the titanium composite remained scale-free and its frictional response was markedly different. No corrosion scales were formed on the titanium composite after aggressive exposure to salts; however, a reduction in friction was still observed. Unlike the crystalline sodium chloride deposits that tended to remain dry, hygroscopic magnesium chloride deposits absorbed ambient moisture from the air, liquefied, and retained a persistent lubricating effect on the titanium surfaces.

Blau, Peter Julian [ORNL; Truhan, Jr., John J [ORNL; Kenik, Edward A [ORNL

2007-01-01

79

Comparative analysis of the behavior to corrosion of forged and cast austenitic stainless steel when used in a surgical prosthesis  

International Nuclear Information System (INIS)

The selection of a material to be used in implants involves tests that cover aspects relative to its resistance to corrosion and its bio-compatibility. Testing the material implanted in the human body is a very difficult process or it is impossible via direct electrochemistry. Because of this laboratory tests have been developed that simulate the natural setting of the material in the organism using saline solutions that are kept at 37oC and pH 7.4. The material that is to be used should be resistant to corrosion in the body so that ions are not released into the organism and the device should maintain its integrity in service and not to suffer degradation. This work compares the behavior to corrosion of samples of a cast prosthesis (lower tibia, made of stainless steel ACI CF 3M) and a forged prosthesis (femorals, made of stainless steel ASTM F 621) with laminated bars of the same quality (stainless steel ASTM F 138). The samples were characterized with physical and electrochemical tests under three different thermal conditions: solubilized, annealed and forged or cast. The test pieces were submitted to electrochemical direct current tests during their immersion in a 0.9% deoxygenated NaCl solution and thermostatisized at 37oC. The Cr and Fe content in solution at the end of the electrochemical test was evaluated together with the micro hardness of the material and the characterization of the final stage of the material was carried out by optic microscopy and sweep electronics (CW)

2004-11-01

80

Corrosion rate of unalloyed steels and cast irons in reducing granitic groundwaters and chloride solutions  

International Nuclear Information System (INIS)

Measurements of the corrosion rate of unalloyed steel have been made under conditions representative for repositories in the granitic bedrock of Northern Switzerland using two independent methods: (1) immersion tests in two representative groundwaters, with and without bentonite; (2) hydrogen evolution measurements in these groundwaters. The immersion tests were carried out at 80"0C and 140"0C. In both cases the corrosion rate was higher than 50 ?m/a as determined at the end of the first observation period of about 500 h. Corrosion rates of under 10 ?m/a were estimated after the first 500 h. The corrosion rates were similar in both groundwaters with mineralizations of approx. 3 g/l and 14 g/l respectively, and were generally higher at 80"0C than at 140"0C. The hydrogen evolution measurements allow an hourly determination of the corrosion rate, with a sensitivity expressed as a corrosion rate of better than 0.1 ?m/a. The results generally confirm the observation made in the immersion testing; high corrosion rates were observed over the first few days but then decreased to values well below 10 ?m/a. The steady state corrosion rates measured were 1.1 ?m/a, 6.5 ?m/a, and 2.5 ?m/a at 25"0C, 50"0C, and 80"0C respectively in the water with the higher mineralization. The inverse temperature effect on corrosion rate above 50"0C is attributed to a change in the nature of the passive film at higher temperatures

1985-09-09

 
 
 
 
81

MCC corrosion tests at reference testing conditions for A27 cast steel in Hanford ground water  

International Nuclear Information System (INIS)

The Materials Characterization Center (MCC) at Pacific Northwest Laboratory is performing three kinds of corrosion tests for the Basalt Waste Isolation Project (BWIP) to establish the interlaboratory reproducibility and uncertainty of corrosion rates of container materials for high-level nuclear waste. The three types of corrosion tests were selected to address two distinct conditions that are expected in a repository constructed in basalt. An air/steam test is designed to address corrosion during the operational period and static pressure vessel and flowby tests are designed to address corrosion under conditions that bound the conditions during the post-closure period of the repository. The results of tests at reference testing conditions, which were defined to facilitate interlaboratory comparison of data, are presented. Data are reported for the BWIP/MCC-105.5 Air/Steam Test, BWIP/MCC-105.1 Static Pressure Vessel, and BWIP/MC-105.4 Flowby Test. In those cases where data are available from a second laboratory, a statistical analysis of interlaboratory results is reported and expected confidence intervals for mean corrosion rates are given. Other statistical treatment of data include analyses of the effects of vessel-to-vessel variations, test capsule variations for the flowby test, and oven-to-oven variations for air/steam tests. 5 references, 4 figures, 9 tables

1987-01-01

82

Corrosion behaviour of water waste on the gray cast iron sanitary pipelines  

International Nuclear Information System (INIS)

The works of Plato (427-347 B.C.) contained the written description of corrosion. Plato defined rust as the earthy component separating out of the metal. (Georgius Agrico La) held to the same opinion some 2000 years later in his great mineralogical work De Natura Fossilium Iron rust (rat. Ferrug or Rubigo) is, so to speak, assertion of metallic iron. Iron can be protected against this defect by various wrapping, such as red lead, white lead, gypsum, bitumen or tar. Gaius Secundus Pliny also mentioned bitumen, pitch, white lead, and gypsum as protecting iron and bronze against corrosion. He reported that Alexander the Great had constructed Ponton Bridge at Zeugmar on the Euphrates with the aid of an iron chain. Link's that were inserted later suffered rust attacks, While the original ones remained immune. The opinion, sometimes expressed today, that modern iron inferior and more corrosion than old iron, was thus current even in ancient times. The concept of the corrosion process derived from the latin corrodere ( to eat away, to destroy ), first appeared in the philosophical transaction in 1667. It was discussed in German from the Frensh on the manufacture of white lead in 1785 and was mentioned in 1836 in the translation of an English paper by Savy on the cathodic protection of iron in sea water. However, almost unit the present day, the term was indiscriminately for corrosion reaction effects, and corrosion damage

2002-01-01

83

Development and assessment of a biodegradable solvent cast polyester fabric small-diameter vascular graft.  

Science.gov (United States)

Adjusting the mechanical properties of polyester-based vascular grafts is crucial to achieving long-term success in vivo. Although previous studies using a fabric-based approach have achieved some success, a central issue with pure poly(lactic acid) (PLA) or poly(glycolic acid) (PGA) grafts sealed with poly(DL-caprolactone-co-lactic acid) (P(CL/LA)) has been stenosis. Intimal hyperplasia, a leading cause of stenosis, can be caused by the mechanical incompatibility of synthetic vascular grafts. Investigating the performance of poly(glycolic-co-lactic acid) (PGLA) grafts could lead to insight into whether graft stenosis stems from mechanical issues such as noncompliance and unfavorable degradation times. This could be achieved by examining grafts with tunable mechanical properties between the ranges of such properties in pure PGA and PLA-based grafts. In this study, we examined PGLA-based grafts sealed with different P(CL/LA) solutions to determine the PGLA-P(CL/LA) grafts' mechanical properties and tissue functionality. Cell attachment and proliferation on graft surfaces were also observed. For in vivo assessment, grafts were implanted in a mouse model. Mechanical properties and degradation times appeared adequate compared to recorded values of vessels used in autograft procedures. Initial neotissue formation was observed in the grafts and patency maintained during the pilot study. This study presents a ?1-mm diameter degradable graft demonstrating suitable mechanical properties and in vivo pilot study success, enabling further investigation into the tuning of mechanical properties to reduce complications in degradable polyester fabric-based vascular grafts. PMID:23852776

Melchiorri, Anthony J; Hibino, Narutoshi; Brandes, Zachary R; Jonas, Richard A; Fisher, John P

2014-06-01

84

Effect of melting conditions on the resistance of cast magnaliums to stress corrosion cracking  

Energy Technology Data Exchange (ETDEWEB)

The resistance of AL311 and AL27-1 alloys to stress corrosion cracking is investigated as a function of melting conditions with emphasis on the effects of increased iron and silicon contents in the charge, contents of oxide inclusions, porosity, and the amount of hydrogen formed during the interaction of molten metals with air moisture. It is shown, in particular, that an increase in Fe content up to 0.53 percent and Si content to 0.73 percent does not increase the susceptibility of the Al-Mg alloys to stress-corrosion cracking, whereas hydrogen content significantly affects the stress corrosion cracking behavior of the alloys after prolonged room-temperature storage. 8 references.

Gorodkova, O.M.; Kurtasova, L.A.; Babkin, IU.A.; Polianskii, V.M.

1989-02-01

85

The corrosion performance of die-cast magnesium alloy MRI230D in 3.5% NaCl solution saturated with Mg(OH)2  

International Nuclear Information System (INIS)

The environmental behavior of die-cast magnesium alloy MRI230D designated for high-temperature applications was evaluated in comparison with regular AZ91D alloy. The microstructure examination was carried out using SEM, TEM, and X-ray diffraction analysis; the corrosion performance in 3.5% NaCl solution was evaluated by immersion test, salt spray testing, potentiodynamic polarization analysis, and stress corrosion behavior by Slow Strain Rate Testing (SSRT). Although the general corrosion resistance of MRI230D was slightly improved compared to that of AZ91D alloy its stress corrosion resistance was relatively reduced. The variations in the environmental behavior of the two alloys were mainly due to the differences in their chemical composition and microstructure after die casting. In particular, the differences were related to the reduced Al content in MRI230D and the addition of Ca to this alloy, which consequently affected its relative microstructure and electrochemical characteristics. - Research Highlights: ?Corrosion and SCC resistance of a new Mg alloy MRI230D was evaluated vs. regular AZ91D. ?MRI230D has a minor advantage in corrosion performance compared with AZ91D. ?The SCC resistance of MRI230D by SSRT analysis was relatively reduced. ?The reduced SCC resistance of MRI230D was due to the detrimental effect of Ca on ductility.

2010-11-01

86

SCC growth behavior of cast stainless steels in high-temperature water. Influences of corrosion potential, steel type, thermal aging and cold-work  

International Nuclear Information System (INIS)

Recent studies on crack growth rate (CGR) measurement in oxygenated high-temperature pure water conditions, such as normal water chemistry (NWC) in BWRs, using compact tension (CT) type specimens have shown that stainless steel weld metal are susceptible to stress corrosion cracking (SCC). On the other hand, the authors reported that no significant SCC growth was observed on stainless steel weld metals in PWR primary water at temperatures from 250degC to 340degC. Cast austenitic stainless steels are widely used in light water reactors, and there is a similarity between welded and cast stainless steels in terms of the microstructure of the ferrite/austenite duplex structure. However, there are a few reports giving CGR data on cast stainless steels in the BWRs and PWRs. The principal purpose of this study was to examine the SCC growth behavior of cast stainless steels in simulated PWR primary water. A second objective was to examine the effects on SCC growth in hydrogenated and oxygenated water environments at 320degC of: (1) corrosion potential; (2) steels type (Mo in alloy); (3) thermal-aging (up to 400degC x 40 kh); and (4) cold-working (10%). The results were as follows: (1) No significant SCC growth was observed on all types of cast stainless steels: aged (400degC x 40 kh) of SCS14A and SCS13A and 10% cold-working, in hydrogenated (low-potential) water at 320degC. (2) Aging at 400degC x 40 kh SCS14A (10%CW) markedly accelerated the SCC growth of cast material in high-potential water at 320degC, but no significant SCC growth was observed in the hydrogenated water, even after long-term thermal aging (400degC x 40 kh). (3) Thus, cast stainless steels have excellent SCC resistance in PWR primary water. (4) On the other hand, significant SCC growth was observed on all types of cast stainless steels: 10%CW SCS14A and SCS13A, in 8 ppm-oxygenated (high-potential) water at 320degC. (5) No large difference in SCC growth was observed between SCS14A (Mo) and SCS13A. (6) No large effect on SCC growth was observed in specimens before and after aging up to 400degC for 10 kh. (7) Long-term aging at 400degC for 40 kh markedly accelerated the SCC growth of cast stainless steel. According to these results, a clear corrosion potential dependence on SCC growth behavior of cast stainless steels was recognized. (author)

2011-10-01

87

Effect of yttrium-rich misch metal on the microstructures, mechanical properties and corrosion behavior of die cast AZ91 alloy  

Energy Technology Data Exchange (ETDEWEB)

Die cast AZ91-xYmm (x = 0-0.8 wt.%) magnesium alloys with excellent tensile properties and corrosion resistance behavior were successfully prepared by a simple addition of yttrium-rich misch metal (Ymm) to AZ91. Influences of Ymm on the microstructure, mechanical properties and corrosion behavior of AZ91 were investigated. The results showed that addition of Ymm to die cast AZ91 alloy could refine the microstructure including primary {alpha}-Mg and eutectic {beta}-Mg{sub 17}Al{sub 12}. When the content of Ymm reached 0.8 wt.% a small quantity of Al{sub 2}Y phase would form. The tensile properties were improved greatly with addition of Ymm to AZ91. The creep rate of the AZ91-Ymm alloys, tested at 150 deg. C/50 MPa, was one order of magnitude lower than that of AZ91. When addition of Ymm was more than 0.3 wt.%, the salt-spray corrosion resistance of AZ91-Ymm alloys could be 30-40 times of that of AZ91. The improvement of corrosion resistance with addition of Ymm was confirmed by the results of electrochemical polarization experiments. Mechanism of the improvement of mechanical properties and corrosion behavior caused by Ymm was also discussed.

Zhang Jinghuai [State Key Laboratory of Rare Earth Resources Application, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Graduate School of the Chinese Academy of Science, Beijing 100049 (China); Niu Xiaodong; Qiu Xin [State Key Laboratory of Rare Earth Resources Application, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Liu Ke [State Key Laboratory of Rare Earth Resources Application, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Graduate School of the Chinese Academy of Science, Beijing 100049 (China); Nan Changming [Shanxi Wenxi Yinguang Magnesium Group, Shanxi 043800 (China); Tang Dingxiang [State Key Laboratory of Rare Earth Resources Application, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Meng Jian [State Key Laboratory of Rare Earth Resources Application, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)], E-mail: jmeng@ciac.jl.cn

2009-03-05

88

Effect of yttrium-rich misch metal on the microstructures, mechanical properties and corrosion behavior of die cast AZ91 alloy  

International Nuclear Information System (INIS)

Die cast AZ91-xYmm (x = 0-0.8 wt.%) magnesium alloys with excellent tensile properties and corrosion resistance behavior were successfully prepared by a simple addition of yttrium-rich misch metal (Ymm) to AZ91. Influences of Ymm on the microstructure, mechanical properties and corrosion behavior of AZ91 were investigated. The results showed that addition of Ymm to die cast AZ91 alloy could refine the microstructure including primary ?-Mg and eutectic ?-Mg17Al12. When the content of Ymm reached 0.8 wt.% a small quantity of Al2Y phase would form. The tensile properties were improved greatly with addition of Ymm to AZ91. The creep rate of the AZ91-Ymm alloys, tested at 150 deg. C/50 MPa, was one order of magnitude lower than that of AZ91. When addition of Ymm was more than 0.3 wt.%, the salt-spray corrosion resistance of AZ91-Ymm alloys could be 30-40 times of that of AZ91. The improvement of corrosion resistance with addition of Ymm was confirmed by the results of electrochemical polarization experiments. Mechanism of the improvement of mechanical properties and corrosion behavior caused by Ymm was also discussed

2009-03-05

89

Radiographic aspects and angioarchitectural arrangements in corrosion casts of the blood supply to the human sternocleidomastoid muscle by the sternocleidomastoid branch of the occipital artery  

Directory of Open Access Journals (Sweden)

Full Text Available The contribution of the sternocleidomastoid branch of the occipital artery (superior arterial pedicle - SAP to the irrigation of the sternocleidomastoid muscle (SCM was evaluated in fresh human cadavers by injecting radiological dye and a resin for microvasculature corrosion casts. From its insertion in the mastoid process of the temporal bone, the SCM was divided into superior, medium, and inferior thirds. In most of the SCM, The SAP are formed by two longitudinal parallel branches. In all specimens, the radiological dye injected into the SAP reached or trespassed the middle part of the studied SCM. The SAP was poorly distributed in the lowermost region of the inferior third of the SCM, suggesting the contribution of other arteries or pedicles. The corrosion casts of the microvasculature showed a profuse network of microscopic vessels in those levels where the SAP was detected.

Fróes Luis Bernardo

1999-01-01

90

Corrosion and protection of heterogeneous cast Al-Si (356) and Al-Si-Cu-Fe (380) alloys by chromate adn cerium inhibitors  

Science.gov (United States)

In this study, the localized corrosion and conversion coating on cast alloys 356 (Al-7.0Si-0.3Mg) and 380 (Al-8.5Si-3.5Cu-1.6Fe) were characterized. The intermetallic phases presence in the permanent mold cast alloy 356 are primary-Si, Al5FeSi, Al8Si6Mg3Fe and Mg2Si. The die cast alloy 380 is rich in Cu and Fe elements. These alloying elements result in formation of the intermetallic phases Al 5FeSi, Al2Cu and Al(FeCuCr) along with primary-Si. The Cu- and Fe-rich IMPS are cathodic with respect to the matrix phase and strongly govern the corrosion behavior of the two cast alloys in an aggressive environment due to formation of local electrochemical cell in their vicinity. Results have shown that corrosion behavior of permanent mould cast alloy 356 is significantly better than the die cast aluminum alloy 380, primarily due to high content of Cu- and Fe-rich phases such as Al2Cu and Al 5FeSi in the latter. The IMPS also alter the protection mechanism of the cast alloys in the presence of inhibitors in an environment. The presence of chromate in the solution results in reduced cathodic activity on all the phases. Chromate provides some anodic inhibition by increasing pitting potentials and altering corrosion potentials for the phases. Results have shown that performance of CCC was much better on 356 than on 380, primarily due to inhomogeneous and incomplete coating deposition on Cu- and Fe- phases present in alloy 380. XPS and Raman were used to characterize coating deposition on intermetallics. Results show evidence of cyanide complex formation on the intermetallic phases. The presence of this complex is speculated to locally suppress CCC formation. Formation and breakdown of cerium conversion coatings on 356 and 380 was also analyzed. Results showed that deposition of cerium hydroxide started with heavy precipitation on intermetallic particles with the coatings growing outwards onto the matrix. Electrochemical analysis of synthesized intermetallics compounds in the presence of soluble cerium cations showed that of anodic and cathodic activity was not as strongly inhibited as was observed for chromate ions. Overall cerium conversion coating showed good performance on Al-Si (356) ally, but poor performance on Fe- and Cu-rich alloy (380).

Jain, Syadwad

91

Radiographic aspects and angioarchitectural arrangements in corrosion casts of the blood supply to the human sternocleidomastoid muscle by the sternocleidomastoid branch of the occipital artery / Aspectos radiográficos e da microvasculatura do músculo esternocleidomastóideo pelo pelo ramo da artéria occipital  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese A contribuição do ramo esternocleidomastóideo da artéria occipital para a irrigação do músculo esternocleidomastóideo foi avaliada em cadáveres humanos não fixados, através da injeção de contraste radiográfico e de resina polimerizável para estudo da microvasculatura. O músculo foi dividido nos terç [...] os superior, médio e inferior, a partir da sua inserção no processo mastóideo do osso temporal. Na maioria dos músculos, o pedículo superior apresentou-se formado por dois ramos paralelos longitudinais. Em todos os casos, o contraste radiográfico atingiu ou ultrapassou a parte média do músculo. Na parte mais distal do terço inferior, há pouca ou nenhuma contribuição do pedículo superior para a irrigação dessa região muscular sugerindo a contribuição de outros vasos para a sua irrigação. Os modelos de corrosão demonstraram a presença de uma profusa rede vascular no interior do músculo. Abstract in english The contribution of the sternocleidomastoid branch of the occipital artery (superior arterial pedicle - SAP) to the irrigation of the sternocleidomastoid muscle (SCM) was evaluated in fresh human cadavers by injecting radiological dye and a resin for microvasculature corrosion casts. From its insert [...] ion in the mastoid process of the temporal bone, the SCM was divided into superior, medium, and inferior thirds. In most of the SCM, The SAP are formed by two longitudinal parallel branches. In all specimens, the radiological dye injected into the SAP reached or trespassed the middle part of the studied SCM. The SAP was poorly distributed in the lowermost region of the inferior third of the SCM, suggesting the contribution of other arteries or pedicles. The corrosion casts of the microvasculature showed a profuse network of microscopic vessels in those levels where the SAP was detected.

Luis Bernardo, Fróes; Erasmo Magalhães Castro de, Tolosa; Roberto de Souza, Camargo; Eduardo, Pompeu; Edson Aparecido, Liberti.

92

Dominância coronariana em corações humanos em moldes por corrosão Coronary dominance patterns in the human heart investigated by corrosion casting  

Directory of Open Access Journals (Sweden)

Full Text Available OBJETIVO: Esse trabalho tem como objetivo analisar os padrões de dominância circulatória de corações humanos, o número de ramos que a artéria coronária direita fornece ao ventrículo esquerdo, o número de ramos que a artéria coronária esquerda fornece ao direito e a presença de anastomoses intercoronarianas, com sua localização e frequência. MÉTODOS: Foram produzidos 25 moldes de corações submetidos à instilação de acrílico colorido e posterior corrosão com ácido clorídrico, no Laboratório de Cirurgia Experimental da FURB. Peças com lesões e cicatrizes não foram usadas. RESULTADOS: Os corações pertenciam a indivíduos de ambos os sexos, sendo 17 (68% de indivíduos do sexo masculino, com idade média de 40,2 anos (15 a 70 anos. A dominância direita ocorreu em 18 (72% peças, com 1, 2, 3 e 4 ramos em 2, 14, 2 e 1 moldes, respectivamente; a dominância esquerda foi observada em 5 (20% casos, com 1 ramo em 4 moldes e 2 em 1 molde; e a dominância balanceada foi verificada em 2 (8% moldes. Houve diferença significativa entre a dominância direita e esquerda (? > 5%, direita e balanceada (? > 5% e sem significância entre esquerda e balanceada (? OBJECTIVES: The aim of this work was to analyze the dominance patterns of the circulation of the human heart, the number of branches from the right coronary artery to the left ventricle, the number of branches from the left coronary artery to the right ventricle and the frequency and location of intercoronary anastomoses. METHODS: Casts were made of 25 hearts by the injection of colored acrylic resin and subsequent corrosion using hydrochloric acid at the experimental surgery laboratory of Furb. Specimens with lesions or scars were discarded. RESULTS: The hearts, from both men (17 - 68% and women (8 - 32%, had a mean age of 40.2 (15 to 70 years-old. Right dominance occurred in 18 (72% subjects, with 1, 2, 3 and 4 branches leading to the left ventricle in 2, 14, 2 and 2 casts, respectively. Left dominance occurred in 5 (20% with 1 branch leading to the right ventricle in 4 molds and 2 in one. Balanced circulation was observed in two molds (8%. There were significant differences between right and left dominance (? > 5% and between right dominance and balanced circulation (? > 5%, however the same was not true between left dominance and balanced circulation (? < 5%. CONCLUSION: The most common form of coronary circulation is right dominance with an average of 2.16 branches leading to the left ventricle: when dominance is left, the average is 1.2 branches. No intercoronary anastomoses were observed.

Décio Cavalet Soares Abuchaim

2009-12-01

93

The role of aluminum distribution on the local corrosion resistance of the microstructure in a sand-cast AM50 alloy  

International Nuclear Information System (INIS)

Highlights: •Site-specific analytical electron microscopy was performed on corroded AM50. •Areas close to eutectic microstructure show less corrosion damage. •Eutectic Mg grains develop an Al-rich layer between the alloy and corrosion product. •We demonstrate, using low-loss EELS, that the Al-rich layer is metallic in character. •Primary ?-Mg grains, with lower Al content, do not develop the Al-rich layer and corrode severely. -- Abstract: Site-specific analytical electron microscopy was performed on a corroded sand-cast AM50 alloy. Areas close to partially divorced eutectic were the regions with less corrosion damage. The corrosion product layer in these areas consisted of a columnar section of predominantly amorphous MgO. At the alloy interface, an aluminum-rich layer was identified. Electron energy-loss spectroscopy suggests this layer is metallic in character. The corrosion product film on the primary ?-Mg grains possessed a bi-layer morphology: a thin columnar film and a thicker, porous sub-layer. The formation of the Al-rich layer depends on the Al content in solid solution at a specific location

2013-12-01

94

Effect of Heat Treatments on the Microstructure, Hardness and Corrosion Behavior of Nondendritic AlSi9Cu3(Fe Cast Alloy  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper we studied the influence of heat treatments on properties of AlSi9Cu3(Fe nondendritic cast alloy. Solution heat treatment, six hours at 520 °C, while making the grains more spherical modifies corrosion morphology into intergranular corrosion and corrosion surrounding spherical particles in 3 % NaCl solution. Past solution treatment, quenching at 520 °C after one hour with two weeks of natural aging transform the shape of grains into equiaxes form. Two weeks of natural aging and 30 minutes of aging at 150, 200, 250 °C after solution treatment and quenching give birth to the "Chinese script" form of the Al15(MnFe3Si intermetallic particles. The prolongation of the duration period of aging to one hour at 200 °C is sufficient to transform the morphology of corrosion into located corrosion by pitting, and a longer aging cancels the "Chinese script" form. DOI: http://dx.doi.org/10.5755/j01.ms.19.3.1397

Nacer ZAZI

2013-09-01

95

Mechanical and corrosion behaviour of as-cast and annealed Zr60Cu20Al10Fe5Ti5 bulk metallic glass  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The influence of thermally-induced structural relaxation and crystallization on the mechanical and electrochemical corrosion behaviour of a Zr60Cu20Al10Fe5Ti5 metallic glass has been studied. The hardness, H, and reduced Young's modulus, E-r, increase upon annealing at 648 K (i.e., close to the glass transition) from H = 6.7 GPa and E-r = 79.4 GPa (as-cast state) to H = 7.0 and E-r = 86.7 GPa (structurally relaxed state). The influence of the free volume annihilation, caused by the annea...

Gonzalez, S.; Pellicer, E.; Surinach, S.; Baro, M. D.; Sort, J.

2012-01-01

96

Physics-Based Stress Corrosion Cracking Component Reliability Model cast in an R7-Compatible Cumulative Damage Framework  

International Nuclear Information System (INIS)

This is a working report drafted under the Risk-Informed Safety Margin Characterization pathway of the Light Water Reactor Sustainability Program, describing statistical models of passives component reliabilities. The Risk-Informed Safety Margin Characterization (RISMC) pathway is a set of activities defined under the U.S. Department of Energy Light Water Reactor Sustainability Program. The overarching objective of RISMC is to support plant life-extension decision-making by providing a state-of-knowledge characterization of safety margins in key systems, structures, and components (SSCs). The methodology emerging from the RISMC pathway is not a conventional probabilistic risk assessment (PRA)-based one; rather, it relies on a reactor systems simulation framework in which physical conditions of normal reactor operations, as well as accident environments, are explicitly modeled subject to uncertainty characterization. RELAP 7 (R7) is the platform being developed at Idaho National Laboratory to model these physical conditions. Adverse effects of aging systems could be particularly significant in those SSCs for which management options are limited; that is, components for which replacement, refurbishment, or other means of rejuvenation are least practical. These include various passive SSCs, such as piping components. Pacific Northwest National Laboratory is developing passive component reliability models intended to be compatible with the R7 framework. In the R7 paradigm, component reliability must be characterized in the context of the physical environments that R7 predicts. So, while conventional reliability models are parametric, relying on the statistical analysis of service data, RISMC reliability models must be physics-based and driven by the physical boundary conditions that R7 provides, thus allowing full integration of passives into the R7 multi-physics environment. The model must also be cast in a form compatible with the cumulative damage framework that R7 is being designed to incorporate. Primary water stress corrosion cracking (SCC) of reactor coolant system Alloy 82/182 dissimilar metal welds has been selected as the initial application for examining the feasibility of R7-compatible physics-based cumulative damage models. This is a potentially risk-significant degradation mechanism in Class 1 piping because of its relevance to loss of coolant accidents. In this report a physics-based multi-state model is defined (Figure ES-1), which describes progressive degradations of dissimilar metal welds from micro-crack initiation to component rupture, while accounting for the possibility of interventions and repair. The cumulative damage representation of the multi-state model and its solutions are described, along with the conceptual means of integration into the R7 environment.

2011-01-01

97

A galvanic corrosion study of brass/stainless steel and brass/cast iron couples; Estudio de corrosion galvanica en pares laton/acero inoxidable y laton/fundicion de hierro  

Energy Technology Data Exchange (ETDEWEB)

Corrosion attack in heat exchanger systems is a topic of main interest for the maintenance in each industrial plant. These are multi galvanic systems with particular geometric and fluidodynamic complexity. Corrosive damages include zinc selective dealeation in copper alloys. In order to explain zinc dealeation attack, this paper deals with laboratory scale testing, characterization and interactions between two copper and zinc alloys (Yellow brass UNS C268 and Admiralty brass UNS C443) compared to AISI 316 stainless steel and cast iron. The tests were performed at 20 degree centigrade in 1.5 % NaCl and 1.5 % Na{sub 2}SO{sub 4} solutions, pH 8 and each material was characterized by potentiodynamic sweeps. The couples are analyzed by studying transient galvanic currents. We conclude about the cause of the analyzed pathology, brass protection potential ranges and its coupling compatibility with other metals. (Author) 33 refs.

Ohanian, M.; Diaz, V.; Corengia, M.; Zinola, C. F.

2011-07-01

98

Determination of Testicular Blood Flow in Camelids Using Vascular Casting and Color Pulsed-Wave Doppler Ultrasonography  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We describe the vasculature of the camelid testis using plastic casting. We also use color pulsed-wave Doppler ultrasonography to measure testicular blood flow and compare the differences between testicular blood flow in fertile and infertile camelids. The testicular artery originates from the ventral surface of the aorta, gives rise to an epididymal branch, and becomes very tortuous as it approaches the testis. Within the supratesticular arteries, peak systolic velocity (PSV) was higher in f...

2011-01-01

99

Corrosion  

International Nuclear Information System (INIS)

The corrosion behavior of materials in melts with different anions are considered. Topics presented include iron- and nickel-based alloys, flouride melts, nitrate and nitride melts, hydroxide melts, carbonate melts, and sulfate melts

1982-01-01

100

Effect of heat treatment on the wear and corrosion behaviors of a gray cast iron coated with a COLMONOY 88 alloy deposited by high velocity oxygen fuel (HVOF thermal spray  

Directory of Open Access Journals (Sweden)

Full Text Available The present work has been conducted in order to determine the influence of heat treatment on the wear and corrosion behaviours of a gray cast iron substrate coated with a Ni base coating deposited by HVOF thermal spray. The wear resistance of the coatings was obtained using a reciprocating wear tester by rubbing a 10 mm diameter steel ball on the coatings at normal atmospheric conditions. Corrosion tests were performed using potentiodynamic polarization measurements in a 3,5 % NaCl solution. It was observed that the corrosion and wear resistance of the coatings increased along with the reduction of porosity and roughness by the heat treatment.

A. Öz

2013-07-01

 
 
 
 
101

Stress corrosion cracking of gas-tungsten arc welds in continuous-cast AZ31 Mg alloy sheet  

International Nuclear Information System (INIS)

AZ31 Mg alloy sheet was welded using a gas-tungsten arc (GTA) process over inserts containing 2.3-9.3 wt.% Al. The welded specimens were susceptible to SCC in distilled water, with susceptibility increasing with decreasing weld metal Al (or ? particle) concentration. Primary stress corrosion cracks initiated at the weld metal-HAZ interface by stress-assisted localised dissolution and propagated through the weld and base metals by transgranular and intergranular H-assisted fracture (TG-HAF and IG-HAF) respectively. The IG fracture mode may be intrinsic to the texture imparted upon the base metal by rolling. The increase in SCC susceptibility with decreasing weld metal Al concentration is contrary to the purported roles of ? particles in promoting localised corrosion and as crack nucleation sites, but corresponds with increases in weld - base metal galvanic current density and weld metal localised corrosion susceptibility.

2009-09-01

102

Erosion-corrosion and surface protection of A356 Al/ZrO{sub 2} composites produced by vortex and squeeze casting  

Energy Technology Data Exchange (ETDEWEB)

Erosive-corrosive wear behavior of Al-Si-Mg (A356 Al) alloy and its composite reinforced by ZrO{sub 2} and produced by vortex and squeeze techniques has been studied in water containing 40% sand slurry. The worn surfaces of investigated alloys have been studied and the mechanism of material removal from the specimen surface was examined to be associated with number of subsequent and repetitive stages. The possibility of Ni coating for Al composites by electrochemical deposition is investigated. The surface layer was characterized by microhardness measurements, optical microscope, scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) analysis. The electrochemical results obtained from polarization studies for Ni-coated, A356 Al alloy and composites in 3.5% sodium chloride solution indicated higher protection exhibited by Ni coatings due to the nickel properties. The squeezed cast composite is characterized by high corrosion and wear resistance comparing the composite produced by vortex process. This study revealed that the Ni-coated materials provide higher abrasive resistance and therefore a longer service life compared to A356 Al-ZrO{sub 2}.

El-Khair, M.T. Abou [Central Metallurgical Research and Development Institute, CMRDI, P.O. 87 Hellwan, Cairo (Egypt); Aal, A. Abdel [Central Metallurgical Research and Development Institute, CMRDI, P.O. 87 Hellwan, Cairo (Egypt)], E-mail: foralsayed@yahoo.com

2007-04-25

103

Erosion-corrosion and surface protection of A356 Al/ZrO2 composites produced by vortex and squeeze casting  

International Nuclear Information System (INIS)

Erosive-corrosive wear behavior of Al-Si-Mg (A356 Al) alloy and its composite reinforced by ZrO2 and produced by vortex and squeeze techniques has been studied in water containing 40% sand slurry. The worn surfaces of investigated alloys have been studied and the mechanism of material removal from the specimen surface was examined to be associated with number of subsequent and repetitive stages. The possibility of Ni coating for Al composites by electrochemical deposition is investigated. The surface layer was characterized by microhardness measurements, optical microscope, scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) analysis. The electrochemical results obtained from polarization studies for Ni-coated, A356 Al alloy and composites in 3.5% sodium chloride solution indicated higher protection exhibited by Ni coatings due to the nickel properties. The squeezed cast composite is characterized by high corrosion and wear resistance comparing the composite produced by vortex process. This study revealed that the Ni-coated materials provide higher abrasive resistance and therefore a longer service life compared to A356 Al-ZrO2

2007-04-25

104

Effect of ferrite on cast stainless steels  

Energy Technology Data Exchange (ETDEWEB)

Premature failure of stainless steel castings in bleach washing service is attributed to poor casting quality high porosity and to a high ferrite content, which makes the castings susceptible to corrosion by hot acid chloride solutions. A survey of the chemical compositions and ferrite contents of corrosion-resistant castings in bleach plants at three pulp mills found high [delta]-ferrite levels in the austenitic matrix due to the improper balance between austenite and ferrite stabilizers.

Nadezhdin, A.; Cooper, K. (Noranda Technology Centre, Pointe Claire, Quebec (Canada)); Timbers, G. (James Maclaren Inc., Quebec (Canada). Kraft Pulp Division)

1994-09-01

105

Effect of sulfate on the transformation of corrosion scale composition and bacterial community in cast iron water distribution pipes  

Science.gov (United States)

The stability of iron corrosion products and the bacterial composition of biofilm in drinking water distribution systems (DWDS) could have great impact on the water safety at the consumer ends. In this work, pipe loops were setup to investigate the transformation characteristics ...

106

Heat and corrosion resistant cast CN-12 type stainless steel with improved high temperature strength and ductility  

Science.gov (United States)

A cast stainless steel alloy and articles formed therefrom containing about 0.5 wt. % to about 10 wt. % manganese, 0.02 wt. % to 0.50 wt. % N, and less than 0.15 wt. % sulfur provides high temperature strength both in the matrix and at the grain boundaries without reducing ductility due to cracking along boundaries with continuous or nearly-continuous carbides. Alloys of the present invention also have increased nitrogen solubility thereby enhancing strength at all temperatures because nitride precipitates or nitrogen porosity during casting are not observed. The solubility of nitrogen is dramatically enhanced by the presence of manganese, which also retains or improves the solubility of carbon thereby providing additional solid solution strengthening due to the presence of manganese and nitrogen, and combined carbon. Such solution strengthening enhances the high temperature precipitation-strengthening benefits of fine dispersions of NbC. Such solid solution effects also enhance the stability of the austenite matrix from resistance to excess sigma phase or chrome carbide formation at higher service temperatures. The presence of sulfides is substantially eliminated.

Mazias, Philip J. (Oak Ridge, TN); McGreevy, Tim (Morton, IL); Pollard,Michael James (East Peoria, IL); Siebenaler, Chad W. (Peoria, IL); Swindeman, Robert W. (Oak Ridge, TN)

2007-08-14

107

Influence of thermal aging on primary water stress corrosion cracking of cast duplex stainless steel (second report). Consideration on fractography after slow strain rate technique  

International Nuclear Information System (INIS)

In order to evaluate the stress corrosion cracking (SCC) susceptibility of cast duplex stainless steel which is used for the main coolant pipe of pressurized water reactors (PWRs), the slow strain rate technique (SSRT) and the constant load test (CLT) of the materials were performed in simulated primary water at 360degC. The cast duplex stainless steel contains ferrite phase with ranging from 8 to 23% and its mechanical properties are affected by long time thermal aging. Therefore, we paid attention to the influence of its ferrite content and thermal aging on the SCC susceptibility of this unaged and aged stainless steel and prepared three kinds of specimen with different ferrite contents (23%, 15% and 8%). The brittle fracture of the unaged specimens after SSRT mainly consists of quasi-cleavage fracture in austenitic phase. After aging, it changes to a mixture of quasi-cleavage fracture in both austenitic and ferritic phases. Microcracks were observed on the unaged specimen surfaces and aged ones for 10,000 hours at 400degC after about 10,000 hours of the CLT under the load condition of 1.2?2.0 times of yield strength. The crack initiation sites of CLT specimens are similar to SSRT fracture surfaces. The SCC susceptibility of this 23% ferrite material increases with aging time at 400degC. The SCC susceptibility of 15% and 23% ferrite materials are higher than that of 8% ferrite material with aging condition for 30,000h at 400degC. (author)

2003-10-01

108

Corrosion  

International Nuclear Information System (INIS)

A corrosion resistant nuclear fuel element. It comprises: an elongated cladding container formed from a zirconium alloy tube consisting essentially of by weight percent 0.5 to 2.0 percent tin, 0.24 to 0.40 percent of a solute composed of copper, nickel and iron, and the balance zirconium; and a central core of a body of nuclear fuel material selected from the group consisting of compounds of uranium, plutonium, thorium and mixtures thereof disposed in an d partially filling the container so as to leave a gap between the container and the core and an internal cavity at one end of the container an enclosure integrally secured and sealed at each end of the container and a nuclear fuel material retaining means positioned in the cavity

1989-05-25

109

Heat and corrosion resistant cast CF8C stainless steel with improved high temperature strength and ductility  

Science.gov (United States)

A CF8C type stainless steel alloy and articles formed therefrom containing about 18.0 weight percent to about 22.0 weight percent chromium and 11.0 weight percent to about 14.0 weight percent nickel; from about 0.05 weight percent to about 0.15 weight percent carbon; from about 2.0 weight percent to about 10.0 weight percent manganese; and from about 0.3 weight percent to about 1.5 weight percent niobium. The present alloys further include less than 0.15 weight percent sulfur which provides high temperature strength both in the matrix and at the grain boundaries without reducing ductility due to cracking along boundaries with continuous or nearly-continuous carbides. The disclosed alloys also have increased nitrogen solubility thereby enhancing strength at all temperatures because nitride precipitates or nitrogen porosity during casting are not observed. The solubility of nitrogen is dramatically enhanced by the presence of manganese, which also retains or improves the solubility of carbon thereby providing additional solid solution strengthening due to the presence of manganese and nitrogen, and combined carbon.

Maziasz, Philip J. (Oak Ridge, TN); McGreevy, Tim (Washington, IL); Pollard, Michael James (Peoria, IL); Siebenaler, Chad W. (Dunlap, IL); Swindeman, Robert W. (Oak Ridge, TN)

2010-08-17

110

Bimetallic layered castings alloy steel – grey cast iron  

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Full Text Available Purpose: In paper is presented technology of bimetallic layered castings based on founding method of layer coating directly in cast process so-called method of mould cavity preparation.Design/methodology/approach: Prepared bimetallic layered castings consist two fundamental parts i.e. bearing part and working part (layer. The bearing part of bimetallic layered casting is typical foundry material i.e. pearlitic grey cast iron, whereas working part (layer is depending on accepted variant plates of alloy steels sort X6Cr13, X12Cr13, X10CrNi18-8 and X2CrNiMoN22-5-3. The ratio of thickness between bearing and working part is 8:1. The verification of the bimetallic layered castings was evaluated on the basis of ultrasonic NDT (non-destructive testing, structure and macro- and microhardness researches. Moreover was made computer simulation of solidification of bimetallic layered casting in NovaFlow&Solid software.Findings: The results of studies and their analysis show efficiency of new, innovative technology of corrosion and heat resisting layered castings.Research limitations: In further research, authors of this paper are going to application of different material on bearing part of bimetallic layered casting.Practical implications: Prepared bimetallic layered castings according to work out technology can work in conditions, which require from working surface layer of element a high heat resistance and/or corrosion resistance in medium for example of industrial water.Originality/value: The value of this paper resides in new effective method of manufacture of heat resisting castings, mainly for lining of quenching car to coke production

T. Wróbel

2011-04-01

111

49 CFR 192.487 - Remedial measures: Distribution lines other than cast iron or ductile iron lines.  

Science.gov (United States)

...measures: Distribution lines other than cast iron or ductile iron lines. 192.487...measures: Distribution lines other than cast iron or ductile iron lines. (a) General corrosion. Except for cast iron or ductile iron pipe,...

2009-10-01

112

49 CFR 192.487 - Remedial measures: Distribution lines other than cast iron or ductile iron lines.  

Science.gov (United States)

...measures: Distribution lines other than cast iron or ductile iron lines. 192.487...measures: Distribution lines other than cast iron or ductile iron lines. (a) General corrosion. Except for cast iron or ductile iron pipe,...

2012-10-01

113

Improvement of corrosion resistance in NaOH solution and glass forming ability of as-cast Mg-based bulk metallic glasses by microalloying  

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Full Text Available The influences of the addition of Ag on the glass forming ability (GFA and corrosion behavior were investigated in the Mg-Ni-based alloy system by X-ray diffraction (XRD and electrochemical polarization in 0.1 mol/L NaOH solution. Results shows that the GFA of the Mg-Ni-based BMGs can be improved dramatically by the addition of an appropriate amount of Ag; and the addition element Ag can improve the corrosion resistance of Mg-Ni-based bulk metallic glass. The large difference in atomic size and large negative mixing enthalpy in alloy system can contribute to the high GFA. The addition element Ag improves the forming speed and the stability of the passive film, which is helpful to decrease the passivation current density and to improve the corrosion resistance of Mg-Ni-based bulk metallic glass.

Peng Hao

2011-02-01

114

Influence of hydronium, sulfate, chloride and other non-carbonate ions on hydrogen generation by anaerobic corrosion of granular cast iron.  

Science.gov (United States)

Permeable reactive barriers are successfully applied for the removal of various contaminants. The concomitant reduction of hydrogen ions and the subsequent formation of hydrogen gas by anaerobic corrosion lead to decreased pore volume filled with water and thus residence times, so called gas clogging. Long term column experiments were conducted to elucidate the impact of ubiquitous water constituents on the formation of hydrogen gas and potential passivation due to corrosion products. The collected gas volumes revealed a relation to the hydronium concentration (pH) but were only slightly increased in the presence of chloride and sulfate and not significantly influenced in the presence of phosphate, silicate, humic acid and ammonium compared to deionized water. Significant gas volumes within the reactive filling were verified by gravimetry. The presence of nitrate completely eliminated hydrogen formation by competition for electrons. Solid phase analyses revealed that neither chloride nor sulfate was incorporated in corrosion products in concentrations above 0.1 weight percent, and they did not alter the formation of mainly magnetite in comparison to deionized water. PMID:23954066

Ruhl, Aki S; Jekel, Martin

2013-10-15

115

Influence of reinforcement grade and matrix composition on corrosion resistance of cast aluminium matrix composites (A3xx.x/SiCp) in a humid environment  

Energy Technology Data Exchange (ETDEWEB)

A study of the influence of the silicon carbide (SiC{sub p}) proportion and the matrix concentration of four aluminium metal matrix composites (A360/SiC/10p, A360/SiC/20p, A380/SiC/10p, A380/SiC/20p) exposed to high relative humid environment was carried out under simulation in a climatic chamber. The matrix of A360/SiC/xxp composites was virtually free of copper while the A380/SiC/xxp matrix contained 3.13-3.45wt% Cu and 1.39-1.44wt% Ni. The kinetics of the corrosion process was studied on the basis of gravimetric tests. The nature of corrosion products was analysed by Scanning Electron Microscopy (SEM) and Low Angle X-Ray Diffraction (XRD) before and after accelerated testing to determine the influence of microstructural changes on corrosion behaviour during exposure to the corrosive environment. The corrosion damage to Al/SiCp composites was low at 80% Relative Humidity (RH) and increased with temperature, SiCp proportion, relative humidity and Cu matrix concentration. The main attack nucleation sites were the interface region between the matrix and the reinforcement particles. The corrosion process was influenced more by the concentration of alloy elements in the matrix than by the proportion of SiCp reinforcement. (Abstract Copyright [2003], Wiley Periodicals, Inc.) [German] Eine Studie zum Einfluss des Siliziumkarbidanteils (SiCp) und der Zusammensetzung des Grundwerkstoffs von vier Aluminiummatrixverbundwerkstoffen (A360/SiC/10p, A360/SiC/20p, A380/SiC/10p, A380/SiC/20p), die in Umgebungen mit relativ hoher Feuchtigkeit ausgelagert waren, wurde unter simulierten Bedingungen in einer Klimakammer durchgefuehrt. Die Matrix des A360/SiC/xxp-Verbundwerkstoffs war praktisch Kupfer-frei waehrend die A380/SiC/xxp Matrix 3,13-3,45 Gew.-% Cu und 1,39-1,44 Gew.-% Ni enthielt. Die Kinetik des Korrosionsprozesses wurde auf der Basis von gravimetrischen Messungen studiert. Die Beschaffenheit der Korrosionsprodukte wurde mittelt REM-Untersuchungen und Kleinwinkelroentgendiffraktometrie (XRD) vor und nach der beschleunigten Pruefung analysiert, um den Einfluss der Gefuegeveraenderungen auf das Korrosionsverhalten waehrend der Auslagerung in der korrosiven Umgebung zu bestimmen. Der Korrosionsschaden an den Al/SiCp-Verbundwerkstoffen war niedrig bei 80% relativer Feuchte und nahm mit der Temperatur, dem SiCp-Anteil, der relativen Feuchte und der Kupferkonzentration der Matrix zu. Die Hauptkeimbildungsbereiche fuer den Angriff befanden sich an der Grenzflaeche zwischen der Matrix und den Verstaerkungspartikeln. Der Korrosionsprozess wurde mehr durch die Konzentration der Legierungselemente in der Matrix als durch den Anteil der SiCp-Verstaerkung beeinflusst. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

Pardo, A.; Viejo, F.; Carboneras, M. [Departamento de Ciencia de Materiales, Facultad de Quimica Universidad Complutense, 28040, Madrid (Spain); Merino, M.C. [Departamento de Ciencia de Materiales, Facultad de Quimica Universidad Complutense, 28040, Madrid (Spain); Departamento de Tecnologia Industrial, Universidad Alfonso X El Sabio, 28691, Villanueva de la Canada, Madrid (Spain); Lopez, M.D. [Escuela Superior de Ciencias Experimentales y Tecnologia, Universidad Rey Juan Carlos, 28931, Mostoles, Madrid (Spain); Merino, S. [Departamento de Tecnologia Industrial, Universidad Alfonso X El Sabio, 28691, Villanueva de la Canada, Madrid (Spain)

2003-05-01

116

Anodization of cast aluminium alloys produced by different casting methods  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper the usability of two casting methods, of sand and high pressure cast for the anodization of AlSi12 and AlSi9Cu3 aluminium cast alloys was investigated. With defined anodization parameters like electrolyte composition and temperature, current type and value a anodic alumina surface layer was produced. The quality, size and properties of the anodic layer was investigated after the anodization of the chosen aluminium cast alloys. The Alumina layer was observed used light microscope, also the mechanical properties were measured as well the abrasive wear test was made with using ABR-8251 equipment. The researches included analyze of the influence of chemical composition, geometry and roughness of anodic layer obtained on aluminum casts. Conducted investigations shows the areas of later researches, especially in the direction of the possible, next optimization anodization process of aluminum casting alloys, for example in the range of raising resistance on corrosion to achieve a suitable anodic surface layer on elements for increasing applications in the aggressive environment for example as materials on working building constructions, elements in electronics and construction parts in air and automotive industry.

K. Labisz

2008-08-01

117

Salt Bath Oxinitriding of Gray Cast Iron  

Science.gov (United States)

Salt bath oxinitriding is a duplex surface treatment developed to improve tribological and corrosion properties of ferrous materials. In this research, gray cast iron samples were nitrided at the temperature range of 480°C-580°C, and then oxidized in an oxidative salt bath. The phase composition of surface layer was identified by X-ray diffraction. Using a microhardness tester, hardness of nitrided gray cast iron was measured. Corrosion behavior of treated (nitrided and oxinitrided) samples was evaluated using potentiodynamic polarization technique in 3.5% NaCl solution. XRD analyses indicate that the surface layer in nitrided and oxinitrided samples is composed of ?-iron nitride (Fe2-3N) and magnetite (Fe3O4), respectively. Results show that the corrosion resistance of gray cast iron can be improved up to 170%.

Ahmadi, M.; Teimouri, M.; Aliofkhazraee, M.; Mousavi Khoee, S. M.

118

Selected properties of new „duplex” cast steel  

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Full Text Available In this paper selected properties of new „duplex” cast steel are presented. The new cast steel was devised in HYDRO-VACUUM company in Grudzi?dz, where “duplex” cast steel for pump elements is smelted. The goal was to devise a new grade of “duplex” cast steel of better physicochemical properties and cheaper than now applied. It was demonstrated, that there is the possibility of devising the new grade of “duplex” cast steel. It is characterized by higher mechanical properties, similar wear resistance and greater corrosion resistance in 15% water solution of H2SO4 in comparison to now applied “duplex” cast steel. The chemical composition was selected to obtain in microstructure about of 50% ferrite and 50% austenite. It guarantee the highest properties and the lowest costs of its smelting.In the paper results of: the microstructure, Rm, Rp0,2, A5, HB, wear resistance and corrosion resistance in water solution of 15% HCl and H2SO4 acids of new cast steel was presented. They were compared with now applied in HYDRO-VACUUM company “duplex” cast steel.

S. Pietrowski

2011-10-01

119

Malformações vasculares Vascular malformations  

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Full Text Available Com o conhecimento cada vez maior da angiogênese, as anomalias vasculares foram divididas em tumores e malformações vasculares. As malformações vasculares, objeto deste trabalho, são categorizadas ou pela natureza dos canais vasculares (capilares, arteriais, venosos ou linfáticos, ou pelo tipo de fluxo (alto ou baixo, ou ainda pela distribuição (localizadas ou difusas. Além disso, há as malformações complexas combinadas, nas quais se encaixa a maioria das síndromes vasculares. Os autores apresentam uma revisão do asssunto, discorrendo sobre características clínicas, diagnóstico e tratamento dessas anomalias.As a result of increased knowledge on angiogenesis, vascular anomalies have been separated into tumors and vascular malformations. Vascular malformations, the subject of this review, are classified either by the nature of the vessels (capillary, arterial, venous or lymphatic, type of flow (high or low or even by distribution (localized or diffuse. Furthermore there are the complex-combined malformations, a feature present in most vascular syndromes. A review of the clinical aspects, diagnosis and treatment of vascular malformations is presented in this paper.

Bernardo Gontijo

2004-02-01

120

Electromagnetic casting  

Energy Technology Data Exchange (ETDEWEB)

Electromagnetic casting (EMC) is a technology that is used extensively in the aluminum industry to cast ingots with good surface finish for subsequent rolling into consumer product. The paper reviews briefly some investigations from the eighties wherein models for EMC were developed. Then more recent work is examined wherein more realistic 3D models have been developed, the traditional studies of electromagnetic and magnetohydrodynamic phenomena have been supplemented with research on heat transport, and the stability of the metal free surface has been examined. The paper concludes with three generalizations concerning modeling that may have wider applicability than EMC.

Evans, J.W.; Kageyama, R. [Univ. of California, Berkeley, CA (United States); Deepak [Motorola Corp., Phoenix, AZ (United States); Cook, D.P. [Reynolds Metals Co., Richmond, VA (United States); Prasso, D.C. [Intel Corp., Aloha, OR (United States); Nishioka, S. [NKK Corp., Kawasaki (Japan)

1995-12-31

 
 
 
 
121

A scanning electron-microscopic, stereo-pair study of methacrylate corrosion casts of the mouse palatal and molar periodontal microvasculature.  

Science.gov (United States)

Microvascular beds of the palate, gingiva and periodontal ligament had interconnected but distinct, regional patterns. The palatal vasculature reflected mucosal-crest morphology: crestal capillary vessels of the rugae anastomosed with sagitally-orientated rows of 8 microns capillary loops, and, in the inter-rugal troughs, these formed a flat plexus overlying collecting veins more than 100 microns in diameter. Maxillary and mandibular molar ligaments had similar microvascular patterns. The molar gingiva had a circular, outer capillary and inner venous system linked by radial anastomoses. The outer (7 microns) capillaries enclosed the three molars in a continuous horizontal loop coursing beneath the crestal epithelium; the inner (10-15 microns) venous vessels encircled each molar just below the epithelial attachment. Glomerulus-like vascular formations, with an arterial and venous stalk, were associated with the inner circular system and extended toward the crevicular epithelium. Axially aligned, post-capillary, periodontal-ligament vessels (21 microns) anastomosed with the inner circular system, forming different patterns in the occlusal, middle and apical thirds. The apical pattern comprised an enveloping plexus of anastomosing venous vessels supplied by arterio-venous shunts; similar shunts were present throughout the ligament. The microvascular bed of the mandibular inter-radicular ligament was characterized by the presence of a large venous ampulla measuring 60 by 200 microns. Some regions of the ligament microvasculature drained via the medullary vessels into 50 microns-diameter venules located interdentally deep to the molar apices. Volumetrically, the ligament microvascular bed was predominantly of post-capillary venules, and morphologically, a paired arterial and venous system was not demonstrated. PMID:3479097

Wong, R S; Sims, M R

1987-01-01

122

Nodular cast iron and casting monitoring  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper quality monitoring of nodular cast iron and casting made of it is presented. A control system of initial liquid cast iron to spheroidization, after spheroidization and inoculation with using of TDA method was shown. An application of an ultrasonic method to assessment of the graphite form and the metal matrix microstructure of castings was investigated.

S. Pietrowski

2008-10-01

123

Casting methods  

Energy Technology Data Exchange (ETDEWEB)

A casting device includes a covered crucible having a top opening and a bottom orifice, a lid covering the top opening, a stopper rod sealing the bottom orifice, and a reusable mold having at least one chamber, a top end of the chamber being open to and positioned below the bottom orifice and a vacuum tap into the chamber being below the top end of the chamber. A casting method includes charging a crucible with a solid material and covering the crucible, heating the crucible, melting the material, evacuating a chamber of a mold to less than 1 atm absolute through a vacuum tap into the chamber, draining the melted material into the evacuated chamber, solidifying the material in the chamber, and removing the solidified material from the chamber without damaging the chamber.

Marsden, Kenneth C.; Meyer, Mitchell K.; Grover, Blair K.; Fielding, Randall S.; Wolfensberger, Billy W.

2012-12-18

124

Examination of the corrosion and erosion resistance of metallic cast and wrought materials in stagnant and flowing, highly concentrated sulfuric acid. Final report. [X1 CrNi 25 20; X1 CrNiSi 18 15; X1 CrNiMoNb 28 4 2; NiCr 29 Fe (Nicrofer 6030)]. Untersuchungen zur Korrosions- und Erosionsbestaendigkeit metallischer Guss- und Knetwerkstoffe in ruhender und stroemender hochkonzentrierter Schwefelsaeure. Schlussbericht  

Energy Technology Data Exchange (ETDEWEB)

A number of stainless steels with different microstructures as well as nickel alloys with different alloy variations were subjected to a test loop using a 98,5 to 98,7% sulfuric acid from a sulfuric acid-cast iron plant. In addition, laboratory tests in stagnant sulfuric acid were carried out, some of which under electrochemical control. The temperature range was 100 - 200deg C. Materials with a high chromium content were not influenced by the flow velocity, whereas Si-alloyed austenitic stainless steel 1.4361 showed a better corrosion resistance with rising flow velocity at temperatures between 100 and 150deg C. The nickel alloy 2.4642 could be used without any risk up to 150deg C. The corrosion rates determined were distinctly below 0.1 mm/a. The addition of molybdenum to the nickel alloy increased the corrosion rate, whereas the admixture of tungsten reduced it. The austenitic stainless steel 1.4335 can likewise be regarded as virtually stable above 150deg C. The best corrosion behaviour over the whole temperature range, i.e. a corrosion rate of less than 0.01 mm/a, exhibited only the ferritic stainless steel 1.4575. The stainless cast steel 1.4136 Sonder proved to be a suitable pump material. Light microscopic and scanning electron microscopic examinations indicate a dependency of corrosion on the flow velocity. Signs of erosion corrosion combined with cavitation are particularly observed on materials with a distinct corrosion rate. (orig.) With 27 refs., 9 tabs., 33 figs.

Bruecken, V.; Wallis, E.

1990-11-14

125

The effect of recasting on corrosion of DUCINOX prosthetic alloy  

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Full Text Available The effect of recasting, up to two times, Ni-Cr (DUCINOX prosthetic alloy on its corrosion properties was carried out. The corrosion measurements were done in deoxygenated Fusayama Meyer artificial saliva solution at temperature of 37°C. In the study following electrochemical methods were used: measurement of free corrosion potential Ecor in open circuit, measurement of polarization resistance according to Stern-Geary's method and measurement of potentiodynamic characteristic in wide range of anodic polarization. In general, it can be stated that casting number weakly influence on corrosion properties of investigated alloy. At free corrosion potential there is no monotonic dependence of corrosion parameters versus casting number. However, at extreme anodic potentials monotonic changes of corrosion parameters with increasing casting number is observed. Obtained results and drawn conclusions are partially compatible with literature data.

L. Klimek

2009-07-01

126

Enrichment of Casting Surface in Founding Process  

Directory of Open Access Journals (Sweden)

Full Text Available A lot of cast steel and cast iron properties, also usable, depend on physical and chemical properties of surface layer, such as: hardness, corrosion resistance, abrasive wear resistance. The paper presents directly method of surface enrichment on casting in founding process. Layer in form of high-speed steel HS 18–0–1plate was placed on G25CrSiMnMoNi 4–4–4–2,5–4 cast steel hammer of crusher. To investigations it was used light microscopy and scanning electron microscope. Microanalysis of chemical microanalysis of chemical composition and hardness measurements of transient zone between cast steel and steel were made. Analysis of research result show that, exists possibility of increase in hardness and abrasive wear resistance by put on casting surface a tool steel or sintered carbides plates, which are from scrap after waste of turning tool or face milling cutter. Moreover, applied activated alloy is very useful in this method of casting surface enrichment directly in founding process.

J. Szajnar

2007-07-01

127

About some corrosion mechanisms of AZ91D magnesium alloy  

Energy Technology Data Exchange (ETDEWEB)

The present work is dedicated to a study of the corrosion resistance of AZ91D (91% Mg) alloy in wet environments. Three industrial alloys obtained by die-casting or sand casting were subjected to salt spray corrosion tests (ASTM-B117 standard) and immersion tests. Weight loss kinetic curves were measured. Surface analysis was performed by X-ray photoelectron diffraction (XPS). After corrosion the sand cast alloy presents a surface mainly enriched in hydroxides and carbonates while the die-cast alloy presents a surface enriched also in mixed Mg-Al oxides. The quantitative analysis of the rate Mg/Al shows an enrichment in aluminium for the die-cast alloys in comparison to the sand cast alloy.

Ballerini, Gaia [Dipartimento di Chimica, Polo Scientifico di Sesto Fiorentino, Universita di Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino, Fi (Italy)]. E-mail: gaajaba@yahoo.it; Bardi, Ugo [Dipartimento di Chimica, Polo Scientifico di Sesto Fiorentino, Universita di Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino, Fi (Italy); Bignucolo, Roberto [EBU Process Engineering, Progetti, Innovazione, Processo IVECO, Via Lungo Stura Lazio 49, 10156 Torino (Italy); Ceraolo, Giuseppe [EBU Process Engineering, Progetti, Innovazione, Processo IVECO, Via Lungo Stura Lazio 49, 10156 Torino (Italy)

2005-09-01

128

About some corrosion mechanisms of AZ91D magnesium alloy  

International Nuclear Information System (INIS)

The present work is dedicated to a study of the corrosion resistance of AZ91D (91% Mg) alloy in wet environments. Three industrial alloys obtained by die-casting or sand casting were subjected to salt spray corrosion tests (ASTM-B117 standard) and immersion tests. Weight loss kinetic curves were measured. Surface analysis was performed by X-ray photoelectron diffraction (XPS). After corrosion the sand cast alloy presents a surface mainly enriched in hydroxides and carbonates while the die-cast alloy presents a surface enriched also in mixed Mg-Al oxides. The quantitative analysis of the rate Mg/Al shows an enrichment in aluminium for the die-cast alloys in comparison to the sand cast alloy

2005-09-01

129

Special thermite cast irons  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The given paper deals with the problems of the synthesis of cast iron by metallothermy synthesis. On the basis of investigated method of calculations structures of charges have been arranged and cast iron has been synthesized further. Peculiarities metallothermic smelting were found, mechanical properties and structure of received cast iron were investigated and different technologies for cast iron receiving were worked out.

2008-01-01

130

Phase Transformation in Cast Superaustenitic Stainless Steels  

Energy Technology Data Exchange (ETDEWEB)

Superaustenitic stainless steels constitute a group of Fe-based alloys that are compositionally balanced to have a purely austenitic matrix and exhibit favorable pitting and crevice corrosion resistant properties and mechanical strength. However, intermetallic precipitates such as sigma and Laves can form during casting or exposure to high-temperature processing, which degrade the corrosion and mechanical properties of the material. The goal of this study was to accurately characterize the solid-solid phase transformations seen in cast superaustenitic stainless steels. Heat treatments were performed to understand the time and temperature ranges for intermetallic phase formations in alloys CN3MN and CK3MCuN. Microstructures were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy and wavelength dispersive spectroscopy (EDS, WDS). The equilibrium microstructures, composed primarily of sigma and Laves within purely austenitic matrices, showed slow transformation kinetics. Factors that determine the extent of transformation, including diffusion, nucleation, and growth, are discussed.

Nathaniel Steven Lee Phillips

2006-12-12

131

Final Report, Volume 1, Metallurgical Evaluation of Cast Duplex Stainless Steels and their Weldments  

Energy Technology Data Exchange (ETDEWEB)

Duplex stainless steels (DSS) are being specified for chloride containing environments due to their enhanced pitting and stress corrosion cracking resistance. They exhibit improved corrosion performance over the austenitic stainless steels. Duplex stainless steels also offer improved strength properties and are available in various wrought and cast forms. Selected grades of duplex stainless steel castings and their welds, in comparison with their wrought counterparts, were evaluated, regarding corrosion performance and mechanical properties and weldability. Multiple heats of cast duplex stainless steel were evaluated in the as-cast, solution annealed (SA) static cast and SA centrifugal cast conditions, while their wrought counterparts were characterized in the SA condition and in the form of as-rolled plate. Welding, including extensive assessment of autogenous welds and a preliminary study of composite welds (shielded metal arc weld (SMAW)), was performed. The evaluations included critical pitting temperature (CPT) testing, intergranular corrosion (IGC) testing, ASTM A923 (Methods A, B and C), Charpy impact testing, weldability testing (ASTM A494), ferrite measurement and microstructural evaluations. In the study, the corrosion performances of DSS castings were characterized and assessed, including the wrought counterparts for comparison. The evaluation filled the pore of lack of data for cast duplex stainless steels compared to wrought materials. A database of the pitting corrosion and IGC behavior of cast and wrought materials was generated for a greater depth of understanding for the behavior of cast duplex stainless steel. In addition, improved evaluation methods for DSS castings were developed according to ASTM A923, A262, G48 and A494. The study revealed that when properly heat treated according to the specification, (1) DSS castings have equal or better pitting and intergranular corrosion resistance than their wrought counterparts; (2) Welding reduces the pitting and intergranular corrosion resistance for both the wrought and cast duplex alloys; (3) Castings generally have better toughness than their wrought counterparts in the temperature range of �������¢����������������80���������������°C to +20���������������°C; (4) All shield metal arc (SMA) test welds in DSS castings, with recommended or over matching filler metal, indicate that welding is not a significant factor when considering DSS applications.

Wen, Songqing; Lundin, Carl, W.; Batten, Greg, W.

2005-09-30

132

Final Report, Volume 1, Metallurgical Evaluation of Cast Duplex Stainless Steels and their Weldments  

Energy Technology Data Exchange (ETDEWEB)

Duplex stainless steels (DSS) are being specified for chloride containing environments due to their enhanced pitting and stress corrosion cracking resistance. They exhibit improved corrosion performance over the austenitic stainless steels. Duplex stainless steels also offer improved strength properties and are available in various wrought and cast forms. Selected grades of duplex stainless steel castings and their welds, in comparison with their wrought counterparts, were evaluated, regarding corrosion performance and mechanical properties and weldability. Multiple heats of cast duplex stainless steel were evaluated in the as-cast, solution annealed (SA) static cast and SA centrifugal cast conditions, while their wrought counterparts were characterized in the SA condition and in the form of as-rolled plate. Welding, including extensive assessment of autogenous welds and a preliminary study of composite welds (shielded metal arc weld (SMAW)), was performed. The evaluations included critical pitting temperature (CPT) testing, intergranular corrosion (IGC) testing, ASTM A923 (Methods A, B and C), Charpy impact testing, weldability testing (ASTM A494), ferrite measurement and microstructural evaluations. In the study, the corrosion performances of DSS castings were characterized and assessed, including the wrought counterparts for comparison. The evaluation filled the pore of lack of data for cast duplex stainless steels compared to wrought materials. A database of the pitting corrosion and IGC behavior of cast and wrought materials was generated for a greater depth of understanding for the behavior of cast duplex stainless steel. In addition, improved evaluation methods for DSS castings were developed according to ASTM A923, A262, G48 and A494. The study revealed that when properly heat treated according to the specification, (1) DSS castings have equal or better pitting and intergranular corrosion resistance than their wrought counterparts; (2) Welding reduces the pitting and intergranular corrosion resistance for both the wrought and cast duplex alloys; (3) Castings generally have better toughness than their wrought counterparts in the temperature range of -80 C to +20 C; (4) All shield metal arc (SMA) test welds in DSS castings, with recommended or over matching filler metal, indicate that welding is not a significant factor when considering DSS applications.

Wen, Songqing; Lundin, Carl, W.; Batten, Greg, W.

2005-09-30

133

Streptococcus mutans attachment on a cast titanium surface  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study examined by means of scanning electron microscopy (SEM), the attachment of Streptococcus mutans and the corrosion of cast commercially pure titanium, used in dental dentures. The sample discs were cast in commercially pure titanium using the vacuum-pressure machine (Rematitan System). The surfaces of each metal were ground and polished with sandpaper (#300-4000) and alumina paste (0.3 µm). The roughness of the surface (Ra) was measured using the Surfcorder rugosimeter SE 1700. Fou...

Sicknan Soares da Rocha; Adilson César Abreu Bernardi; Antônio Carlos Pizzolitto; Gelson Luis Adabo; Elisabeth Loshchagin Pizzolitto

2009-01-01

134

Fatigue Assessment of Cast Components : Influence of Cast Defects  

Digital Repository Infrastructure Vision for European Research (DRIVER)

 This thesis is on the fatigue assessment of cast components with special attention to defects. The primary material in view is nodular cast iron, but also cast steel is considered. However, the fatigue behaviour is in principle valid for general use on other cast metals.The first two papers is about general cast material behaviour in fatigue loading. The materials considered are a high strength alloyed cast steel and a medium strength nodular cast iron. It is concluded that cast defects is ...

2008-01-01

135

Special thermite cast irons  

Directory of Open Access Journals (Sweden)

Full Text Available The given paper deals with the problems of the synthesis of cast iron by metallothermy synthesis. On the basis of investigated method of calculations structures of charges have been arranged and cast iron has been synthesized further. Peculiarities metallothermic smelting were found, mechanical properties and structure of received cast iron were investigated and different technologies for cast iron receiving were worked out.

Yu. Zhiguts

2008-07-01

136

Solidification of heavy castings  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Quality of the casting material is influenced by great numbers of material properties, metallurgical treatment, and particular solidification conditions too. In the case of solidification of heavy castings the properties and quality of the casting material are considerably changed in consequence of running segregation phenomena, worsen metal feeding conditions, and microporosity formation etc. It can even result in defaulting the required strengths and plasticity of the casting material. The ...

2011-01-01

137

Casting and Molding  

Science.gov (United States)

This activity was designed for blind learners, but all types of learners can explore the process used to cast and mold molten metal, glass, and plastics. Using gelatin, the learner will work with a variety of molds to create castings. When the shapes are unmolded, the learner can tactually explore the casts.

Blind, Perkins S.

2012-06-26

138

Corrosion cracking  

International Nuclear Information System (INIS)

This book presents the papers given at a conference on alloy corrosion cracking. Topics considered at the conference included the effect of niobium addition on intergranular stress corrosion cracking, corrosion-fatigue cracking in fossil-fueled-boilers, fracture toughness, fracture modes, hydrogen-induced thresholds, electrochemical and hydrogen permeation studies, the effect of seawater on fatigue crack propagation of wells for offshore structures, the corrosion fatigue of carbon steels in seawater, and stress corrosion cracking and the mechanical strength of alloy 600

1985-12-02

139

Corrosion '85  

International Nuclear Information System (INIS)

These proceedings collect papers on corrosion in energy technology. Topics include: corrosion of low-nickel weldments in coal gasification atmospheres, materials for fuel cells, corrosion of Cr steels, materials failures in sour gas service, hydrogen sulfide corrosion, steels in coal liquids, pipeline protection, mothballing in oil field producing facilities, corrosion resistance of nuclear waste containment vessels, optimization of a PWR decontamination process, and core debris from Three Mile Island

1985-03-25

140

High quality casting materials  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The paper briefly presents results of the new developed high quality cast materials.Design/methodology/approach: The following materials are: hypereutectoid cast steel with various microstructure modular graphite obtained in as-cast condition (raw state, ductile cast iron of bainite-martensitic carbides structure obtained in a raw state, aluminum bronzes and silumins with additives of: chromium, molybdenum, wolfram, vanadium.Findings: These alloys are characterized primarily by significant mechanical properties and high wear resistance. It was also discussed getting of layer products by combination of steel or cast iron using alphinated layer with silumin.Practical implications: The paper discusses the high quality cast alloy, layer products and presents the high quality casting materials in the point of view principles of materials selection.Originality/value: The above problem is shown in the background of “Rules of material selection” as well as a model of production system in company.

S. Pietrowski

2010-11-01

 
 
 
 
141

Exploitation of rare earth metals in cast steel production for power engineering  

Directory of Open Access Journals (Sweden)

Full Text Available The paper presents results of experiments carried out on industrial melts. There has been tested the REM influence on carbon properties (0.20%C as well as austenitic cast steel Cr-Ni 18/8+Ti type.It was found that REM cause an essential improvement of cast steels impact strength and in case of austenitic cast steel – also the corrosion resistance improvement in boiling 65%HNO3 (Huey test.

J. Kasi?ska

2008-12-01

142

Clinical pathology and retinal vascular structure in the Bardet-Biedl syndrome.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A comparative study of clinical pathology and retinal vascular structure is described as studied by vascular casting in an eye of a patient with the Bardet-Biedl syndrome. At the time of examination the eye had been almost blind for at least 4 years. The histopathological examination showed a largely uniform loss of the outer retinal layers. The gross pathological examination of the cast ocular fundus showed three distinct zones, an inner zone inside the temporal vascular arcades where retina...

Bek, T.; Rosenberg, T.

1995-01-01

143

Developing of chromium cast steel on sleeves of heavy machines  

Directory of Open Access Journals (Sweden)

Full Text Available The results of investigations of hardness, impact resistance, abrasive and corrosive wear of selected chromium cast steel with destination on sleeves of heavy machines were introduced in the article. First results of exploational investigations talked over on the end.

J. Kilarski

2010-10-01

144

High integrity automotive castings  

Energy Technology Data Exchange (ETDEWEB)

This paper described the High Integrity Magnesium Automotive Casting (HI-MAC) program, which was developed to ensure the widespread adoption of magnesium in structural castings. The program will encourage the use of low pressure permanent molds, squeeze casting, and electromagnetic pumping of magnesium into dies. The HI-MAC program is currently investigating new heat treatment methods, and is in the process of creating improved fluid flow and solidification modelling to produce high volume automotive components. In order to address key technology barriers, the program has been divided into 8 tasks: (1) squeeze casting process development; (2) low pressure casting technology; (3) thermal treatment; (4) microstructure control; (5) computer modelling and properties; (6) controlled molten metal transfer and filling; (7) emerging casting technologies; and (8) technology transfer throughout the automotive value chain. Technical challenges were outlined for each of the tasks. 1 ref., 3 tabs., 5 figs.

Weiss, D. [Eck Industries Inc., St. Manitowoc, WI (United States)

2007-07-01

145

Stereometry specification of anodisation surface of casting aluminium alloys  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The aim of the work is presents the influence of casting method and anodic treatment parameters on properties of an anodic layer formed on aluminum casting alloys.Design/methodology/approach: Investigations were carried out on the laser profile measurement gauge MicroProf from company FRT on two casting aluminum alloys which both were founding by pressure die casting and gravity casting.Findings: The researches included analyze of the influence of chemical composition, geometry and roughness of anodic layer obtained on aluminum casts.Research limitations/implications: Contributes to research on anodic layer for aluminum casting alloys.Practical implications: Conducted investigations lay out the areas of later researches, especially in the direction of the possible, next optimization anodization process of aluminum casting alloys, e.g. in the range of raising resistance on corrosion.Originality/value: The range of possible applications increases for example as materials on working building constructions, elements in electronics and construction parts in air and motorization industry in the aggressive environment.

J. Konieczny

2008-04-01

146

Die casting plutonium  

International Nuclear Information System (INIS)

A successful method of die casting plutonium is described. The method is an improvement over conventional pour-cast techniques in that the plutonium can be solidified more rapidly. One advantage of rapid solidification is that cast structures can be improved. Another advantage is that the plutonium has little time to react with its surroundings, so experimenters can choose from a larger selection of die construction materials

1977-01-01

147

New casting coatings  

International Nuclear Information System (INIS)

In this project the results of the researches about the influence of the four types of ceramic coatings of the evaporating patterns (on the basis of talc, mullite, zircon and cordierite) on the talc of the Lost Foam process and the castings quality are presented. For the valid evaluation of the results, some parallel examinations of the quality of castings obtained by casting in sand were carried out. (Original)

2003-09-24

148

Microbial Corrosion.  

Science.gov (United States)

The studies on microbial corrosion described in the report emphasize the mechanisms of anaerobic corrosion produced by sulfate-reducing bacteria, primarily those in the genus Desulfovibrio. As a pure culture of a marine strain of Desulfovibrio had been is...

W. P. Iverson J. Churney

1970-01-01

149

Multi-layers castings  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In paper is presented the possibility of making of multi-layers cast steel castings in result of connection of casting and welding coating technologies. First layer was composite surface layer on the basis of Fe-Cr-C alloy, which was put directly in founding process of cast carbon steel 200–450 with use of preparation of mould cavity method. Second layer were padding welds, which were put with use of TIG – Tungsten Inert Gas surfacing by welding technology with filler on Ni matrix, Ni and...

2010-01-01

150

Solidification of heavy castings  

Directory of Open Access Journals (Sweden)

Full Text Available Quality of the casting material is influenced by great numbers of material properties, metallurgical treatment, and particular solidification conditions too. In the case of solidification of heavy castings the properties and quality of the casting material are considerably changed in consequence of running segregation phenomena, worsen metal feeding conditions, and microporosity formation etc. It can even result in defaulting the required strengths and plasticity of the casting material. The work deals with changes of chemical composition and changes of mechanical properties in places with a long solidification time corresponding to them.

A. Zadera

2011-01-01

151

Vascular anomalies  

Directory of Open Access Journals (Sweden)

Full Text Available Management of vascular anomalies is an emerging multidisciplinary, super-specialisation field involving several surgical, medical and radiological specialties. Over the years, development in this field has been limited because of complex nomenclature and lack of consensus on the best practice for treatment of some of the more complex vascular anomalies. It was only in 1996 that the International Society of the Study of Vascular Anomalies defined nomenclature for the anomalies and gave clear guidelines on management, allowing for improved clinical practices. As in all fields of clinical medicine, the correct diagnosis of the vascular anomalies is essential to choose the appropriate treatment. This paper gives clear guidelines for diagnosis, understanding of the anomalies and discusses their management.

Murthy Jyotsna

2005-01-01

152

Hormonal Effects on Periosteal Microvessels: A Microvascular Cast Study.  

Science.gov (United States)

Plastic microvascular casts have been used primarily to study the three-dimensional distribution of small blood vessels in soft tissues, but in the two studies reported in bone, one investigated the vascular distribution of rat vertebrae and the other the...

S. W. Whitson R. Williams R. M. Hay D. Atkison C. Muratore

1988-01-01

153

Color Casts Detection and Adjustment  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents a new method for detection and adjustment color cast. Using the neural network to detect color cast and classify images into three subsets: no cast, real cast, and intrinsic cast (image presenting a cast due to a predominant color that must be preserved). We have a database of 700 images which are downloaded from internet or acquired using various digital still cameras. We randomly select 350 images from the database for the neural network learning, and the others are for ...

Sheng-Fuu Lin; Huang-Tsun Chen; Tsung-Han Lin

2011-01-01

154

Cast iron - a predictable material  

Digital Repository Infrastructure Vision for European Research (DRIVER)

High strength compacted graphite iron (CGI) or alloyed cast iron components are substituting previously used non-ferrous castings in automotive power train applications. The mechanical engineering industry has recognized the value in substituting forged or welded structures with stiff and light-weight cast iron castings. New products such as wind turbines have opened new markets for an entire suite of highly reliable ductile iron cast components. During the last 20 years, casting process s...

2011-01-01

155

High temperature corrosion of metals  

International Nuclear Information System (INIS)

This paper covers three main topics: 1. high temperature oxidation of metals and alloys, 2. corrosion in sulfur containing environments and 3. structural changes caused by corrosion. The following 21 subjects are discussed: Influence of implanted yttrium and lanthanum on the oxidation behaviour of beta-NiA1; influence of reactive elements on the adherence and protective properties of alumina scales; problems related to the application of very fine markers in studying the mechanism of thin scale formation; oxidation behaviour of chromia forming Co-Cr-Al alloys with or without reactive element additions; growth and properties of chromia-scales on high-temperature alloys; quantification of the depletion zone in high temperature alloys after oxidation in process gas; effects of HC1 and of N2 in the oxidation of Fe-20Cr; investigation under nuclear safety aspects of Zircaloy-4 oxidation kinetics at high temperatures in air; on the sulfide corrosion of metallic materials; high temperature sulfide corrosion of Mn, Nb and Nb-Si alloys; corrosion behaviour or NiCrAl-based alloys in air and air-SO2 gas mixtures; sulfidation of cobalt at high temperatures; preoxidation for sulfidation protection; fireside corrosion and application of additives in electric utility boilers; transport properties of scales with complex defect structures; observations of whiskers and pyramids during high temperature corrosion of iron in SO2; corrosion and creep of alloy 800H under simulated coal gasification conditions; microstructural changes of HK 40 cast alloy caused by exploitation in tubes in steam reformer installation; microstructural changes during exposure in corrosive environments and their effect on mechanical properties; coatings against carburization; mathematical modeling of carbon diffusion and carbide precipitation in Ni-Cr-based alloys. (MM)

1987-12-02

156

Multi-layers castings  

Directory of Open Access Journals (Sweden)

Full Text Available In paper is presented the possibility of making of multi-layers cast steel castings in result of connection of casting and welding coating technologies. First layer was composite surface layer on the basis of Fe-Cr-C alloy, which was put directly in founding process of cast carbon steel 200–450 with use of preparation of mould cavity method. Second layer were padding welds, which were put with use of TIG – Tungsten Inert Gas surfacing by welding technology with filler on Ni matrix, Ni and Co matrix with wolfram carbides WC and on the basis on Fe-Cr-C alloy, which has the same chemical composition with alloy, which was used for making of composite surface layer. Usability for industrial applications of surface layers of castings were estimated by criterion of hardness and abrasive wear resistance of type metal-mineral.

J. Szajnar

2010-01-01

157

Innovative cast iron pipes. Part 1. Corrosion protection of buried cast iron pipes on the basis of a zinc-aluminium alloy 85-15; Gussrohr-Innovation. T. 1. Korrosionsschutz von erdueberdeckten Rohrleitungen aus duktilem Gusseisen auf Basis einer Zink-Aluminium-Legierung 85-15  

Energy Technology Data Exchange (ETDEWEB)

On the basis of more than 50 years of experience with zinc-coated pipes and more than 25 years of experience with the alloy ZnAl 85-15, an innovative coating system was developed for pipes made of ductile cast iron. While the conventional system consists of a Zn coating of 200 g/m{sup 2} and a bitumen coating, the ZnAl 85-15 coating is twice as thick, i.e. 400 g/m{sup 2}, and has a blue epoxy resin cover coating which identifies the pipes as water pipes. (orig.)

Mischo, Michael [SAINT-GOBAIN PAM DEUTSCHLAND GmbH und Co. KG, Saarbruecken (Germany)

2009-07-15

158

Wear and corrosion behaviour of Al6061-TiO{sub 2} composites  

Energy Technology Data Exchange (ETDEWEB)

The present investigation deals with preparation of Al 6061-TiO{sub 2} composites by liquid metallurgy route, which is the most popular technique. Metallographic study, hardness, friction, wear and corrosion tests have been conducted on the cast Al 6061-TiO{sub 2}. The corroding medium used is 3.5%Nacl. An improvement in hardness and wear resistance, lowering of coefficient of friction of the cast composites was observed with increased content of TiO{sub 2} in the composites. However, deterioration of corrosion resistance of the cast composites has been observed for the cast composites when compared with the matrix alloy. (orig.)

Ramesh, C.S. [Research Centre, Dept. of Mechanical Engineering, Ghousia Coll. of Engineering Ramanagaram, Karnataka (India); Anwar Khan, A.R.; Safiulla, M. [Ghousia Coll. of Engineering Ramanagaram, Karnataka (India)

2003-07-01

159

The ancient Chinese casting techniques  

Directory of Open Access Journals (Sweden)

Full Text Available In the course of Chinese civilization, which lasted more than 5,000 years, casting production has made a huge contribution. In this paper, some representative metal castings were presented. According to their forming techniques, they can be grouped into stone mould casting, clay mould casting, ablation casting, lost wax casting, stack casting, permanent mould casting, sand casting, etc. According to their materials, they can be categorized into tin bronze, bimetallic bronze, malleable cast iron, ductile cast iron, brass, cupronickel alloy (Packtong, etc. According to their surface decorative techniques they can be devided into gem inlay, gilding, gold and silver inlay, copper inlay, engraved decoration, surface tin-enrichment, mother-of-pearl inlay, burnished works with gold or silver inlay, surface coloring and cloisonné enamel, etc.

Tan Derui

2011-02-01

160

The spheroidisation of VC carbides in high- vanadium cast iron  

Directory of Open Access Journals (Sweden)

Full Text Available High-vanadium cast iron is a type of white cast iron, in which a regular fibrous ? + VC eutectic with about 20 vol.% of vanadium carbidescrystallises. The paper presents the results of research during which the high-vanadium cast iron was subjected to spheroidisation treatmentwith magnesium Elmag 5800 master alloy. The purpose of this operation was to obtain the VC carbides of a spheroidal shape. The studyalso included metallographic examinations and testing of mechanical properties carried out on high-vanadium cast iron of a eutecticcomposition in as-cast condition and after the spheroidising treatment. The attempt to spheroidise the vanadium carbides has proved to be quite successful. The introduction of magnesium alloy has made nearly one half of the crystallised vanadium carbides acquire a spheroidal shape. The, obtained in this way, high-vanadium cast iron with vanadium carbides of a spheroidal shape showed very high mechanical andplastic properties. The tensile strength Rm increased by 60% compared to the as-cast alloy, while ductility increased more than twenty times. The presented results are based on the initial trials, but further studies of this new material are planned, mainly to check itsresistance to abrasion, to impacts and corrosion. Tests are also planned to increase the fraction of spheroidal carbides and measure theeffect of their content on the mechanical and tribological properties

M. Kawalec

2011-07-01

 
 
 
 
161

CASTE FRAMEWORK AT NATIONAL LEVEL  

Directory of Open Access Journals (Sweden)

Full Text Available Caste is an important element of the Indian political process. It is legitimate. Caste has been inequality creating in Indian society. Therefore its influence on power shaping & Policy Making process. In this sense caste element has got sphere of influence in political process. Relationship between Caste & politics has been more eminent. Caste has been influencing on politics & politics has been influenced by caste. Limitation of Dominant caste at national level: dominant caste has been demanding for representation on national level. But their demands were not accepted by forward castes. The forward caste has been controlling National level power. Dominant caste has been controlling the state level power.Hinduvat Framework has Successes but Caste Framework has Failure. ST'S Community is not related to Caste Politics. Caste framework is Failure to inclusion of all backward Caste. Caste framework had not successful to decided Social & Economic Public Policy. Because of this caste framework is empty so it has no capacity to competing with other frameworks. It has own Sense of Political Efficacy but on national level it made no impact.

PRAKASH PAWAR

2013-04-01

162

Clean Metal Casting  

Energy Technology Data Exchange (ETDEWEB)

The objective of this project is to develop a technology for clean metal processing that is capable of consistently providing a metal cleanliness level that is fit for a given application. The program has five tasks: Development of melt cleanliness assessment technology, development of melt contamination avoidance technology, development of high temperature phase separation technology, establishment of a correlation between the level of melt cleanliness and as cast mechanical properties, and transfer of technology to the industrial sector. Within the context of the first task, WPI has developed a standardized Reduced Pressure Test that has been endorsed by AFS as a recommended practice. In addition, within the context of task1, WPI has developed a melt cleanliness sensor based on the principles of electromagnetic separation. An industrial partner is commercializing the sensor. Within the context of the second task, WPI has developed environmentally friendly fluxes that do not contain fluorine. Within the context of the third task, WPI modeled the process of rotary degassing and verified the model predictions with experimental data. This model may be used to optimize the performance of industrial rotary degassers. Within the context of the fourth task, WPI has correlated the level of melt cleanliness at various foundries, including a sand casting foundry, a permanent mold casting foundry, and a die casting foundry, to the casting process and the resultant mechanical properties. This is useful in tailoring the melt cleansing operations at foundries to the particular casting process and the desired properties of cast components.

Makhlouf M. Makhlouf; Diran Apelian

2002-02-05

163

Clean Metal Casting; FINAL  

International Nuclear Information System (INIS)

The objective of this project is to develop a technology for clean metal processing that is capable of consistently providing a metal cleanliness level that is fit for a given application. The program has five tasks: Development of melt cleanliness assessment technology, development of melt contamination avoidance technology, development of high temperature phase separation technology, establishment of a correlation between the level of melt cleanliness and as cast mechanical properties, and transfer of technology to the industrial sector. Within the context of the first task, WPI has developed a standardized Reduced Pressure Test that has been endorsed by AFS as a recommended practice. In addition, within the context of task1, WPI has developed a melt cleanliness sensor based on the principles of electromagnetic separation. An industrial partner is commercializing the sensor. Within the context of the second task, WPI has developed environmentally friendly fluxes that do not contain fluorine. Within the context of the third task, WPI modeled the process of rotary degassing and verified the model predictions with experimental data. This model may be used to optimize the performance of industrial rotary degassers. Within the context of the fourth task, WPI has correlated the level of melt cleanliness at various foundries, including a sand casting foundry, a permanent mold casting foundry, and a die casting foundry, to the casting process and the resultant mechanical properties. This is useful in tailoring the melt cleansing operations at foundries to the particular casting process and the desired properties of cast components

2002-01-01

164

Cast reinforced metal composites; Proceedings of the International Symposium on Advances in Cast Reinforced Metal Composites, Chicago, IL, Sept. 26-30, 1988  

Energy Technology Data Exchange (ETDEWEB)

The present conference on state-of-the-art cast MMCs discusses topics on their fundamental microstructural and mechanical properties, the method of MMC 'squeeze casting', the thermomechanical behavior of cast MMCs, and the tribology, damping, corrosion and erosion properties of cast MMCs. Attention is given to the kinetics of fiber preform infiltration, the bonding of SiC and Al, a chemical analysis of the fiber-matrix interface in model Al-matrix MMCs, porosity in vortex method-produced foundry MMCs, the solidification of Al and Zn alloys containing discontinuous SiC fibers, the liquid pressure forming of MMCs, and the strengthening of P/M vs melted SiC/Al MMCs. Also discussed are the deformation-mechanism mapping of SiC/Al MMCs, the thermal cycling of alumina (FP)/Mg-alloy MMCs, the corrosion properties of MMCs, and the damping capacity of Al-alloy matrix MMCs.

Fishman, S.G.; Dhingra, A.K.

1988-01-01

165

Symptomatic stent cast.  

LENUS (Irish Health Repository)

Biliary stent occlusion is a major complication of endoscopic stent insertion and results in repeat procedures. Various theories as to the etiology have been proposed, the most frequently studied is the attachment of gram negative bacteria within the stent. Several studies have shown prolongation of stent patency with antibiotic prophylaxis. We report the case of stent occlusion from a cast of a previously inserted straight biliary stent; a "stent cast" in an 86-year-old woman with obstructive jaundice. This was retrieved with the lithotrypter and she made an uneventful recovery. This is the first reported case of a biliary stent cast.

Keohane, John

2012-02-03

166

Vascular Proliferation  

Science.gov (United States)

This FlashTM animation depicts vascularization of the early germ disc. It is shown in the context of a transverse section through a trilaminar germ disc and yolk sac. Clicking shows the cardiogenic field developing into the heart tube, along with vasculogenesis of the major vessels. Clicking again shows angiogenesis of peripheral vessels throughout the developing embryo and yolk sac.

PhD Jack D Thatcher (West Virginia School of Osteopathic Medicine Structural Biology)

2009-11-20

167

Bainite obtaining in cast iron with carbides castings  

Directory of Open Access Journals (Sweden)

Full Text Available In these paper the possibility of upper and lower bainite obtaining in cast iron with carbides castings are presented. Conditions, when in cast iron with carbides castings during continuous free air cooling austenite transformation to upper bainite or its mixture with lower bainte proceeds, have been given. A mechanism of this transformation has been given, Si, Ni, Mn and Mo distribution in the eutectic cell has been tested and hardness of tested castings has been determined.

S. Pietrowski

2010-01-01

168

Casting critical components  

Science.gov (United States)

Investment casting is an essential processing route for critical rotating and static aero gas turbine components and for a wide spectrum of high integrity parts. These must perform reliably under arduous operating conditions involving high stresses and, frequently, extremely hostile environments. The advanced technology, in-process controls, rigorous specifications, and stringent testing and inspection procedures required for high integrity investment castings are considered along with some examples of the technological 'spin-off' into diverse industry sectors.

McCallum, R.

1982-06-01

169

A Winning Cast  

Science.gov (United States)

Howmet Research Corporation was the first to commercialize an innovative cast metal technology developed at Auburn University, Auburn, Alabama. With funding assistance from NASA's Marshall Space Flight Center, Auburn University's Solidification Design Center (a NASA Commercial Space Center), developed accurate nickel-based superalloy data for casting molten metals. Through a contract agreement, Howmet used the data to develop computer model predictions of molten metals and molding materials in cast metal manufacturing. Howmet Metal Mold (HMM), part of Howmet Corporation Specialty Products, of Whitehall, Michigan, utilizes metal molds to manufacture net shape castings in various alloys and amorphous metal (metallic glass). By implementing the thermophysical property data from by Auburn researchers, Howmet employs its newly developed computer model predictions to offer customers high-quality, low-cost, products with significantly improved mechanical properties. Components fabricated with this new process replace components originally made from forgings or billet. Compared with products manufactured through traditional casting methods, Howmet's computer-modeled castings come out on top.

2001-01-01

170

Cast iron zinc galvanizing improved by high temperature oxidation process  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: To evaluate influence of the high-temperature oxidation, as the preliminary stage previous to coating with zinc on the change of surface layer structure as well as subsurface layer of cast iron with flake, vermicular and nodular graphite.Design/methodology/approach: The experiment was led in the temperature range: 850-1050ºC in ambient air. Samples have been taken out from the furnace separately after: 2-12 hours. After scale layer removal the hot dip zinc coating in industrial conditions has carried out. Received effects were compared to these obtained during cast iron coating without preliminary thermal processing. To observation both optical and scanning microscope was applied. Sample’s surface quality was described additionally by roughness measurements.Findings: As the consequence of conducted high-temperature oxidation in subsurface layer of cast iron pores have been created, that in result of coating in liquid zinc were filled with new phase and in this way the new zone with different properties was obtained. Cast iron layer enriched in zinc is considerably thicker than layers got with application of other methods.Research limitations/implications: It is suggested to verify the corrosion resistance of cast iron coated with zinc according to presented method and compare of got results with classic zinc coating effects.Practical implications: The proposed method consisted on combining of hot dip zinc coating of cast iron with previous high temperature oxidation makes possible creation of sub-surface layer with composite character, composed of “after –graphite” voids filled with zinc and metallic matrix, without necessity of pressure processing.Originality/value: New application of high temperature corrosion as the heat treatment improving effects obtained after cast iron zinc coating.

D. J?drzejczyk

2010-11-01

171

MicroCT scanner performance and considerations for vascular specimen imaging  

International Nuclear Information System (INIS)

Obtaining three-dimensional geometrical data of vascular systems is of major importance to a number of research areas in medicine and biology. Examples are the characterization of tumor vasculature, modeling blood flow, or genetic effects on vascular development. The performance of the General Electric Medical Systems MS8 microCT scanner is examined in the context of these applications. The system is designed to acquire high-resolution images of specimens up to 5 cm in diameter. A maximum resolution of 38 lp/mm at the 10% modulation transfer function level or 22 ?m full width at half maximum of the plane spread function can be achieved with 8.5 ?m voxels and a 17 mm field of view. Three different contrast agents are discussed and applied for imaging of small animal vasculature: corrosion casting material Batson's No. 17 with an added lead pigment, silicon rubber MICROFIL MV122, and a suspension of barium sulfate (Baritop) in gelatin. Contrast for all of these agents was highly variable in different vessels as well as within the same vessel. Imaging of PMMA tubing filled with MICROFIL shows that even vessels below 20 ?m in diameter are detectable and that diameter estimation of vessels based on thresholding is possible with a precision of 2-3 pixels

2004-02-01

172

Evaluation of microstructural effects on the corrosion behaviour of AZ91D magnesium alloy  

DEFF Research Database (Denmark)

The effect of microconstituents on the corrosion and electrochemical behaviour of AZ91D alloy prepared by die-casting and ingot casting route has been investigated in 3.5% NaCl solution at pH 7.25. The experimental techniques used include constant immersion technique, in-situ corrosion monitoring, and potentiodynamic polarisation experiments. Surface examination and analytical studies were carried out using optical and scanning electron microscopy, EDX and XRD. The corrosion behaviour of microconstituents namely primary alpha, eutectic alpha and beta phases was significantly different. Goring of aluminum showed influence on corrosion behaviour more significantly in ingot material. Areas with aluminium concentration less than about 8% were found to be prone to corrosion attack compared with either those with higher amount of aluminium or beta phase. Die-cast material with smaller grain size and fine beta phase offered marginally lower corrosion rate and better passivation compared with the ingot. In die-cast and ingot, hydrogen evolution took place preferentially on beta phase. XRD pattern of non-corroded and corroded surface revealed the removal of beta phase from alloy surface during corrosion. The corrosion products for ingot consisted of Mg(OH)(2) with small amounts beta phase, magnesium-aluminum oxide and MgH2 while for die-cast, the product showed a highly amorphous structure. (C) 2000 Elsevier Science Ltd. All rights reserved.

Ambat, Rajan

2000-01-01

173

Corrosion Engineering.  

Science.gov (United States)

A description is provided for a Corrosion and Corrosion Control course offered in the Continuing Engineering Education Program at the General Motors Institute (GMI). GMI is a small cooperative engineering school of approximately 2,000 students who alternate between six-week periods of academic study and six weeks of related work experience in…

White, Charles V.

174

Evaluation of the Ability of the Peripheral Vasodilator Buflomedil to Improve Vascular Patency after Acute Frostbite.  

Science.gov (United States)

The extent of microvascular damage from frostbite can be accurately demonstrated by vascular microcorrosion casting techniques (Daum et al). In this investigation. the peripheral vasodilator buflomedil was evaluated for its ability to ameliorate microcirc...

D. Morehouse J. Tejada M. P. Hamlet P. S. Daum W. D. Bowers

1988-01-01

175

Corrosion-electrochemical behaviour and mechanical properties ofaluminium alloy-321, alloyed by barium  

International Nuclear Information System (INIS)

The purpose of present work is studying of influence of barium additionson electrochemical corrosion of casting aluminium-copper alloy Al-321,containing as base alloying components copper, chromium, manganese, titanium,zirconium, cadmium

1995-01-01

176

Corrosion Behavior of Magnesium Alloy AP65 in 3.5% Sodium Chloride Solution  

Science.gov (United States)

Magnesium alloy AP65 was prepared by melting and casting. The corrosion behavior of the as-cast and solid solution (T4)-treated AP65 alloys in 3.5% sodium chloride solution was investigated by corrosion morphology observation, immersion test, and electrochemical measurements. The results show that the second phase Mg17Al12 surrounded by a lead-enriched area distributes discontinuously along the grain boundaries in the as-cast AP65 alloy. The lead-enriched areas with high activity are susceptible to be attacked during immersion test and can act as places for preferential anodic dissolution. The corrosion resistance of the as-cast AP65 alloy can be improved after T4 treatment and the T4-treated alloy suffers general corrosion.

Wang, Nai-guang; Wang, Ri-chu; Peng, Chao-qun; Feng, Yan

2012-07-01

177

Streptococcus mutans attachment on a cast titanium surface  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english This study examined by means of scanning electron microscopy (SEM), the attachment of Streptococcus mutans and the corrosion of cast commercially pure titanium, used in dental dentures. The sample discs were cast in commercially pure titanium using the vacuum-pressure machine (Rematitan System). The [...] surfaces of each metal were ground and polished with sandpaper (#300-4000) and alumina paste (0.3 µm). The roughness of the surface (Ra) was measured using the Surfcorder rugosimeter SE 1700. Four coupons were inserted separately into Falcon tubes contained Mueller Hinton broth inoculated with S. mutans ATCC 25175 (10(9) cuf) and incubated at 37 °C. The culture medium was changed every three days during a 365-day period, after which the falcons were prepared for observations by SEM. The mean Ra value of CP Ti was 0.1527 µm. After S. mutans biofilm removal, pits of corrosion were observed. Despite the low roughness, S. mutans attachment and biofilm formation was observed, which induced a surface corrosion of the cast pure titanium.

Sicknan Soares da, Rocha; Adilson César Abreu, Bernardi; Antônio Carlos, Pizzolitto; Gelson Luis, Adabo; Elisabeth Loshchagin, Pizzolitto.

178

Streptococcus mutans attachment on a cast titanium surface  

Directory of Open Access Journals (Sweden)

Full Text Available This study examined by means of scanning electron microscopy (SEM, the attachment of Streptococcus mutans and the corrosion of cast commercially pure titanium, used in dental dentures. The sample discs were cast in commercially pure titanium using the vacuum-pressure machine (Rematitan System. The surfaces of each metal were ground and polished with sandpaper (#300-4000 and alumina paste (0.3 µm. The roughness of the surface (Ra was measured using the Surfcorder rugosimeter SE 1700. Four coupons were inserted separately into Falcon tubes contained Mueller Hinton broth inoculated with S. mutans ATCC 25175 (10(9 cuf and incubated at 37 °C. The culture medium was changed every three days during a 365-day period, after which the falcons were prepared for observations by SEM. The mean Ra value of CP Ti was 0.1527 µm. After S. mutans biofilm removal, pits of corrosion were observed. Despite the low roughness, S. mutans attachment and biofilm formation was observed, which induced a surface corrosion of the cast pure titanium.

Sicknan Soares da Rocha

2009-03-01

179

Development of an Innovative Laser-Assisted Coating Process for Extending Lifetime of Metal Casting Dies. Final Report  

Energy Technology Data Exchange (ETDEWEB)

Die casting dies used in the metal casting industry fail due to thermal fatigue cracking accompanied by the presence of residual tensile stresses, corrosion, erosion and wear of die surfaces. This phase 1 SBIR Final Report summarize Karta Technologies research involving the development of an innovative laser coating technology for metal casting dies. The process involves depositing complex protective coatings of nanocrystalline powders of TiC followed by a laser shot peening. The results indicate a significant improvement in corrosion and erosion resistance in molten aluminum for H13 die casting die steels. The laser-coated samples also showed improved surface finish, a homogeneous and uniform coating mircrostructure. The technology developed in this research can have a significant impact on the casting industry by saving the material costs involved in replacing dies, reducing downtime and improving the quality.

Madhav Rao Gonvindaraju

1999-10-18

180

[Vascular ultrasonography].  

Science.gov (United States)

Vascular ultrasound plays an important role in the visual depiction of arteries, veins, and changes of tissue in lymphatic diseases. In the case of arteries, this ranges from endothelial dysfunction over measuring the increase of intima media thickness to the detection of stenoses, occlusion, or aneurysm. Ultrasound helps to differentiate in functional arterial diseases such as primary and secondary Raynaud's syndrome as well as arterial compression syndromes like entrapment syndrome of different arterial regions or the chronic exceptional compartment syndrome of the lower leg. Ultrasound plays a central role in the diagnosis of rare arterial diseases like large vessel vasculitis, arterial dissection, cystic adventitial degeneration, and the differentiation of vascular malformation especially in children, thus, permitting ultrasound-guided intervention and follow-up controls. In venous thrombosis, sonography is the primary imaging method, while follow-up controls help in the prediction of recurrent venous thrombosis. Ultrasound is a tool to determine the cause and severity of chronic venous insufficiency and allows different therapeutic procedures for the treatment of varicose veins to be visually monitored. PMID:22358939

Stiegler, H

2012-03-01

 
 
 
 
181

Evaluation on the Corrosion of the Three Ni-Cr Alloys with Different Composition  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Dental casting alloys are widely used in contact with oral tissue for many years now. With the development of new dental alloys over the past 15 years, many questions remain unanswered about their biologic safety. Concepts and current issues concerning the response to the biologic effects of dental casting alloys are presented. In this paper, samples of three commercially available nickel-chrome (Ni-cr) casting alloys (Dentaurum, Bego, Sankin) were taken to assess their corrosion behavior...

2011-01-01

182

Pressure Casting in Investment Molds.  

Science.gov (United States)

A study was made of methods for pressure casting nonferrous alloys into investment molds. The experimental methods were compared with standard suction casting practices. The best method studied was the direct pressure diaphragm method. By this method, met...

S. Lipson F. Ripkin

1964-01-01

183

Electrochemical behaviour and corrosion of Mg-Y alloys  

International Nuclear Information System (INIS)

Highlights: ? The corrosion performance of Mg-Y alloys reported over the largest compositional range to date. ? Quantitative microscopy identified the Mg-Y intermetallic that formed. ? Quantification of intermetallic electrochemistry via the microcell technique. ? A rational description of the corrosion response for Mg-Y alloys based on kinetics is given. - Abstract: Corrosion of cast magnesium-yttrium (Y) alloys with systematic Y additions up to a nominal 18 wt.% were studied. Corrosion performance was related to the quantitative alloy microstructure and found to increase significantly with the level of alloying and volume fraction of the Mg-Y intermetallic present. In the alloy microstructures, Mg24Y5 was principally formed; the electrochemistry of which was characterised using the electrochemical microcell method. Electrochemical testing revealed the fundamental corrosion behaviour of Mg-Y alloys and elucidated the corrosion mechanisms at play.

2011-06-01

184

"Souvenir" casting silicosis.  

Science.gov (United States)

A case of silicosis in a 47-year-old worker who was employed for many years in a small souvenir casting shop is described. This work site demonstrates many unfavorable characteristics of small industries, such as lack of awareness of the need for safety measures, exposure control, protection of workers, and lack of compliance with environmental and medical-legal standards. PMID:7924512

Carel, R S; Salman, H; Bar-Ziv, J

1994-10-01

185

Wear resistance of cast iron  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper investigations of abrasive and adhesive wear resistance of different cast iron grades have been presented. Examinations showed, that the most advantageous pair of materials is the cast iron – the hardened steel with low-tempered martensite. It was found, that martensitic nodular cast iron with carbides is the most resistant material.

2008-01-01

186

Wear resistance of cast iron  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper investigations of abrasive and adhesive wear resistance of different cast iron grades have been presented. Examinations showed, that the most advantageous pair of materials is the cast iron – the hardened steel with low-tempered martensite. It was found, that martensitic nodular cast iron with carbides is the most resistant material.

S. Pietrowski

2008-10-01

187

Mix/Cast Contamination Control  

Science.gov (United States)

Presented is a training handbook for Mix/Cast Contamination Control; a part of a series of training courses to qualify access to Mix/Cast facilities. Contents: List Contamination Control Requirements; Identify foreign objects debris (FOD), Control Areas and their guidelines; Describe environmental monitoring; List Contamination Control Initiatives; Describe concern for Controlled Materials; Identify FOD Controlled Areas in Mix/Cast.

Wallentine, M.

2005-01-01

188

Container material for the disposal of highly radioactive wastes: corrosion chemistry aspects  

International Nuclear Information System (INIS)

Prior to disposal in crystalline formations it is planned to enclose vitrified highly radioactive waste from nuclear power plants in metallic containers ensuring their isolation from the groundwater for at least 1,000 years. Appropriate metals can be either thermodynamically stable in the repository environment (such as copper), passive materials with very low corrosion rates (titanium, nickel alloys), or metals such as cast iron or unalloyed cast steels which, although they corrode, can be used in sections thick enough to allow for this corrosion. The first part of the report presents the essentials of corrosion science in order to enable even a non-specialist to follow the considerations and arguments necessary to choose the material and design the container against corrosion. Following this, the principles of the long-term extrapolation of corrosion behaviour are discussed. The second part summarizes and comments upon the literature search carried out to identify published results relevant to corrosion in a repository environment. Results of archeaological studies are included wherever possible. Not only the general corrosion behaviour but also localized corrosion and stress corrosion cracking are considered, and the influence of hydrogen on the material behaviour is discussed. Taking the corrosion behaviour as criterion, the author suggests the use either of copper or of cast iron or steel as an appropriate container material. The report concludes with proposals for further studies. (Auth.)

1984-01-01

189

Influence of continuous casting conditions on grey cast iron structure  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The main aim of investigations was the unification of flake graphite morphology in cast iron ingots in conditions of forced convection of liquid metal in the continuous casting mould, which contains electromagnetic stirrer.Design/methodology/approach: To investigations of grey cast iron ingots were used laboratory stand of continuous casting, which contains continuous casting mould with inductor of rotate electromagnetic field.To investigations were made metallographic researches on scanning electron microscope and investigations of usable properties i.e. measurements of hardness and machinability.Findings: The results of investigations and their analysis show possibility of unification of flake graphite morphology in cast iron structure, and distribution of hardness on cross-section of ingot and its machinability.Research limitations/implications: In further research, authors of this paper are going to application of introduced method of continuous casting with use of electromagnetic field in industrial tests.Practical implications: The work presents method of unification of structure and properties, which are particularly important in continuous casting. Uniform morphology of flake graphite in structure of cast iron ingots for automobile industry is very important in viewpoint of machinability.Originality/value: Contributes to improvement in quality of grey cast iron continuous casted ingots.

J. Szajnar

2010-03-01

190

Control of cast iron and casts manufacturing by Inmold method  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper the usability of cast iron spheroidizing process in mould control by ATD method as well as by ultrasonic method were presented. Structure of instrumentation needed for control form performance of cast iron spheroidizing by Inmold method was illustrated. Author, pointed out that amount of magnesium master alloy should obtain 0,8 ÷ 1,0% of mass in form at all. Such quantity of preliminary alloy assure of obtain of nodular graphite in cast iron. In consequence of this, is reduce the cast iron liquidus temperature and decrease of recalescence temperature of graphite-eutectic crystallization in compare with initial cast iron. Control of casts can be carried out by ultrasonic method. In plain cast iron, ferritic-pearlitic microstructure is obtaining. Additives of 1,5% Cu ensure pearlitic structure.

S. Pietrowski

2009-07-01

191

Characterization of Al-Mn particles in AZ91D investment castings  

International Nuclear Information System (INIS)

Manganese is currently added to Mg-Al alloys in order to improve the corrosion behavior of cast components. A part of this manganese is dissolved in the magnesium matrix and the balance is found as fine Al(Mn,Fe) particles dispersed within castings. For AZ91D specimens prepared using the plaster mould investment casting process, these particles were observed in very large quantity at the surface of castings. These particles were characterized by scanning electron microscopy and electron probe microanalysis. It was found that they consist of Al8Mn5 phase and that their morphology and size depend on local solidification conditions. Their presence at the surface of the castings is related to low solidification rates and reduced thermal gradients at the mould/metal interface

2007-10-01

192

Point corrosion in steel 17 247  

International Nuclear Information System (INIS)

Susceptibility to point and intergranular corrosion was studied for titanium-stabilized steel CSN 17 247. Specimens were used from two melts featuring different surface finish, placed in three different corrosion media, viz.: 10% iron chloride solution, a solution of copper sulfate, sulfuric acid and distilled water with an addition of copper dust, and a boiling solution of 65% nitric acid. The specimens did not show susceptibility to intergranular corrosion in the sulfuric acid medium. In the boiling nitric acid, the melt with a higher titanium level and a coarser grain showed a lower corrosion rate than that with a lower titanium level, finer grain and the presence of delte-ferrite in the structure. An intensive course of point corrosion was found in the iron chloride medium. As for working, the lowest corrosion rate was found for conventional metal cutting treated surfaces, a higher rate for electrolytically polished surfaces. The highest rate of corrosion was observed for cast grit blasted surfaces. (Z.M.). 3 tabs., 8 refs

1987-12-01

193

Corrosion behaviour of solution nitrided stainless steels  

International Nuclear Information System (INIS)

The case of near net shape parts made from austenitic steel X2CrNiMo17-13-2 and austenitic-ferritic steels X2CrNiMoN22-5-3 (wrought) and G-X3CrNiMoCuN26-6-3-3 (cast) is interstitially enriched with nitrogen by the diffusion-based process ''solution nitriding''. In order to obtain good corrosion resistance and mechanical properties, the solution nitriding parameters and the applied cooling time are selected so, that precipitates are avoided (X2CrNiMo17-13-2, X2CrNiMoN22-5-3). However, in case of a superimposed hydroabrasive load, the presence of nitrides in the case is found to be beneficial. The solution nitrided and the solution annealed conditions of the steels are compared with respect to their susceptibility to corrosion by means of electrochemical polarisation curves. The erosion corrosion behaviour of the materials is analysed in pilot scale flow-loop tests using particle loaded corrosive and particle loaded non-corrosive media. It is shown that ''solution nitriding'' leads to improved corrosion behaviour and/or improved erosion corrosion resistance, in particular in the case of the duplex steels. (orig.)

1998-05-24

194

Can Dynamic Bubble Templating Play a Role in Corrosion Product Morphology.  

Science.gov (United States)

Dynamic templating as a result of cathodic hydrogen gas production is suggested as a possible mechanism for the formation of tube-like corrosion products on an unlined cast iron pipe in a drinking water distribution system. Mounds of corrosion product, wi...

B. J. Little K. G. Scheckel R. I. Ray T. L. Gerke

2012-01-01

195

Effects of Cr - Ni 18/9 Austenitic Cast Steel Modification by Mischmetal  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents the results of Cr - Ni 18/9 austenitic cast steel modifications by mischmetal. The study was conducted on industrial melts. Cast steel was melted in an electric induction furnace with a capacity of 2000 kg and a basic lining crucible. .The mischmetal was introduced into the ladle during tapping of the cast steel from the furnace. The effectiveness of modification was examined with the carbon content of 0.1% and the presence of ? ferrite in the structure of cast steel stabilized with titanium. The changes in the structure of cast steel and their effect on mechanical properties and intergranular corrosion were studied. It was found that rare earth metals decrease the sulfurcontent in cast steel and above all, they cause a distinct change in morphology of the ? ferrite and non-metallic inclusions. These changes have improved mechanical properties. R02, Rm, and A5 and toughness increased significantly. There was a great increase of the resistance to intergranular corrosion in the Huey test. The study confirmed the high efficiency of cast steel modification by mischmetal in industrial environments. The final effect of modification depends on the form and manner of placing mischmetal into the liquid metal and the melting technology, ie the degree of deoxidation and desulfurization of the metal in the furnace.

M. Gajewski

2012-12-01

196

Quality of the joint between cast steel and cast iron in bimetallic castings  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The paper presents conception and production method of skeleton composite castings with use of cast steel G35CrSiMnMoNi skeletoncasting and chromium cast iron EN-GJN-XCr15 filling. Working elements in winning machines and devices, which work in intensiveaberasive wear i.e. liner of exhausters, percussive and ram hammers, are destination of bimetallic castings. Skeleton geometry was basedon three-dimensional symmetrical cubic net consisting of circular connectors and nodes joining 6 connectors...

2008-01-01

197

Corrosion amalgams  

International Nuclear Information System (INIS)

The release of copper, mercury, silver, tin or zinc from conventional, dispersed phase and spherical high copper content amalgams immersed in artificial saliva solutions for periods up to 30 d has been measured using nuclear tracer techniques. During initial corrosion, i.e. within a few hours, substantial amounts of mercury were found to be present in particulate matter in the three types of amalgams. The release of particulate matter was pronounced for the dispersed phase type of amalgam. After about 30 d electrochemical corrosion was found to be the predominant process for release of various corrosion products. Zinc was demonstrated to be the major corrosion product released to the artificial saliva solutions from conventional as well as dispersed phase amalgams. Due to low radioactivity levels silver and tin could not be quantitatively asayed. However, the upper limits of release of silver and tin in the artificial saliva solutions referring to exposure periods up to 30 d were estimated to 0.1 ?g and 25 ?g respectively. The chemical state of the various corrosion products has been evaluated. The deposition of CuCl_2 . 3 Cu(OH)_2 on the surfaces of copper rich amalgams was observed according to X-ray diffraction analysis. (author)

1981-01-01

198

Color Casts Detection and Adjustment  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a new method for detection and adjustment color cast. Using the neural network to detect color cast and classify images into three subsets: no cast, real cast, and intrinsic cast (image presenting a cast due to a predominant color that must be preserved. We have a database of 700 images which are downloaded from internet or acquired using various digital still cameras. We randomly select 350 images from the database for the neural network learning, and the others are for testing. From each training image, we can calculate 13 statistical parameters as input to the neural network. The second part is the white balance algorithm which is applied to the image while a real cast is found by the color cast detector. The test image is divided into m blocks. For each block, the output weighting can be obtained by a fuzzy system and the luminance weighted value is also calculated. Finally, we can obtain the new amplifier gains of the R, G, and B channel to adjust the color cast. If the input image be classified as no cast or intrinsic cast, white balance algorithm is not applied.

Sheng-Fuu Lin

2011-07-01

199

Cast iron - a predictable material  

Directory of Open Access Journals (Sweden)

Full Text Available High strength compacted graphite iron (CGI or alloyed cast iron components are substituting previously used non-ferrous castings in automotive power train applications. The mechanical engineering industry has recognized the value in substituting forged or welded structures with stiff and light-weight cast iron castings. New products such as wind turbines have opened new markets for an entire suite of highly reliable ductile iron cast components. During the last 20 years, casting process simulation has developed from predicting hot spots and solidification to an integral assessment tool for foundries for the entire manufacturing route of castings. The support of the feeding related layout of the casting is still one of the most important duties for casting process simulation. Depending on the alloy poured, different feeding behaviors and self-feeding capabilities need to be considered to provide a defect free casting. Therefore, it is not enough to base the prediction of shrinkage defects solely on hot spots derived from temperature fields. To be able to quantitatively predict these defects, solidification simulation had to be combined with density and mass transport calculations, in order to evaluate the impact of the solidification morphology on the feeding behavior as well as to consider alloy dependent feeding ranges. For cast iron foundries, the use of casting process simulation has become an important instrument to predict the robustness and reliability of their processes, especially since the influence of alloying elements, melting practice and metallurgy need to be considered to quantify the special shrinkage and solidification behavior of cast iron. This allows the prediction of local structures, phases and ultimately the local mechanical properties of cast irons, to asses casting quality in the foundry but also to make use of this quantitative information during design of the casting. Casting quality issues related to thermally driven stresses in castings are also gaining increasing attention. State-of-the-art tools allow the prediction of residual stresses and iron casting distortion quantitatively. Cracks in castings can be assessed, as well as the reduction of casting stresses during heat treatment. As the property requirements for cast iron as a material in design strongly increase, new alloys and materials such as ADI might become more attractive, where latest software developments allow the modeling of the required heat treatment. Phases can be predicted and parametric studies can be performed to optimize the alloy dependent heat treatment conditions during austenitization, quenching and ausferritization. All this quantitative information about the material's performance is most valuable if it can be used during casting design. The transfer of local properties into the designer? world, to predict fatigue and durability as a function of the entire manufacturing route, will increase the trust in this old but highly innovative material and will open new opportunities for cast iron in the future. The paper will give an overview on current capabilities to quantitatively predict cast iron specific defects and casting performance and will highlight latest developments in modeling the manufacture of cast iron and ADI as well as the prediction of iron casting stresses.

Jorg C. Sturm

2011-02-01

200

An overview of the corrosion aspect of dental implants (titanium and its alloys)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Titanium and its alloys are used in dentistry for implants because of its unique combination of chemical, physical, and biological properties. They are used in dentistry in cast and wrought form. The long term presence of corrosion reaction products and ongoing corrosion lead to fractures of the alloy-abutment interface, abutment, or implant body. The combination of stress, corrosion, and bacteria contribute to implant failure. This article highlights a review of the various aspects of corros...

Chaturvedi T

2009-01-01

 
 
 
 
201

Metal Corrosion  

Science.gov (United States)

This learning activity will allow students the opportunity to observe long term corrosion of materials. The instructor will set up several jars or beakers filled with either fresh or salt water, and the class will observe the corrosion of nails, pennies and aluminum foil over time. This activity would be appropriate for grade 4 through college level students. Two weeks should be set aside to observe the results of the experiment. Student, instructor and course evaluation questions are included. This document will serve as a framework for instructors and may be downloaded in PDF format.

Stoebe, Thomas G.

2011-09-22

202

USGS CoreCast  

Science.gov (United States)

Just about everyone seems to be creating a podcast these days, and a number of government agencies have entered the fray as of late. The United States Geological Survey recently decided to hang out their own podcast shingle, and the results of their labors can be explored here. The site states that their "CoreCast" is "natural science from the inside out", which seems like an appropriate label. The podcasts range in length from two to fifteen minutes, and they cover topics such as polar bear research, sex-changing fish, and climate change. One podcast that shouldn't be overlooked is "This Episode of CoreCast is Highly Questionable". In a mere three minutes, host Scott Horvath responds to a number of questions in an engaging fashion. After listening to an episode or two, visitors will probably want to sign up to receive email updates about new episodes.

203

Development of a pre-vascularized 3D scaffold-hydrogel composite graft using an arterio-venous loop for tissue engineering applications.  

Science.gov (United States)

Hyaluronic acid (HA) and fibrin glue (FG) are effective hydrogels for tissue engineering applications as they support tissue in-growth, retain growth factors, and release them slowly with time. The scaffolds, in combination with a hydrogel, effectuate a successful graft. However, the survival of a graft entirely depends upon a functional vascular supply. Therefore, hydrogels must support the in-growing vasculature. To study and compare the vascular patterns, HA and FG hydrogel-containing PLDLLA-TCP-PCL scaffolds were implanted in the groin of male Lewis rats and supplied with a micro-surgically prepared arterio-venous (A-V) loop. The rats were perfused with a vascular contrast media after 4 and 8 weeks and sacrificed for further analysis. The specimens were scanned with micro-CT to find the vascular growth patterns. Corrosion casting of blood vessels followed by SEM demonstrated a high vascular density near the parent blood vessels. Histologically, HA and FG implanted animal groups showed significant angiogenetic activity, especially within the pores of the scaffold. However, formation of new blood vessels was more conspicuously observed at 4 weeks in FG than HA implants. Furthermore, by 8 weeks, the number and pattern of blood vessels were comparable between them. At this time, HA was still present indicating its slow degradation. The finding was confirmed by histomorphometric analysis. This experimental study demonstrates that HA containing composite scaffold systems permit stabile in-growth of blood vessels due to sustained degradation over 8 weeks. HA is a potential matrix for a tissue engineered composite graft. PMID:21680609

Rath, Subha N; Arkudas, Andreas; Lam, Christopher Xf; Olkowski, Radoslaw; Polykandroitis, Elias; Chróscicka, Anna; Beier, Justus P; Horch, Raymund E; Hutmacher, Dietmar W; Kneser, Ulrich

2012-09-01

204

The Development of Corrosion Resistant Zirconium Alloy  

International Nuclear Information System (INIS)

Corrosion test of Zr alloy consisting of quenching and tempering Zry-2,Zry-4 cast, Zr-1% Nb cast, has been. conducted. In corrosion test, thechanges during ?-quenching, tempering and corrosion test at varioustemperature and time in autoclave water medium, can be seen. The treatmentconsisted of heating at 1050 oC for 30 minutes, quenching in water andtempering at 200 oC, 300 oC, 400 oC, 500 oC, 600 oC as well as corrosiontests at 225 oC, 275 oC, 325 oC at 4, 8, 12 hours. Sample preparation forcorrosion test was based on ASTM G-2 procedure, which consisted of washing,rinsing, pickling (3.5 cc HF 50%; 2.9 cc HNO3 65% and 57 cc AMB),neutralizing in 0.1 M Al(NO3)3, 9 H2O and ultrasonic rinsing/washing.Measurement performed are weight gain during corrosion, hardness test andmicrostructure observation using microscope optic. The results show that?-quenching of Zr alloy which was followed by tempering can turn ?martensite into tempered ?1martensit. The increase of temperingtemperature decreases the Zr alloy hardness and the lowest hardness ispossessed by Zr-1% Nb alloy. The corrosion test at 275 oC and 325 oC showsthat the weight gain depends on the tempering temperature, the temperingtemperature of 400 oC and 200 oC gives the maximum weight gain for Zry-2,Zry-4 cast, Zr-1% Nb. The largest number of hydride formed during corrosionis found in Zry-2, while the small one is in Zr-1% Nb. (author)

2000-07-25

205

EFFECT OF THE HEAT AND SURFACE LASER TREATMENT ON THE CORROSION DEGRADATION OF THE Mg-Al ALLOYS  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper there is presented the corrosion behavior of the cast magnesium alloys as cast state, after heat and laser treatment. Pitting corrosion resistance of the analyzed alloys was carried out using the potentiodynamic electrochemical method (direct current, based on a anodic polarization curve. On the basis of the achieved anodic polarization curves, using the Tefel extrapolation method near to the corrosion potential, the quantitative data were determined, which describe the electrochemical corrosion process of the investigated alloys: value of the corrosion potential Ecorr (mV, polarization resistance RP (kohm.cm2, corrosion current density icorr (10-6A/cm2, corrosion rate Vcorr (mm/year as well the mass loss Vc (g/m2<.

Leszek A. Dobrza?ski

2011-09-01

206

Metal casting extended assessments  

International Nuclear Information System (INIS)

In 1997, the Industrial Assessment Center program of the US Department of Energy initiated Extended Assessments as an option for some of their in-plant assessments. Intended for larger, more complex manufacturing facilities, the multi-day Extended Assessment allows the plant assessment team to explore more complex recommendations with the intent of encouraging major process and equipment changes. In this paper the authors describe the results of Extended Assessments at plants in the Metal Casting Industry, one of the DOE Industries of the Future. They visited five plants, two foundries and three die casting plants, with combined annual sales of $134 million and a combined annual production volume of 35,300 tons. The recommendations offered potential savings to each plant of an average $417,000 or 1.5% of average gross sales. A number of generalizations can be observed based on the assessments in the cast metals industry. First is that many of the smaller firms in this industry have been slow to adopt innovative technology. Off the shelf technologies are available that will help these firms reach the 21st Century. The concept of remelt of metal or scrap in the plant is an operation that can be improved. They found approximately two pounds of metal melted for every pound shipped. Finally, many opportunities exist outside of the core plant operations to reduce operating costs

1999-06-15

207

Metal casting extended assessments  

Energy Technology Data Exchange (ETDEWEB)

In 1997, the Industrial Assessment Center program of the US Department of Energy initiated Extended Assessments as an option for some of their in-plant assessments. Intended for larger, more complex manufacturing facilities, the multi-day Extended Assessment allows the plant assessment team to explore more complex recommendations with the intent of encouraging major process and equipment changes. In this paper the authors describe the results of Extended Assessments at plants in the Metal Casting Industry, one of the DOE Industries of the Future. They visited five plants, two foundries and three die casting plants, with combined annual sales of $134 million and a combined annual production volume of 35,300 tons. The recommendations offered potential savings to each plant of an average $417,000 or 1.5% of average gross sales. A number of generalizations can be observed based on the assessments in the cast metals industry. First is that many of the smaller firms in this industry have been slow to adopt innovative technology. Off the shelf technologies are available that will help these firms reach the 21st Century. The concept of remelt of metal or scrap in the plant is an operation that can be improved. They found approximately two pounds of metal melted for every pound shipped. Finally, many opportunities exist outside of the core plant operations to reduce operating costs.

Ambs, L.; Kosanovic, D.; Muller, M.; Kasten, D.

1999-07-01

208

General corrosion, irradiation-corrosion, and environmental-mechanical evaluation of nuclear waste package structural barrier materials. Progress report  

Energy Technology Data Exchange (ETDEWEB)

Pacific Northwest Laboratory is studying the general corrosion, irradiation-corrosion, and environmentally enhanced crack propagation of five candidate materials in high-temperature aqueous environments simulating those expected in basalt and tuff repositories. The materials include three cast ferrous materials (ductile cast iron and two low-alloy Cr-Mo cast steels) and two titanium alloys, titanium Grade 2 (commercial purity) and Grade 12 (a Ti-Ni-Mo alloy). The general corrosion results are being obtained by autoclave exposure of specimens to slowly replenished simulated ground water flowing upward through a bed of the appropriate crushed rock (basalt or tuff), which is maintained at the desired test temperature (usually 250/sup 0/C). In addition, tests are being performed in deionized water. Metal penetration rates of iron-base alloys are being derived by stripping off the corrosion product film and weighing the specimen after the appropriate exposure time. The corrosion of titanium alloy specimens is being determined by weight gain methods. The irradiation-corrosion studies are similar to the general corrosion tests, except that the specimen-bearing autoclaves are held in a /sup 60/Co gamma radiation field at dose rates up to 2 x 10/sup 6/ rad/h. For evaluating the resistance of the candidate materials to environmentally enhanced crack propagation, three methods are being used: U-bend and fracture toughness specimens exposed in autoclaves; slow strain rate studies in repository-relevant environments to 300/sup 0/C; and fatigue crack growth rate studies at ambient pressure and 90/sup 0/C. The preliminary data suggest a 1-in. corrosion allowance for iron-base barrier elements intended for 1000-yr service in basalt or tuff repositories. No evidence has yet been found that titanium Grade 2 or Grade 12 is susceptible to environmentally induced crack propagation or, by extension, to stress corrosion cracking.

Westerman, R.E.; Pitman, S.G.; Nelson, J.L.

1982-09-01

209

Evaluation on the corrosion of the three ni-cr alloys with different composition.  

Science.gov (United States)

Dental casting alloys are widely used in contact with oral tissue for many years now. With the development of new dental alloys over the past 15 years, many questions remain unanswered about their biologic safety. Concepts and current issues concerning the response to the biologic effects of dental casting alloys are presented. In this paper, samples of three commercially available nickel-chrome (Ni-cr) casting alloys (Dentaurum, Bego, Sankin) were taken to assess their corrosion behavior, using potentiodynamic polarization method (electrochemical method) with fusayama artificial saliva as an electrolyte medium to check for their biocompatibility. The parameters for corrosion rate and corrosion resistance were obtained from computer-controlled corrosion schematic instrument, namely, potentiostat through corrosion software (power CV). The results obtained were analyzed by classic Tafel analysis. Statistical analysis was done by Student's t-test and ANOVA test. It was concluded that Dentarum and Bego showed satisfactory corrosive behavior, with exception of Sankin which depicted higher corrosion rate and least resistance to corrosion. Thus, the selection of an alloy should be made on the basis of corrosion resistance and biologic data from dental manufactures. PMID:21461232

Rao, Srinivasa B; Chowdhary, Ramesh

2011-01-01

210

Contemporary art casting’s education in Guangdong  

Directory of Open Access Journals (Sweden)

Full Text Available Based on the practical experience of establishing three art casting laboratories in three different colleges of Guangdong, this paper focuses on the development of contemporary art casting’s education. By analyzing the reason for the shortage of professionals nowadays and the characteristics of modern foundry industry in the Pearl River Delta, the authors try to find out what kind of knowledge structures a modern foundry industry professional should have. Then, from the viewpoint of education, the authors introduce how to combine the art casting laboratory and the creative art casting course as a new teaching pattern, on the one hand, to attract more students to study casting technology, on the other hand, to train them to be qualified professionals for the modern foundry industry.

Wu Chunmiao

2012-02-01

211

Casting larger polycrystalline silicon ingots  

Energy Technology Data Exchange (ETDEWEB)

Solarex has developed and patented a directional solidification casting process specifically designed for photovoltaics. In this process, silicon feedstock is melted in a ceramic crucible and solidified into a large grained semicrystalline silicon ingot. In-house manufacture of low cost, high purity ceramics is a key to the low cost fabrication of Solarex polycrystalline wafers. The casting process is performed in Solarex designed casting stations. The casting operation is computer controlled. There are no moving parts (except for the loading and unloading) so the growth process proceeds with virtually no operator intervention Today Solarex casting stations are used to produce ingots from which 4 bricks, each 11.4 cm by 11.4 cm in cross section, are cut. The stations themselves are physically capable of holding larger ingots, that would yield either: 4 bricks, 15 cm by 15 an; or 9 bricks, 11.4 cm by 11.4 an in cross-section. One of the tasks in the Solarex Cast Polycrystalline Silicon PVMaT Program is to design and modify one of the castings stations to cast these larger ingots. If successful, this effort will increase the production capacity of Solarex`s casting stations by 73% and reduce the labor content for casting by an equivalent percentage.

Wohlgemuth, J.; Tomlinson, T.; Cliber, J.; Shea, S.; Narayanan, M.

1995-08-01

212

Continuous roll casting of aluminium alloys – casting parameters analysis  

Directory of Open Access Journals (Sweden)

Full Text Available The main goal of the paper was to present the influence of casting parameters on casting conditions and interference of casting parameters on the final strip characteristics such as constant strip thickness, surface quality and roughness of aluminum alloys sheet 6,30 to 6,50 mm thick. The study shows that casting speed, roll force and roll gap should have the greatest influence on the final strip thickness, and that the examined parameters agree well with the theoretical standpoints.

E. Krsti? Vukelja

2010-04-01

213

The application and field experience of high strength 12% Cr centrifugally cast pipe for gas gathering system  

Energy Technology Data Exchange (ETDEWEB)

Centrifugal cast method is one of the processes to provide high quality seamless pipe. The advantages of the process are (1) heavy wall pipe can be manufactured (2) relatively flexible in material selection for manufacturing pipe. For sweet corrosion environment caused by CO{sub 2} where carbon steels can not be used, centrifugally cast 12% Cr martensitic stainless steel pipes and fittings have been developed. One of the key factors of this material applied to pipeline is the weldability, especially high hardness of the welds or its heat affected zone which causes for brittle rupture as well as stress corrosion cracking of the pipeline. Cast 12% Cr pipe which has high strength with low hardness even at the weld joint has been developed. Besides of the development of straight pipe, several types of fittings have been developed. These pipes and fittings have been used for natural gas gathering lines and booster compression lines in sweet corrosion service.

Yoshitake, A.; Teraoka, M.; Torigoe, T. [Kubota Corp., Hirakata, Osaka (Japan). Hirakata Plant; Amako, S. [Kubota America Corp., Houston, TX (United States)

1995-10-01

214

Corrosion and hydrogen permeation of A216 grade WCA steel in hydrothermal magnesium-containing brines  

International Nuclear Information System (INIS)

The US Department of Energy's Salt Repository Project (SRP) is investigating the general corrosion resistance of cast mild steel as a candidate material for waste package containers. Evaluation of this material is being performed at the Pacific Northwest Laboratory in environments simulating expected repository conditions. The present work addresses two potential failure modes of the reference waste package container: failure by general corrosion processes, and failure by internal hydrogen pressurization by permeation of corrosion product hydrogen. General corrosion studies of mild steel (ASTM A216 grade WCA) in the as-cast and normalized conditions were conducted in hydrothermal halite-saturated (saturated at ambient temperature) brine environments simulating a dissolution and an inclusion brine. Corrosion tests were also performed in brines similar to the inclusion brine but containing magnesium concentrations ranging from 1,000 to 30,000 ppm to investigate the effect of magnesium on the corrosion behavior. In addition, long-term (to 18 months) corrosion tests have been carried out using two-phase salt/brine environments (excess salt tests). Corrosion rates of the cast mild steel in brine were found to increase with increasing temperature and with increasing magnesium concentration. Some possible mechanisms that explain the observed behavior are presented. The corrosion rates observed in the excess-salt tests tend to decrease with time, at 200 degree and 150 degree C; and as-cast material corrodes more slowly than does normalized material. Corrosion-product hydrogen rapidly permeated a mild steel tubing corrosion/permeation specimen immersed in brine. The rate of permeation at 150 degree C was high enough to cause concern regarding potential container overpressurization

1988-03-08

215

Cast dielectric composite linear accelerator  

Energy Technology Data Exchange (ETDEWEB)

A linear accelerator having cast dielectric composite layers integrally formed with conductor electrodes in a solventless fabrication process, with the cast dielectric composite preferably having a nanoparticle filler in an organic polymer such as a thermosetting resin. By incorporating this cast dielectric composite the dielectric constant of critical insulating layers of the transmission lines of the accelerator are increased while simultaneously maintaining high dielectric strengths for the accelerator.

Sanders, David M. (Livermore, CA); Sampayan, Stephen (Manteca, CA); Slenes, Kirk (Albuquerque, NM); Stoller, H. M. (Albuquerque, NM)

2009-11-10

216

Corrosion behavior of carbon steels under tuff repository environmental conditions  

International Nuclear Information System (INIS)

Carbon steels may be used for borehole liners in a potential high-level nuclear waste repository in tuff in Nevada. Borehole liners are needed to facilitate emplacement of the waste packages and to facilitate retrieval of the packages, if required. Corrosion rates of low carbon structural steels AISI 1020 and ASTM A-36 were determined in J-13 well water and in saturated steam at 1000C. Tests were conducted in air-sparged J-13 water to attain more oxidizing conditions representative of irradiated aqueous environments. A limited number of irradiation corrosion and stress corrosion tests were performed. Chromium-molybdenum alloy steels and cast irons were also tested. These materials showed lower general corrosion but were susceptible to stress corrosion cracking when welded. 4 references, 4 tables

1984-11-26

217

Corrosion behavior of carbon steels under tuff repository environmental conditions  

International Nuclear Information System (INIS)

Carbon steels may be used for borehole liners in a potential high-level nuclear waste repository in tuff in Nevada. Borehole liners are needed to facilitate emplacement of the waste packages and to facilitate retrieval of the packages, if required. Corrosion rates of low carbon structural steels AISI 1020 and ASTM A-36 were determined in J-13 well water and in saturated steam at 100"0C. J-13 well water is representative of water which has percolated through the tuff horizon where the repository would be located. Tests were conducted in air-sparged J-13 water to attain stronger oxidizing conditions. a limited number of irradiation corrosion and stress corrosion tests were performed. Chromium-molybdenum alloy steels and cast irons were also tested. These materials showed lower general corrosion but were susceptible to stress corrosion cracking when welded. 4 refs., 7 tabs

1984-01-01

218

Plant Vascular Biology 2013: vascular trafficking.  

Science.gov (United States)

About 200 researchers from around the world attended the Third International Conference on Plant Vascular Biology (PVB 2013) held in July 2013 at the Rantapuisto Conference Center, in Helsinki, Finland (http://www.pvb2013.org). The plant vascular system, which connects every organ in the mature plant, continues to attract the interest of researchers representing a wide range of disciplines, including development, physiology, systems biology, and computational biology. At the meeting, participants discussed the latest research advances in vascular development, long- and short-distance vascular transport and long-distance signalling in plant defence, in addition to providing a context for how these studies intersect with each other. The meeting provided an opportunity for researchers working across a broad range of fields to share ideas and to discuss future directions in the expanding field of vascular biology. In this report, the latest advances in understanding the mechanism of vascular trafficking presented at the meeting have been summarized. PMID:24431156

Ursache, Robertas; Heo, Jung-Ok; Helariutta, Ykä

2014-04-01

219

Corrosion Doctors  

Science.gov (United States)

This site provides a vast amount of general information about various kinds of degradation processes and their impacts on earth systems and human health. It features modules on corrosion effects by natural waters, microbial processes, atmospheric processes, global warming, global dimming (due to particulate matter) and toxic elements. The site also features a recommended reading list, glossary, periodic table of toxic elements, self-administered quizzes, and a long list of related links.

Doctors, Corrosion

220

Colour Metallography of Cast Iron - Chapter 5: White Cast Iron (?  

Directory of Open Access Journals (Sweden)

Full Text Available Cast iron, as a traditional metal material, has advantages of low total cost, good castability and machinability, good wear resistance and low notch sensitivity, and is still facing tough challenge in quality, property and variety of types etc. Experts and engineers studying and producing iron castings all around world extremely concern this serious challenge. Over more than 30 years, a great of research work has been carried out on how to further improve its property, expand its application and combine cast iron technology with some hi-techs (for example, computer technology. Nevertheless, cast iron is a multi-element and multi-phase alloy and has complex and variety of structures and still has great development potential in structure and property. For further studying and developing cast iron, theoretical research work is important promise, and the study on solidification process and control mechanism of graphite morphology is fundamental for improving property of cast iron and developing new type of cast iron. Metallography of cast iron normally includes two sections: liquid phase transformation and solid phase transformation. The book, Colour Metallography of Cast Iron, uses colour metallography technique to study solidification structures of cast irons: graphite, carbides, austenite and eutectics; and focuses on solidification processes. With progress of modern solidification theory, the control of material solidification process becomes important measure for improving traditional materials and developing new materials. Solidification structure not only influences mechanical and physical properties of cast iron, but also affects its internal quality. The book uses a large amount of colour photos to describe the formation of solidification structures and their relations. Crystallization phenomena, which cannot be displayed with traditional metallography, are presented and more phase transformation information is obtained from these colour metallographic photos.Except for focusing on the effect of high carbon phases in cast iron, in this book, special attention is also paid to the effect of austenite on solidification, graphite morphology, and quality of cast iron; at the same time, the study on the solidification behaviours in the region around eutectic cells and its effects on mechanical properties of cast iron, are also emphasized.

Zhou Jiyang

2011-08-01

 
 
 
 
221

Colour Metallography of Cast Iron - White Cast Iron (?  

Directory of Open Access Journals (Sweden)

Full Text Available Cast iron, as a traditional metal material, has advantages of low total cost, good castability and machinability, good wear resistance and low notch sensitivity, and is still facing tough challenge in quality, property and variety of types etc. Experts and engineers studying and producing iron castings all around world extremely concern this serious challenge. Over more than 30 years, a great of research work has been carried out on how to further improve its property, expand its application and combine cast iron technology with some hi-techs (for example, computer technology. Nevertheless, cast iron is a multi-element and multi-phase alloy and has complex and variety of structures and still has great development potential in structure and property. For further studying and developing cast iron, theoretical research work is important promise, and the study on solidification process and control mechanism of graphite morphology is fundamental for improving property of cast iron and developing new type of cast iron. Metallography of cast iron normally includes two sections: liquid phase transformation and solid phase transformation. The book, Colour Metallography of Cast Iron, uses colour metallography technique to study solidification structures of cast irons: graphite, carbides, austenite and eutectics; and focuses on solidification processes. With progress of modern solidification theory, the control of material solidification process becomes important measure for improving traditional materials and developing new materials. Solidification structure not only influences mechanical and physical properties of cast iron, but also affects its internal quality. The book uses a large amount of colour photos to describe the formation of solidification structures and their relations. Crystallization phenomena, which cannot be displayed with traditional metallography, are presented and more phase transformation information is obtained from these colour metallographic photos. Except for focusing on the effect of high carbon phases in cast iron, in this book, special attention is also paid to the effect of austenite on solidification, graphite morphology, and quality of cast iron; at the same time, the study on the solidification behaviours in the region around eutectic cells and its effects on mechanical properties of cast iron, are also emphasized.

Zhou Jiyang

2011-11-01

222

Improved Foundry Castings Utilizing CAD/CAM.  

Science.gov (United States)

The CAD/Cam Casting process is being developed as an aid to casting engineers in designing better steel castings in a fraction of the time presently required. The computer routines incorporate drafting routines and computer assisted computations relative ...

T. Wassel J. Chevalier R. Nariman W. S. Hwang S. Miller

1981-01-01

223

Corrosion behavior of Mg–2.4Zn alloy micro-alloyed with Ag and Ca  

International Nuclear Information System (INIS)

Highlights: •Corrosion of four new cast Mg–Zn alloys in NaCl solution is carried out. •Effect of alloying addition (Ag, Ca, Ag + Ca) and ageing on corrosion is studied. •Size and distribution of precipitates play major role in corrosion. •Ca-containing alloys show good corrosion resistance. •Carbonate layer imparts good corrosion resistance to ZX60 and ZQX600 alloy. -- Abstract: The corrosion behavior of few cast Mg–Zn alloys, micro-alloyed with Ag and/or Ca (0.1 at.% each), has been investigated in 3.5 wt.% NaCl solution with the help of dynamic polarization, electrochemical impedance spectroscopy, and immersion tests. The effect of microstructures on corrosion behavior has been discussed thoroughly. The corrosion products formed on the immersed samples have been characterized by X-ray diffraction and Fourier transformed infrared spectroscopy. It has been observed that the Ca containing alloys show good corrosion resistance. This is attributed to the particular microstructure and carbonate-based protective film (corrosion products) formed on the surface

2014-01-01

224

Cast iron-base alloy for cylinder/regenerator housing  

Science.gov (United States)

NASACC-1 is a castable iron-base alloy designed to replace the costly and strategic cobalt-base X-40 alloy used in the automotive Stirling engine cylinder/generator housing. Over 40 alloy compositions were evaluated using investment cast test bars for stress-rupture testing. Also, hydrogen compatibility and oxygen corrosion resistance tests were used to determine the optimal alloy. NASACC-1 alloy was characterized using elevated and room temperature tensile, creep-rupture, low cycle fatigue, heat capacity, specific heat, and thermal expansion testing. Furthermore, phase analysis was performed on samples with several heat treated conditions. The properties are very encouraging. NASACC-1 alloy shows stress-rupture and low cycle fatigue properties equivalent to X-40. The oxidation resistance surpassed the program goal while maintaining acceptable resistance to hydrogen exposure. The welding, brazing, and casting characteristics are excellent. Finally, the cost of NASACC-1 is significantly lower than that of X-40.

Witter, Stewart L.; Simmons, Harold E.; Woulds, Michael J.

1985-01-01

225

Development of Lead-Free Copper Alloy-Graphite Castings  

Energy Technology Data Exchange (ETDEWEB)

In this project, graphite is used as a substitute for lead in order to maintain the machinability of plumbing components at the level of leaded brass. Graphite dispersed in Cu alloy was observed to impart good machinability and reduce the sizes of chips during machining of plumbing components in a manner similar to lead. Copper alloys containing dispersed graphite particles could be successfully cast in several plumbing fixtures which exhibited acceptable corrosion rate, solderability, platability, and pressure tightness. The power consumption for machining of composites was also lower than that of the matrix alloy. In addition, centrifugally cast copper alloy cylinders containing graphite particles were successfully made. These cylinders can therefore be used for bearing applications, as substitutes for lead-containing copper alloys. The results indicate that copper graphite alloys developed under this DOE project have a great potential to substitute for lead copper alloys in both plumbing and bearing applications.

Rohatgi, P.K. [Univ. of Wisconsin-Milwaukee (US)

1999-10-01

226

Use of electron microscopy on microstructure characterization of high chromium cast irons  

Directory of Open Access Journals (Sweden)

Full Text Available The physical metallurgy underlying the development of cast microstructures in abrasion resistant high chromium cast irons, and their structural modification by thermal treatments is relatively complex. Structural characterisation via electron microscopy therefore has a key role to play in furthering our understanding of the phase transformations that control the microstructures and hence the service performances of these irons as wear parts. This paper shows how both scanning and especially transmission electron microscopy can provide valuable information on the nature of eutectic and secondary carbides and on the matrix structures in these irons. Particular attention is given to current characterisation research on conventionally cast 30%Cr irons that are used for applications involving corrosive wear e.g. slurry pumps and on a semi-solid cast 27%Cr iron that has a potential for applications in industry.

J.T.H. Pearce

2007-02-01

227

Colour Metallography of Cast Iron  

Directory of Open Access Journals (Sweden)

Full Text Available Cast iron, as a traditional metal material, has advantages of low total cost, good castability and machinability, good wear resistance and low notch sensitivity, and is still facing tough challenge in quality, property and variety of types etc. Experts and engineers studying and producing iron castings all around world extremely concern this serious challenge. Over more than 30 years, a great of research work has been carried out on how to further improve its property, expand its application and combine cast iron technology with some hi-techs (for example, computer technology. Nevertheless, cast iron is a multi-element and multi-phase alloy and has complex and variety of structures and still has great development potential in structure and property. For further studying and developing cast iron, theoretical research work is important promise, and the study on solidification process and control mechanism of graphite morphology is fundamental for improving property of cast iron and developing new type of cast iron.Metallography of cast iron normally includes two sections: liquid phase transformation and solid phase transformation. The book, Colour Metallography of Cast Iron , uses colour metallography technique to study solidification structures of cast irons: graphite, carbides, austenite and eutectics; and focuses on solidification processes. With progress of modern solidification theory, the control of material solidification process becomes important measure for improving traditionalmaterials and developing new materials. Solidification structure not only influences mechanical and physical properties of cast iron, but also affects its internal quality. The book uses a large amount of colour photos to describe the formation of solidification structures and their relations. Crystallization phenomena, which cannot be displayed with traditional metallography, are presented and more phase transformation information is obtained from these colour metallographic photos.Except for focusing on the effect of high carbon phases in cast iron, in this book, special attention is also paid to the effect of austenite on solidification, graphite morphology, and quality of cast iron; at the same time, the study on the solidification behaviours in the region around eutectic cells and its effects on mechanical properties of cast iron, are also emphasized.

Zhou Jiyang

2009-05-01

228

Effect of heat treatment on corrosion resistance of WE54 alloy  

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Full Text Available Purpose: Poor corrosion resistance is one of the main causes to prevent magnesium alloys for wide applications.The addition of rare earth elements (RE is an effective way to improve corrosion resistance of magnesiumalloys. Heat treatment condition can also influence the corrosion behavior of magnesium alloys. The purpose ofthe investigation was to study the corrosion resistance of WE54 alloy after heat treatment.Design/methodology/approach: The study was conducted on WE54 alloy in the as-cast condition and after heattreatment at 250-300?C for periods of time 4 – 96 h. Immersion test was performed using not deaerated 3.5%NaCl solution at room temperature. Specimens were placed in 3.5% NaCl solution for periods of time betweenone and 7 days. The dissolution rates (mg cm-2 day-1 were determined by weight loss measurements. Afterimmersion test, the microstructure and the appearances of the corroded structure were examined by scanningelectron microscopy.Findings: The corrosion rate of WE54 alloy strongly depends on heat treatment condition. WE54 alloy in theas-cast and after solution treated have similar corrosion behavior, different from that of aged specimens. Thecurves of corrosion rate for aged specimens were higher than that for as-cast and solution treated conditions. Itwas also noticed that the longer time of ageing the higher corrosion rates were observed.Research limitations/implications: The knowledge about corrosion behavior of Mg-RE-Zr alloys is currentlyunder evaluation on many speciality applications where lightweight connected with optimum corrosionresistance are required.Practical implications: The knowledge about corrosion behavior of Mg-RE-Zr alloys is currently underevaluation on many speciality applications where lightweight connected with optimum corrosion resistance arerequired.Originality/value: This paper includes the effect of heat treatment condition on corrosion resistance of WE54magnesium alloy.

T. Rzycho?

2007-01-01

229

Synergistic effect of cavitation erosion and corrosion of various engineering alloys in 3.5% NaCl solution  

Energy Technology Data Exchange (ETDEWEB)

The cavitation erosion and corrosion characteristics of various engineering alloys including grey cast iron, steels, copper-based alloys and stainless steels were studied by means of a 20 kHz ultrasonic vibrator at a peak-to-peak amplitude of 30 {mu}m in distilled water and in 3.5% NaCl solution at 23 C. The contributions of pure mechanical erosion, electrochemical corrosion, and the synergism between erosion and corrosion to the overall cavitation erosion-corrosion in 3.5% NaCl solution were determined. It was found that in 3.5% NaCl solution, the effect of corrosion on the overall cavitation erosion-corrosion was most pronounced in mild steel and grey cast iron, and negligible in stainless steels. The stainless steels only suffered pure mechanical erosion in 3.5% NaCl solution in the presence of cavitation owing to the unfavourable local environment for pit growth. (orig.)

Kwok, C.T.; Cheng, F.T. [Hong Kong Polytechnic, Kowloon (Hong Kong). Dept. of Applied Physiscs; Man, H.C. [Department of Manufacturing Engineering, The Hong Kong Polytechnic University, Hung Hom,, Hong Kong, Kowloon (China)

2000-10-15

230

The Influence of Corrosion on the Microstructure of Thermally Treated ZA27/SiCp Composites  

Directory of Open Access Journals (Sweden)

Full Text Available The influence of corrosion on the microstructure of ZA27/SiCp composites was examined. The composites were produced by compo casting technique and then subjected to the thermal treatment (T4 regime. Microstructural examinations were performed after 30-day exposure of thermally treated composites in the sodium-chloride solution. Corrosion processes have occurred in the composite matrix. Corrosion did not affect SiC particles in the composites. The local progress of corrosion in depth of the composite matrix was noticed in micro-cracks. Corrosion resistance of ZA27/SiCp composites was evaluated based on the mass loss of composite samples during the immersion test. It was found that corrosion resistance of the composites decreased with increase in content of SiC particles. The applied thermal treatment had a negative influence on the corrosion resistance of ZA27/SiCp composites.

B. Bobi?

2014-03-01

231

Heart and Vascular Diseases  

Science.gov (United States)

... NHLBI Express FYI from the NHLBI Heart and Vascular Diseases Publication topics on this page: Cholesterol Congenital Heart ... Pressure Obesity and Physical Activity Other Heart and Vascular Diseases Peripheral Arterial Diseases Recipes Topics from the Diseases ...

232

Diabetes and Vascular Disease  

Science.gov (United States)

... eventually to amputation. Diabetes is linked to several vascular diseases: Retinopathy, which is an abnormal growth of blood ... Stroke Peripheral Artery Disease (PAD) Causes Diabetes causes vascular disease if there is too much glucose in the ...

233

Control of cast iron and casts manufacturing by Inmold method  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper the usability of cast iron spheroidizing process in mould control by ATD method as well as by ultrasonic method were presented. Structure of instrumentation needed for control form performance of cast iron spheroidizing by Inmold method was illustrated. Author, pointed out that amount of magnesium master alloy should obtain 0,8 ÷ 1,0% of mass in form at all. Such quantity of preliminary alloy assure of obtain of nodular graphite in cast iron. In consequence of this, is reduce t...

2009-01-01

234

The effect of defects at the steel - concrete interface, exposure regime and cement type on pitting corrosion in concrete  

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Abstract The effects of defects at the steel-concrete interface, the exposure regime, and the cement type, on the initiation of pitting corrosion in specially designed concrete corrosion cells were investigated. Concrete/mortar corrosion cells with cast-in mild steel electrodes representing the reinforcement were exposed for wetting-drying cycles or submerged in NaCl solution. ParalIei field exposure testes were carried out in sea water. The microstructure o...

Sandberg, Paul

1998-01-01

235

Corrosion resistance of Mg-RE-Zr alloys  

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Full Text Available Purpose: Magnesium alloys are widely used in the automotive and aerospace industries. Data concerning corrosion of Mg alloys are numerous, but those concerning Mg-RE alloys are scarce. In this paper, the corrosion behavior of cast magnesium alloys containing rare earth elements (WE54, WE43 and Elektron21 were investigated by immersion test in 3.5% NaCl for times up to 7 days.Design/methodology/approach: The study was conducted on WE54, WE43 and Elektron 21 alloys in the as-cast condition. Immersion test was performed using not deaerated 3.5% NaCl solution at room temperature. Several specimens were placed in 3.5% NaCl solution for periods of time between one and 7 days. The dissolution rates (mg/cm-2day-1 were determined by weight loss measurements.Findings: Elektron 21 alloy exhibits the highest corrosion rate during the immersion test, while WE54 and WE43 alloys had a similar corrosion behavior. The corrosion rates of WE54 and Elektron 21 alloys incresed lineally with increasing the exposure time in 3.5% NaCl, and that of WE43 was almost unchanged and finally reached maximum value 0.26 mg/cm-2day-1.Research limitations/implications: The knowledge about corrosion behavior of Mg-RE-Zr alloys is currently under evaluation on many speciality applications where lightweight connected with optimum corrosion resistance are requiredPractical implications: The comparative results of corrosion behavior of new Mg-RE-Zr alloys leads to optimum choice of alloy for application in automotive, aircraft and aerospace industries.Originality/value: This paper includes the comparative results of corrosion resistance investigations of new Mg-RE–Zr alloys.

A. Kie?bus

2007-03-01

236

A Quantitative Approach to Casting Solidification: Freezing of Cast Iron.  

Science.gov (United States)

The separate processes involved in casting solidification, such as eutectic nucleation and growth, have been previously studied separately in controlled experiments. The interaction of the separate processes has now been treated, using the freezing of cas...

W. Oldfield

1966-01-01

237

Strip casting with fluxing agent applied to casting roll  

Science.gov (United States)

A strip caster (10) for producing a continuous strip (24) includes a tundish (12) for containing a melt (14), a pair of horizontally disposed water cooled casting rolls (22) and devices (29) for electrostatically coating the outer peripheral chill surfaces (44) of the casting rolls with a powder flux material (56). The casting rolls are juxtaposed relative to one another for forming a pouting basin (18) for receiving the melt through a teeming tube (16) thereby establishing a meniscus (20) between the rolls for forming the strip. The melt is protected from the outside air by a non-oxidizing gas passed through a supply line (28) to a sealing chamber (26). A preferred flux is boron oxide having a melting point of about 550.degree. C. The flux coating enhances wetting of the steel melt to the casting roll and dissolves any metal oxide formed on the roll.

Williams, Robert S. (Fairfield, OH); O'Malley, Ronald J. (Miamisburg, OH); Sussman, Richard C. (West Chester, OH)

1997-01-01

238

Instant Casting Movie Theater: The Future Cast System  

Science.gov (United States)

We have developed a visual entertainment system called “Future Cast” which enables anyone to easily participate in a pre-recorded or pre-created film as an instant CG movie star. This system provides audiences with the amazing opportunity to join the cast of a movie in real-time. The Future Cast System can automatically perform all the processes required to make this possible, from capturing participants' facial characteristics to rendering them into the movie. Our system can also be applied to any movie created using the same production process. We conducted our first experimental trial demonstration of the Future Cast System at the Mitsui-Toshiba pavilion at the 2005 World Exposition in Aichi Japan.

Maejima, Akinobu; Wemler, Shuhei; Machida, Tamotsu; Takebayashi, Masao; Morishima, Shigeo

239

CAST results and Axion review  

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We present results from the CERN Axion Solar Telescope (CAST) and the Axion Dark Matter eXperiment (ADMX), together with a brief review on prospects on Axion searches with a variety of experimental techniques. CAST has explored masses up to 0.64 eV setting the most stringent limit on the axion-photon coupling, apart for the micro-eV region where ADMX is the most competitive experiment. CAST is aiming at surpassing the 1eV WMAP upper limit and possibly revisiting the operatio...

Geralis, T.; Collaboration, For The Cast

2009-01-01

240

Initiation of vascular development.  

Science.gov (United States)

The initiation of vascular development occurs during embryogenesis and the development of lateral organs, such as lateral roots and leaves. Understanding the mechanism underlying the initiation of vascular development has been an important goal of plant biologists. Auxin flow is a crucial factor involved in the initiation of vascular development. In addition, recent studies have identified key factors that regulate the establishment of vascular initial cells in embryos and roots. In this review, we summarize the recent findings in this field and discuss the initiation of vascular development. PMID:24111590

Ohashi-Ito, Kyoko; Fukuda, Hiroo

2014-06-01

 
 
 
 
241

Colour Metallography of Cast Iron - White Cast Iron (?)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Cast iron, as a traditional metal material, has advantages of low total cost, good castability and machinability, good wear resistance and low notch sensitivity, and is still facing tough challenge in quality, property and variety of types etc. Experts and engineers studying and producing iron castings all around world extremely concern this serious challenge. Over more than 30 years, a great of research work has been carried out on how to further improve its property, expand its application ...

2011-01-01

242

Colour Metallography of Cast Iron - Chapter 5: White Cast Iron (?)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Cast iron, as a traditional metal material, has advantages of low total cost, good castability and machinability, good wear resistance and low notch sensitivity, and is still facing tough challenge in quality, property and variety of types etc. Experts and engineers studying and producing iron castings all around world extremely concern this serious challenge. Over more than 30 years, a great of research work has been carried out on how to further improve its property, expand its application ...

2011-01-01

243

The mechanism of the end grain corrosion of stainless steel in nitric acid solutions and its prevention  

International Nuclear Information System (INIS)

Austenitic stainless steels with low carbon content have good corrosion resistance in nitric acid solutions. However, these steels are susceptible to corrosion in nitric acid solutions which contain highly oxidizing ions such as Cr2O72-, Run+ etc. One of these is called 'End Grain Corrosion' or 'Tunnelling Corrosion'. In this type of corrosion, a part of the cross-section of plate is preferentially attacked severely. In this study, it was clarified that the end grain corrosion was caused by intergranular corrosion (IGC) at phosphorus segregated areas which were induced during casting. And it was also found that the decrease of P content less than 0.015%, and heat treatments to reduce segregation of P were very effective to prevent the end grain corrosion. (author)

1995-08-01

244

Effect of Al additions and heat treatment on corrosion properties of Mg-Al based alloys  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: In this paper there is presented the corrosion behavior of cast magnesium alloys in as cast state and after heat treatment.Design/methodology/approach: The following results concern scanning electron microscopy investigations in the SE as well BSE observation mode, for better phase contrast results, also qualitative microanalysis was applied for chemical composition investigations of the surface. Pitting corrosion resistance was carried out using the potentiodynamic electrochemical method (direct current, based on anodic polarisation curve. Based on the achieved anodic polarisation curves, using the Tefel extrapolation method near to the corrosion potential, the quantitative data were determined, which describe the electrochemical corrosion process of the investigated alloys: value of the corrosion potential Ecor (mV, polarisation resistance Rp (k?/cm2, corrosion current density icor (?A/cm2, corrosion rate Vp (mm/year as well the mass loss Vc (g/m2.Findings: Surface morphology of the samples after corrosion test performed after and before heat treatment show irregular shaped pinholes and numerous cracks on the material surface layer.Research limitations/implications: The applied cooling rate and alloy additions seems to be a good compromise for properties and microstructures, nevertheless further tests should be carried out in order to examine different cooling rates and parameters of solution treatment process and aging process.Practical implications: Investigation results concerning the surface layer presents some interesting findings connected to the layer morphology, which can be of high interest for practical application for the reason of better layer quality as well as surface layer properties. Limitation of surface damage including irregular shaped pinholes and numerous cracks is of very high importance for decreasing the influence of pitting corrosion onto the surface layer corrosion resistance in very width range o applications.Originality/value: The value of this paper is to define the influence of heat treatment parameters and aluminium addition on corrosion resistance properties of magnesium-aluminium cast alloys.

L.A. Dobrza?ski

2011-01-01

245

DEGRADATION WORKS OF MONUMENTAL ART CAST BRONZE UNDER THE INFLUENCE OF ENVIRONMENTAL FACTORS  

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Full Text Available Intensive pollution, combined with the lack of conservation of monuments exposed to these environments make the main cause of deterioration of cultural objects to atmospheric corrosion metal. This paper proposes a study of the main factors leading to degradation Bronze alloy, cast bronze monuments exposed to open atmosphere: corrosive environmental factors, stability and products of corrosion of bronze. In general, all corrosion products present on a metal surface are indicated as 'skate', can be composed of single-layer or multilayer products. The paper also includes a case study on the influence of environmental factors on degradation Matthias monument statue in Cluj-Napoca, Romania. Visual inspection of the monument informs us that have white spots, gray, reddish not consistent with the base color green patina, surfaces showing depigmentation, the rain washed areas, crystallization, deposition of air-borne particles.

Delia NICA-BADEA

2012-11-01

246

Pipe Lines – External Corrosion  

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Two areas of corrosion occur in pipe lines: corrosion from the medium carried inside the pipes; corrosion attack upon the outside of the pipes (underground corrosion. Electrolytic processes are also involved in underground corrosion. Here the moisture content of the soil acts as an electrolyte, and the ions required to conduct the current are supplied by water-soluble salts (chlorides, sulfates, etc.) present in the soil. The nature and amount of these soluble materials can vary within a wide...

Dan Babor

2008-01-01

247

Towards Corrosion Detection System  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Corrosion is a natural process that seeks to reduce the binding energy in metals. The end result of corrosion involves a metal atom being oxidized. Surface corrosion on aluminum aircraft skins, near joints and around fasteners, is often an indicator of buried structural corrosion and cracking In this paper we proposed a new method on which we are moving towards designing a method to detect the corrosion within the metals, the new method has defined texture analysis as the main method for this...

Zaidan, B. B.; Zaidan, A. A.; Alanazi, Hamdan O.; Rami Alnaqeib

2010-01-01

248

Long term stability analysis of cast iron shaft linings after Coal Mine closure and flooding  

International Nuclear Information System (INIS)

This paper presents the results of a study conducted to analyse the long term stability of the cast iron shaft lining after coal mine closure and flooding. The attention is mainly focused on the behaviour during the critical phase of flooding as well as the phase corresponding to the disappearance of the water pressure and the stabilization of the environment. This pluri-disciplinary study was conducted by a team combining specialists in rock mechanics who identified the main risks and the conditions of stability of the lining and specialists in metallurgy who studied the composition of the cast iron and its corrosion behaviour after exposure to mine water. (authors)

2005-11-16

249

Long term stability analysis of cast iron shaft linings after Coal Mine closure and flooding  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the results of a study conducted to analyse the long term stability of the cast iron shaft lining after coal mine closure and flooding. The attention is mainly focused on the behaviour during the critical phase of flooding as well as the phase corresponding to the disappearance of the water pressure and the stabilization of the environment. This pluri-disciplinary study was conducted by a team combining specialists in rock mechanics who identified the main risks and the conditions of stability of the lining and specialists in metallurgy who studied the composition of the cast iron and its corrosion behaviour after exposure to mine water. (authors)

Hadj-Hassen, F. [Ecole des Mines de Paris - CGES, 77 - Fontainebleau (France); Bienvenu, Y. [Ecole des Mines de Paris, CM, 91 - Evry (France); Noirel, J.F. [Charbonnages de France, DTN, 57 - Freyming Merlebach (France); Metz, M. [charbonnages de France, ESA, 57 - Freyming Merlebach (France)

2005-07-01

250

Tribocorrosion studies in centrifugally cast al-matrix siCp-reinforced functionally graded composites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The present work reports results obtained from a series of preliminary experiments aiming at complementing the current knowledge about the wear behaviour of centrifugally-cast FGM Al/SiCp composites, through concurrent corrosion processes. Precursor MMC’s were prepared by rheocasting, using 118.8 µm SiC particles and an Al-10Si–2.2 Mg alloy. Those MMC’s were then molten and centrifugally cast in order to produce cylindrical FGMMC’s. Discs machined from the top surface of each s...

Velhinho, A.; Botas, J. D.; Ariza, E.; Gomes, J. R.; Rocha, L. A.

2004-01-01

251

Deconstructing the Caste Hegemony: Lambada Oral Literature  

Directory of Open Access Journals (Sweden)

Full Text Available Indian society is very carefully and dexterouslystratified on the basis of castes and sects. This carefulnessand dexterity are used not only to divide the society intothousands of sections but also to protect and preserve thissystem for ages, banning and barring mobility andinteraction between castes. Each caste has a caste lowerthan itself in hierarchy. Even the most downtrodden anddiscriminated against section like “untouchables” are dividedsharply among themselves according to their castes andpractice untouchability against one another. Subservience toone caste and subjugating another caste will put eachcaste’s agenda, position and attitude in tact by making itrigid in its hierarchical behaviour.

Suneetha Rani Karamsi

2010-05-01

252

Niobium in gray cast iron  

International Nuclear Information System (INIS)

The potential for utilization of niobium in gray cast iron is appraised and reviewed. Experiments described in literature indicate that niobium provides structural refinement of the eutectic cells and also promotes pearlite formation. (Author)

1984-01-01

253

Direct Cast Titanium Alloy Strip.  

Science.gov (United States)

This research project successfully demonstrated the feasibility of induction melting titanium alloys in a segmented copper crucible and casting them into solid strip up to 300 mm (12 in) wide from a unique graphite tundish using melt overflow rapid solidi...

H. L. Fraser L. E. Hackman M. Aindow T. A. Gasper

1990-01-01

254

A New 'Shell Casting' Technic.  

Science.gov (United States)

A new shell investment was formulated that hardened rapidly enough so that consecutive layers could be applied to a wax pattern without requiring intermediate drying cycles between each layer. This new 'shell casting investment' is a two component system....

E. R. Dootz R. G. Craig F. A. Peyton

1966-01-01

255

Casting Using A Polystyrene Pattern  

Science.gov (United States)

New technique for making metal aircraft models saves significant amount of time and effort in comparison with conventional lost-wax method. Produces inexpensive, effective wind-tunnel models. Metal wind-tunnel model cast by use of polystyrene pattern.

Vasquez, Peter; Guenther, Bengamin; Vranas, Thomas; Veneris, Peter; Joyner, Michael

1993-01-01

256

Colour Metallography of Cast Iron  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Cast iron, as a traditional metal material, has advantages of low total cost, good castability and machinability, good wear resistance and low notch sensitivity, and is still facing tough challenge in quality, property and variety of types etc. Experts and engineers studying and producing iron castings all around world extremely concern this serious challenge. Over more than 30 years, a great of research work has been carried out on how to further improve its property, expand its application ...

2009-01-01

257

Virtualisation of casting engineering  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: Fast response to an enquiry, minimization of costs of identification of best-suited process solution, as well as a capacity to tackle new challenges is the shortest description of the requirements posed by the contemporary market of machines and equipment. These, in consequence, called for making use of mathematical models and their solution by means of simulation algorithms.Design/methodology/approach: The notable effectiveness of numerical methods streamlined the production preparation process. Maintaining competitiveness, even more tough because of economic factors, is only possible due to cost-effective operation, high quality and well-timed order completion. These, on the other hand, can be facilitated by a broad application of IT tools aiding production management and preparation.Findings: Integration of systems aiding design processes, systems used for simulating selected elements of technologies, as well as of systems supporting instrumentation manufacturing calls for a need to solve a number of complex problems related to IT, mathematical modelling, logistics and knowledge management. Software packages for a simulation of processes that are indispensable in order to achieve the designed distribution of matter structures and condition are of particular importance.Research limitations/implications: Despite the fact that there is a wide range of software for these purposes available on the market, there is a need to build and integrate into IT systems new purpose-developed solutions customised to technologies applied and non-standard problems.Originality/value: Virtualization of casting engineering

J.S. Suchy

2007-09-01

258

Inoculation of chromium white cast iron  

Directory of Open Access Journals (Sweden)

Full Text Available It has been proved that an addition of boron carbide introduced as an inoculant to the chromium white cast iron changes the structureof castings. Castings after inoculation revealed a different structure with numerous grains. Primary precipitates of chromium carbide also appeared, reducing the mechanical properties of as-cast parts. Properly established heat treatment regime makes chromium iron castings regain their, originally high, mechanical properties.

D. Kopyci?ski

2009-01-01

259

Manufacturing synthetic cast iron for NPP components  

International Nuclear Information System (INIS)

The process of producing synthetic cast iron grade SCH30-SCH40 to manufacture cast parts for NPPs with the use of melting in commercial frequency induction furnaces has been developed and introduced. Strict observation of the manufacturing procedure permits to obtain high-quality cast iron with flake graphite for NPP main castings without using expensive modifiers. Cast iron smelted according to the suggested technology is characterized by high strength indices at tension (400 MPa) and bending (540 MPa)

1984-01-01

260

Geometric aspects of the casting process  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Manufacturing is the process of converting raw materials into useful products. Among the most important manufacturing processes, casting is a commonly used manufacturing process for plastic and metal objects. The industrial casting process consists of two stages. First, liquid is filled into a cavity formed by two cast parts. After the liquid has hardened, one cast part retracts, carrying the object with it. Afterwards, the object is ejected from the retracted cast part. In both retraction an...

Ahn, H. -k

2001-01-01

 
 
 
 
261

Corrosion resistance of Elektron 21 magnesium alloy  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: Elektron 21 magnesium alloy containing neodymium, gadolinium and zinc has high strength, good corrosion resistance and excellent castability. It is designed mainly for aerospace applications. The purpose of the investigation was to study the corrosion resistance of Elektron 21 magnesium alloy in as cast condition and after heat treatment in 3.5% NaCl saturated with Mg(OH2 solution.Design/methodology/approach: Solution treatment was performed at 525°C/8h/water, while ageing treatments at following conditions 250°C/4-96h/air. Immersion test was performed in 3.5% NaCl saturated with Mg(OH2 solution at room temperature. Specimens were placed in 3.5% NaCl solution for periods of time between one and 5 days. After immersion test, the microstructure and the appearances of the corroded structure were examined by optical microscopy (Olympus GX-70 and a scanning electron microscopy (Hitachi S3400.Findings: The corrosion rates of Elektron 21 alloy increased with increasing the exposure time and finally (after 5 days reached maximum value 0.092 mg/cm-2day-1. Solution treatment at 520°C for 8 h caused decrease in corrosion rate (0.072 mg cm-2 day-1 due to dissolving of intermetallic phase precipitates at matrix. Ageing at 200°C for 4h and 16h caused next decrease in corrosion rate to value 0.052 and 0,055 mg cm-2 day-1 respectively, while after ageing for 48h corrosion rate increase to value 0.067 mg cm-2 day-1, due to increase of volume fraction and size of ?’ phase and precipitations of equilibrium ? phase. It was also noticed that the longer time of ageing the higher corrosion rates were observed.Research limitations/implications: Future researches should include investigations of the influence of other environments on the corrosion resistance of Elektron 21 alloy.Practical implications: The improvement of corrosion resistance of Elektron 21 alloy can cause increase in it application in aerospace industry.Originality/value: The relationship between the ageing parameters, microstructure and corrosion resistance in Elektron 21 magnesium alloy was specified.

A. Kie?bus

2007-05-01

262

Corrosion testing of selected packaging materials for disposal of high-level waste glass in rock-salt formations  

International Nuclear Information System (INIS)

In previous corrosion studies performed in salt brines, unalloyed steels, Ti 99.8-Pd and Hastelloy C4 have proved to be the most promising materials for long-term resistant packagings to be used in heat-generating waste (vitrified HLW, spent fuel) disposal in rock-salt formations. Investigations of the iron-base materials Ni-Resist D2 and D4, cast iron and Si-cast iron have also been carried out in order to complete the results available to date. The three steels (fine-grained steel, low-carbon steel, cast steel) investigated and Ti 99.8-Pd resisted pitting and crevice corrosion as well as stress-corrosion cracking under all test conditions. Gamma dose-rates of 1 Gy/h - 100 Gy/h or H_2S concentrations in the brines as well as welding and explosion plating did not influence noticeably the corrosion behaviour of the materials. Furthermore, the determined corrosion rates of the steels (50 ?m/a-250 ?m/a, depending on the test conditions) are intercomparable and imply technically acceptable corrosion allowances for the thick-walled containers discussed. For Ti 99.8-Pd no detectable corrosion was observed. By contrast, Hastelloy C4 proved susceptible to pitting and crevice corrosion at gamme dose-rates higher than 1 Gy/h and in the presence of H_2S (25 mg/l) in Q-brine. The materials Ni Resist D2 and D4, cast iron and Si-cast iron corroded at negligible rates in the in-situ experiments performed in rock salt/limited amounts of NaCI-brine. Nevertheless, these materials must be ruled out as container materials because they have proved to be susceptible to pitting and intergranular corrosion in previous laboratory studies conducted with MgCI_2-rich brine (Q-brine) in excess. 15 refs.; 29 figs.; 7 tabs

1991-01-01

263

Unique intermetallics combat wear and corrosion  

International Nuclear Information System (INIS)

Properties of Tribaloy materials are reviewed. Examination of these materials shows that both high-temperature wear and corrosion resistance are provided by dispersing a hard intermetallic phase in a softer cobalt or nickel-base alloy matrix. The materials are supplied as powders which can be plasma sprayed or hot isostatically pressed into 99.5 percent dense parts. Most grades can be shell mold or investment cast; and Tribaloy welding rods are available for hardfacing applications. Tribaloy powders can also be blended with other powders, such as nickel or Monel. The blend can then be plasma sprayed or compacted by conventional P/M techniques. (U.S.)

1975-01-01

264

Corrosion test of structural materials for thermo-chemical and electrolytic hybrid hydrogen production cycle  

International Nuclear Information System (INIS)

Corrosion behavior of structural materials for thermo-chemical and electrolytic hydrogen production cycle was investigated in liquid and gaseous sulfuric acid in the temperature range of 200-500degC. The cycle is one of the hydrogen production methods using sulfuric acid and the maximum temperature through the processes is about 500degC. In this study, corrosion tests of candidate structural materials for equipment of the hydrogen production plant were performed at the conditions each equipment will be used. The concentration of sulfuric acid was 95 mass% in all experiments and maximum test duration was 500 h. Only high Si cast iron had good corrosion resistance in the boiling sulfuric acid, whereas high Si cast iron and Hastelloy C276 had good corrosion resistance in the sulfurous acid gas atmosphere (vaporized sulfuric acid or mixture of sulfur dioxide and water vapor). Furthermore, post test analysis by optical microscope and SEM-EDX were performed. (author)

2006-12-01

265

General corrosion, irradiation-corrosion, and environmental-mechanical evaluation of nuclear-waste-package structural-barrier materials. Progress report  

International Nuclear Information System (INIS)

Pacific Northwest Laboratory is studying the general corrosion, irradiation-corrosion, and environmentally enhanced crack propagation of five candidate materials in high-temperature aqueous environments simulating those expected in basalt and tuff repositories. The materials include three cast ferrous materials (ductile cast iron and two low-alloy Cr-Mo cast steels) and two titanium alloys, titanium Grade 2 (commercial purity) and Grade 12 (a Ti-Ni-Mo alloy). The general corrosion results are being obtained by autoclave exposure of specimens to slowly replenished simulated ground water flowing upward through a bed of the appropriate crushed rock (basalt or tuff), which is maintained at the desired test temperature (usually 250"0C). In addition, tests are being performed in deionized water. Metal penetration rates of iron-base alloys are being derived by stripping off the corrosion product film and weighing the specimen after the appropriate exposure time. The corrosion of titanium alloy specimens is being determined by weight gain methods. The irradiation-corrosion studies are similar to the general corrosion tests, except that the specimen-bearing autoclaves are held in a "6"0Co gamma radiation field at dose rates up to 2 x 10"6 rad/h. For evaluating the resistance of the candidate materials to environmentally enhanced crack propagation, three methods are being used: U-bend and fracture toughness specimens exposed in autoclaves; slow strain rate studies in repository-relevant environments to 300"0C; and fatigue crack growth rate studies at ambient pressure and 90"0C. The preliminary data suggest a 1-in. corrosion allowance for iron-base barrier elements intended for 1000-yr service in basalt or tuff repositories. No evidence has yet been found that titanium Grade 2 or Grade 12 is susceptible to environmentally induced crack propagation or, by extension, to stress corrosion cracking

1982-01-01

266

Surface properties and corrosion behavior of Co-Cr alloy fabricated with selective laser melting technique.  

Science.gov (United States)

We sought to study the corrosion behavior and surface properties of a commercial cobalt-chromium (Co-Cr) alloy which was fabricated with selective laser melting (SLM) technique. For this purpose, specimens were fabricated using different techniques, such as SLM system and casting methods. Surface hardness testing, microstructure observation, surface analysis using X-ray photoelectron spectroscopy (XPS) and electrochemical corrosion test were carried out to evaluate the corrosion properties and surface properties of the specimens. We found that microstructure of SLM specimens was more homogeneous than that of cast specimens. The mean surface hardness values of SLM and cast specimens were 458.3 and 384.8, respectively; SLM specimens showed higher values than cast ones in hardness. Both specimens exhibited no differences in their electrochemical corrosion properties in the artificial saliva through potentiodynamic curves and EIS, and no significant difference via XPS. Therefore, we concluded that within the scope of this study, SLM-fabricated restorations revealed good surface properties, such as proper hardness, homogeneous microstructure, and also showed sufficient corrosion resistance which could meet the needs of dental clinics. PMID:23553145

Xin, Xian-zhen; Chen, Jie; Xiang, Nan; Wei, Bin

2013-12-01

267

Zinc-The key to preventing corrosion  

Science.gov (United States)

Centuries before it was identified as an element, zinc was used to make brass (an alloy of zinc and copper) and for medicinal purposes. Metallic zinc and zinc oxide were produced in India sometime between the 11th and 14th centuries and in China in the 17th century, although the discovery of pure metallic zinc is credited to the German chemist Andreas Marggraf, who isolated the element in 1746. Refined zinc metal is bluish-white when freshly cast; it is hard and brittle at most temperatures and has relatively low melting and boiling points. Zinc alloys readily with other metals and is chemically active. On exposure to air, it develops a thin gray oxide film (patina), which inhibits deeper oxidation (corrosion) of the metal. The metal's resistance to corrosion is an important characteristic in its use.

Kropschot, S.J.; Doebrich, Jeff L.

2011-01-01

268

Corrosion of container materials under clay repository conditions  

International Nuclear Information System (INIS)

The work done in Belgium on steels and a number of corrosion-resistant materials is discussed. Laboratory screening tests have been performed to find candidate container materials. Materials of interest have been further tested in surface clays and are being tested in deep clay formations at the Mol site. These tests have concentrated on characterizations of the clay environment under equilibrium and disturbed conditions. The performance of some materials will be monitored for up to 50000 hours in the form of conventional corrosion specimens. Eventually corrosion and performance tests will be performed on full-size or scaled-down containers. The effects of parameters identified as being important based on characterization of the clay environment will be studied further in the laboratory. Electrochemical measurements and experiments on the effects of gamma radiation have been started. The materials that have been tested in clay environments include corrosion allowance materials - carbon steel, unalloyed cast iron, and cast iron alloyed with silicon and nickel - as well as corrosion resistant materials: AISI 304, 316 and 430 stainless steels; aluminum alloys; nickel 200; Inconel 600 and 625; Incoloy 800; Hastelloy C4 and B; and titanium grades 2 and 7

1990-01-01

269

Vascular malformations in pediatrics  

International Nuclear Information System (INIS)

Vascular malformations are the cause of nearly all non-traumatic intracranial hemorrhage in children beyond the neonatal stage. Therefore, any child presenting with spontaneous intracranial hemorrhage should be evaluated for child abuse and for vascular malformations. Intracerebral malformations of the cerebral vasculature include vein of Galen malformations, arteriovenous malformation (AVM), cavernomas, dural arteriovenous fistulas, venous anomalies (DVA), and capillary teleangiectasies. Although a few familial vascular malformation have been reported, the majority are sporadic. Clinical symptoms, diagnostic and therapeutic options are discussed. (orig.)

2003-11-01

270

Vascular Precursor Cells  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Understanding the mechanisms that regulate the proliferation and differentiation of human stem and progenitor cells is critically important for the development and optimization of regenerative medicine strategies. For vascular regeneration studies, specifically, a true “vascular stem cell” population has not yet been identified. However, a number of cell types that exist endogenously, or can be generated or propagated ex vivo, function as vascular precursor cells and can participate in an...

Chaudhury, Hera; Goldie, Lauren C.; Hirschi, Karen K.

2011-01-01

271

Arginase and vascular aging  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Vascular and associated ventricular stiffness is one of the hallmarks of the aging cardiovascular system. Both an increase in reactive oxygen species production and a decrease in nitric oxide (NO) bioavailability contribute to the endothelial dysfunction that underlies this vascular stiffness, independent of other age-related vascular pathologies such as atherosclerosis. The activation/upregulation of arginase appears to be an important contributor to age-related endothelial dysfunction by a ...

2008-01-01

272

Corrosion performance of Al-base metal-matrix-composites (MMC). Al ki MMC no taishokusei  

Energy Technology Data Exchange (ETDEWEB)

Stress corrosion cracking (SCC) and pitting corrosion resistances were studied of 6061 and 7075 Al-base metal-matrix-composites (MMC). The MMC was prepared by squeeze casting method in the laboratory, and SiC whisker, Al{sub 2}O{sub 3} and carbon fibers were used as reinforcements. The SCC resistance was evaluated by small strain rate tensile test (SSRT), and the pitting corrosion resistance was determined with a pitting potential through potentio-dynamic polarization. The conductive reinforcement fibers deteriorated the corrosion resistance of the MMC, while the non-conductive fibers had no effect on the corrosion resistance although had effect on cathodic reaction in corrosion. In the 6061 Al matrix with no SCC susceptibility, the MMC offered no SCC resistant susceptibility, while in the 7075 Al matrix with different SCC susceptibilities due to heat treatment, the SCC susceptibility of the MMC corresponded to the SCC resistance of the matrix. 13 refs., 9 figs., 4 tabs.

Shimizu, Y.; Nishimura, T.; Tamura, M. (NKK Co., Kanagawa (Japan). Steel Research Center)

1991-06-15

273

Research on the squeeze cast technology of the castings with large ratio of height to thickness  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The squeeze cast technology is only applicable, at present, to the castings with a ratio of height to thickness less than 3.5. Researching the squeeze cast technology for castings with a large ratio of height to thickness will broaden the applicable range of the advanced casting technology. This paper describes a study of the temperature distribution during solidification for castings with a ratio of height to thickness of 7 by the methods of experiment and computer simulation. The shrinkage ...

2005-01-01

274

Vascular endothelial growth factor and vascular homeostasis.  

Science.gov (United States)

Vascular endothelial growth factor (VEGF) is the angiogenic factor promoting and orchestrating most, if not all, processes of neovascularization taking place in the embryo and the adult. VEGF is also required to sustain newly formed vessels and plays additional multiple roles in the maintenance and function of certain mature vascular beds. Correspondingly, perturbations in VEGF signaling may impact organ homeostasis in multiple ways. Here we briefly review potential consequences of VEGF loss of function in adult organs. Different vascular beds display highly variable dependencies on VEGF for survival, and its loss of function may trigger the regression of many VEGF-dependent vasculatures. Normal turnover of blood vessels, in conjunction with the fact that VEGF is indispensable for compensatory angiogenesis to restore adequate perfusion, accounts for progressive vascular rarefaction under conditions of chronic VEGF inhibition of even vasculatures that are not intrinsically dependent on VEGF. Because blood vessels may have paracrine functions other than their traditional role in tissue perfusion, vascular regression resulting from VEGF withdrawal may cause substantial collateral tissue damage. VEGF may also impact tissue homeostasis via acting directly on nonvascular cells expressing cognate receptors. In the particular case of the lung, constitutive abundant expression of VEGF together with the fact that its receptors are distributed on both endothelial and epithelial cells is compatible with multiple homeostatic VEGF functions in the adult lung. Indeed, experimental inhibition of VEGF in the mature lung produces lesions resembling common lung pathologies, including emphysema and respiratory distress syndrome. PMID:22052928

Lazarus, Alon; Keshet, Eli

2011-11-01

275

[Pulmonary vascular disease].  

Science.gov (United States)

This review article discusses three topics related to pulmonary vascular disease: 1) pulmonary vascular changes associated with portal hypertension, 2) ANCA-associated pulmonary vasculitis, and 3) Takayasu's arteritis. Hepatopulmonary syndrome and pulmonary hypertension have recently been reported as pulmonary vascular changes accompanied with portal hypertension. Endogenous vasoactive agents that reach the pulmonary circulation through porto-systemic shunt vessels are thought to contribute to these vascular changes. In ANCA-associated vasculitis, hemorrhage, interstitial pneumonitis, and nodular lesions are common manifestations in the lung. In Takayasu's arteritis, CT occasionally demonstrates mosaic attenuation owing to pulmonary arteritis and peripheral reticulolinear changes probably due to thromboembolism. PMID:11321813

Takahashi, K

2001-03-01

276

Corrosion Studies on Concrete Using Treated and Untreated Textile Effluent and Impact of Corrosion Inhibitor  

Directory of Open Access Journals (Sweden)

Full Text Available An attempt was made to use the waste water from textile industry for construction purpose, so that the shortage in water can be greatly reduced and the waste water can be suitably disposed for safe guarding the environment.  The basic properties of the treated and untreated water from the textile industry were tested and the results were found to be satisfactory such that it can be used for construction purposes.  By using the waste water from the textile industry cubes, cylinders and beams were casted and tested for its mechanical properties (compressive strength, tensile strength, flexural strength etc and the result was found to be satisfactory.  Hence the experiment was continued on for durability studies where the corrosion attack was also studied.  The results of other durability studies were found to be satisfactory.  In this experimental study the results of specimen’s casted using treated and untreated textile water were compared with the specimens casted with potable water.  Since there was some corrosion, admixtures were added to counter act the same and the results were found to be satisfactory. 

K Nirmalkumar

2009-02-01

277

Microvascularization on collared peccary placenta : a microvascular cast atudy in late pregnancy  

DEFF Research Database (Denmark)

The microvascularization of the collared peccary (Tayassu tajacu) placenta was studied by vascular casts and immunolocalization of a-smooth muscle actin and vimentin, to identify the three dimensional organization and vascular flow interrelation in the microvasculature between the maternal and fetal compartments of the placentae. The immunolocalization of vimentin in the vascular endothelium and in the smooth muscle cells of blood vessels showed indented capillaries along the uterine epithelium and the trophoblast at the sides of complementary maternal and fetal microfolds, or rugae. This confers the three-dimensional structure observed in vascular casts. On the maternal side, casts demonstrated uterine folds coated by with primary and secondary ridges, and by areolae dispersed between these ridges. The arteriole runs through the center/middle of ridges, branching at the top into a microvascular network wall in a basket-like fashion. At the base of these baskets venules were formed. On the fetal side, arterioles branched centrally in the fetal rugae into a capillary network in a bulbous form, complementary to the opposite maternal depressions forming the baskets. At the base of the bulbous protrusions, the fetal venules arise. The blood vessel orientation in the materno-fetal interface of the placentae of collared peccaries suggests a blood flow pattern of the type countercurrent to cross current. The same pattern has been reported in domestic swine demonstrating that, even after 38 million years, the Tayassuidae and Suidae families exhibit similar placental morphology, which is here characterized at the microvascular level.

Santos, Tatiana Carlesso; Oliveira, Moacir Franco

2012-01-01

278

Development of vacuum die-casting process  

Directory of Open Access Journals (Sweden)

Full Text Available The vacuum die-casting process, started 25 years ago in Japan, has been widely applied. This technology contributes very much to improvement of castings quality. The main factor causing the defects of die castings is the trapped air in the mold cavity, while the key technology of vacuum die-casting process is to avoid the trapped air effectively by evacuating the cavity before casting. At the same time, due to the shot speed and the casting pressure reduced in half, the service life of the die is prolonged and the productivity is enhanced, as well. Vacuum die-casting process is of great signifi cance in improving the die castings quality and making up the shortcomings of super-high-speed shot casting.

Masashi Uchida

2009-05-01

279

Experience of corrosion and corrosion protection in seawater systems in the Nordic countries  

Energy Technology Data Exchange (ETDEWEB)

A summary is given of the experience of the corrosion resistance of pumps, heat exchangers, valves and pipings in different seawater cooling systems in Denmark, Finland, Norway and Sweden. For pumps and heat exchangers the experience have been so extensive that a clear picture of today's status can be given. Owing to more scanty data concerning valves and pipes the survey of the corrosion in these components is less well substantiated. The commonest pumps in the cooling systems of power stations are vertically extended shaft pumps. To counteract corrosion on column and casing with organic surface coating and on stainless steel shafts and impellers under shutdown conditions, these should be provided with internal and external cathodic protection. For heat exchangers, both tube and plate, titanium has proved to be far and away the best choice. In the optimal blanket solution for a titanium heat exchanger the tubes are seal-welded to tube shuts of explosion-bonded titanium clad steel. Pipings of rubber-lined carbon steel or thick coatings og solvent-free epoxy resin have shown very good corrosion resistance in the seawater systems of power stations. Valves in seawater cooling systems have been affected, in particular, by corrosion due to defectively executed or damaged organic coating on cast iron. Different seawater-resistant bronzes (gunmetal, tin, bronze and aluminium bronze) are therefore preferable as valve material. 14 references.

Henrikson, S.

1985-01-01

280

Localized corrosion information using high resolution measurement devices  

DEFF Research Database (Denmark)

High performance demand for several engineering alloys and components, and miniaturization of electronics and development of MEMS requires better understanding of local corrosion characteristics frequently down to µm scale. This is because in metallic materials corrosion is a sensitive function of microstructure, in particular the local electrochemical activities of several microstructural heterogeneities such as second phase particles and grain boundaries. The overall corrosion behaviour of the material is determined by the local interaction of several microstructural features. On the other hand in engineering components, structural heterogeneities of a higher scale could be produced by joining and processing techniques such as welding (eg. heat affected zone and nugget), cutting and machining operations. In all these cases understanding the corrosion properties of an individual microstructural region in conjunction with microstructural analysis, using advanced microscopic tools, becomes very important. Corrosion of microelectronics circuits and MEMs is also a recent problem, which demands measurement resolution down to few microns as the components are extremely small, and measurement needs to be carried out without damaging the entire component. These limitations can be overcome by the use of high resolution corrosion measurement devices, which in various forms are being used by few investigators. One popular approach is the so called microelectrochemical set up, which use a pipette connected to a system to control the solution flow at the tip. Through addition of reference and counter electrodes, the pipette system becomes a microscopic electrochemical cell, which can then be used with high precision to determine the electrochemical characteristics of the microstructural region of interest. The capability of the technique could be further enhanced by adding new features such as high resolution video visualization systems, fretting/tribo-corroson attachments, and also by integrating it with stress corrosion testing, corrosion investigation of concrete for a few to name with. The corrosion group in MPT, Technical University of Denmark has developed various types of microelectrochemical devices with resolutions 1 mm - 10 m; also integrated them with stress corrosion testing, fretting corrosion measurements and potential profiling for complex geometries such as die-cast and engine components. This paper describe the methods and the results of local corrosion investigations of aluminium alloy microstructure, friction stir welds, spot-welds, cast components and microelectronic devices.

Ambat, Rajan

2005-01-01

 
 
 
 
281

The corrosion resistance of titanium - ruthenium alloys in hydrochloric acid media  

International Nuclear Information System (INIS)

Alloys of the Ti-Ru system in the cast state and in the annealed state have been investigated. The investigated samples were prepared by the method of induction melting in the helium atmosphere. The corrosion resistance was investigated by the weight method in the solution of hydrochloric acid. The results of the corrosion experiments were calculated as a mean value of two parallel samples. 2 tabs., 4 refs

1990-01-01

282

Comparison Of Metal Corrosion Inhibition By Gravimetric And Linear Polarization Resistance Methods  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Studies were conducted to evaluate the effectiveness of various dosages of the selected silicate and phosphate compounds applied for corrosion inhibition of cast iron, copper, lead, and galvanized steel specimens. The compounds selected for study were zinc polyphosphate (Calgon C-39), zinc orthophosphate (Virchem V-931), sodium metasilicate and glassy silicate. The effectiveness of these compounds for corrosion inhibition were studied under differing water quality conditions using gravimetric...

Banerji, Shankha

1992-01-01

283

STME T/C casting technology  

Science.gov (United States)

The T/C casting technology developed by the National Launch System for the Space Transportation Main Engine is described. Special attention is given to the selection of JBK-75 as the combustion chamber casting alloy, some unique casting issues, and the development castings which were produced. Current plans call for producing a 650K full cast jacket mockup in the 4500 pound furnace. Once a 650K mockup casting has been successfully produced, a design of experiments (DOE) will be conducted to establish the best gating system. This will be followed by the design of permanent wax pattern tooling, gating tooling, and process fixtures, and, finally, by a process DOE.

Lobitz, J. R.; Ackerman, P. C.; Weber, S. L.

1992-07-01

284

Some observations on the strength and fatigue properties of samples extracted from cast iron water mains  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The strength and fatigue properties of cast iron samples taken from water distribution mains have been investigated. Specimens were sourced from three sections of pipe which had experienced varying amounts of corrosion in service, enabling the variable of pipe condition to be incorporated within the study. The strengths in four-point flexure of small specimens from the pipes examined were described using Weibull statistics; different characteristic strengths and Weibull moduli were obtained, ...

Belmonte, Hms; Mulheron, Mj; Smith, Pa

2009-01-01

285

Research on the squeeze cast technology of the castings with large ratio of height to thickness  

Directory of Open Access Journals (Sweden)

Full Text Available The squeeze cast technology is only applicable, at present, to the castings with a ratio of height to thickness less than 3.5. Researching the squeeze cast technology for castings with a large ratio of height to thickness will broaden the applicable range of the advanced casting technology. This paper describes a study of the temperature distribution during solidification for castings with a ratio of height to thickness of 7 by the methods of experiment and computer simulation. The shrinkage porosity distribution in the castings and the mechanical properties of the castings were also researched. The experimental and simulated results show that increasing squeeze force, or enhancing mold temperature,cannot reduce the shrinkage porosities in the castings. When castings solidify in a sequential manner and the squeeze force effectively acts on the surface of the liquid metal, the shrinkage porosities in the castings are eliminated and mechanical properties are clearly improved.

LI Chen-xi

2005-11-01

286

Modelling of Corrosion Cracks  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Modelling of corrosion cracking of reinforced concrete structures is complicated as a great number of uncertain factors are involved. To get a reliable modelling a physical and mechanical understanding of the process behind corrosion in needed.

Thoft-christensen, Palle

2010-01-01

287

Modelling of Corrosion Cracks  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Modelling of corrosion cracking of reinforced concrete structures is complicated as a great number of uncertain factors are involved. To get a reliable modelling a physical and mechanical understanding of the process behind corrosion in needed.

Thoft-christensen, Palle

2003-01-01

288

CAST Physics Proposal to SPSC  

CERN Document Server

The CAST experiment has the potential to search for solar axions (dark matter particle candidates) or other particles with similar coupling. E.g., paraphtons (Hidden Sector), chameleons (dark energy), while considering the possibility whether CAST could be transformed to an antenna for relic axions with rest mass up to 0.1 to 1meV. While axion searches suggest detectors with lower background, paraphoton and chameleon searches require detectors with sub-keV threshold energy and the use of transparent windows in front of the Micromegas detectors, which cover 3 out of the 4 CAST magnet exits. Ongoing theoretical estimates and experimental investigations will define the priorities of the suggested 4 physics items of this proposal for the period 2012-2014.

CAST, Collaboration

2011-01-01

289

Plasmapheresis in myeloma cast nephropathy.  

Science.gov (United States)

Renal failure in multiple myeloma is frequent, and portends a dismal prognosis. Precipitation of free light chains in tubules contributes to development of cast nephropathy and renal failure. Treatment with plasmapheresis is reported as an adjunct to chemotherapy in these patients, but evidence regarding its efficacy in the literature is conflicting. In this article, we report the case of a 63-year-old man who presented with severe acute renal failure due to myeloma cast nephropathy and whose kidney function improved significantly following treatment with dexamethasone and a course of 8 plasma exchanges. We then provide a review of the technical aspects of plasmapheresis, followed by an analysis of the randomized trials that have been published to date on the efficacy of plasmapheresis for myeloma cast nephropathy. PMID:23249872

Chapdelaine, Isabelle; Madore, François

2013-01-01

290

Vascular Plant Image Gallery  

Science.gov (United States)

Texas A&M University's Bioinformatics Working Group offers this no-nonsense botany teaching resource. Vascular plants are arranged alphabetically by family from Acanthaceae to Zygophyllaceae and users simply click for the images. Brief descriptions are provided (which may indicate the popular name of the plant). The site is searchable. Familiarity with vascular plant taxonomic nomenclature is assumed.

Manhart, James R.

291

Vascular Intracranial Hypertension  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Intracranial hypertension is one of the most important syndromes in neurology and neurosurgery; raised intracranial pressure is the most common cause of death in neurosurgery. A recent classification of intracranial hypertension is based upon the etiopathogenesis of intracranial hypertension: a) parenchymatous intracranial hypertension, b) vascular intracranial hypertension, c) meningeal intracranial hypertension and d) idiopathic intracranial hypertension. Vascular etiologies can individuali...

2004-01-01

292

Energy Consumption of Die Casting Operations  

Energy Technology Data Exchange (ETDEWEB)

Molten metal processing is inherently energy intensive and roughly 25% of the cost of die-cast products can be traced to some form of energy consumption [1]. The obvious major energy requirements are for melting and holding molten alloy in preparation for casting. The proper selection and maintenance of melting and holding equipment are clearly important factors in minimizing energy consumption in die-casting operations [2]. In addition to energy consumption, furnace selection also influences metal loss due to oxidation, metal quality, and maintenance requirements. Other important factors influencing energy consumption in a die-casting facility include geographic location, alloy(s) cast, starting form of alloy (solid or liquid), overall process flow, casting yield, scrap rate, cycle times, number of shifts per day, days of operation per month, type and size of die-casting form of alloy (solid or liquid), overall process flow, casting yield, scrap rate, cycle times, number of shifts per day, days of operation per month, type and size of die-casting machine, related equipment (robots, trim presses), and downstream processing (machining, plating, assembly, etc.). Each of these factors also may influence the casting quality and productivity of a die-casting enterprise. In a die-casting enterprise, decisions regarding these issues are made frequently and are based on a large number of factors. Therefore, it is not surprising that energy consumption can vary significantly from one die-casting enterprise to the next, and within a single enterprise as function of time.

Jerald Brevick; clark Mount-Campbell; Carroll Mobley

2004-03-15

293

Cementite Solidification in Cast Iron  

Science.gov (United States)

Two hypereutectic cast irons (5.01 pct Cr and 5.19 pct V) were cast and the polished surfaces of test pieces were deep-etched and analyzed via scanning electron microscopy. The results show that graphite lamellae intersect the cementite and a thin austenite film nucleates and grows on the cementite plates. For both compositions, graphite and cementite can coexist as equilibrium phases, with the former always nucleating and growing first. The eutectic carbides grow from the austenite dendrites in a direction perpendicular to the primary plates.

Coronado, J. J.; Sinatora, A.; Albertin, E.

2014-06-01

294

Cementite Solidification in Cast Iron  

Science.gov (United States)

Two hypereutectic cast irons (5.01 pct Cr and 5.19 pct V) were cast and the polished surfaces of test pieces were deep-etched and analyzed via scanning electron microscopy. The results show that graphite lamellae intersect the cementite and a thin austenite film nucleates and grows on the cementite plates. For both compositions, graphite and cementite can coexist as equilibrium phases, with the former always nucleating and growing first. The eutectic carbides grow from the austenite dendrites in a direction perpendicular to the primary plates.

Coronado, J. J.; Sinatora, A.; Albertin, E.

2014-04-01

295

High-Performance Corrosion-Resistant Iron-Based Amorphous Metals: The Effects of Composition, Structure and Environment on Corrosion Resistance  

Energy Technology Data Exchange (ETDEWEB)

New corrosion-resistant, iron-based amorphous metals have been identified from published data or developed through combinatorial synthesis, and tested to determine their relative thermal phase stability, microstructure, mechanical properties, damage tolerance, and corrosion resistance. Some alloy additions are known to promote glass formation and to lower the critical cooling rate [F. Guo, S. J. Poon, Applied Physics Letters, 83 (13) 2575-2577, 2003]. Other elements are known to enhance the corrosion resistance of conventional stainless steels and nickel-based alloys [A. I. Asphahani, Materials Performance, Vol. 19, No. 12, pp. 33-43, 1980] and have been found to provide similar benefits to iron-based amorphous metals. Many of these materials can be cast as relatively thick ingots, or applied as coatings with advanced thermal spray technology. A wide variety of thermal spray processes have been developed by industry, and can be used to apply these new materials as coatings. Any of these can be used for the deposition of the formulations discussed here, with varying degrees of residual porosity and crystalline structure. Thick protective coatings have now been made that are fully dense and completely amorphous in the as-sprayed condition. An overview of the High-Performance Corrosion Resistant Materials (HPCRM) Project will be given, with particular emphasis on the corrosion resistance of several different types of iron-based amorphous metals in various environments of interest. The salt fog test has been used to compare the performance of various wrought alloys, melt-spun ribbons, arc-melted drop-cast ingots, and thermal-spray coatings for their susceptibility to corrosion in marine environments. Electrochemical tests have also been performed in seawater. Spontaneous breakdown of the passive film and localized corrosion require that the open-circuit corrosion potential exceed the critical potential. The resistance to localized corrosion is seawater has been quantified through measurement of the open-circuit corrosion potential (E{sub corr}), the breakdown potential (E{sub crit}) and the repassivation potential (E{sub rp}). The greater the difference between the open-circuit corrosion potential and the repassivation potential ({Delta}E), the more resistant a material is to modes of localized corrosion such as pitting and crevice corrosion. Cyclic polarization (CP) was used as a means of measuring the critical potential (E{sub crit}) relative to the open-circuit corrosion potential (E{sub corr}). Linear polarization (LP) has been used to determine the corrosion current (i{sub corr}) and the corresponding corrosion rate. Other aspects of the materials will also be discussed, as well as potential applications.

Farmer, J; Choi, J S; Haslam, J; Lian, T; Day, S; Yang, N; Blue, C; Peters, W; Bayles, R; Lewandowski, J; Perepezko, J; Hildal, K; Lavernia, E; Ajdelsztajn, A; Grave, O; Aprigliano, L; Kaufman, L; Boudreau, J; Branagan, D J; Beardsley, B

2006-04-11

296

Corrosion control software and corrosion monitoring  

Energy Technology Data Exchange (ETDEWEB)

Software Data Bases and Expert Systems for the management of corrosion and of non-destructive testing for process industries are hereby presented. Their on-line integration with the data obtained on the field using reliable corrosion probes allows the most convenient planning of the necessary controls and corrective actions.

Farina, C.A.; Felicioli, G.; Grassini, U.; Olivani, F. [Donegani Anticorrosione S.r.l., Novara (Italy); Faita, G. [Univ. of Milan (Italy); Salva, D.; Verzotto, F. [Antea S.r.l., Sandrigo (Italy)

1997-12-01

297

Erosion-corrosion  

International Nuclear Information System (INIS)

A literature study on erosion-corrosion of pipings in the nuclear industry was performed. Occurred incidents are reviewed, and the mechanism driving the erosion-corrosion is described. Factors that influence the effect in negative or positive direction are treated, as well as programs for control and inspection. Finally, examples of failures from databases on erosion-corrosion are given in an attachment

1999-01-01

298

Management of Reinforcement Corrosion  

DEFF Research Database (Denmark)

Reinforcement corrosion is the most important cause for deterioration of reinforced concrete structures, both with regard to costs and consequences. Thermodynamically consistent descriptions of corrosion mechanisms are expected to allow the development of innovative concepts for the management of reinforcement corrosion.

Küter, André; Geiker, Mette Rica

299

Cast-a-Box: Casting Conditions and Macroporosity  

Science.gov (United States)

An illustration of three-dimensional finite difference simulation of heat conduction with phase change and complex boundary conditions, this requires students to adjust boundary conditions to make the top surface of a regular hexahedral "casting" to freeze last, eliminating macroporosity.

Powell, Adam C., IV

2004-08-24

300

Microstructure and Corrosion Properties of AlCoCrFeNi High Entropy Alloy Coatings Deposited on AISI 1045 Steel by the Electrospark Process  

Science.gov (United States)

Electrospark deposition (ESD) was employed to clad the AlCoCrFeNi high-entropy alloy (HEA) on AISI 1045 carbon steel. The relationship between the microstructure and corrosion properties of the HEA-coated specimens was studied and compared with that of the copper-molded cast HEA material. Two major microstructural differences were found between the cast HEA material and the HEA coatings. First, the cast material comprises both columnar and equiaxed crystals with a columnar-to-equiaxed transition (CET), whereas the HEA coatings consist of an entirely columnar crystal structure. The CET phenomenon was analyzed based on Hunt's criterion. Second, unlike the cast HEA material, there was no obvious Cr-rich interdendritic segregation and nano-sized precipitate distributed within the dendrites of the HEA coating. With regard to corrosion properties, the corrosion current of the HEA-coated specimen was significantly lower than for the 1045 steel and the cast HEA material. This was attributed to the ESD specimen having a relatively high Cr oxide and Al oxide content at the surface. Moreover, for the ESD specimen, the absence of Cr-rich interdendritic phase and second-phase precipitation resulted in a relatively uniform corrosion attack, which is different from the severe galvanic corrosion attack that occurred in the cast specimen.

Li, Q. H.; Yue, T. M.; Guo, Z. N.; Lin, X.

2013-04-01

 
 
 
 
301

Resistance to corrosion by water at high temperatures of Al-Fe-Ni alloy after prolonged heat treatment. Influence of Ti and Zr additions  

International Nuclear Information System (INIS)

The influence of titanium and zirconium additions on the heterogeneity texture of Al-Fe-Ni alloys, and the resultant effect on their corrosion resistance, is briefly recalled. The present article records the results of corrosion tests on these alloys after prolonged heat treatment. Without additions, the eutectic structure of the basis alloy is subject to a coalescence, which results in a deterioration of corrosion resistance. This effect applies equally to the as-cast and to the wrought conditions. The addition of titanium or zirconium retards this deterioration very considerably, both for the as-cast and wrought alloys. (author)

1959-10-14

302

A Benchmark Study on Casting Residual Stress  

Science.gov (United States)

A benchmark study was undertaken for casting residual stress measurements through neutron diffraction, which was subsequently used to validate the accuracy of simulation prediction. The "stress lattice" specimen geometry was designed such that subsequent castings would generate adequate residual stresses during solidification and cooling of ductile cast iron, without any cracks. The residual stresses in the cast specimen were measured using neutron diffraction. Considering the difficulty in accessing the neutron diffraction facility, these measurements can be considered as a benchmark for casting simulation validations. Simulations were performed using the identical specimen geometry and casting conditions for predictions of residual stresses. The simulation predictions were found to agree well with the experimentally measured residual stresses. The experimentally validated model can be subsequently used to predict residual stresses in different cast components. This enables incorporation of the residual stresses at the design phase along with external loads for accurate predictions of fatigue and fracture performance of the cast components.

Johnson, E. M.; Watkins, T. R.; Schmidlin, J. E.; Dutler, S. A.

2012-05-01

303

Electrochemical Etching of Titanium-Alloy Castings.  

Science.gov (United States)

This study was conducted to determine whether a potentiostatic electrochemical method could be used to etch selectively either the dendrites or the interdendritic material from Ti cast structures and thereby reveal their microstructures. Cast binary titan...

J. C. Griess S. A. David R. J. Gray C. W. Houck

1983-01-01

304

Cognitive Approach in Castings’ Quality Control  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Every year production volume of castings grows, especially grows production volume of non-ferrous metals, thanks to aluminium. As a result, requirements to castings quality also increase. Foundry men from all over the world put all their efforts to manage the problem of casting defects. In this article the authors present an approach based on the use of cognitive models that help to visualize inner cause-and-effect relations leading to casting defects in the foundry process. T...

Bast, Ju?rgen; Kamaev, Valeriy; Polyakova, Irina; Tikhonin, Andrey; Zabolotsky, Maxim; Kudashov, Natalia

2008-01-01

305

Behaviour of oxygen in cast irons  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Purpose: Cast irons are the basic structural material and they form 75% of the world production of castings. The crystallization of cast iron and the formation of graphite are a complex process influencing by oxygen. The aim of our study is to identify the role of oxygen in Fe-C-Si melts.Design/methodology/approach: Continuous comparison of changes in metal composition and oxygen activity during melting, pouring, and solidification of experimental castings, using metallographic methods and mi...

2008-01-01

306

A study of the connection mechanism of cast-in high chromium cast iron - carbon cast steel by cast-in process  

Energy Technology Data Exchange (ETDEWEB)

The connection mechanism of high chromium cast iron--carbon cast steel by cast-in process was studied by analyzing the microstructure and the alloying component in the transition zone with scanning electron microscope observation. The experiment results show that sordite pearlite and ferrite constitute microstructure of transition zone and the connection of metallurgy is formed because of the diffusion reaction, interface reaction and formation of the new compound phase during the cast-in process. (orig.)

Liu Xiang; Shen Shuxi; Xu Qiaoyu [School of Mechanical Engineering, Xinjiang Univ., Urumqi, XJ (China)

2003-07-01

307

Developing technological process of obtaining giality casts  

Directory of Open Access Journals (Sweden)

Full Text Available The article considers the process of manufacturing castings using sand-resin forms and alloying furnace. Were the optimal technological parameters of manufacturing shell molds for the manufacture of castings of heating equipment. Using the same upon receipt of castings by casting in shell molds furnace alloying and deoxidation of the metal will provide consumers with quality products and have a positive impact on the economy in general engineering.

A. Issagulov

2014-10-01

308

Engineering Support / Corrosion Prevention and Control Evaluation.  

Science.gov (United States)

AIRCRAFT CORROSION: Corrosion Prevention and Control Evaluation * 3D Mapping * Pressure Washing. ENGINEERING SUPPORT: Maintenance Engineering Calls * Maintenance Engineering Order * Corrosion Prevention Techniques * ACE/Corrosion website.

D. R. Duran

2009-01-01

309

Pediatric vascular access  

Energy Technology Data Exchange (ETDEWEB)

Pediatric interventional radiologists are ideally suited to provide vascular access services to children because of inherent safety advantages and higher success from using image-guided techniques. The performance of vascular access procedures has become routine at many adult interventional radiology practices, but this service is not as widely developed at pediatric institutions. Although interventional radiologists at some children's hospitals offer full-service vascular access, there is little or none at others. Developing and maintaining a pediatric vascular access service is a challenge. Interventionalists skilled in performing such procedures are limited at pediatric institutions, and institutional support from clerical staff, nursing staff, and technologists might not be sufficiently available to fulfill the needs of such a service. There must also be a strong commitment by all members of the team to support such a demanding service. There is a slippery slope of expected services that becomes steeper and steeper as the vascular access service grows. This review is intended primarily as general education for pediatric radiologists learning vascular access techniques. Additionally, the pediatric or adult interventional radiologist seeking to expand services might find helpful tips. The article also provides education for the diagnostic radiologist who routinely interprets radiographs containing vascular access devices. (orig.)

Donaldson, James S. [Northwestern University, Feinberg School of Medicine, Department of Medical Imaging, Children' s Memorial Hospital, Chicago, IL (United States)

2006-05-15

310

Pediatric vascular access  

International Nuclear Information System (INIS)

Pediatric interventional radiologists are ideally suited to provide vascular access services to children because of inherent safety advantages and higher success from using image-guided techniques. The performance of vascular access procedures has become routine at many adult interventional radiology practices, but this service is not as widely developed at pediatric institutions. Although interventional radiologists at some children's hospitals offer full-service vascular access, there is little or none at others. Developing and maintaining a pediatric vascular access service is a challenge. Interventionalists skilled in performing such procedures are limited at pediatric institutions, and institutional support from clerical staff, nursing staff, and technologists might not be sufficiently available to fulfill the needs of such a service. There must also be a strong commitment by all members of the team to support such a demanding service. There is a slippery slope of expected services that becomes steeper and steeper as the vascular access service grows. This review is intended primarily as general education for pediatric radiologists learning vascular access techniques. Additionally, the pediatric or adult interventional radiologist seeking to expand services might find helpful tips. The article also provides education for the diagnostic radiologist who routinely interprets radiographs containing vascular access devices. (orig.)

2006-05-01

311

Graphite formation in cast iron  

Science.gov (United States)

In the first phase of the project it was proven that by changing the ratio between the thermal gradient and the growth rate for commercial cast iron samples solidifying in a Bridgman type furnace, it is possible to produce all types of graphite structures, from flake to spheroidal, and all types of matrices, from ferritic to white at a certain given level of cerium. KC-135 flight experiments have shown that in a low-gravity environment, no flotation occurs even in spheroidal graphite cast irons with carbon equivalent as high as 5%, while extensive graphite flotation occurred in both flake and spheroidal graphite cast irons, in high carbon samples solidified in a high gravity environment. This opens the way for production of iron-carbon composite materials, with high carbon content (e.g., 10%) in a low gravity environment. By using KC-135 flights, the influence of some basic elements on the solidification of cast iron will be studied. The mechanism of flake to spheroidal graphite transition will be studied, by using quenching experiments at both low and one gravity for different G/R ratios.

Stefanescu, D. M.

1985-01-01

312

Advanced Lost Foam Casting Technology  

Energy Technology Data Exchange (ETDEWEB)

This report describes the research done under the six tasks to improve the process and make it more functional in an industrial environment. Task 1: Pattern Pyrolysis Products and Pattern Properties Task 2: Coating Quality Control Task 3: Fill and Solidification Code Task 4: Alternate Pattern Materials Task 5: Casting Distortion Task 6: Technology Transfer

Charles E. Bates; Harry E. Littleton; Don Askeland; Taras Molibog; Jason Hopper; Ben Vatankhah

2000-11-30

313

ENVIRONMENTAL ASSESSMENT OF IRON CASTING  

Science.gov (United States)

Sampling of ductile iron casting in green sand molds with phenolic isocyanate cores and in phenol-formaldehyde bound shell molds did not provide definitive proof that environmentally hazardous organic emission occur. Both molding systems produced the same type of major emissions,...

314

Cern Axion Solar Telescope (CAST)  

CERN Multimedia

The CERN Solar Axion Telescope, CAST, aims to shed light on a 30-year-old riddle of particle physics by detecting axions originating from the 15 million degree plasma in the Sun 's core. Axions were proposed as an extension to the Standard Model of particle physics to explain why CP violation is observed in weak but not strong interactions.

2002-01-01

315

Inoculation Effects of Cast Iron  

Directory of Open Access Journals (Sweden)

Full Text Available The paper presents a solidification sequence of graphite eutectic cells of A and D types, as well as globular and cementite eutectics. The morphology of eutectic cells in cast iron, the equations for their growth and the distances between the graphite precipitations in A and D eutectic types were analyzed. It is observed a critical eutectic growth rate at which one type of eutectic transformed into another. A mathematical formula was derived that combined the maximum degree of undercooling, the cooling rate of cast iron, eutectic cell count and the eutectic growth rate. One type of eutectic structure turned smoothly into the other at a particular transition rate, transformation temperature and transformational eutectic cell count. Inoculation of cast iron increased the number of eutectic cells with flake graphite and the graphite nodule count in ductile iron, while reducing the undercooling. An increase in intensity of inoculation caused a smooth transition from a cementite eutectic structure to a mixture of cementite and D type eutectic structure, then to a mixture of D and A types of eutectics up to the presence of only the A type of eutectic structure. Moreover, the mechanism of inoculation of cast iron was studied.

E. Fra?

2012-12-01

316

Molding A Cast Metals Program  

Science.gov (United States)

The cast metals program, a two-year associate degree program, at Muskegon Community College, Musegon, Michigan operates in close cooperation with the local foundry industry to provide a background for entry-level technical jobs and for continued studies toward a four-year degree. (EA)

Trumble, Dale E.

1975-01-01

317

Towards Corrosion Detection System  

Directory of Open Access Journals (Sweden)

Full Text Available Corrosion is a natural process that seeks to reduce the binding energy in metals. The end result of corrosion involves a metal atom being oxidized. Surface corrosion on aluminum aircraft skins, near joints and around fasteners, is often an indicator of buried structural corrosion and cracking In this paper we proposed a new method on which we are moving towards designing a method to detect the corrosion within the metals, the new method has defined texture analysis as the main method for this approach, the proposed enhancement shows less false positive and less false negative. The main functions used in this approach beside texture analysis are Edge detection, structure element and image dilation. The new approach has designed to detect a part of the image that has been affected by the corrosion, the tested images has showed a good result lying on detecting the corrosion part from the image.

B.B.Zaidan

2010-05-01

318

Surface films and corrosion of copper  

Energy Technology Data Exchange (ETDEWEB)

In Sweden and Finland the spent nuclear fuel is planned to be encapsulated in cast iron canisters that have an outer shield made of copper. The copper shield is responsible for the corrosion protection of the canister construction. General corrosion of the copper is not expected to be the limiting factor in the waste repository environment when estimating the life-time of the canister construction. However, different forms of localised corrosion, i.e. pitting, stress corrosion cracking, or environmentally assisted creep fracture may cause premature failure of the copper shield. Of the probable constituents in the groundwater, nitrites, chlorides, sulphides and carbonates have been suggested to promote localised corrosion of copper. The main assumption made in planning this research program is that the surface films forming on copper in the repository environment largely determine the susceptibility of copper to the different forms of localised corrosion. The availability of reactants, which also may become corrosion rate limiting, is investigated in several other research programs. This research program consists of a set of successive projects targeted at characterising the properties of surface films on copper in repository environment containing different detrimental anions. A further aim was to assess the significance of the anion-induced changes in the stability of the oxide films with regard to localised corrosion of copper. This report summarises the results from a series of investigations on properties of surface films forming on copper in water of pH = 8.9 at temperature of 80 deg C and pressure of 2 MPa. The main results gained so far in this research program are as follows: The surface films forming on copper in the thermodynamic stability region of monovalent copper at 80 deg C consist of a bulk part (about 1 mm thick) which is a good ionic and electronic conductor, and an outer, interfacial layer (0.001 - 0.005 mm thick) which shows p-type semiconductor properties. The thin outer layer controls the corrosion properties of copper, corrosion rate being limited by ionic transport through the layer and the charge transfer step of the film dissolution. Chlorides cause a breakdown of the oxide film in the stability region of divalent copper, but they seem to have no effect on the properties of the film in the stability region of monovalent copper; oxidising conditions with simultaneous exposure to chlorides are thus expected to subject copper to localised corrosion. Sulphides at the concentration of 10 ppm dissolved H{sub 2}S were found not to promote the formation of a three-dimensional film of Cu{sub 2}S (or other copper sulphides), thus the mechanisms of localised corrosion which operate under reducing conditions and are based on the formation of copper sulphides seem not to be valid. In the presence of 10 ppm H{sub 2}S the corrosion rate of copper is controlled by the charge transfer step of the dissolution of the outer layer 57 refs, 35 figs, 7 tabs

Hilden, J.; Laitinen, T.; Maekelae, K.; Saario, T.; Bojinov, M. [VTT Manufacturing Technology, Espoo (Finland)

1999-03-01

319

Prototype casting fabrication by stereolithography  

Energy Technology Data Exchange (ETDEWEB)

A new product development technology is emerging which could have a major impact on the investment casting industry. It's identified by several names, the most common of which is STEREOLITHOGRAPHY.'' This technology involves a three-dimensional printing process which will yield plastic parts (polymer models) from solid, surface, or wireframe CAD files. The concept links a CAD database to a process which guides a laser beam to solidify liquid photo-curable polymer into a programmed shaped. The process can produce models in far less time and at far less cost than can be done by other known (conventional) model producing methods. Parts that would normally require weeks or months to prototype with conventional processes can be produced in a matter of hours by Stereolithography. The Allied-Signal Inc., Kansas City Division, is engaged in a development project (funded by the Department of Energy) which is aimed at establishing this process as a practical, expedient, and cost-effective method fabricating prototype investment castings. The early phases of the project include procurement of a special designed test unit for several companies (Service Centers) involved in fabrication of models. These models are produced in various materials and used in experimental casting programs being conducted with four casting suppliers (two ferrous and two non-ferrous). This presentation will cover the objectives of the project and the results obtained up to this time. We will also briefly review future plans for the continuation of the project, until this new technology has been proven as a viable process for rapid development of investment castings.

Cromwell, W.E.

1990-11-01

320

Studies of the transition zone in steel – chromium cast iron bimetallic casting  

Directory of Open Access Journals (Sweden)

Full Text Available In this work authors presented the results of transition zone studies on steel – cast iron interface in bimetallic casting. During the investigations cylindrical castings with different diameter were prepared of cast iron with steel rods placed in the center. From each bimetallic casting a microsection was prepared for microhardness tests and metalographic analysis, consisting of transition zone measurement, point and linear analysis as well as quantitative analysis.

S. Tenerowicz

2010-01-01

 
 
 
 
321

Monitoring corrosion rates and localised corrosion in low conductivity water  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Monitoring of low corrosion rates and localised corrosion in a media with low conductivity is a challenge. In municipal district heating, quality control may be improved by implementing on-line corrosion monitoring if a suitable technique can be identified to measure both uniform and localised corrosion. Electrochemical techniques (LPR, EIS, crevice corrosion current) as well as direct measurement

Hilbert, Lisbeth Rischel

2007-01-01

322

Corrosion studies on containment materials for vitrified heat generating waste  

International Nuclear Information System (INIS)

Mean corrosion rates of carbon steels, monitored by Rsub(p) measurements on specimens in on-going long term immersion tests, are presented. True corrosion rates measured on specimens from two dismantled tests after > 2 years exposure were about 25 ?m yr"-"1 for both cast and forged steel buried in granite at 90 C but only approx. 3 and 7 ?m yr"-"1 for the same materials, respectively, in bentonite. Extreme value statistical analysis of maximum pit penetrations observed in experimental studies, to compensate for the small area of test specimens compared with a container, indicates that after 1000 years the maximum pit depth could be 200 mm. Overall, tests with ?-radiation on carbon steel specimens immersed in deaerated seawater at 90 C show that there is an acceleration of corrosion rate with continued exposure at the three radiation dose rates used. However in deaerated groundwater at 90 C the general corrosion rate of forged 0.2% carbon steel is < 3 ?m yr"-"1 at a dose rate of 10"5 Rads h"-"1. Threshold stresses for the initiation of stress corrosion cracking in carbon steel parent and weld metal have been estimated. Preliminary experiments have been initiated to investigate the effect of sulphate reducing bacteria on the corrosion of carbon steel buried in bentonite. (author)

1985-01-01

323

Magnetic resonance vascular imaging  

International Nuclear Information System (INIS)

The basis principles of MRI are reviewed in order to understand how blood flow effects arise in conventional imaging. Then some of the ways these effects have ben used in MRI techniques specifically designed for vascular imaging, are considered. (author)

1989-01-01

324

Women and Vascular Disease  

Science.gov (United States)

... disease Trauma Uterine fibroids Varicoceles and male infertility Varicose veins Venous access catheters Vertebroplasty Women and vascular disease ... recognized in women. According to a survey of primary care physicians conducted in 2002, nearly all recognized ...

325

Land-based turbine casting initiative  

Energy Technology Data Exchange (ETDEWEB)

To meet goals for the ATS program, technical advances developed for aircraft gas turbine engines need to be applied to land-based gas turbines. These advances include directionally solidified and single crystal castings, alloys tailored to exploit these microstructures, complex internal cooling schemes, and coatings. The proposed program to scale aircraft gas turbine casting technology up to land based gas turbine size components is based on low sulfur alloys, casting process development, post-cast process development, and establishing casting defect tolerance levels. The inspection side is also discussed.

Mueller, B.A.; Spicer, R.A. [Howmet Corp., Whitehall, MI (United States)

1995-12-31

326

[Complex vascular access].  

Science.gov (United States)

Availability of a proper vascular access is a basic condition for a proper extracorporeal replacement in end-stage chronic renal failure. However, biological factors, management and other problems, may variously condition their middle-long term survival. Therefore, personal experience of over 25 years has been critically reviewed in order to obtain useful information. In particular "hard" situations necessitating complex procedures have been examined but, if possible, preserving the peripherical vascular features. PMID:9578652

Mangiarotti, G; Cesano, G; Thea, A; Hamido, D; Pacitti, A; Segoloni, G P

1998-03-01

327

Behaviour of oxygen in cast irons  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: Cast irons are the basic structural material and they form 75% of the world production of castings. The crystallization of cast iron and the formation of graphite are a complex process influencing by oxygen. The aim of our study is to identify the role of oxygen in Fe-C-Si melts.Design/methodology/approach: Continuous comparison of changes in metal composition and oxygen activity during melting, pouring, and solidification of experimental castings, using metallographic methods and microanalysis. Determination of total oxygen content in cast iron by the high temperature extraction method.Findings: Oxygen activity in graphitic cast irons is determined during manufacture of liquid metal and its pouring mainly by carbon and silicon activities. Silicon deoxidates cast irons at lower temperatures, at higher temperatures this function is taken over by carbon. Logarithmic dependences of oxygen activity on temperature for individual graphite forms (lamellar, vermicular, and spheroidal ones have been obtained. Determination of total oxygen content in cast iron on the other hand gives valuable information for controlling surface and internal quality of cast irons.Practical implications: Possibility of control the cast iron structure and graphitization during crystallization by monitoring the oxygen content with an indirect method of oxygen activity measurement in the melt before metal pouring the mould.Originality/value: The used method gives reproducible results which are comparable under different conditions of metal melting and pouring. Obtained knowledge extends the understanding in the field of cast irons crystallization by less known influence of oxygen.

T. Elbel

2008-10-01

328

Prediction of Part Distortion in Die Casting  

Energy Technology Data Exchange (ETDEWEB)

The die casting process is one of the net shape manufacturing techniques and is widely used to produce high production castings with tight tolerances for many industries. An understanding of the stress distribution and the deformation pattern of parts produced by die casting will result in less deviation from the part design specification, a better die design and eventually more productivity and cost savings. This report presents methods that can be used to simulate the die casting process in order to predict the deformation and stresses in the produced part and assesses the degree to which distortion modeling is practical for die casting at the current time. A coupled thermal-mechanical finite elements model was used to simulate the die casting process. The simulation models the effect of thermal and mechanical interaction between the casting and the die. It also includes the temperature dependant material properties of the casting. Based on a designed experiment, a sensitivity analysis was conducted on the model to investigate the effect of key factors. These factors include the casting material model, material properties and thermal interaction between casting and dies. To verify the casting distortion predictions, it was compared against the measured dimensions of produced parts. The comparison included dimensions along and across the parting plane and the flatness of one surface.

R. Allen Miller

2005-03-30

329

On the role of surface roughness in the corrosion of pure magnesium in vitro.  

Science.gov (United States)

The relationship between surface roughness and degradation behavior in magnesium (Mg) biomaterials is still a controversial issue. This study aims to clarify the relationship between surface roughness and corrosion rate of pure Mg. Pure Mg samples with surface roughness values (Ra) of 0.59, 2.68, and 9.12 ?m were cast using an indirect solid-free form fabrication method. The in vitro corrosion behavior was evaluated using hydrogen evolution, mass loss, potentiodynamic polarization, and electrochemical impedance spectroscopy. It was confirmed that surface roughness had a significant influence on the corrosion rate of pure Mg, with increasing roughness resulting in an accelerated corrosion rate. However, pitting corrosion was not observed, suggesting that surface roughness does not affect the pitting potential of Mg. PMID:22566378

Nguyen, T L; Blanquet, A; Staiger, M P; Dias, G J; Woodfield, T B F

2012-07-01

330

Effect of Cr on the corrosion resistance of Cu-6Ni-4Sn alloys  

International Nuclear Information System (INIS)

The corrosion characteristics of Cu-6% Ni-4% Sn-x% Cr alloys in an acid-chloride solution (0.1 M H2SO4 + 0.0056 M NaCl) at pH 1.2, were studied as a function of the chromium content. Three kinds of Cu-6% Ni-4% Sn-x% Cr alloys were prepared by melting and casting, followed by thermomechanical treatments. The corrosion behavior of the Cu-6% Ni-4% Sn-x% Cr alloys was investigated using electrochemical corrosion test and surface analyses (optical microscopy, electron probe microanalysis and scanning electron microscopy). The addition of Cr was found to prevent the localized corrosion behavior, which is caused by the decreased Sn-rich precipitates in Cu-6% Ni-4% Sn-x% Cr alloys. These precipitates induced galvanic corrosion due to the difference of the chemical composition

2008-05-08

331

Modelling the corrosion-induced cracking of reinforced concrete structures exposed to the atmosphere  

International Nuclear Information System (INIS)

The prediction of concrete cracking due to corrosion in atmospheric/carbonated conditions is a major issue for the evaluation of the durability of structures and the choice of maintenance policies. Because of the complexity of the phenomenon, a fully predictive approach is still missing. The proposed work can be considered as one step in this direction. It deals with a modelling study achieved at the Commissariat a l'Energie Atomique (CEA) with the CAST3M finite elements software. Model is constituted of three components: (1) concrete hydric behaviour, (2) rebar corrosion and (3) mechanical consequences on concrete (mainly concrete cracking). Actual developments consider analogies between rebar corrosion mechanisms and atmospheric corrosion ones, assuming that corrosion processes are influenced by the relative humidity evolution of atmosphere and/or of concrete. (authors)

2011-01-01

332

Oil ash corrosion  

International Nuclear Information System (INIS)

In this paper a review of experience with oil ash corrosion is presented along with current design practices used to avoid excessive tube wastage. Factors influencing oil ash corrosion include fuel chemistry, boiler operation, and boiler design. These factors are interdependent and determine the corrosion behavior in utility boilers. Oil ash corrosion occurs when vanadium-containing ash deposits on boiler tube surfaces become molten. These molten ash deposits dissolve protective oxides and scales causing accelerated tube wastage. Vanadium is the major fuel constituent responsible for oil ash corrosion. Vanadium reacts with sodium, sulfur, and chlorine during combustion to produce lower melting temperature ash compositions, which accelerate tube wastage. Limiting tube metal temperatures will prevent ash deposits from becoming molten, thereby avoiding the onset of oil ash corrosion. Tube metal temperatures are limited by the use of a parallel stream flow and by limiting steam outlet temperatures. Operating a boiler with low excess air has helped avoid oil ash corrosion by altering the corrosive combustion products. Air mixing and distribution are essential to the success of this palliative action. High chromium alloys and coatings form more stable protective scaled on tubing surfaces, which result in lower oil ash corrosion rates. However, there is not material totally resistant to oil ash corrosion

1991-02-01

333

Casting materials in manufacturing pumps for mines  

Energy Technology Data Exchange (ETDEWEB)

Development of casting is discussed at the POWEN Mining Equipment Plant in Zabrze. Types of mining equipment manufactured by the Plant, types of iron and steels and casting house development are evaluated. Types of casting metals used for manufacturing elements of pumps for underground coal mines are analyzed. The following metal types are comparatively evaluated: copper cast iron (ZlCu1,6), spheroidal copper cast iron (ZsCu1,0), 4 types of alloy cast steel (LH18S2, L21OH21, LH14N, LH18N9). Chemical composition, physical properties and mechanical properties of the casting alloys are analyzed. Methods for heat treatments and machining are discussed. Effects of alloy type on friction and wear are investigated. Two types of bronze also used for manufacturing pumps are comparatively evaluated: tin bronze, also containing zinc and lead, and silicon-manganese-zinc bronze. 4 refs.

Borek, K.; Gorniok, J.

1986-11-01

334

The microbial corrosion; La corrosion microbienne  

Energy Technology Data Exchange (ETDEWEB)

Underestimated for a long time, corrosion due to microorganisms induces degradation, sometimes fulminant, of a lot of metallic structures in the world. Searchers are using plentiful analytical tools to understand this phenomenon. (O.M.)

Beech, I.B. [University of Portsmouth, School of Pharmacy - Biomedical Science, Chemistry-Physics and Radiography, Portsmouth (United Kingdom)

1999-02-01

335

Corrosion Behaviour of Heat - Treated Al-6063/ SiCp Composites Immersed in 5 wt% NaCl Solution  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The influence of SiC volume percent and temper conditions (namely, as-cast, solutionized, and artificial age hardening at 180°C and 195°C) on the corrosion behaviour of Al (6063) composites and its monolithic alloy immersed in 5wt% NaCl solution has been investigated. Al (6063) - SiC particulate composites containing 6, 12 and 15 volume percent SiC were produced by premixing the SiC particles with borax additive and then adopting two step stir casting. Mass loss and corrosion rate measureme...

Alaneme, Kenneth

2011-01-01

336

Structural Aspects of the Behavior of Lead-Free Solder in the Corrosive Solution  

Science.gov (United States)

In oxidizing environments, most tin-based lead (Pb)-free alloys form a tin oxide that is easily eroded or mechanically damaged, affecting corrosion resistance and thus reliability of the soldered joints. In this study, the effect of microstructure heterogeneity on corrosion behavior of Pb-free solder candidate systems has been investigated on the example of as-cast and heat-treated alloys. The research was focused on a comparison between the corrosion resistance of binary Sn-Zn and ternary Sn-Zn-Cu alloys. Accelerated corrosion tests were performed by means of electrochemical methods in the sodium sulfate solution (VI), Na2SO4, of about 0.5 M concentration, pH adjusted to 2 by means of concentrated H2SO4 acid. In these tests, the corrosion potentials as well as polarization curves were determined for the selected alloys in as-cast state and after their heat treatment using different combinations of processing parameters. The measurements of basic electrochemical characteristics were made, i.e., the corrosion current ( i corr ?A/cm2) and Tafel coefficients, both cathodic ( b c V/dec) and anodic ( b a V/dec) ones. Detailed structural characterization of as-cast and heat-treated alloys before and after accelerated corrosion tests has been made under a wide range of magnifications using light microscopy and scanning electron microscopy observations. The results showed that structural heterogeneity of the examined alloys, attributed to the presence of secondary phases, and affected by their size and distribution, significantly influences the behavior of the examined Pb-free Sn-Zn-based alloys in the corrosive environment.

Pietrzak, K.; Grobelny, M.; Makowska, K.; Sobczak, N.; Rudnik, D.; Wojciechowski, A.; Sienicki, E.

2012-05-01

337

Corrosion testing in coal preparation environments  

Energy Technology Data Exchange (ETDEWEB)

Equipment that is used in coal preparation is subjected to various forms of corrosion and mechanical wear. The Kentucky Center for Energy Research Laboratory is conducting ongoing wear tests at TVA's Paradise coal preparation plant to measure the performance of typical metals of construction in various process areas of the plant. Results of a 2500 hour test are reported and compared to baseline results that were obtained from an earlier test. Comparison of data from these two tests indicate that wear results are reasonably reproducible within the operating variations of the plant. Stainless steel and high chromium cast iron samples experience low or negligible wastage rates. Low carbon steel, Cor-Ten A, Ni Hard 1 and Ni Hard 4 samples experienced significant wastage rates as a result of general corrosion attack due to the presence of dissolved oxygen in highly conductive process water. Localized corrosion was also observed in all samples except for the austenitic stainless steels. The highest wastage rates for almost all samples occurred in the location handling the largest-sized fraction of coal in the plant, indicating an added abrasive wear contribution. Long term testing in the plant continues.

Heink, J.B.; Stencel, J.M.; Abner, T.; Gonzalez, R.E.

1987-01-01

338

SRB seawater corrosion project  

Science.gov (United States)

The corrosion behavior of 2219 aluminum when exposed to seawater was characterized. Controlled corrosion experiments at three different temperatures (30, 60 and 100 C) and two different environments (seawater and 3.5 percent salt solution) were designed to elucidate the initial stages in the corrosion process. It was found that 2219 aluminum is an active catalytic surface for growth of Al2O3, NaCl, and MgO. Formation of Al2O3 is favored at lower temperatures, while MgO is favored at higher temperatures. Visible corrosion products are formed within 30 minutes after seawater exposure. Corrosion characteristics in 3.5 percent salt solution are different than corrosion in seawater. Techniques utilized were: (1) scanning electron microscopy, (2) energy dispersive x-ray spectroscopy, and (3) Auger electron spectroscopy.

Bozack, M. J.

1991-01-01

339

Inoculation Effects of Cast Iron  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The paper presents a solidification sequence of graphite eutectic cells of A and D types, as well as globular and cementite eutectics. The morphology of eutectic cells in cast iron, the equations for their growth and the distances between the graphite precipitations in A and D eutectic types were analyzed. It is observed a critical eutectic growth rate at which one type of eutectic transformed into another. A mathematical formula was derived that combined the maximum degree of undercooling, t...

2012-01-01

340

Tunneling corrosion mechanism of the hot forged austenitic stainless steel in highly oxidizing nitric acid  

International Nuclear Information System (INIS)

Austenitic Stainless Steels have been used for reprocessing plants where spent nuclear fuels are dealt with in hot nitric acid. Conventional stainless steels are resistant enough to nitric acid. However, they are prone to localized corrosion when nitric acid becomes highly oxidizing with birth of oxidants such as Ce"4"+ or Cr"6"+ ion during the reprocessing. Pitting type corrosion, so-called tunneling or end-grain corrosion occurred on the forgings of 25%-20%-Nb stainless steel (310Nb stainless steel) in such nitric acid solutions because of transpassive corrosion. It has been well known that metal surfaces of steel products casted, forged or rolled are susceptible to the tunneling corrosion in aggressive corrosion media. Nevertheless, neither clear explanations of the mechanism nor definite countermeasures have been proposed yet. This paper describes the mechanism and countermeasures on the tunneling corrosion of stainless steels in nitric acid relevant to spent nuclear fuel reprocessing. The results obtained are as follows: both general and intergranular corrosion occur on austenitic stainless steels in boiling 8N HNO_3 with Cr"6"+ions. Tunneling corrosion is initiated and propagates at the metal surfaces of 310Nb stainless steel forgings along chromium depleted areas vertical to metal flows. The grooves due to the tunneling corrosion are of diameters of 0.5 to 2 mm with a maximum depth of 6mm depending on exposure time and Cr"6"+ concentration in nitric acid. Tunneling corrosion proceeds by build up of galvanic corrosion cells with Cr depleted parts as anodes and their neighborhoods as cathodes. The Cr depleted parts are formed during solidification of ingots and still retained parallel to the metal flow even after forging. The ESR (Electro Slag Remelting) is one of the useful preventive methods to tunneling corrosion from the view point of steel homogenization

1993-09-19

 
 
 
 
341

Erosion-corrosion; Erosionkorrosion  

Energy Technology Data Exchange (ETDEWEB)

A literature study on erosion-corrosion of pipings in the nuclear industry was performed. Occurred incidents are reviewed, and the mechanism driving the erosion-corrosion is described. Factors that influence the effect in negative or positive direction are treated, as well as programs for control and inspection. Finally, examples of failures from databases on erosion-corrosion are given in an attachment 32 refs, 16 figs, tabs

Aghili, B

1999-05-01

342

The Microbial Corrosion of Iron.  

Science.gov (United States)

The investigation showed the potential and magnitude for microbial corrosive effects on iron in marine environments. Aerobic and anaerobic corrosion cells can be developed by a wide variety of microorganisms. Aerobic corrosion is developed through metabol...

C. H. Oppenheimer

1967-01-01

343

Stress Corrosion in Prestressing Steel.  

Science.gov (United States)

Contents: Research into the embrittlement of prestressing steel (stress corrosion)--general review of the subject; Potential dynamic polarization curves and steel corrosion; Corrosion of reinforcement in concrete due to calcium chloride; and Endurance tes...

P. C. Kreijger W. L. Sluijter F. Etienne J. W. Boon F . Bergsma

1977-01-01

344

Operational experiences of corrosion in seawater-cooled heat exchanges in Finnish and Swedish power plants  

International Nuclear Information System (INIS)

A survey has been made of the corrosion behaviour of seawater cooled heat exchangers in Finnish and Swedish power plants. Of the tube materials only titanium and a few high alloy stainless steels have been entirely corrosion resistant during 2-3 years of operation. Aluminium brass has been attacked by erosion corrosion and pitting, and CuNi 70/30 by erosion corrosion. The failure rate (FR) for aluminium brass is normally below 0,1, which is less than half of that reported from American power stations cooled with pure seawater. The survey shows that FeSO_4 dosage and cathodic protection with impressed current from Fe anodes reduces the corrosion of aluminium brass. On the other hand no conclusions can be drawn about the effect of sponge ball cleaning or chlorination. Tube plates of Muntz metal, Naval Brass and type 316 clad steel have exhibited very marginal corrosion problems. In the latter, however, the corrosion in the tube to tube plate crevices has increased after changing from copper alloy to titanium tubes. In water boxes of carbon steel and cast iron with organic coating the corrosion problems have been small. Stainless steel type 304 has been attacked by crevice corrosion, but not the high alloy type 904 L

1982-09-24

345

Improved corrosion resistance of a high-strength Mg–Al–Mn–Ca magnesium alloy made by rapid solidification powder metallurgy  

International Nuclear Information System (INIS)

Highlights: ? Corrosion behavior of an Mg–Al–Mn–Ca alloy produced by SWAP was investigated. ? The SWAPed Mg alloy has superior mechanical property and high corrosion resistance. ? The high corrosion resistance is partly attributed to the dispersed intermetallic particles. ? Dispersion of intermetallic phase is favorable to the improvement of corrosion resistance. - Abstract: The mechanical property and in particular the corrosion behavior of an Mg–Al–Mn–Ca alloy produced by spinning water atomization process (SWAP) were investigated and compared to those of the alloys made by gravity cast and hot extrusion. It is found that the SWAPed alloy has not only superior mechanical properties but also distinguished corrosion resistance. The corrosion resistance of the SWAPed alloy is about 2.5 and 10 times higher than that of the hot-extruded and as-cast alloys, respectively, when immersed in 0.1 M NaCl solution. Potentiodynamic polarization shows that both the anodic and cathodic current densities of the three alloys in 0.1 M NaCl solution are in the order of SWAPed alloy < hot-extruded alloy < as-cast alloy. The depressed cathodic and anodic reactions of the SWAPed alloy are attributed to the fine dispersed intermetallic phase and the supersaturated composition in ?-Mg matrix, respectively. The present results demonstrate that the corrosion resistance of magnesium alloys can be greatly improved via the dispersion of intermetallic phase by the process such as SWAP.

2012-05-15

346

Naphthenic corrosion resistance, mechanical properties and microstructure evolution of experimental Cr-Mo steels with high Mo content  

Digital Repository Infrastructure Vision for European Research (DRIVER)

One method to face the effects of naphthenic acid corrosion in petroleun refining plants is to use alloys with good resistance to this kind of corrosion. For this purpose, molybdenum additions to chromium containing steels are specially recommended. In this work, experimental Fe-9Cr-xMo (x = 5, 7 and 9 wt. (%)) ingots were cast, forged and hot rolled before being tested in a naphthenic acid environment. Evolution of the mechanical properties with composition is presented. The precipitation an...

Lorena Braga Moura; Rodrigo Freitas Guimarães; Hamilton Ferreira Gomes de Abreu; Hélio Cordeiro de Miranda; Sérgio Souto Maior Tavares1

2012-01-01

347

Corrosion resistance of neodymium composite materials reinforced with metal powders  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The goal of the study is to investigate the corrosion resistance of hard magnetic composite materials Nd-Fe-B with 5%, 10% and 15% by weight of iron powder, casting copper alloy with tin CuSn10, steel corrosion-resistant X2CrNiMo17-12-2 and Epidian100 (2.5% by mass as a binder in a humid environment at 40°C and 5% NaCl solution at 35°C and to determine their current-voltage characteristics.Design/methodology/approach: The investigations of corrosion resistance of hard magnetic composite materials in climate chambers were carried out : test 1 (temperature 40°C, relative humidity 93%, duration 96 h, test 2 (temperature 35°C, 5% NaCl solution, duration 6 h. Pitting corrosion were made in an environment of 5% NaCl solution at 35°C.Findings: The results of corrosion tests allows to determinate that the best corrosion show composite materials with addition of 15% of CuSn10 or X2CrNiMo17-12-2.Practical implications: Composite materials Nd-Fe-B – polymer matrix can greatly expand the application possibilities of hard magnetic materials however further examination to obtain materials with improved properties are still needed.Originality/value: Results show corrosion resistance of Nd-Fe-B - polymer matrix composite materials determined by different methods. Results are the base for further investigations of the impact of corrosion environment on the magnetic properties of such composite materials.

M. Dzieko?ska

2012-12-01

348

Vascular nevi in children  

Directory of Open Access Journals (Sweden)

Full Text Available Background: Vascular nevi are cutaneous anomalies of angiogenesis and vasculogenesis resulting in various different clinical presentations. Aim: The purpose of our descriptive study was to observe the various types of vascular nevi in children and their features. Methods: A total of 4256 pediatric cases attending the dermatology OPD during the study period from August 2002 to August 2004 were screened for vascular nevi. Results: Out of these, 19 children (0.44% had vascular nevi-17 hemangiomas of infancy (HOIs and 2 port-wine stains. The mean age of the affected children was 1.3 years (ranging from 2.5 months to 8 years. There were 13 girls and 6 boys. Seventeen (89.5% patients had progressing lesions and two (10.5% had non-involuting ones. A solitary lesion was seen in ten (52.6% cases and two to five lesions were present in five (26.3% cases. The nevi were distributed over multiple sites in seven (36.8% cases, the head and neck in six (31.6% cases, the chest and lower limb in two (10.5% cases each, and the upper limbs and genitalia in one (5.3% case each. Among the hemangiomas of infancy, 15 (88.2% cases of superficial type and 2 (11.8% cases of deep type were seen. The cutaneous complications included ulceration in four cases and infection in one. Conclusions: HOIs were the most common vascular nevi of childhood.

Senthilkumar M

2006-01-01

349

Compilation of Hanford corrosion studies  

International Nuclear Information System (INIS)

Experimental Hanford corrosion studies are reviewed with the intent of identifying the types and rates of corrosion encountered, surveying the experimental techniques used to gather corrosion data, and indicating how these data contribute to tank failure predictions. The experimental studies in this document can be divided into the following areas: general and pitting corrosion, stress corrosion cracking, corrosivity of solidified high-level waste, and cathodic protection. (U.S.)

1975-01-01

350

Corrosion behaviour of container materials for the disposal of high-level waste forms in rock salt formations  

International Nuclear Information System (INIS)

Extensive laboratory-scale experiments to evaluate the long-term corrosion behaviour of selected materials in brines and first in situ experiments were performed. In the laboratory experiments the materials Ti 99.8-Pd, Hastelloy C4 and hot-rolled low carbon steel as well cast steel, spheroidal cast iron, Si-cast iron and the Ni-Resists type D2 and D4 were investigated. The investigated parameters were: temperature, gamma-radiation and different compositions of salt brines. (orig./PW)

1987-01-01

351

Microstructure 2007of WE43 casting magnesium alloy  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: WE43 is a high-strength magnesium alloy characterized by good mechanical properties both at an ambient and elevated temperature (up to 300°C. It contains mainly yttrium and neodymium. The aim of this paper is to present the results of research on the microstructure of the WE43 magnesium alloy in an as-cast condition.Design/methodology/approach: For the microstructure observation, a Reichert metallographic microscope MeF2 and a HITACHI S-3400N scanning electron microscope with a Thermo Noran EDS equipped with SYSTEM SIX were used. A qualitative phase analysis was performed with a JEOL JDX-7S diffractometer. Microstrucutral examinations were performed JEOL 3010 transmission electron microscope.Findings: Based on the investigation carried out it was found that the microstructure of WE43 alloy after continuous casting consists of ?-Mg matrix and irregular precipitates of Mg41Nd5, rectangular particles of MgY phase, particles of Mg24Y5, longitudinal precipitates of ? (Mg14Nd2Y compound at grain boundaries and the grain interiors. All of these phases contain yttrium and neodymium. Research limitations/implications: Future researches should contain investigations of the influence of heat treatment parameters on microstructure, corrosion resistance and mechanical properties of WE43 alloy.Practical implications: WE43 magnesium alloy is used in the aircraft industry, for wheels, engine casings, gear box casings and rotor heads in helicopters. Results of investigation may be useful for development casting technology of the Mg-Y-Nd alloys.Originality/value: The results of the researches make up a basis for the next investigations of magnesium alloys with addition of Y and Nd designed to exploitation at temperature to 300°C.

A. Kie?bus

2007-03-01

352

Selective Leaching of Gray Cast Iron: Electrochemical Aspects  

International Nuclear Information System (INIS)

Currently, to keep step with increases in energy consumption, much attention has been paid to the construction of new nuclear power plants (NPPs) and to the continued operation of NPPs. For continued operation, the selective leaching of materials should be evaluated by visual inspections and hardness measurements as a part of One-Time Inspection Program according to the requirements of the guidelines for continued operation of pressured water reactors (PWRs) in Korea and license renewals in the United States, entitled the 'Generic Aging Lessons Learned (GALL) report.' However, the acceptance criteria for hardness have yet to be provided. Recently, USNRC released a new draft of the GALL report for comment and plans to publish its formal version by the end of 2010. In the new draft, the quantitative acceptance criteria for hardness are given at last: no more than a 20 percent decrease in hardness for gray cast iron and brass containing more than 15 percent zinc. Selective leaching is the preferential removal of one of the alloying elements from a solid alloy by corrosion processes, leaving behind a weakened spongy or porous residual structure. The materials susceptible to selective leaching include gray cast iron and brass, which are mainly used as pump casings and valve bodies in the fire protection systems of NPPs. Since selective leaching proceeds slowly during a long period of time and causes a decrease in strength without changing the overall dimensions of original material, it is difficult to identify. In the present work, the selective leaching of gray cast iron is investigated in terms of its electrochemical aspects as part of an ongoing research project to study the changes in metal properties by selective leaching

2010-10-01

353

Prefabrication of axial vascularized tissue engineering coral bone by an arteriovenous loop: A better model  

Energy Technology Data Exchange (ETDEWEB)

The most important problem for the survival of thick 3-dimensional tissues is the lack of vascularization in the context of bone tissue engineering. In this study, a modified arteriovenous loop (AVL) was developed to prefabricate an axial vascularized tissue engineering coral bone in rabbit, with comparison of the arteriovenous bundle (AVB) model. An arteriovenous fistula between rabbit femoral artery and vein was anastomosed to form an AVL. It was placed in a circular side groove of the coral block. The complex was wrapped with an expanded-polytetrafluoroethylene membrane and implanted beneath inguinal skin. After 2, 4, 6 and 8 weeks, the degree of vascularization was evaluated by India ink perfusion, histological examination, vascular casts, and scanning electron microscopy images of vascular endangium. Newly formed fibrous tissues and vasculature extended over the surfaces and invaded the interspaces of entire coral block. The new blood vessels robustly sprouted from the AVL. Those invaginated cavities in the vascular endangium from scanning electron microscopy indicated vessel's sprouted pores. Above indexes in AVL model are all superior to that in AVB model, indicating that the modified AVL model could more effectively develop vascularization in larger tissue engineering bone. - Highlights: Black-Right-Pointing-Pointer A modified arteriovenous loop (AVL) model in rabbit was developed in this study. Black-Right-Pointing-Pointer Axial prevascularization was induced in a larger coral block by using the AVL. Black-Right-Pointing-Pointer The prefabrication of axial vascularized coral bone is superior as vascular carrier.

Dong Qingshan [Department of Oral and Maxillofacial Surgery, Wuhan General Hospital of Guangzhou Military Command, Wuhan 430070 (China); Shang Hongtao; Wu Wei [Department of Oral and Maxillofacial Surgery, School of Stomatology, Fourth Military Medical University, Xi' an 710032 (China); Chen Fulin [Lab of Tissue Engineering, Faculty of Life Science, Northwest University, Xi' an 710069 (China); Zhang Junrui [Department of Oral and Maxillofacial Surgery, School of Stomatology, Fourth Military Medical University, Xi' an 710032 (China); Guo Jiaping [Department of Oral and Maxillofacial Surgery, Wuhan General Hospital of Guangzhou Military Command, Wuhan 430070 (China); Mao Tianqiu, E-mail: tianqiumao@126.com [Department of Oral and Maxillofacial Surgery, School of Stomatology, Fourth Military Medical University, Xi' an 710032 (China)

2012-08-01

354

High Cr white cast iron/carbon steel bimetal liner by lost foam casting with liquid-liquid composite process  

Directory of Open Access Journals (Sweden)

Full Text Available Liners in wet ball mill for mineral processing industry must bear abrasive wear and corrosive wear, and consequently, the service life of the liner made from traditional materials, such as Hadfield steel and alloyed steels, is typically less than ten months. Bimetal liner, made from high Cr white cast iron and carbon steel, has been successfully developed by using liquid-liquid composite lost foam casting process. The microstructure and interface of the composite were analyzed using optical microscope, SEM, EDX and XRD. Micrographs indicate that the boundary of bimetal combination regions is staggered like dogtooth, two liquid metals are not mixed, and the interface presents excellent metallurgical bonding state. After heat treatment, the composite liner specimens have shown excellent properties, including hardness > 61 HRC, fracture toughness ?k >16.5 J·cm-2 and bending strength >1,600 MPa. Wear comparison was made between the bimetal composite liner and alloyed steel liner in an industrial hematite ball mill of WISCO, and the results of eight-month test in wet grinding environment have proved that the service life of the bimetal composite liner is three times as long as that of the alloyed steel liner.

Xiao Xiaofeng

2012-05-01

355

Delamination wear mechanism in gray cast irons  

International Nuclear Information System (INIS)

An investigation of the friction and sliding wear of gray cast iron against chromium plated cast irons was carried out on a newly constructed reciprocating friction and wear tester. The tests were the first to be done on the test rig under dry conditions and at the speed of 170 cm/min, and variable loads of 20-260 N for a duration of 15 min. to 3 hours. The gray cast iron surfaces worn by a process of plastic deformation at the subsurface, crack nucleation, and crack growth leading to formation of plate like debris and therefore the delamination theory applies. No evidence of adhesion was observed. This could be due to formation of oxides on the wear surface which prevent adhesion. channel type chromium plating ''picked'' up cast iron from the counter-body surfaces by mechanically trapping cast iron debris on and within the cracks. The removal of the plated chromium left a pitted surface on the cast iron

2000-02-01

356

Homogenity of Die Casting and Returning Material  

Directory of Open Access Journals (Sweden)

Full Text Available Homogeneity of die castings is influenced by wide range of technological parameters as piston velocity in filling chamber of die casting machine, filling time of mould cavity, temperature of cast alloy, temperature of the mould, temperature of filling chamber, surface pressure on alloy during mould filling, final pressure and others. Based on stated parameters it is clear, that main parameters of die casting are filling time of die mould cavity and velocity of the melt in the ingates. Filling time must ensure the complete filling of the mould cavity before solidification process can negatively influence it. Among technological parameters also belong the returning material, which ratio in charge must be constrained according to requirement on final homogeneity of die castings. With the ratio of returning material influenced are the mechanical properties of castings, inner homogeneity and chemical composition.

J. Malik

2012-04-01

357

Gating of Permanent Molds for ALuminum Casting  

Energy Technology Data Exchange (ETDEWEB)

This report summarizes a two-year project, DE-FC07-01ID13983 that concerns the gating of aluminum castings in permanent molds. The main goal of the project is to improve the quality of aluminum castings produced in permanent molds. The approach taken was determine how the vertical type gating systems used for permanent mold castings can be designed to fill the mold cavity with a minimum of damage to the quality of the resulting casting. It is evident that somewhat different systems are preferred for different shapes and sizes of aluminum castings. The main problems caused by improper gating are entrained aluminum oxide films and entrapped gas. The project highlights the characteristic features of gating systems used in permanent mold aluminum foundries and recommends gating procedures designed to avoid common defects. The study also provides direct evidence on the filling pattern and heat flow behavior in permanent mold castings.

David Schwam; John F. Wallace; Tom Engle; Qingming Chang

2004-03-30

358

Seal welded cast iron nuclear waste container  

International Nuclear Information System (INIS)

An article of manufacture is described comprising a cast iron container having an opening at one end and a cast iron plug; a first nickel-carbon alloy fusion weldable insert surrounding the opening and metallurgically bonded to the cast iron container at the one end of the container; a second nickel-carbon alloy insert metallurgically bonded to the cast iron plug located within the opening and surrounded by the first insert the inserts being jointed by a fusion bond in the opening without heating the cast iron container to an austenite formation temperature thereby sealing the interior of the container from the exterior ambient outside the opening; the nickel-carbon alloy containing about 2 to 5 w% carbon; and both the nickel-carbon alloy insert and the cast iron container have a microstructure containing a graphite phase

1987-01-01

359

Advanced casting technologies for lightweight automotive applications  

Directory of Open Access Journals (Sweden)

Full Text Available This paper provides an overview of alloy and process developments in aluminum and magnesium castings for lightweight automotive applications. Wear-resistant aluminum alloys, creep-resistant and high strength/ductility magnesium alloys have been developed for automotive applications. On the process front, vacuum-assisted die casting and high vacuum die casting technologies have been developed for high-integrity body and chassis applications. Thin-wall and hollow casting components are being produced by low-pressure die casting processes for structural applications. Overcasting technology is gaining traction and has enabled mixed material designs for automotive sub-systems such as engine cradles and instrument panel beams. Simulation tools developed to predict the interfacial interactions of the dissimilar components and the structural integrity of the overcast systems are being validated in the casting trials.

Alan A. Luo

2010-11-01

360

Vascular graft infections.  

Science.gov (United States)

Prosthetic vascular grafting is a commonly performed procedure that is central to the management of arterial disease and renal failure. Though rare, vascular graft infections (VGI) are potentially devastating, and carry a high rate of mortality and amputation. Despite extensive research and clinical experience, VGI remain a daunting therapeutic challenge for surgeons and infectious disease specialists. This article reviews the pathogenesis of VGI, in particular the role of biofilms, as well as the current state of clinical management including diagnostic modalities, surgical options for treatment, antimicrobial therapy, and preventive measures. PMID:22284375

Young, Michael H; Upchurch, Gilbert R; Malani, Preeti N

2012-03-01

 
 
 
 
361

Strong exploration of a cast iron pipe failure model  

International Nuclear Information System (INIS)

A physical probabilistic failure model for buried cast iron pipes is described, which is based on the fracture mechanics of the pipe failure process. Such a model is useful in the asset management of buried pipelines. The model is then applied within a Monte-Carlo simulation framework after adding stochasticity to input variables. Historical failure rates are calculated based on a database of 81,595 pipes and their recorded failures, and model parameters are chosen to provide the best fit between historical and predicted failure rates. This provides an estimated corrosion rate distribution, which agrees well with experimental results. The first model design was chosen in a deliberate simplistic fashion in order to allow for further strong exploration of model assumptions. Therefore, first runs of the initial model resulted in a poor quantitative and qualitative fit in regards to failure rates. However, by exploring natural additional assumptions such as relating to stochastic loads, a number of assumptions were chosen which improved the model to a stage where an acceptable fit was achieved. The model bridges the gap between micro- and macro-level, and this is the novelty in the approach. In this model, data can be used both from the macro-level in terms of failure rates, as well as from the micro-level such as in terms of corrosion rates

2008-06-01

362

Large-area electron beam irradiation for surface polishing of cast titanium.  

Science.gov (United States)

Cast titanium is a known hard-to-polish material, and its final polishing step is a perpetual challenge. The best way to tackle this challenge lies in automatic and non-mechanical polishing methods. Against this background, the suitability of large-area electron beam (EB) irradiation was examined in this study. In parallel, the optimum condition for efficient surface polishing was investigated. Cast titanium specimens were prepared, whereby their surface glossiness, surface roughness, and corrosion resistance were measured before and after EB irradiation. After EB irradiation, favorable results were observed: the cast titanium surface became smooth, the glossiness increased, and corrosion resistance was enhanced. These results were attributed to the low heat conductivity of titanium. With mechanical polishing, this property results in temperature rise and burnout reaction of the titanium surface with oxygen and the abrasives. However, during EB irradiation, the low heat conductivity of titanium was an advantage in raising the surface temperature to the melting point, such that a smooth surface was yielded after solidification. Based on the results obtained, automatic polishing by EB seemed to be a suitable polishing method for metal frameworks of removable dentures, and an efficient one too by saving time and effort. PMID:19822988

Tokunaga, Junko; Kojima, Tetsuya; Kinuta, Soichiro; Wakabayashi, Kazumichi; Nakamura, Takashi; Yatani, Hirofumi; Sohmura, Taiji

2009-09-01

363

The cavitational erosion resistance of the B2-type Fe-Al casting alloys  

Directory of Open Access Journals (Sweden)

Full Text Available The problem of the destruction of turbo-machinery components is very complex, because it consists of processes of erosion and corrosion. The most dangerous factor is the cavitation phenomenon, which is very difficult to eliminate through the use of design solutions. It causes deterioration of the operating characteristics of machinery and equipment, such as water turbines, steam turbines, centrifugal pumps, screw vessels, cylinder liners with water-cooled engines, acoustic probe. The most commonly used method of limiting the destruction of cavitation phenomenon is the optimum choice of parameters of geometric and hydraulic machines, the appropriate design of elements and streamlined flow and providing working conditions of flow devices. The above-mentioned methods by design, the size of flow devices are limited, so better action to prevent the flow of erosion may use the material for greater resistance to erosion and cavitation corrosion is the alloy of intermetallic FeAl phase, which production costs are low compared to cast steel and cast iron alloy based on chromium and nickel.The paper presents results of an investigation carried out for cavitational resistance of the B2-type Fe-Al casting alloys using a flux-impact measuring device. The intermetallic FeAl alloys proved to have good resistance to this type of erosion in comparison to other construction materials, investigated by flux-impact device.

R. Jasionowski

2010-01-01

364

Casting voids influence on spheroid graphite cast iron high-cycle fatigue strength  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The influence of casting voids on spheroid cast iron cracking threshold is investigated. The experimental results and their analytical and numerical analysis basing on linear fracture mechanics is presented.

Bobyliov, Konstantin

2008-01-01

365

Newly developed vacuum differential pressure casting of thin-walled complicated Al-alloy castings  

Directory of Open Access Journals (Sweden)

Full Text Available The newly designed vacuum differential pressure casting (VDPC unit was introduced, by which the capability of the VDPC process to produce thin-walled complicated Al-alloy castings, that are free from oxides, gas pore and shrinkage cavity and thus enhance overall part quality, was studied. Experimental results were compared with those of traditional gravity pouring and vacuum suction casting. The first series of experiments were focused on investigating thecastability of thin section Al-alloy casting. In the second series of experiments the metallographic evidence, casting strength and soundness were examined. Finally, case studies of very interesting thin walled complicated casting applications were described. The advantages of the described technique have made possible to produce thin walled complicated Al-alloy casting (up to a section thickness of 1 mm, which is not practical for gravity pouring and vacuum suction casting.

Xuanpu DONG

2005-05-01

366

Optimization of Castings by using Surrogate Models  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this thesis structural optimization of castings and thermomechanical analysis of castings are studied. In paper I an optimization algorithm is created by using Matlab. The algorithm is linked to the commercial FE solver Abaqus by using Python script. The optimization algorithm uses the successive response surfaces methodology (SRSM) to create global response surfaces. It is shown that including residual stresses in structural optimization of castings yields an optimal shape that differs si...

Gustafsson, Erik

2007-01-01

367

Thermal gradient analysis of solidifying casting  

Directory of Open Access Journals (Sweden)

Full Text Available For description of casting solidification and crystallization process the thermal derivative analysis (TDA is commonly used. Besides the process kinetics considered in TDA method to describe the solidification process, the thermal gradient analysis can be also used for this purpose [1, 2]. In conducted studies analysis of thermal gradient distribution inside the solidifying wedge casting was shown which enabled determination of heat flow intensity on casting section.

J. Sucho?

2008-08-01

368

Microsegregation in Nodular Cast Iron with Carbides  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper results of microsegregation in the newly developed nodular cast iron with carbides are presented. To investigate the pearlitic and bainitic cast iron with carbides obtained by Inmold method were chosen. The distribution of linear elements on the eutectic cell radius was examined. To investigate the microsegregation pearlitic and bainitic cast iron with carbides obtained by Inmold method were chosen.The linear distribution of elements on the eutectic cell radius was examined. Tes...

2012-01-01

369

Directional Solidification of Nodular Cast Iron  

Science.gov (United States)

Cerium enhances formation of graphite nodules. Preliminary experiments in directional solidification of cast iron shows quantitative correlation of graphite microstructure with growth rate and thermal gradient, with sufficient spheroidizing element to form spheroidal graphite under proper thermal conditions. Experimental approach enables use of directional solidification to study solidification of spheriodal-graphite cast iron in low gravity. Possible to form new structural materials from nodular cast iron.

Curreri, P. A.; Stefanescu, D. M.; Hendrix, J. C.

1987-01-01

370

Methods for Casting Subterranean Ant Nests  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The study of subterranean ant nests has been impeded by the difficulty of rendering their structures in visible form. Here, several different casting materials are shown to make perfect casts of the underground nests of ants. Each material (dental plaster, paraffin wax, aluminum, zinc) has advantages and limitations, which are discussed. Some of the materials allow the recovery of the ants entombed in the casts, allowing a census of the ants to be connected with features of their nest archite...

Tschinkel, Walter R.

2010-01-01

371

Ferritic-austenitic cast steel - selected problems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The author has been involved in the problems occurring in the manufacture of ferritic-austenitic cast steel castings for many years. The author’s remarks and investigation results reported in this article will enable potential manufacturers to determine their own technical capabilities and structural determinants related to the chemical composition of material, which are crucial to the good quality of a casting. Particular emphasis should be laid on the role of enhanced carbon content, the ...

2011-01-01

372

As-cast titanium aluminides microstructure modification  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Two cast g titanium aluminides, Ti47Al and Ti50Al (at. %), were obtained by arc melting under an argon atmosphere. The as-cast microstructure modification by annealing under protective argon atmosphere and hot isostatic pressing (HIP) was analysed by optical and scanning electron microscopy with microanalysis facilities. As-cast structures presented strong microsegregations, being composed of primary a dendrites (with low Al content), whic...

Duarte A.; Viana F.; Santos Henrique M.C.M.

1999-01-01

373

Hot corrosion behavior of low pressure plasma sprayed NiCoCrAlY+Ta coatings on nickel base superalloys  

International Nuclear Information System (INIS)

The hot corrosion behavior of NiCoCrAlY+Ta coatings obtained by low-pressure plasma spraying has been investigated (type I hot corrosion with T = 850"0C). These coatings have been deposited on two nickel-base superalloys and on a cast alloy of the same composition as the coating. Comparison of the cyclic oxidation behavior at 850"0C between the sprayed coating and the cast alloy shows that the sprayed material exhibits a satisfactory and higher resistance than the cast alloy. In the latter case, repeated spalling of the oxide scale results from fractures often associated with Y-rich oxide protrusions. Hot corrosion experiments (salt-spraying test with T = 850"0C and thermal cycling in air every hour) have been conducted on two cast alloys, NiCoCrAl+Ta and NiCoCrAlY+Ta. The Y-containing alloy has a better corrosion resistance than the other alloy which is subject to extensive oxide spallation. In both cases, morphologies typical of basic fluxing processes, involving Cr, Al, Y, and Ta can be observed in highly attacked zones. Finally, tests on plasma sprayed coatings show a high resistance to hot corrosion of these coatings, regardless of the substrate used: a fine adherent alumina layer is formed, and only a limited fluxing of Cr, Al, and Y takes place. The quite different results obtained on cast and sprayed alloys imply that data relative to cast alloys can be unreliable when one wants to predict high temperature behavior and especially lifetimes of overlay coatings

1985-01-01

374

Static corrosion of construction materials exposed to superphosphoric acid made from various sources of phosphate rock  

Energy Technology Data Exchange (ETDEWEB)

Corrosion tests were performed with various construction materials, such as carbon steel, cast iron, stainless steels, nickel and nickel-based alloys, copper and its alloys, aluminum alloy, zirconium alloy, and tantalum, exposed to wet-process superphosphoric acids (approximately 70% P{sub 2}O{sub 5}) from all the suppliers in the United States and to a technical-grade (55% P{sub 2}O{sub 5}) acid made by the electric furnace process. The study was conducted in response to reports from pipe-reactor users of excessive corrosion by superphosphoric acids and electric furnace acid. Test temperatures were ambient (approximately 21{degrees}C or 70{degrees}F), 66{degrees}C (150{degrees}F), and 93{degrees}C (200{degrees}F). Test results showed that temperature was a significant factor in acid corrosivity. Electric furnace acid was more corrosive than the superphosphoric acids. Carbon steel, cast iron, and aluminum alloy were not resistant to either the superphosphoric acids or the electric furnace acid. Nickel-chromium (Ni-Cr) and nickel-molybdenum (Ni-Mo) based alloys and tantalum exhibited adequate corrosion resistance in the superphosphoric acids and the electric furnace acid. Stainless steels performed well in all test acids at all test temperatures with some exceptions in the electric furnace acid at 93{degrees}C. Zirconium alloy, copper and its alloys, pure nickel, and Monel 400 provided adequate corrosion resistance to all test acids at ambient temperature only.

Nguyen, D.T.; McDonald, C.L.; McGill, K.E.

1994-10-01

375

Influence of rare earth metals addition on the corrosion behaviour of copper in alkaline environment  

International Nuclear Information System (INIS)

Highlights: ? The corrosion properties of as cast Cu91.6Nd8.4 and Cu90.5Er9.5 (at.%) eutectic alloys have been investigated. ? Electrochemical results are compared with those obtained on pure copper. ? Rare earth metals (Nd, Er) significantly improve the corrosion resistance of pure copper. - Abstract: The corrosion properties of as cast Cu91.6Nd8.4 and Cu90.5Er9.5 (at.%) eutectic alloys is investigated in naturally aerated 1 M NaOH solution, pH = 14, at room temperature, by means of potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements. The results are compared with those obtained on pure Cu in order to assess the influence of rare earth (RE) elements on its corrosion behaviour. Microstructural characterization of the alloys investigated was carried out using scanning electron microscopy (SEM) coupled with electron probe microanalysis (EPMA). The electrochemical tests reveal that Cu–RE (RE = Nd, Er) alloys significantly improve resistance to corrosion compared with pure Cu, in spite of their two-phase microstructure. Spatial distribution and volume fraction of Cu6Nd and Cu5Er intermetallic compounds are microstructural features which play a very important role in determining the corrosion behaviour of Cu91.6Nd8.4 and Cu90.5Er9.5 eutectic alloys.

2012-05-01

376

Exploratory shaft liner corrosion estimate  

Energy Technology Data Exchange (ETDEWEB)

An estimate of expected corrosion degradation during the 100-year design life of the Exploratory Shaft (ES) is presented. The basis for the estimate is a brief literature survey of corrosion data, in addition to data taken by the Basalt Waste Isolation Project. The scope of the study is expected corrosion environment of the ES, the corrosion modes of general corrosion, pitting and crevice corrosion, dissimilar metal corrosion, and environmentally assisted cracking. The expected internal and external environment of the shaft liner is described in detail and estimated effects of each corrosion mode are given. The maximum amount of general corrosion degradation was estimated to be 70 mils at the exterior and 48 mils at the interior, at the shaft bottom. Corrosion at welds or mechanical joints could be significant, dependent on design. After a final determination of corrosion allowance has been established by the project it will be added to the design criteria. 10 refs., 6 figs., 5 tabs.

Duncan, D.R.

1985-10-01

377

Corrosion: A people problem  

Energy Technology Data Exchange (ETDEWEB)

It is people that are involved in the process of designing, building, and maintaining equipment and structures. People who are not familiar with good corrosion design and practices end up compromising system performance. Examples of the way people can affect these compromises using the eight forms of corrosion are discussed in the paper.

Menke, J.

1999-07-01

378

Erosion/corrosion newslettter  

Energy Technology Data Exchange (ETDEWEB)

Information is presented concerning corrosion-erosion wear testing of ductile metals and brittle ceramics; two-phase gas flow and two-phase liquid flow; corrosion testing of oil shale retort components; erosion of alloys for coal liquefaction systems; and protective coatings for alloys used in fossil fuel combustion systems.

Levy, A.V.

1981-06-01

379

Corrosion evaluation technology  

Energy Technology Data Exchange (ETDEWEB)

A multifrequency ACPD system was assembled which can measure very small crack. Stress corrosion cracking test system with SSRT operating high temperature was installed. Stress corrosion cracking test of newly developed alloy 600 and existing alloy 600 was carried out in steam atmosphere of 400 deg C. No crack was observed in both materials within a test period of 2,000 hrs. Corrosion fatigue test system operating at high temperature was installed in which fatigue crack was measured by CDPD. Lead enhanced the SCC of the Alloy 600 in high temperature water, had a tendency to modify a cracking morphology from intergranular to transgranular. Pit initiation preferentially occurred at Ti-rich carbide. Resistance to pit initiation decreased with increasing temperature up to 300 deg C. Test loop for erosion corrosion was designed and fabricated. Thin layer activation technique was very effective in measuring erosion corrosion. Erosion corrosion of a part of secondary side pipe was evaluated by the Check Family Codes of EPRI. Calculated values of pipe thickness by Check Family Codes coincided with the pipe thickness measured by UT with an error of {+-} 20%. Literature review on turbine failure showed that failure usually occurred in low pressure turbine rotor disc and causes of failure are stress corrosion cracking and corrosion fatigue. (author). 12 refs., 20 tabs., 77 figs.

Kim, Uh Chul; Han, Jeong Ho; Nho, Kye Ho; Lee, Eun Hee; Kim, Hong Pyo; Hwang, Seong Sik; Lee, Deok Hyun; Hur, Do Haeng; Kim, Kyung Mo

1997-09-01

380

Corrosion in power engineering  

International Nuclear Information System (INIS)

The proceedings contain full texts of 28 contributions, out of which 3 fall within the INIS subject scope. These are concerned with general corrosion problems in nuclear power industry and with corrosion effects of decontamination solutions on the structural materials of primary circuits of nuclear power plants. (Z.M.)

1990-03-27

 
 
 
 
381

Reduce FCC corrosion  

Energy Technology Data Exchange (ETDEWEB)

Efficiency of fluid catalytic cracking (FCC) vapor recovery units can be significantly reduced by corrosion and fouling. The fundamentals of FCC light ends corrosion, including diagnoses, control and monitoring of hydrogen blistering, general metal loss, pitting, erosion and under-deposit attack are discussed, relating actual unit problems to effective treatment program solutions.

Walker, H.B.

1984-01-01

382

New progresses of Chinese art casting  

Directory of Open Access Journals (Sweden)

Full Text Available The Chinese art casting with 5 000 years history has been rapidly developed in recent ten years. This benefits from the great development of Chinese economy, the large-scale urban construction and transformation, the increasing demands for the cultural work of art, the loose religious environment and the expanding international market. The Art Casting Technical Committee of China Foundry Association has been established for 10 years. Almost 90 art casting enterprises joined in the organization, not including nearly thousand enterprises of foreign capital and massive domestic workshop type. It is estimated that the scale and the output of art castings in mainland China have situated the world front row.

Tan Derui

2007-05-01

383

Microstructure and fracture of cast iron  

International Nuclear Information System (INIS)

In the present paper the effects of graphite morphology and matrix structure on the fracture toughness of cast iron are demonstrated in detail. It is shown that the fracture toughness of nodular cast iron is mainly influenced by the ductility of the matrix, whereas the fracture toughness of gray cast iron is primarily influenced by its graphite morphology (length and number of flakes). In addition it is shown, that for a given matrix toughness the fracture toughness of nodular cast iron is also affected by the number of nodules or the distance between them. The fracture toughness increases proportionally with the neasest-neighbour distance between nodules. (orig.)

1989-06-02

384

Ductile iron castings fabricated using metallic moulds  

International Nuclear Information System (INIS)

The features and suitability of high requirements ductile iron castings production using metallic moulds have been studied in the present work. The structural and mechanical properties of the produced castings have been analysed and compared to the corresponding ones but fabricated using green sand moulds according to a conventional production process. The higher cooling rate in the metallic moulds is the main cause for the appearance of the detected structural changes in castings. The mechanical and microstructural properties obtained directly on castings are remarkable due to the higher nodule count among other factors. Finally, the benefits and inconveniences found in this kind of production methodology using metallic moulds are also discussed. (Author)

2013-01-01

385

The structure of abrasion-resisting castings made of chromium cast iron  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this study presents the analyse of chrome iron cast structure (as-cast condition) which are used in rugged conditions abrasion-percussive and high temperature. While producing the casts of chrome iron major influence has been preserve the structure of technologi cal process parameters. The addition to Fe-C-Cr alloy Ni, Mo or Cu and then proper heat treatment leads to the improvement of functional and mechanical cast qualities. Then it is possible to develop high mechanical properties which...

2011-01-01

386

Optimization of casting conditions for heat and abrasion resistant large grey iron castings  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Numerical simulation technology was applied for optimizing the casting design and conditions in large cast iron castings for marine engine. By the simulation of mold filling and solidification sequences the problems of the previous casting conditions were analyzed and marked improvements for large cylinder liner parts were derived from these results. Especially the amount and positions of chills were optimized to increase the mechanical properties and to minimize the shrinkage and microporosi...

2007-01-01

387

Corrosion fatigue of steels  

International Nuclear Information System (INIS)

Corrosion fatigue phenomena can be classified into two main groups according to the electrochemical state of the metal surface in the presence of electrolytes: the active and the passive state with an important sub-group of corrosion fatigue in the unstable passive state. The allowable stress for structures exposed to the conjoint action of corrosion and fatigue is influenced by many factors: kind of media, number of cycles, frequency, mean stress, size, notches, loading mode, alloy composition and mechanical strength. A critical literature review shows contradictory results if a classification by the electrochemical surface state is not applied. Case histories and counter measures illustrate the practical importance of corrosion fatigue in many branches of industry as well as the urgent need for a better knowledge about the mutual influence of the phenomena to get rules by which the engineer can appraise the risk of corrosion fatigue. (orig.)

1975-11-21

388

Knowledge of corrosive damage  

International Nuclear Information System (INIS)

The book is intended to present as comprehensively as possible the state of the art of corrosion science and existing insight into corrosive damaging mechanisms and phenomena as occurring in metals and alloys in natural environments, technical applications and under industrial operating conditions, together with the existing knowledge for corrosion detection and characterization. The publication contains a wealth of pictures illustrating a large number of optical appearances of corrosive damage and discusses the mechanisms on the basis of graphical representations and the influencing parameters involved. The authors have compiled a practice-oriented source of information and guidance unique in its comprehensiveness and value for anybody professionally involved in activities for analysis, detection and identification as well as prevention of corrosive damage. (orig./CB)

1998-01-01

389

Spray casting project final report  

International Nuclear Information System (INIS)

Lockheed Martin Energy Systems, Inc. (Energy Systems), along with other participating organizations, has been exploring the feasibility of spray casting depleted uranium (DU) to near-net shape as a waste minimization effort. Although this technology would be useful in a variety of applications where DU was the material of choice, this effort was aimed primarily at gamma-shielding components for use in storage and transportation canisters for high-level radioactive waste, particularly in the Multipurpose Canister (MPC) application. In addition to the waste-minimization benefits, spray casting would simplify the manufacturing process by allowing the shielding components for MPC to be produced as a single component, as opposed to multiple components with many fabrication and assembly steps. In earlier experiments, surrogate materials were used to simulate the properties (specifically reactivity and density) of DU. Based on the positive results from those studies, the project participants decided that further evaluation of the issues and concerns that would accompany spraying DU was warranted. That evaluation occupied substantially all of Fiscal Year 1995, yielding conceptual designs for both an intermediate facility and a production facility and their associated engineering estimates. An intermediate facility was included in this study to allow further technology development in spraying DU. Although spraying DU to near-net shape seems to be feasible, a number of technical, engineering, and safety issues would need to be evaluated before proceeding with a production facility. This report is intended to document the results from the spray-casting project and to provide information needed by anyone interested in proceeding to the next step

1996-01-01

390

Spray casting project final report  

Energy Technology Data Exchange (ETDEWEB)

Lockheed Martin Energy Systems, Inc. (Energy Systems), along with other participating organizations, has been exploring the feasibility of spray casting depleted uranium (DU) to near-net shape as a waste minimization effort. Although this technology would be useful in a variety of applications where DU was the material of choice, this effort was aimed primarily at gamma-shielding components for use in storage and transportation canisters for high-level radioactive waste, particularly in the Multipurpose Canister (MPC) application. In addition to the waste-minimization benefits, spray casting would simplify the manufacturing process by allowing the shielding components for MPC to be produced as a single component, as opposed to multiple components with many fabrication and assembly steps. In earlier experiments, surrogate materials were used to simulate the properties (specifically reactivity and density) of DU. Based on the positive results from those studies, the project participants decided that further evaluation of the issues and concerns that would accompany spraying DU was warranted. That evaluation occupied substantially all of Fiscal Year 1995, yielding conceptual designs for both an intermediate facility and a production facility and their associated engineering estimates. An intermediate facility was included in this study to allow further technology development in spraying DU. Although spraying DU to near-net shape seems to be feasible, a number of technical, engineering, and safety issues would need to be evaluated before proceeding with a production facility. This report is intended to document the results from the spray-casting project and to provide information needed by anyone interested in proceeding to the next step.

Churnetski, S.R.; Thompson, J.E.

1996-08-01

391

Control of cast iron microstructure  

Science.gov (United States)

The use of microgravity for industrial research in the processing of cast iron was investigated. Solidification experiments were conducted using the KC-135 and F-104 aircraft, and an experiment plan was developed for follow-on experiments using the Shuttle. Three areas of interest are identified: (1) measurement of thermophysical properties in the melt; (2) understanding of the relative roles of homogeneous nucleation, grain multiplication, and innocultants in forming the microstructure; and (3) exploring the possibility of obtaining an aligned graphite structure in hypereutectic Fe, Ni, and Co.

Graham, J.; Lillybeck, N.; Franco, N.; Stefanescu, D. M.

1985-01-01

392

Centrifugal casting of refractory concretes  

Energy Technology Data Exchange (ETDEWEB)

Refractory pipe liners are required when extremely hot gases or abrasive solids are transported between processing units in coal gasification plants. One promising technique for producing refractory pipe (or refractory pipe liners) is centrifugal casting. For this study, the effect of processing variables such as workability, additives, reinforcement and spinning time, and centrifugal force were evaluated using four commercial refractory concretes. In addition, data on characteristics such as strength, density, abrasion, and spalling resistance of 5-inch-diam refractory pipe were developed. Techniques for forming large-diameter (19-inch) refractory pipe also were evaluated.

Marchewka, T.L.; Heystek, H.

1979-01-01

393

Microdefects in cast multicrystalline silicon  

Energy Technology Data Exchange (ETDEWEB)

The microdefect etching behavior of cast multicrystalline BAYSIX and SILSO samples is mainly the same as that of EFG silicon, in spite of the very different growth parameters applied to these two techniques and the different carbon contents of the investigated materials. Intentional decorating of mc silicon with copper, iron and gold did not influence the results of etching and with help of infrared transmission microscopy no metal precipitates at the assumed microdefects could be established. There are many open questions concerning the origin of the assumed, not yet doubtless proved microdefects.

Wolf, E.; Klinger, D.; Bergmann, S. [Inst. of Crystal Growth Berlin (Germany)

1995-08-01

394

Microstructural evolution in a duplex cast steel after quench ageing process  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The effectiveness and usefulness of the quench ageing on the service properties of massive duplex cast steel was presented in this work. The mechanism of precipitation of a ?-Cu phase and its effect on the mechanical properties of the cast steel were investigated.Design/methodology/approach: The microscopic analysis of the cast steel was performed on a Zeiss Axiovert 25 optical microscope. The substructure of ferrite was examined on a JOEL JEM 3010 high-resolution transmission electron microscope. The analysis of chemical composition of selected micro-regions was carried out using a JEOL JSM 5400 scanning microscope equipped with an EDS microanalyzer. The verification of the metallographic examination results was done using the Thermo-Calc program.Findings: The formation of the ?-Cu phase during quench ageing causes an increase in hardness and drop in impact resistance. The ageing parameters have a substantial influence on the ferrite substructure and the degree of coherence, dispersion and amount of the ?-Cu phase. The ageing treatment at 480°C causes the precipitation of the ?-Cu phase coherent with the matrix. This temperature of quench ageing produce also the formation of a ?’-Cr phase and an ?-Fe phase.Practical implications: Duplex cast steels are becoming an irreplaceable material in the elements of equipment exposed to the simultaneous action of corrosive and erosive environment. In the case of massive elements like pumps and pipeline elements, the effect of quench ageing is much lower which is associated with the presence of a large amount of the incoherent ?-Cu phase in the cast steel after the solution heat treatment.Originality/value: The lower temperature of quench ageing duplex cast steels with copper addition should not be lower than 500°C because of the temperature of an undesirable spinodal decomposition of the ferrite in 480°C which is partially responsible for the slight increase in hardness and a drastic drop in plastic properties.

Z. Stradomski

2007-09-01

395

Yield Improvement in Steel Casting (Yield II)  

Energy Technology Data Exchange (ETDEWEB)

This report presents work conducted on the following main projects tasks undertaken in the Yield Improvement in Steel Casting research program: Improvement of Conventional Feeding and Risering Methods, Use of Unconventional Yield Improvement Techniques, and Case Studies in Yield Improvement. Casting trials were conducted and then simulated using the precise casting conditions as recorded by the participating SFSA foundries. These results present a statistically meaningful set of experimental data on soundness versus feeding length. Comparisons between these casting trials and casting trials performed more than forty years ago by Pellini and the SFSA are quite good and appear reasonable. Comparisons between the current SFSA feeding rules and feeding rules based on the minimum Niyama criterion reveal that the Niyama-based rules are generally less conservative. The niyama-based rules also agree better with both the trials presented here, and the casting trails performed by Pellini an d the SFSA years ago. Furthermore, the use of the Niyama criterion to predict centerline shrinkage for horizontally fed plate sections has a theoretical basis according to the casting literature reviewed here. These results strongly support the use of improved feeding rules for horizontal plate sections based on the Niyama criterion, which can be tailored to the casting conditions for a given alloy and to a desired level of soundness. The reliability and repeatability of ASTM shrinkage x-ray ratings was investigated in a statistical study performed on 128 x-rays, each of which were rated seven different times. A manual ''Feeding and Risering Guidelines for Steel Castings' is given in this final report. Results of casting trials performed to test unconventional techniques for improving casting yield are presented. These use a stacked arrangement of castings and riser pressurization to increase the casting yield. Riser pressurization was demonstrated to feed a casting up to four time s the distance of a non-pressurized riser, and can increase casting yield by decreasing the required number of risers. All case studies for this projects were completed and compiled into an SFSA Technical Report that is submitted part of this Final Report

Richard A. Hardin; Christoph Beckermann; Tim Hays

2002-02-18

396

Clean cast steel technology. Final report  

Energy Technology Data Exchange (ETDEWEB)

This report documents the results obtained from the Clean Cast Steel Technology Program financially supported by the DOE Metal Casting Competitiveness Research Program and industry. The primary objective of this program is to develop technology for delivering steel free of oxide macroinclusions to mold cavities. The overall objective is to improve the quality of cast steel by developing and demonstrating the technology for substantially reducing surface and sub-surface oxide inclusions. Two approaches are discussed here. A total of 23 castings were produced by submerge pouring along with sixty conventionally poured castings. The submerged poured castings contained, on average, 96% fewer observable surface inclusions (11.9 vs 0.4) compared to the conventionally poured cast parts. The variation in the population of surface inclusions also decreased by 88% from 5.5 to 0.7. The machinability of the casting was also improved by submerged pouring. The submerge poured castings required fewer cutting tool changes and less operator intervention during machining. Subsequent to these trials, the foundry has decided to purchase more shrouds for continued experimentation on other problem castings where submerge pouring is possible. An examination of melting and pouring practices in four foundries has been carried out. Three of the four foundries showed significant improvement in casting quality by manipulating the melting practice. These melting practice variables can be grouped into two separate categories. The first category is the pouring and filling practice. The second category concerns the concentration of oxidizable elements contained in the steel. Silicon, manganese, and aluminum concentrations were important factors in all four foundries. Clean heats can consistently be produced through improved melting practice and reducing exposure of the steel to atmospheric oxygen during pouring and filling.

Bates, C.E.; Griffin, J.A.

1998-06-01

397

Susceptibility of copper to general and pitting corrosion in saline groundwater  

Energy Technology Data Exchange (ETDEWEB)

In Sweden and Finland the spent nuclear fuel is planned to be encapsulated in cast iron canisters that have an outer shield made of copper, which is responsible for the corrosion protection. In this work the susceptibility of Cu OFP to general and pitting corrosion was investigated in saline (1.45% Cl{sup -}) groundwater at T = 80 deg C and p = 14 MPa using electrochemical techniques and weight loss measurements in autoclave conditions. The results were compared with earlier results gained in similar conditions but in highly saline (5.4% Cl{sup -}) groundwater. The conclusions presented here are strictly applicable only for the present case, where the groundwater was deoxygenated with nitrogen bubbling (ensuring dissolved oxygen level of lower than 5 mg/l) and where there was almost no mass transfer limitation for the corrosion products away from the surface. The main observations made are: The corrosion potential of Cu OFP in all test runs was in the range of -0.10 V{sub SHE} < E{sub corr} < 0.05 V{sub SHE}, i.e. about 0.1 V higher than in the highly saline groundwater; At the corrosion potential active dissolution (corrosion) of Cu OFP takes place, as was the case in highly saline groundwater. However, the corrosion rate based on weight loss measurements of corrosion coupons was 0.014 mm/y, about 30% lower than in the highly saline groundwater. (orig.)

Saario, T.; Maekelae, K.; Laitinen, T.; Bojinov, M. [VTT Manufacturing Technology, Espoo (Finland)

2001-02-01

398

Corrosion of iron-base waste package container materials in salt environments  

International Nuclear Information System (INIS)

Low-carbon ferrous materials are being considered for waste package container materials in high-level nuclear waste salt repositories. The short-term corrosion rates of ASTM Type A216 Grade WCA steel have been determined under both brine-only and moist-salt conditions at 150"0C for time ranging from 1 to 12 months. Tests run in moist salt with low Mg content brine yielded relatively low corrosion rates, below an adjusted value of 0.032 mm (1.3 mils) per year at 150"0C. Corrosion rates in brine-only and moist-salt environments containing high concentrations of Mg were found to be a factor of 20 to 50 higher over the same experimental test times, depending on the steel's heat treatment and the specific test conditions. Austenitizing treatment reduced the corrosion resistance of the material. In the case of the as-cast steel, the measured average corrosion rates decreased with time by more than a factor of two during the 12-month testing program. Post-test examinations have shown that the corrosion product is a complex Fe-Mg hydroxide of amakinite structure, as opposed to the Fe_3O_4 observed in the low-Mg brines. The Mg content of the environment is believed to be a major factor leading to the higher corrosion rates and studies to understand the operative corrosion mechanisms are in progress. 1 ref., 4 figs., 2 tabs

1986-07-20

399

A study on the mechanical and corrosion properties of lead added magnesium alloys  

International Nuclear Information System (INIS)

Highlights: ? Mg is the lightest metal used in structural applications. ? The most important disadvantages of Mg alloys are their low strength and corrosion resistance. ? Different ratios of Pb were added to alloys reinforced with Mg2Si particles. ? According to corrosion tests, corrosion resistance increased with the addition of Pb. -- Abstract: The purpose of this study was to investigate the effect adding Pb at different ratios had on the corrosion properties of Mg alloys. Pb, at a rate of 0.2%, 0.5%, and 1%, was added to Mg-10% Al–12Si. The microstructure characterisation, mechanical and corrosion properties of alloys, produced using a casting method was investigated. Light Optical Microscopy (LOM), X-Ray Diffraction (XRD) analyses and a Scanning Electron Microscope (SEM) were used to conduct the microstructure characterisation of investigated alloys. Corrosion tests were performed by suspending the samples of certain sizes into the 3.5% NaCl solutions measuring the weight loss, and also by potentiodynamic polarisation measurements in the same solution. According to corrosion experiment results, Ikor decreased with the addition of Pb, causing an increase in the corrosion resistance.

2012-05-01

400

Study of corrosive-erosive wear behaviour of Al6061/albite composites  

International Nuclear Information System (INIS)

This investigation analyses the influence of dispersed alumina particles on the wear behaviour of the Al/albite composites in a corrosive environment. The composites were prepared by modified pressure die-casting technique. The corrosive-erosive wear experiments were carried out on a proprietary corrosion-erosion wear tester to study the wear characteristics of the composites. The slurry was made up of water and alumina (size: 90-150 ?m, proportion: 0-30 wt.%), while H2SO4 (0.01, 0.1 and 1N) was added to create the corrosive conditions. Experiments were arranged to test the relationships among the corrosive-erosive wear rate, concentrations of H2SO4 and alumina in the slurry, weight percent of albite in the composite, erosion speed and distance. Wear rate varies marginally at low speeds but sharply increases at higher speeds. The corrosive wear rate logarithmically increased with the increasing concentration of the corrosive medium. The effect of abrasive particles and corrosion medium on the wear behaviour of the composite is explained experimentally, theoretically and using scanning electron microscopy

2006-06-15