Metal treatment – Compositions – Heat treating
Patent
1983-12-21
1986-11-18
Sheehan, John P.
Metal treatment
Compositions
Heat treating
1481261, 420417, 420422, 420424, 420425, 420581, 420129, C21D 156
Patent
active
046234020
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to metal compositions and processes for producing same.
BACKGROUND OF THE INVENTION
Currently known alloys based on metals of Group VIII and nitrides of metals of Groups III through VII employed as alloying materials have low unsatisfactory properties. Usually these alloys contain 3 to 17% of nitrogen, have density of from 2 to 5 g/cm.sup.3, porosity of from 30 to 60%, crushing strength below 2 kg/mm.sup.2. These alloys comprise either a powder or a loose sintered briquette. Nitrogen distribution in these alloys is extremely non-uniform. It is usually combined in large-size nitrides with particles of up to 2 mm which are present in the alloy as individual inclusions non-bonded therebetween.
A low density of the above-mentioned alloys, their high porosity and a non-uniform distribution of nitrogen in the form of large-size nitrides cause a low degree of assimilation of nitrogen by steel and a non-uniform distribution thereof within the ingot volume. A low mechanical strength of the alloys and their powder-like state result in considerable losses of the alloy during operations of alloying, transportation and conditioning, as well as in a sharply lowered degree and stability of assimilation of nitrogen by steel.
To produce the above-mentioned alloys, at the present time alloys are obtained which contain metals of Groups III-VII and iron. Usually the starting alloys are disintegrated to powder, placed into the nitrogen-containing atmosphere, heated to a temperature within the range of from 500.degree. to 1,100.degree. C. and maintained at this temperature for several hours.
These prior art processes feature a high rate of electric power consumption, a long duration of the process and a low quality of the resulting alloys. The alloys produced by these processes usually necessitate an additional processing, i.e. briquetting and sintering.
Thus, known in the art is an alloy based on iron and nitrides of manganese and chromium. To produce this material use is made of an alloy of iron with manganese and chromium which is disintegrated to powder with a particle size of below 2 mm and subjected to nitriding for 4 hours at the temperature of 900.degree. C. The content of nitrogen is 4 to 6%. The resulting powder is additionally briquetted (cf. Japanese Pat. No. 27321, Cl. 10 A 12, 1965).
To obtain a higher content of nitrogen in the alloy, a step-wise nitriding process is employed. In accordance with this process, the starting alloy of iron with manganese is ground to powder with a particle size of below 5 mm, heated for 2 to 4 hours to the temperature of 1,000.degree. C.; the resulting sintered mass is again crushed to powder and subjected to nitriding by passing ammonia for 6-10 hours at a temperature within the range of from 500.degree. to 700.degree. C. The thus-produced powder contain 9 to 11% of nitrogen (cf. Swedish Pat. No. 335,235, 1971).
Known in the art is a process for producing alloys based on iron and nitrides of metals of Groups III-VII, wherein the starting alloy containing two metals of III-VII Groups is employed for intensification of the process and a high content of nitrogen. For example, the starting alloy of iron with chromium and aluminium is ground to powder with a particle size of below 60 mm and subjected to nitriding in the atmosphere of nitrogen or ammonia for 5 hours at the temperature 1,000.degree. C. After nitriding the powder contains up to 9.8% of nitrogen (cf. Japanese Pat. No. 25892 Cl. 10N 16, 1964).
Known is another process for producing alloys based on iron and nitrides of metals of Groups III-VII, wherein use is made of the starting alloy incorporating two metals of III-VII Groups. The starting alloy of iron with vanadium and manganese is ground to powder and heated to a temperature within the range of from 900.degree. to 1,100.degree. C. with nitrogen supply for 8 hours without fusing. The resulting powder contains 6 to 17% of nitrogen. Then it is subjected to briquetting using 2 to 10% of a binder (cf. U.S. Pat. No. 3,304
REFERENCES:
patent: 3304175 (1967-02-01), Madsen et al.
patent: 3356493 (1967-12-01), Danis et al.
patent: 3384455 (1968-05-01), Fuchs
patent: 3650729 (1972-03-01), Kindlimann et al.
patent: 3726643 (1973-04-01), Merzhanov et al.
patent: 3857695 (1974-12-01), Vojkovic
patent: 3998666 (1976-12-01), Cuddy et al.
patent: 4004891 (1977-01-01), Lin et al.
patent: 4043839 (1977-08-01), Hartline et al.
The Condensed Chemical Dictonary, p. 229.
The American Heritage Dictionary of the English Language, pp. 178 and 655.
Borovinskaya Inna P.
Dubovitsky Fedor I.
Kolmakov Anatoly D.
Maximov Jury M.
Merzhanov Alexandr G.
Institut Khimicheskoi Fiziki Akademii Nauk SSSR
Nauchno-Issledovatelsky Institut Prikladnoi Matematiki Pri Tomsk
Sheehan John P.
LandOfFree
Metal composition and process for producing same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Metal composition and process for producing same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Metal composition and process for producing same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1616055