Specialized metallurgical processes – compositions for use therei – Compositions – Consolidated metal powder compositions
Patent
1999-06-17
2000-12-19
Mai, Ngoclan
Specialized metallurgical processes, compositions for use therei
Compositions
Consolidated metal powder compositions
75236, 75244, 75246, 419 11, 419 29, 419 49, C22C 3302
Patent
active
061622753
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The invention relates to a powder-metallurgically manufactured steel for tools, particularly for so called cold work tools, for forming and/or cutting operations. The invention also relates to the tool that is made of the steel and which has attained specific, desired features through a heat treatment which has been adapted the alloy composition and to the powder-metallurgical manufacturing technique. The invention also relates to the integrated process for the manufacturing of the steel, the tool, and the heat treatment of the tool, wherein the expression "integrated" shall mean that the powder-metallurgical manufacturing technique as well as the heat treatment of the tool contribute to the achievement of the desired combination of features of the finished tool.
BACKGROUND OF THE INVENTION
Steels of the type indicated in the preamble usually are referred to as cold work steels. Dies for cold extrusion of metals; deep drawing and powder pressing counter dies; knives and other tools for shearing and cutting, etc., are typical applications of cold work steels. A powder-metallurgically manufactured high speed steel having the composition 1.28 C, about 0.3 Si, about 0.5 Mn, 4.2 Cr, 5.0 Mo, 6.4 W, 3.1 V, balance Fe and impurities, is a well known steel for this type of applications. A drawback of this steel is that it does not have a toughness that satisfies highest demands. Another powder-metallurgically manufactured steel known in the art has the composition 1.5C, 1.0 Si, 0.4 Mn, 8.0 Cr, 1.5 Mo, 4.0 V, balance Fe and impurities. This steel also after tempering has a comparatively high content of rest austenite, which is attributed to the high chromium content, which reduces the hardness. Therefore it is a long felt demand of a material which combines the best features of the said steels. More particularly, this can be expressed such that there is a demand of a steel which affords optimal features as far as toughness, wear resistance and hardness for the intended field of use are concerned at the same time as the total content of alloy elements, and particularly the most exclusive alloy elements, are kept at a comparatively low level in order to make the material favourable also from a cost point of view.
BRIEF DISCLOSURE OF THE INVENTION
It is the purpose of the invention to satisfy the above mentioned demands. This can be achieved therein that the invention is characterized by what is stated in the appending claims. Without binding the invention to any specific theory, the importance of the various alloy elements and the various structure constituents for the achievement of the desired combination of features shall be explained more in detail. As far as percentages are concerned, alloy contents are always measured in weigh-% and structure constituents in volume-% if not anything else is stated.
Carbon and nitrogen shall exist in an amount of at least 1.4% and not more than 1.6%, preferably at least 1.44% and not more than 1.56%; typically 1.5%. Normally, the nitrogen content amounts to not more than 0.1%, but the powder-metallurgical manufacturing technique makes it possible to dissolve as much as about 1% nitrogen, if the carbon content is so low that the total amount of carbon and nitrogen is 1.4-1.6%. A variant of the steel therefore is characterized in that the steel contains a high content of nitrogen, max. 1.0%, e.g. 0.3-1.0% N, which can be achieved through solid phase nitriding of produced powder, wherein the nitrogen can replace carbon in those hard components which shall exist in the steel in the final tool. Thus 40-60% of the carbon 20 and the nitrogen shall be included in undissolved hard components of MX-type, i.e. primary carbides or carbo-nitrides, where M is substantially vanadium and X is carbon and/or nitrogen, while the rest essentially is dissolved in the matrix or is present as precipitated hard components. Lower contents than 1.4% carbon +nitrogen do not afford sufficient hardness and wear resistance, while higher contents than 1.6% can cause embrittlement problem
REFERENCES:
patent: 3809541 (1974-05-01), Steven
patent: 5435827 (1995-07-01), Wisell
patent: 5522914 (1996-06-01), Stasko et al.
patent: 5525140 (1996-06-01), Wisell
patent: 5578773 (1996-11-01), Wisell
Jonsson Karin
Westin Leif
Wisell Henry
Erasteel Kloster Aktiebolag
Mai Ngoclan
LandOfFree
Steel and a heat treated tool thereof manufactured by an integra does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Steel and a heat treated tool thereof manufactured by an integra, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Steel and a heat treated tool thereof manufactured by an integra will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-267899