Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
  • C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium with vanadium
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
  • C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten

Definitions

• the invention relates to a cold work steel according to the preamble of claim 1 and the use of this steel for components and tools.
• Cold work tool steels are used to machine materials at temperatures below 250 ° C, especially at room temperatures. Such processing can be carried out by cutting or non-cutting, the components or tools being subjected to various stresses at the same time.
• the dominant stress (s) or desired property (s) of the part such as compressive strength, hardness, toughness, wear resistance, edge retention, possibly erodibility and the like is usually taken into account by a corresponding choice of the composition of the cold work steel.
• Cr steels with contents of 1.5 to 2.5% C and 10 ⁇ to 17% Cr such as steels according to DIN material no. 1.2379 or AISI type D 7 . Because of their high and coarse carbide content, which is usually arranged in rows, such steels have high wear resistance, but low toughness, so that it is difficult to bend Shear stresses can break or break out the part.
• EP-A1 0 ⁇ 275475 discloses a wear-resistant cold work steel with a very high impact strength, which is produced by a powder metallurgical process and which has a composition of essentially 1.0 vom to 2.5% by weight of C, 6.5 to 11.0 ⁇ % by weight. % Cr and 3.0 ⁇ to 7.0 ⁇ wt .-% V, balance iron.
• alloy with approximately 5% or approximately 8% Cr and a carbon content of approximately 1.0% or approximately 0.5% with additions of Mo, W and V, for example Steels according to DIN material no. 1.2363 or material no. 1.2362 as well as material no. 1.2345 or AISI type A2.
• a die steel with improved impact strength contains according to SU 1.0 ⁇ 73.321 (Chemical Abstracts 10 ⁇ 0 Ges: 178630 ⁇ j) in% by weight Nb 0 ⁇ , 0 ⁇ 5 to 0 ⁇ , 1, Al 0 ⁇ , 0 ⁇ 3 to 0 ⁇ , 0 ⁇ 8 and Ca 0 ⁇ , 0 ⁇ 0 ⁇ 3 to 0 ⁇ , 0 ⁇ 0 ⁇ 5 in a steel base with essentially C 0 ⁇ , 75 to 0 ⁇ , 85, Cr 4.2 to 4.7, Mo 0 ⁇ , 7 to 1.0 ⁇ , W 1.7 to 2 and V 0 ⁇ , 8 to 1.
• CH-A5 585 799 a super high-speed steel based on Mo with great chip removal with essentially in weight% 1.0 ⁇ 5 to 1.50 ⁇ C, 4.0 ⁇ to 5.0 ⁇ Cr, 5.0 ⁇ to 6.0 ⁇ W known, which in addition to iron also has 6.0 ⁇ 5 to 6.95 Mo, 2.16 to 4.5 V, 0 ⁇ , 1 to 4.0 ⁇ Nb and 0 ⁇ , 11 to 0 ⁇ , 25 N.
• the alloy variants those with Cr contents of 10 ⁇ to 17% and those with 5 to 8% Cr, also have the disadvantage that they are usually not sufficiently resistant to tempering, and that with additional surface hardening by nitriding and / or carbonitriding or one Surface coating by means of CVD or PVD processes at temperatures between 350 ⁇ and 60 ⁇ 0 ⁇ ° C the hardness of the base material achieved by previous tempering is reduced.
• the invention has for its object to use the effect of alloying elements in a certain concentration range synergistically and to create a cold work steel with high compressive strength, which has high hardness, toughness, wear resistance and erodability, with good cutting and punching tools formed from this steel Grindability and edge retention are present and, if applicable, when using methods for surface hardening and / or surface coating, which are to be carried out at elevated temperature, there is no decisive disadvantageous influence on the mechanical properties of the base material achieved by prior hardening.
• the concentrations of the carbon content and the nitrogen content and the elements which preferably form carbides and / or nitrides are matched to one another in accordance with the carbon and nitrogen affinity and tendency to form carbide and / or nitride.
• Excessively high carbon contents of over 1.5% result in proportionately large, even coarse carbide grains and thus poor toughness properties of the material, with contents below 0 ⁇ .6% the required mechanical properties, in particular the hardness, are not achieved.
• Chromium, molybdenum, tungsten and vanadium are alloyed for the formation of carbide, whereby according to the invention the respective concentration of these elements takes into account the interaction or the mutual influence 50 ⁇ 0 ⁇ ° C are excreted sub-microscopically, cause high hardness or a quasi increase in secondary hardness and cause a high degree of temper resistance of the steel.
• Aluminum and silicon, which elements make up the ⁇ region severely pinching off the alloy are necessary for several reasons. Surprisingly, the tempering behavior of the steel and its tempering resistance are significantly improved by these ferrite-forming elements in the concentration ranges claimed.
• nitride formation takes place with a corresponding nitrogen content of the alloy, which nitrides hinder grain growth during hardening or during austenitizing at high temperatures.
• Aluminum and silicon are advantageously effective for surface hardening by nitriding or carbonitriding and / or surface coating by means of a CVD or PVD or the like method.
• Niobium is a very strongly carbide-forming element, and even finely separated niobium carbides are difficult to dissolve during hardening, even at high austenitizing temperatures.
• high niobium contents at carbon concentrations of cold work steels lead to coarse niobium carbide grains, so that niobium is only added up to a maximum concentration of 0.5%.
• the steels according to DIN material no. 1.2363 and material no. 1.2379 have a permissible specific pressure load of 2785 N / mm or 30 ⁇ 26 N / mm2 as well as a tempering hardness at 550 ° C of 56 HRC or 60 ° HRC .
• the cold work steel according to the invention has at least a permissible specific compressive strength of 30-22 N / mm2, a tempering hardness of 63.5 HRC and compared to material no. 1.2379 a toughness improved by 28%.
• the punch and die of steel A had a hardness of 63 HRC, and 64,629 punchings could be carried out. Despite an only slightly lower hardness of 62 HRC of steel D, only 20,751 punchings could be carried out, which corresponds to an additional output of the tool according to the invention by approx. 30%.
• a steel B with the composition in% by weight was used for extrusion dies for pressing aluminum video heads.
• the surface of the tool made of steel B was enriched with nitrogen in a bath nitriding process at approx. 570 ° C, after which the hardness of the base material was 63.5 HRC. 40 horr7,320 ⁇ pressings were carried out with this tool without excessive wear, whereas the steel D tool had to be eliminated after 239,865 pressings.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
• Heat Treatment Of Steel (AREA)
• Physical Vapour Deposition (AREA)
• Chemical Vapour Deposition (AREA)
• Forging (AREA)
• Heat Treatment Of Articles (AREA)

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• 1989
  • 1989-10-23 AT AT2423/89A patent/AT393387B/de not_active IP Right Cessation
• 1990
  • 1990-09-13 TW TW079107707A patent/TW199910B/zh active
  • 1990-10-12 DK DK90890280.2T patent/DK0425471T3/da not_active Application Discontinuation
  • 1990-10-12 EP EP90890280A patent/EP0425471B1/de not_active Expired - Lifetime
  • 1990-10-12 DE DE59008009T patent/DE59008009D1/de not_active Expired - Lifetime
  • 1990-10-12 ES ES90890280T patent/ES2068379T3/es not_active Expired - Lifetime
  • 1990-10-12 JP JP2272524A patent/JP2794641B2/ja not_active Expired - Lifetime
  • 1990-10-23 AU AU64922/90A patent/AU631690B2/en not_active Ceased
  • 1990-10-23 ZA ZA908467A patent/ZA908467B/xx unknown
  • 1990-10-23 US US07/601,676 patent/US5160553A/en not_active Expired - Lifetime
  • 1990-10-23 BR BR909005350A patent/BR9005350A/pt not_active IP Right Cessation
  • 1990-10-23 KR KR1019900016926A patent/KR0170386B1/ko not_active IP Right Cessation

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