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
  • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
• • 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
  • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
• • 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
  • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
• • 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
  • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
• • 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
  • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
  • C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel 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
  • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
  • C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum

Definitions

• the invention concerns a steel and the processing method for the manufacture of high strength, fracture-splittable machinery components. This material was developed, for example, for the manufacture of crack connecting rods.
• the steel must be suitable for forging or for other heat forming processes.
• the heat used in the forging is dissipated by controlled cooling to produce a largely pearlitic structure that has an apparent limit of elasticity in excess of 750 N/mm 2 , a tensile strength between 1000 and 1200 N/mm 2 , elongation to fracture of over 10% and reduction in area at fracture of over 25%. Its fracture-splittability is a particularly important feature.
• the desired properties can be obtained by intentionally creating a pearlitic structure with the precipitation of special carbides (niobium and vanadium carbide) and of manganese sulphides by an appropriately formulated chemical composition, controlled temperature management during the heat forming when producing the preliminary material as well as when forging the finished components (thermomechanical treatment), and a suitable heat treatment after completion of the forging or heat forming, as the case may be.
• examples of the steels used for this purpose are either mostly eutectoid compositions with approximately 0.7% C, 0.5 to 0.9% Mn, 0.06 to 0.07% S and possibly 0.1 to 0.2% V (C70S6, 70MnVS4), or an average carbon content of approximately 0.4%, about 1% Mn, 0.06 to 0.07% S and about 0.3% V (36MnVS4) according to customers' technical specifications.
• the aim of this invention is to avoid the cited disadvantages by proposing a new steel which has the required mechanical properties regarding strength (and fatigue strength) and, additionally, good toughness characteristics in tensile tests, combined at the same time with good splittability.
• the steel must also be easy to continuously cast and forge.
• the new steel must use fewer resources when being produced than the known steels by partially substituting the vanadium content with niobium using an appropriately adapted forming and cooling strategy.
• the high value for the apparent limit of elasticity is achieved, other than with the basic composition, by the precipitation of extremely finely dispersed carbides of special carbide formers niobium and vanadium. This requires a solution of the present carbides before the final hot forming process as well as controlled temperature management during the hot forming, followed by a final cooling off stage. Finely dispersed precipitation can be achieved, in particular, by having a low final forming temperature, ending with slightly accelerated cooling. This raises the apparent limit of elasticity in particular, thus improving the elastic limit ratio considerably.
• the tensile strength value of the basic composition comprising 0.5% C, 0.6% Si, 1.0% Mn, 0.23% Cr, 0.2% Ni and 0.14% V can be adjusted to the desired level by slightly accelerated cooling after hot forming.
• the toughness characteristic values are controlled, in particular, by selective alloying with 0.06 to 0.07% sulphur.
• the carbon content and relatively high nitrogen content also act positively in this regard.
• a crystalline fracture or macroscopic deformation is essential for the material to split properly. This is achieved by designing the alloy with high contents of carbon, nitrogen and sulphur, and comparatively low contents of chromium, nickel and molybdenum.
• the invention concerns a steel for the manufacture of fracture-splittable components for the vehicle industry with the following chemical composition in percentages by weight:

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Heat Treatment Of Steel (AREA)
• Heat Treatment Of Articles (AREA)
• Forging (AREA)
• Processing Of Solid Wastes (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=38989625

Family Applications (1)

Country Status (15)

Cited By (1)

Families Citing this family (13)

Citations (2)

Family Cites Families (11)

• 2006
  • 2006-09-01 DE DE102006041146A patent/DE102006041146A1/de not_active Withdrawn
• 2007
  • 2007-06-23 TW TW096122683A patent/TW200825188A/zh unknown
  • 2007-07-27 EP EP07801178A patent/EP2057298B1/de active Active
  • 2007-07-27 CN CNA2007800319547A patent/CN101542007A/zh active Pending
  • 2007-07-27 MX MX2009001971A patent/MX2009001971A/es active IP Right Grant
  • 2007-07-27 RU RU2009111860/02A patent/RU2441093C2/ru not_active IP Right Cessation
  • 2007-07-27 AU AU2007294317A patent/AU2007294317B2/en not_active Ceased
  • 2007-07-27 KR KR1020097003628A patent/KR20090049591A/ko not_active Ceased
  • 2007-07-27 WO PCT/DE2007/001337 patent/WO2008028447A1/de not_active Ceased
  • 2007-07-27 BR BRPI0716206-5A2A patent/BRPI0716206A2/pt not_active IP Right Cessation
  • 2007-07-27 JP JP2009525910A patent/JP2010501733A/ja active Pending
  • 2007-07-27 CA CA002666677A patent/CA2666677A1/en not_active Abandoned
  • 2007-07-27 US US12/310,588 patent/US20100186855A1/en not_active Abandoned
  • 2007-08-02 AR ARP070103409A patent/AR062184A1/es not_active Application Discontinuation
• 2009
  • 2009-02-05 ZA ZA200900848A patent/ZA200900848B/xx unknown

Patent Citations (2)

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