METALLURGY, PRODUCTION TECHNOLOGY, AND PROPERTIES OF DUAL-PHASE SHEET STEELS

The development of dual-phase microstructures consisting of ferrite and martensite in carbon-manganese-silicon and carbon-manganese-silicon-vanadium steels was studied by intercritical annealing hot- and cold-rolled sheet at various temperatures and then control cooling at various rates. It was found that increased silicon content and/or cooling rate promoted martensite formation as expected and increased the tensile strength of dual-phase sheet. Lower intercritical temperatures also produced higher tensile strengths for a given steel and cooling rate. Vanadium additions were found to promote martensite formation and to produce higher tensile strengths than obtained in equivalently processed vanadium-free steels. It is believed that vanadium acts to increase the hardenability of the austenite formed at the annealing temperature. For a given tensile strength, the highest ductility was achieved with steels that were slowly cooled from the intercritical annealing temperature. It appears that carbon diffusion from the high-temperature ferrite is desirable to maximize ductility. Thus, steels with higher hardenability (alloy content) that produce ferrite-martensite microstructures at relatively slow cooling rates were selected for production trials. The strength and ductility values of production dual-phase steel sheet were found to support the values measured for laboratory-produced steels. The strain-hardening response was characterized by the tensile strain required to achieve specific yield strengths as a function of tensile strength of the dual-phase sheet.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/01487191
• Supplemental Notes:
  • Presented at SAE Congress and Exposition, Detroit, 26 February-2 March 1979.
• Corporate Authors:

  Society of Automotive Engineers (SAE)

  400 Commonwealth Drive
  Warrendale, PA  United States  15096
• Authors:
  • Repas, P E
• Publication Date: 1979

Media Info

• Features: References;
• Pagination: 13 p.
• Serial:
  • SAE Technical Paper
  • Publisher: Society of Automotive Engineers (SAE)
  • ISSN: 0148-7191
  • EISSN: 2688-3627
  • Serial URL: http://papers.sae.org/

Subject/Index Terms

• TRT Terms: Dual phase steel; Ductility; Hardness; Metallurgy; Microstructure; Silicon; Strain hardening; Tensile strength; Vanadium; Yield strength
• Old TRIS Terms: Hardenability
• Subject Areas: Safety and Human Factors;

Filing Info

• Accession Number: 00394085
• Record Type: Publication
• Source Agency: National Highway Traffic Safety Administration
• Report/Paper Numbers: SAE 790008, HS-026 874U
• Files: HSL, USDOT
• Created Date: May 31 1985 12:00AM