Strengthening of low-interstitial steels by strain-ageing treatments
- Queen`s Univ., Kingston, Ontario (Canada). Dept. of Materials and Metallurgical Engineering
Formable low-carbon automotive sheet steels can be designed to achieve a 30--50 MPa strength increment during paint baking. This so-called bake hardening process is a form of static strain ageing, whereby dissolved carbon or nitrogen atoms segregate to the dislocations generated during temper rolling and press forming. In ultra-low carbon interstitial-free steels, the concentration of C and N in solution is determined by the equilibrium partitioning between ferrite and precipitates of Ti- or Nb carbonitrides. Thus, during continuous annealing the concentration of interstitial atoms could increase due to precipitate dissolution. The reverse process could occur during cooling due to NbC precipitation at 800--700 C or Fe{sub 3}C precipitation at 400--300 C. The purpose of the present study was to determine the effects of the annealing process variables (temperature, time and cooling rate) on the solute carbon concentration in a series of interstitial free (IF) steels.
- OSTI ID:
- 651142
- Report Number(s):
- CONF-980202-; ISSN 1359-6462; TRN: IM9826%%98
- Journal Information:
- Scripta Materialia, Vol. 39, Issue 4-5; Conference: Annual meeting of the Minerals, Metals and Materials Society (TMS), San Antonio, TX (United States), 15-19 Feb 1998; Other Information: PBD: 4 Aug 1998
- Country of Publication:
- United States
- Language:
- English
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