J. Mater. Sci. Technol. ›› 2011, Vol. 27 ›› Issue (4): 338-343.

• Reviews • 上一篇    下一篇

Repetitive Thermomechanical Processing Towards Ultra Fine Grain Structure in 301, 304 and 304L Stainless Steels

Amir Momeni1,Seyed Mehdi Abbasi2,3   

  1. 1. Amir Kabir university of technology
    2. KNT University of Technology
    3.
  • 收稿日期:2010-10-08 修回日期:2011-02-14 出版日期:2011-04-28 发布日期:2011-04-28
  • 通讯作者: Seyed Mehdi Abbasi

Repetitive Thermomechanical Processing towards Ultra Fine Grain Structure in 301, 304 and 304L Stainless Steels

A. Momeni, S.M. Abbasi   

  1. 1) Department of Mining and Metallurgical Engineering, Amirkabir University of Technology, Tehran, Iran
    2) KNT University of Technology, Tehran, Iran
  • Received:2010-10-08 Revised:2011-02-14 Online:2011-04-28 Published:2011-04-28
  • Contact: Mehdi

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摘要： Thermomechanical processing as a combination of cold rolling and annealing was performed on austenitic stainless steels 301, 304 and 304L. Two cold rolling steps each one up to a reduction of 75 percent were combined with an intermediate annealing at 800?C for 20 minutes. The final annealing was performed at the same temperature and time. Cold rolling contributed in martensite formation at the expense of metastable austenite in the studied stainless steels. The austenite phase in 30l was found to be less stable as compared to that in 304 and 304L. Hence, higher strength characteristics in the as-quenched 301 stainless steels were attribute to the higher volume fraction of martensite. The deformation induced both ??-martensite and ε-martensite. However, the intensity of ε-martensite increased as the stability of austenite decreased. Annealing after cold rolling led to the reversion of austenite from strain induced martensite and the formation of an ultra fine grained structure in the order of 0.5-1 μ. The final grain size was found to be an inverse function of the amount of strain induced martensite. The thermomechanical processing considerably improved the strength characteristics while elongation was degraded simultaneously.

Abstract: Thermomechanical processing as a combination of cold rolling and annealing was performed on austenitic stainless steels 301, 304 and 304L. Two cold rolling steps each one up to a reduction of 75% were combined with an intermediate annealing at 800°C for 20 min. The final annealing was performed at the same temperature and time. Cold rolling contributed to martensite formation at the expense of metastable austenite in the studied materials. Austenite in 30l was found to be less stable than that in 304 and 304L. Hence, higher strength characteristics in the as-quenched 301 stainless steels were attributed to the higher volume fraction of martensite. Both α′-martensite and ε-martensite were found to form as induced by deformation. However, the intensity of ε-martensite increased as the stability of austenite decreased. Annealing after cold rolling led to the reversion of austenite with an ultra fine grained structure in the order of 0.5-1 μm from the strain induced martensite. The final grain size was found to be an inverse function of the amount of strain induced
martensite. The thermomechanical processing considerably improved the strength characteristics while the simultaneous decrease of elongation was rather low.

Key words: Austenitic stainless steel, Cold rolling, Ultra fine grain, Deformation induced
martensite