Tadashi Kawasaki and Gunji Shinoda
An X-ray diffractometer study was made to investigate the ferrite formation caused by cold working and the fading by annealing after cold working for non-stabilized type 304 stainless steel. A mixture of annealed iron powder and stainless steel powder was used as the standard sample containing given wt% of ferrite. Comparing the ratio of the line intensities of the ferrite and the austenite which were obtained from the diffracto-pattern of the cold-worked specimens with that of the standard sample,the quantities of the ferrite transformed from austenite by cold working can be easily determined. The diffraction lines most sensitive to cold working were the (111) line of γ phase and the (110)line of α phase. The ferrite formed by cold working almost completly faded away after annealing for 40 min above 400°.The fact that the hardness of specimens did not regain its original value after 850° annealing may have some connection with the carbide precipitation. Some experiments on the changes of mechanical properties caused by cold and hot working were also made.
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