304 stainless steel after work hardening can adopt high-temperature and low-temperature annealing to restore plasticity, reduce the degree of hardening, and eliminate or reduce residual stress. In order not to sensitize the material, the sensitization temperature range of 500 ℃ ~ 850 ℃ should be avoided during annealing.

Low temperature annealing has little effect on the yield strength of SUS304 stainless steel. Annealing below 500 ℃ has little change in the yield strength value after annealing, and high temperature annealing has a great effect on the yield strength of the sample. When the preform variable is 15%, re decreases to 260mpa after annealing at 1050 ℃, and RM almost decreases linearly with the annealing temperature, but the range of change is much smaller than re. At the same time, the Vickers hardness value of the sample decreases with the increase of annealing temperature.

With the increase of annealing temperature, the elongation of the sample increases obviously, especially in the high-temperature annealing state, re decreases most obviously and reaches the complete softening state. Annealing at 1050 ℃ (holding for 5min, rapid cooling) elongation A and hardness HV reach the best combination of softening.