Vacuum solid solution method for nickel-free high manganese and nitrogen stainless steel

A vacuum solid solution method for stainless steel, comprising:

• step 1:
• placing a workpiece comprising nickel-free manganese and nitrogen stainless steel to be heat treated into a vacuum heat treatment furnace, vacuumizing to 1.0E−2 Pa, initially heating to 650° C. at a speed of 5-15° C./min, and maintaining a temperature of 650° C. for 30-90 min, wherein the nickel-free manganese and nitrogen stainless steel has a nitrogen content of greater than or equal to 0.70 wt % and a manganese content of 10.0-12.0 wt %;
• step 2:
• heat homogenizing the workpiece, comprising heating the workpiece at a speed of 5-15° C./min from 650° C. to a final temperature range of 1150-1185° C. in stages, wherein a whole process of heating from 650° C. to the final temperature range is protected under nitrogen;
• step 3:
• maintaining a temperature of 1150-1185° C. for 60-150 min;
• step 4:
• deoxidizing a surface of the workpiece;
• and
• step 5:
• performing a rapid cooling treatment, comprising cooling the workpiece in nitrogen or argon with pressure greater than or equal to 6 Mpa to 450° C. or below by a cooling speed of 150° C./min or above during a temperature range of 1150-850° C., and by a cooling speed of 80° C./min or above during a temperature range of 650-450° C.