Heat treatment process of S316 martensitic stainless steel

The invention relates to a heat treatment process of S316 martensitic stainless steel. The heat treatment process comprises the following steps: firstly, performing solution treatment on the S316 martensitic stainless steel in an electrothermal furnace, wherein the specific conditions of the solution treatment are specifically as follows: increasing the temperature to 250 DEG C at a temperature rise rate of 300-360 DEG C per hour for preheating, heating to the treatment temperature range of 1110-1130 DEG C at a temperature rise rate of 100-150 DEG C per hour for treatment for 1.5-2 hours, and introducing high-purity Ar gas under the pressure of 60-80MPa during the treatment; secondly, performing quenching treatment on the S316 martensitic stainless steel, namely quickly cooling the S316 martensitic stainless steel below 220 DEG C at a cooling rate of 0.8-1.0 DEG C per second; thirdly, performing redistribution treatment on the S316 martensitic stainless steel, namely quickly putting the quenched S316 martensitic stainless steel into a salt bath treatment environment at 330 DEG C for heating and preserving heat for 3 hours, and then cooling in air until a room temperature; finally, performing tempering treatment on the S316 martensitic stainless steel, namely heating until 320 DEG C at the temperature rise rate of 180 DEG C per hour and preserving heat for 2 hours for once tempering, and then cooling in water until the room temperature.