Heat treatment process of SA508 Gr22 Cl3 nuclear steel plate

1) Preparation heat treatment
SA508-3 steel shall undergo preliminary heat treatment before heat treatment. The heat treatment process of normalizing+tempering is generally adopted for preparation heat treatment.

2) Quenching and tempering heat treatment
SA508-3 steel adopts quenching and tempering heat treatment as performance heat treatment, that is, quenching+high temperature tempering treatment process. Quenching temperature 880-890℃, holding time 10.5h, water cooling. Tempering temperature 635-647℃, holding time 13.5h, air cooling.

3) Post weld heat treatment
It is used to eliminate residual stress and hydrogen formed by cooling after welding. The post-weld heat treatment temperature of SA508-3 steel shall be above 427℃, and the heating and cooling rate shall not exceed 204 ℃/h, nor be lower than 38 ℃/h. During the heating and cooling process, the temperature change shall not be greater than 121℃ within any 15-foot weld interval.