Effect of heat treatment on the cold shortness of stainless steels

Conclusions

• 1. With increase in the quenching temperature of steel 2Kh13. its impact toughness decreases. Such a relationship is not found in the case of steel Kh17N2.

• 2. The cold-shortness threshold of steel 2Kh13, quenched from 1050–1100°C and having BHN 207 is from −40 to −60°C (impact toughness=1.2−3.5 kgm/cm²). For steel Kh17N2 after all heat-treatment conditions ensuring BHN 229-363, the impact toughness in tests down to −70°C is 5 kgm/cm². To ensure a high impact toughness of steel 2Kh13 in tests from 20 to −60°C, the hardness should not exceed BHN 207.

• 3. To increase the resistance to cold-shortness, the following treatment conditions are recommended: for steel 2Kh13, oil-quenching from 950–1000°C; the tempering temperature depends on the required mechanical properties and should not be less than 630°C; for steel Kh17N2, oil-quenching from 950–1040°C; tempering at 450–680° (depending on requirements as to mechanical properties).