Type 302 Grade Stainless Steel Heat Treatment. SS 302 annealing temperature is 1010-1120 °C (1850-2050 °F), recommended temperature is 1400 °C (1900 °F) Oven stress-relief temperature and time for wire: 345 °C (650 °F), 30 minutes. Typical stress relief temperature for SS302 steel spring wire: 425-480 °C (800-900 °F) based on 30 min at