Spheroidise annealing-Steel is heated
to 760 deg C, soaked for about 12 hours –controlled
cooled down to 650 deg C @ 10 deg C/ hour; followed by air-cooling.
For stress relieving: Heat to 620 /650 deg C for 1 hr per
inch of cross section (minimum 1 hr). Cool in air.
Hardening : Heat slowly and
preheat to 650 deg C Austenitise at 790 to 815 deg C; soak
for 10 to 30 minutes followed by oil quenching.
Stabilizing : For intricate jobs, stress relieve temper at 150
to 160 deg C after oil quench and refrigerate at –100
to –195 deg C. Temper immediately after part reaches
room temperature.
Tempering : Immediate tempering
at 175 to 265 deg C for achieving 62 to 57 HRC hardness. |
