Heat treatment process of HPM75 non-magnetic steel round bar

Properties and characteristics of HPM75 non-magnetic steel

HPM75 is a kind of high-strength austenitic non-magnetic die steel, which can maintain stable austenite in various states. Therefore, HPM75 non-magnetic steel has ultra-low permeability, high high temperature strength and hardness, excellent toughness and weldability, excellent mechanical properties and excellent wear resistance. HPM75 non-magnetic steel has been age hardened before leaving the factory, without any heat treatment; And the steel structure is uniform, suitable for precision etching machining.

HPM75 non-magnetic steel round rod heat treatment process (HPM75 quenching/tempering process), HPM75 hardness after heat treatment

1. HPM75 non-magnetic steel ingot: heating temperature 1150-1170℃, heating time ≥8h, starting temperature 1100-1120℃, end temperature ≥950℃, air cooling;

2. HPM75 non-magnetic steel billet: heating temperature 1140-1160℃, heating time ≥8h, starting temperature 1080-1100℃, end temperature ≥950℃, air cooling;

3. Non-magnetic steel HPM75 quenching temperature

4. Tempering temperature of non-magnetic steel HPM75

5. Non-magnetic steel HPM75 quenching process

HPM75 non-magnetic steel high temperature annealing process

HPM75 non-magnetic steel annealing temperature 870-890℃, holding 3-6h, furnace cooling to 500℃ below the oven air cooling. The hardness of HPM75 after annealing is 28-30HRC, and the structure is fine grain austenite + uniform distribution of granular carbide. High temperature annealing can improve the machinability of HPM75 non-magnetic steel.

HPM75 non-magnetic steel solution treatment technology

HPM75 non-magnetic steel solution temperature 1150-1180℃, salt bath furnace insulation 15-20min/mm, box furnace insulation 30min/mm, water cooling, HPM75 solid solution hardness 20-22HRC, metallography: austenite + undissolved primary carbide.

HPM75 non-magnetic steel aging process

HPM75 non-magnetic steel aging temperature 650-700℃, aging 15-20h, air cooling, HPM75 after aging treatment hardness ≥45HRC.

HPM75 non-magnetic steel gas nitrogen carburizing process

HPM75 non-magnetic steel co-permeation temperature 560-570℃, co-permeation time 4-6h, surface hardness 950-1100HV, nitriding layer depth 0.03-0.04mm.

HPM75 non-magnetic steel material quality assurance/Quality safety certification:

HPM75 non-magnetic steel original steel mill material certificate to ensure the quality of die steel.