GCr15 steel common heat treatment process

Partial annealing heating 770~790℃, heat preservation with the furnace cooling below 550℃ air cooling 187~229HBS Ac1745℃, Accm900℃, heating temperature should be between Ac1~ Accm

Isothermal spheroidal annealing heating 770~790℃, 680~700℃ isothermal cooling with the furnace below 550℃ after air cooling 187~229HBS heating temperature should be between Ac1~ Accm, isothermal temperature should be lower than Ar1700℃ line 20℃, in order to obtain granular pearlite structure

Destress annealing heating 600~700℃, heat preservation, air cooling 187~229HBS to eliminate residual stress, eliminate work hardening

Normalizing heating 930~950℃, heat preservation, air cooling 302~388HBS heating temperature is higher than Accm, eliminate segregation, banded structure, reticular structure, refine grain

Quenching heating 830~850℃, heat preservation, oil cooling 62~65HRC quenching heating temperature between Ac1~ Accm, the dissolution of Cr element, improve hardenability, improve the stability of tempering, but also reduce the Ms point, there are many residual austenite

Lower bainite isothermal quenching add 830~850℃, 240~300℃ nitrate bath isothermal, after the bath air cooling 58~62HRC Ms 202℃, isothermal quenching structure is lower bainite + carbide + a small amount of martensite + a very small amount of residual austenite, quenching deformation is small, high strength, good toughness

Tempering heating 150~190℃, holding for 2h, furnace cooling 58~~62HRC emphasizes hardness lower limit and toughness upper limit

Quenching: heating 840~860℃, oil cooling; Tempering: after heating 660~680℃, the furnace is cooled or air-cooled 197~217HBS high-temperature quenching can eliminate carbide tissue defects. The high-temperature tempering results in fine tempered sostenite tissue, which can be used to prepare for the re-quenching. Besides, the toughness can be improved and the strength can be improved at the same time. Requenching: heating temperature 820~840℃, oil cooling

Dual refining quenching and heating 1050℃, heat preservation, 320℃ isothermal 2h after air cooling. Heat 710℃ by tempering and hold for 2 hours. Requenching heating 820℃, heat preservation, oil cooling. After further tempering and heating at 230 ° c, extremely small quenched microstructure was obtained after 2h 62HRC heat preservation, which improved the strength and toughness of the steel

Solid boronizing and boronizing were heated at 920℃, kept warm for 5h, and oil was cooled. Infiltration agent: 3%B4C+5%KBF4+5%(NH2)2CO+87%SiC 1500~1700HV surface to obtain high hardness boride layer, the heart for quenching tissue. The thickness of the permeable layer is 0.145mm

Liquid chromizing was heated at 950℃, kept warm for 4h, oil was cooled, and infiltration agent: 15%Cr2O3+12.5% rare earth silica-magnesium +72.5% borax 1665HV infiltration layer thickness: 0.01056mm. Improve surface resistance, wear resistance and corrosion resistance

Liquid vanadium infiltration was heated at 950℃ for 4 hours. Lower the temperature by 860℃ and keep it warm for 2h; Temperature rise 950℃, heat preservation 4h, oil cooling. Infiltration agent: 90%BaCl2+7%V2O5+3%Na2B4O7+Al powder 2500HV0.1 thickness of infiltration layer: 0.020mm. Improve surface hardness and wear resistance