High alloy steel heat treatment

High alloy steel containing high chromium and chromium in tool steel, high-speed steel and steel matrix, etc. Such steel contains more alloy elements, has the good hardenability, high abrasion resistance and quenching deformation characteristics of small, is widely used as the load big, the production batch, require high wear resistance and complex shape mould. ( 1) High carbon high chromium steel composition characteristics of this kind of steel is a high amount of chromium and carbon, is the most widely application scope in cold work die steel, the largest number. Typical steel grade are Crl2, Crl2MoV, Crl2MolVl ( D2) And Crl2W, etc. The class usually adopts the spheroidizing annealing treatment after forging steel, hardness is 207 ~ 255 hb after annealing. Common quenching process is: 1) Low temperature quenching will Crl2 steel heating to 960 ~ 980 ℃, oil cooling, for more than 62 HRC hardness after quenching. Of Crl2MoV steel, quenching temperature is 1020 ~ 1050 ℃, oil cooling, for more than 62 HRC hardness after quenching. Using this method can make the steel for high hardness, high wear resistance and high precision size, used in cold stamping die. 2) High temperature quenching and high temperature tempering of Crl2 steel for many times, heating to 1050 ~ 1100 ℃, oil cooling, after quenching hardness of 42 ~ 50 HRC. Of Crl2MoV steel, quenching temperature is 1100 ~ 1150 ℃, oil cooling, after quenching hardness of 42 ~ 50 HRC. High temperature quenching and high temperature tempering, steel can get high hardness and wear resistance, used to make work under the high temperature of the mold. Crl2 steel should be promptly tempering after quenching, tempering temperature can according to requirements of hardness. For high hardness of cold stamping die, tempering temperature is between 150 ~ 170 ℃, after tempering hardness of over 60 HRC. For requires a higher strength, hardness and toughness of cold stamping die, tempering temperature from 250 ~ 270 ℃, after tempering hardness of 58 ~ 60 HRC. For high impact toughness and hardness of cold stamping die, tempering temperature can be increased to about 450 ℃, after tempering hardness is 55 ~ 58 HRC, Crl2 steel to avoid 275 ~ 375 ℃ tempering brittleness zone. ( 2) High carbon chromium steel mainly Cr6WV Cr4W2MoV Cr6MolV steel, steel, steel. ( 3) High speed steel when cold extrusion parts of aluminium or copper mold force is not too sharp, Crl2 type steel can be used commonly. But black metal cold extrusion stress, work condition is very bad, puts forward higher requirements on the mold. So you need to adopt more advanced steel, such as high speed steel to manufacture of moulds. High speed steel after heat treatment with high hardness and compressive strength, good abrasion resistance, can satisfy the harsh cold extrusion conditions. Common cold extrusion of high speed steel has W6 Mo5 Cr4 V2 steel, steel, 6 w6mo5cr4v Wl8Cr4V steel. Wl8Cr4V steel has good red hardness, at 600 ℃ still has high hardness and better toughness, but its carbide is bulky, strength and toughness increases with the size. W6Mo5Cr4V2 steel has good red hardness and toughness, surface hardness after quenching can reach 64-66 HRC, is a kind of high speed steel containing low Mo, W, the carbide particles is relatively small, distribution more uniform, the strength and toughness is Wl8Cr4V steel as well. Most of the high speed steel produced by cold extrusion ( Including cold heading) Mould, slightly lower than that of high speed steel cutting tools can be used to quenching temperature of the quenching temperature, if use 1240 ~ 1250 ℃ Wl8Cr4V steel, W6 Mo5 Cr4 V2 steel using 1180 ~ 1200 ℃, then carries on three times of tempering at 560 ℃. Demand for some thin thin wall mold, has high toughness, can further reduce the quenching temperature, in order to improve its service life. But after low temperature quenching, high speed steel compressive strength is reduced, can not be used in high load mold, will also reduce resistance to wear. Table 9. 1. Three common cold extrusion of high speed steel after quenching and tempering temperature after heat treatment hardness and impact toughness. Table 9. 1. Three common cold extrusion of high speed steel after quenching and tempering temperature after heat treatment hardness and impact toughness of quenching temperature / ℃ / HRC hardness without gap impact toughness KGF/cm - 550 ℃, 2500 ℃ 530 ℃ tempering tempering tempering 580 ℃ 500 ℃ tempering tempering 530 ℃ 550 ℃ tempering tempering 580 ℃ tempering six w6mo5cr4vwl8cr4vw6mo5cr4 V212001260122060. 964. 463. 562. 364. 464. 862. 363. 865. 360. 66362. 85. 72. 05. 32. 76. 33. 43. 25. 73. 63. 5