The size of the steel does not change much during heat treatment, quenching and tempering. Because of these characteristics, Cr2 steel is widely used in measuring tools such as sample plates, pallets, sample sets, gauges, block gauges, ring gauges, threaded plug gauges and sample columns, etc., and can also be used to make wire drawing dies and cold heading dies, etc. Cold work mold. Cr2 steel can also be used for low-speed cutting tools that are not too hard. In addition, Cr2 steel can also be used for workpieces such as cold rolls. The chemical composition of Cr2 steel The physical properties of Cr2 steel The relevant physical properties of Cr2 steel are shown in Table 2-14-2 to Table 2-14-7, and its density is 7.83t/m; the saturation magnetic induction Bs is 1.86～1.90T. Table 2-14-2 “Cr2 Steel Critical Temperature Table 2-14-3” Cr2 Steel Line (Expansion) Coefficient Table 2-14-3 “Cr2 Steel Line (Expansion) Coefficient Table 2-14-4 Cr2 Steel Thermal conductivity table 2-14-5 Cr2 steel quality constant pressure heat capacity table 2-14-6 Cr2 steel elastic modulus table 2-14-7 Cr2 steel resistivity Cr2 steel hot working Cr2 steel hot working The process is shown in the table below. Table 2-14-8 The termination temperature of the hot working process of Cr2 steel should not be high, and should be close to the lower limit. After forging, it should be cooled rapidly to 700℃ and then slowly cooled in pit cooling. Attention should be paid to the tendency of Cr2 steel to decarburize.
Chinese GB/JB label: Cr2 Japanese JIS label: SUJ2 American AISI label: L3 American ASTM label: L3 German DIN steel label: 105Cr6 German DIN material label: 1.2067 ISO label: 100Cr2 Taiwan CNS label: SUJ2 British BS label: BL1 /BL3 French AFNOR label: Y100C6 (NF) critical point temperature (approximate value) Ac1 =745°C, Ar1 =710°C, Accm =900°C, Ms=140 ~180°C. The standard softening temperature of cold pressed blanks is 820±10℃, holding for 3~4h, and then at a cooling rate of 5°C/h, slowly furnace cooling to ≤650°C, and air cooling after discharge. Normalizing specification 1) Normalizing temperature 900~920°C, holding time: salt bath furnace 25 ~30s/mm, empty furnace 70 ~90s/mm, air cooling, hardness 302-388HBW. 2) Normalizing temperature 930~950° C, Holding time: salt bath furnace 25 ~ 30s/mm, empty stove 70 ~ 90s/mm, air cooling, hardness 302 ~ 388HBW. Annealing specification Annealing temperature is 770~790°C, holding for 2~4h, and then at a cooling rate of 30°C/h, slowly furnace cooling to 500~600°C, and then air cooling. Specification for isothermal spheroidizing annealing 1) 790~720°C 2 -3h, furnace cooling, 700 ~720°C 3 ~4h, then out of furnace air cooling, hardness ≤229HBW, pearlite structure 2 -5 grade, network carbide grade ≤ level 2. 2) 770~790°C 2~4h, furnace cooling, 680~700°c 4~6h, furnace cooling to 500~600°C, out of furnace air cooling, hardness 179~229HBW. Specification for isothermal spheroidization and softening of cold-pressed blanks (820±10) °C3 ~ 4h, furnace cooling, (720±10) °C 6 -8h, then slowly cooled to ≤600°C, air cooling after discharge, the hardness after treatment is ≤ 229HBW is reduced to ≤179HBW. Quenching temperature is 840~860°C, oil cooling, tempering temperature is 660~680°C, hardness is 229HBW.
Quenching and tempering specifications: Quenching temperature 830~860°C, oil cooling, hardness ≥62HRC, tempering temperature 160~170°C or 200~250°C. 1) Commonly used for cold rolling rolls and cold rolling rolls. 2) After the φ30mm roll is heated and quenched in a salt bath, its hardness value is related to the pretreatment process of the blank. The quenching hardness of the original annealed blank is 65~66.5HRC; the quenching hardness of the quenched and tempered blank is 66~67HRC, and the hardness value is relatively uniform, without quenching cracking. 3) The cold stamping die and the precision pressing zygomatic cold extrusion die made of this steel are tempered by pumping to pumping, and the toughness is good. 4) The steel can be used as a punching die and cold heading die in the bearing industry; in the metallurgical industry, it can be used as a rolling die and cold drawing die for straightening profiles with better results. 5) After using the steel punch to be refined by carbide, then quenched and tempered, the hardness is 59~60HRC, and its flawless impact toughness can reach 15J/cm, which is more than double the conventional treatment, and it will also make the mold use Life span is increased by more than 10 times. 6) It is used for various cold stamping dies in small and medium production batches, as well as integral cold heading dies, punching and shearing tools that need to be used in the hardened state of the thin shell. 7) The small mold adopts martensite graded quenching and austempering process, which has good strength and toughness. 3) Large size cold die can be made. 9) After the large and medium-sized molds are quenched, a thin shell is formed and hardened, which has good impact fatigue resistance. 10) Used to make measuring tools, such as templates, gauges, block gauges, ring gauges, threaded plug gauges, sample columns, pallets, sample sets, etc. 11) Cold working dies such as wire drawing dies and cold heading dies can be made dry. 12) It is mostly used for cutting tools with low speed, small feed, and not very hard materials, such as turning tools, slotting tools, milling cutters, reamers, etc. 13) Used for small and medium-sized plastic molds that are not very complicated.
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