Introduction 4Cr13 4Cr13 steel standard: GB / T 1220-1992 Features and Scope: 4Cr13 steel codenamed S-136, belongs to the type of martensitic stainless steel, good machinability of the steel, heat treatment (quenching and tempering) after having excellent corrosion resistance, polished performance, high strength and wear resistance, suitable for manufacturing withstand high loads, high wear and plastic mold in corrosive media effect, transparent plastic molds, etc., such as heat pumps, valves, valve bearings, medical equipment, springs and other parts. Note: The steel weldability poor, must pay attention when in use. 2 Chemical composition Chemical Composition: Carbon C: 0.36 ~ 0.48 Si Si: ≤0.60 Mn Mn: ≤0.80 sulfur S: ≤0.030 phosphorus P: ≤0.035 chromium Cr: 12.00 ~ 14.00 Ni: to allow the mechanical properties containing ≤0.60 3 Mechanical Properties : Hardness: annealed ,, ≤201HB, indentation diameter 3.9 ~ 4.3mm; quenching, ≥50HV heat treatment and microstructure specifications: Heat treatment specifications: 1) annealing, 800 ~ 900 ℃ slow cooling or rapid cooling to about 750 ℃; 2) quenching, 1050 ~ 1100 ℃ oil cooling; 3) tempered, 200 ~ 300 ℃ rapid cooling. Microstructure: Organizing for the martensitic. 4 delivery status Delivery status: Delivery of steel in the annealed condition. Forging: oil quenching cold work die steel has some cracking susceptibility, forging heating should not rapidly heated, preferably in a preheated 650-750 degrees, forging heating temperature of 1130-1150 degrees, the final forging temperature should be greater than 800-850 degree, to take maximum temperature forging ingots. Take the minimum temperature annealing forging blanks: General annealing using 780-800 degrees, heat 4-6 hours to ≤50 degrees / hour, cooled to 550 degrees baked cooled, isothermal annealing 700-800 degrees insulation using 2-4 sales, then then 670-720 degree heat, keep 2-4 hours to ≤50 ° / hr cooling rate cooled to 500 degrees baked cooled, annealed hardness 241-197HB 5 heat Table 4-17-8 4Cr13 steel annealing hardening heat treatment project back fire heating temperature / ℃ cold furnace cooling from 750 to 800 from 1050 to 1100 air-cooled oil cooler 200 to 300