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How should 40cr seamless steel pipe be quenched and tempered

Date:2024-05-15View:35Tags:ASTM A500,EN10217-1,EN10219-1

This article will provide a detailed introduction to the chemical composition, mechanical properties, heat treatment, and corresponding steel grades and critical point temperatures of 40CR seamless steel pipes. According to the standard GB/T 3077-2008, the chemical composition of 40CR steel pipes includes C 0.37-0.44%, SI 0.17-0.37%, MN 0.50-0.80%, CR 0.80-1.10%, and NI ≤ 0.30%. In terms of mechanical properties, the tensile strength of 40Cr steel pipe is ≥ 980MPa, the yield point is 785MPa, the elongation after fracture is 9%, the area shrinkage is 45%, the energy absorbed by impact is ≥ 47J, and it is ≥ 47J. Moreover, under annealing or high-temperature tempering conditions, the Brinell hardness (HBS100/3000) is 207.

The steel grades corresponding to the 40CR seamless steel pipe include our country's GB standard 40CR, German DIN standard material number 1.17035/1.7045, German DIN standard steel number 41CR4/42GR4, British EN standard steel number 18, British BS standard steel number 41CR4, French AFNOR, French AFNOR standard steel number 42C4, French NF standard steel number 38CR4/41CR4, Italian UNI standard steel number 41CR4, Belgian NBN NBN standard steel number 42CR4, Swedish SS standard steel number 2245, American AISI/SAE/SAE/ASTM/ASTM standard steel number 5140, Japanese JIS JIS standard steel number 5140. SCR440 (H)/SCR440 and international standardized ISO standard steel grade 41CR4.

In terms of heat treatment for 40CR seamless steel pipes, the first quenching heating temperature for 40CR seamless steel pipes is 850 ° C, with oil as the coolant. The tempering heating temperature is 520 ° C, and the coolant is water or oil. The critical temperature (approximate value) is ACM=780 ℃. The standard normalized temperature is 850-870 ℃, and the hardness is 179-229hbs. The standard temperature for softening treatment of cold blank is 740-760 ° C, with a holding time of 4-6 hours. Then, it is cooled at a cooling rate of 5-10 ° C/H to ≤ 600 ° C ≤ 600 ° C, and the blank is released and air cooled. The hardness before treatment is ≤ 217hbs, and the hardness after softening is ≤ 163hbs.

[Quenching and tempering treatment specifications] This product adopts a strict quenching temperature process specification of 850 ± 10 ℃, oil cooling; The tempering temperature is 520 ℃± 10 ℃, cooled by water, oil, and air to ensure the quality stability and reliability of the product.

[Feature] This product belongs to medium carbon modulated steel and cold head mold steel. It is affordable and easy to handle. After appropriate heat treatment, it can achieve certain toughness, plasticity, and resistance to drug resistance. Normalization can promote tissue spheroidization and improve the cutting performance of the blank with a hardness of less than 160hbs. At temperatures ranging from 550 to 570 ℃, steel exhibits the best comprehensive mechanical properties. This steel has higher durability than 45 steel and is suitable for surface hardening treatments such as high-frequency quenching and flame quenching.

[Usage] This product is suitable for manufacturing mechanical parts with medium loads and working at medium speeds, such as steering knuckles, car rear axles, and gears, shafts, worms, worms, rotating shafts, center sleeves, etc. After quenching and tempering at moderate temperature, it is suitable for manufacturing parts with high load, impact force, and medium speed operation, such as gears, spindles, oil pump rotors, slides, kits, etc; After quenching and tempering at low temperatures, it is suitable for manufacturing parts with heavy loads, The body thickness on a cross-section is less than 25mm, such as worms, spindles, axes, collars, etc., with a body thickness of less than 25mm; After quenching, cooling, and high-frequency surface quenching, they are suitable for manufacturing high surface hardness and wear resistant parts that are durable and have no impact, such as gears, sleeves, shafts, shafts, spindles, crankshafts, spindles, spindles, and pins.