40Cr steel bearings
   40Cr China China GB standard steel, 40Cr steel is the most widely used mechanical manufacturing of steel. After quenching with good mechanical properties, good low temperature impact toughness and notch sensitivity. Good hardenability of steel, when quenched in water quenching to Ф28 ~ 60mm, when oil quenching hardenability to Ф15 ~ 40mm. In addition to quenching of this steel is also suitable for external cyanide and high-frequency quenching treatment. Cutting is better, when the hardness HB174 ~ 229, the relative machinability of 60%. The production of steel suitable for medium-sized plastic molds.

Basic Information
According to the standard GB / T 3077-1999 standard corresponding to the foreign: JIS G4053 ASTM A29 / ISO 683-18:1996
Chemical composition
Grade C Si Mn Cr Ni P S CU
40Cr 0.37 ~ 0.44 0.17 ~ 0.37 0.50 ~ 0.80 0.80 ~ 1.10 ≤ 0.030 ≤ 0.035 ≤ 0.035 ≤ 0.030

Mechanical properties
Blank sample size (mm): 25 Heat treatment:

The first quenching temperature (℃): 850; Coolant: Oil

  Second quenching temperature (℃): - tempering heating temperature (℃): 520; coolant: water, oil 40CR roundwood
  Tensile strength (σb / MPa): ≧ 980

Yield point (σs / MPa): ≧ 785

Elongation (δ5 /%): ≧ 9

Reduction of (ψ /%): ≧ 45

Impact absorbed energy (Aku2 / J): ≧ 47

  Brinell hardness (HBS100/3000) (annealing or tempering condition): ≦ 207
    40cr Introduction
[Reference] corresponding to steel GB of standard steel in China is 40Cr, the German DIN standard material number 1.17035/1.7045, the German DIN standard steel 41Cr4/42Gr4, British Standard EN 18 steel, the British BS standard steel 41Cr4, the French AFNOR standard steel 42C4, the French NF standard steel 38Cr4/41Cr4, Italy UNI standard steel 41Cr4, the Belgian standard NBN steel 42Cr4, the Swedish standard SS 2245 steel, the U.S. AISI / SAE / ASTM standards for steel No. 5140, Japan's JIS standard steel SCr440 (H) / SCr440, U.S. AISI / SAE / ASTM standards for steel No. 5140, International Organization for Standardization ISO standard steel 41Cr4.

 [Critical temperature] (approximate) Acm = 780 ℃

    [Specification] normalizing temperature 850 ~ 870 ℃, the hardness 179 ~ 229HBS.

[Specification] cold rough softening temperature of 740 ~ 760 ℃, holding time 4 ~ 6h, and then to 5 ~ 10 ℃ / h of cooling rate, cooling to ≤ 600 ℃, baked air-cooled. Prior to treatment hardness ≤ 217HBS, soften the hardness ≤ 163HBS.

 [Health protection swinging iron tempered specification] (670 ± 10) ℃ × 2h, with the furnace temperature, (710 ± 10) ℃ × 2h, with furnace cooling, (670 ± 10) ℃ × 2h, with the furnace temperature, (710 ± 10) ℃ × 2h, then cooled with the furnace, (670 ± 10) ℃ × 2h, with the furnace temperature, (710 ± 10) ℃ × 2h, with the furnace temperature, a total of three cycles, and then cooled to 550 ℃, baked air-cooled. Treatment hardness 153HBS.

    [Specification] quenching quenching temperature 850 ℃ ± 10 ℃, oil cooling; tempering temperature of 520 ℃ ± 10 ℃, water, oil, air-cooled.