Material Name: 50 uniform digital code: U20502
Executive Standard GB / T 699-1988
Machining:
(A) the shaft of the rough shaft parts can be used according to requirements, production type, equipment condition and structure, choice of bars, forgings, blank forms. For the cylindrical shaft diameter or less, generally the main bar; the large difference in diameter for the cylindrical axis or major axis of the ladder, often used in forging, which saves material and reduces the workload of machining, but also improved mechanical properties. According to the different scale of production, rough way of forging free forging and forging two. Many small and medium batch production using free forging, forging used a large number of mass production.

    (B) shaft material shaft should be based on different working conditions and use of the use of different materials and different heat treatment specifications (eg, quenching, normalizing, quenching, etc.) to obtain a certain strength, toughness and wear resistance. 50 is a shaft of steel commonly used materials, it is cheap after quenching and tempering (or normalized), the available good cutting performance, but also to obtain a higher strength and toughness, such as mechanical properties, surface hardness after quenching up to 45 ~ 52HRC. 40Cr alloy structural steel suitable for medium accuracy and high speed shaft parts, such steel after quenching and after quenching, has good mechanical properties. GCr15 bearing steel and spring steel 65Mn, after quenching and high-frequency surface hardening, the surface hardness of up to 50 ~ 58HRC, and high fatigue resistance and good wear resistance, can produce high precision shaft. Precision machine tool spindle (such as grinding wheel axis, coordinate boring machine spindle) can be used 38CrMoAIA nitrided steel. This steel after quenching and surface nitriding, not only to obtain high surface hardness, but also to maintain the Ministry of soft core, so the resistance to impact toughness. And case hardening steels, heat treatment it has a small deformation, the higher the hardness characteristics. No. 50 steel is widely used in machinery manufacturing, steel, mechanical properties of this well. But this is a medium carbon steel, hardened performance is not good, 50 steel can be hardened to HRC42 ~ 46. So if you need surface hardness, but also want to play No. 50 steel superior mechanical properties, often the case hardening steel surface 50 so that we can obtain the required surface hardness.

Features:

    High-strength carbon-carbon structural steel, after quenching with high strength and hardness, the steel can be cut middle, cold plastic deformation is low, poor welding, heat treatment, no temper brittleness, but lower hardenability, the critical diameter of the water is 13 * 30mm, and the tendency to crack when quenched in water. This steel is usually in normalizing or quenching and tempering, or other high-frequency surface hardening heat treatment before use.

Chemical composition:

   (Mass fraction,%) C 0.47 ~ 0.55, Si 0.17 ~ 0.37, Mn 0.50 ~ 0.80, P ≤ 0.035, S ≤ 0.035, Ni ≤ 0.30, Cr ≤ 0.15, Cu ≤ 0.25

Mechanical properties:

Tensile strength σb (MPa): ≥ 630 (64)

Yield strength σs (MPa): ≥ 375 (38)

Elongation δ5 (%): ≥ 14

Reduction of area ψ (%): ≥ 40

Impact energy Akv (J): ≥ 31 (4)

Impact toughness αkv (J/cm2): ≥ 39 (4)

Hardness: no heat treatment, ≤ 241HB; annealed steel, ≤ 207HB

Sample Size: Sample size is 25mm.

Reference number corresponding to the German DIN standard steel material number 1.1213, the German DIN standard steel Cf53, China GB standard steel 50, the British BS standard steel 060A52, the French AFNOR standard steel XC48TS, French NF standard steel C50, Italy UNI Standard steel C53, Belgian standard NBN steel C53, the Swedish standard SS 1674 steel, the U.S. AISI / SAE / ASTM standard steel 1050, Japanese JIS standard steel S50C/S53C, International Organization for Standardization ISO standard steel C50E4.

Critical temperature (approximate) Ac1 = 725 ℃, Ac3 = 760 ℃, Ar3 = 721 ℃, Ar1 = 690 ℃

Normalizing standard temperature 830 ℃ ± 10 ℃, air-cooled.

Ordinary quenching and tempering standard quenching temperature 830 ℃ ± 10 ℃, water, oil cooling; tempering temperature of 600 ℃ ± 10 ℃, water and oil cooling.

Applies to:

Create dynamic load, impact load is not a good wear resistance and mechanical parts required, such as forged gears, shaft friction disc, spindle, spindle motor, roller, rod, spring washers, etc.