Normalizing specification and mechanical properties analysis of No. 50 steel

No. 50 steel is a medium carbon and high strength carbon structural steel. As a common steel, it is widely used in the industrial field, especially the plate, which is not only a typical cold work die steel material, but also often used as a processing raw materials by the machinery factory to produce various mechanical parts.

Features: No. 50 steel has medium machinability, low cold deformation plasticity, poor weldability, no temper brittleness during heat treatment, but low hardenability. The critical diameter in water is 13-30mm, and there is a tendency to crack during water quenching. No. 50 steel is usually used after heat treatment such as normalizing, or quenching and tempering, or high-frequency surface quenching.

Delivery status: unheated, hardness ≤ 241HBS; annealed, hardness ≤ 207HBS

Chemical composition mass fraction of No. 50 steel: C 0.47-0.55, Si 0.17-0.37, Mn 0.5-0.80, P≤0.035, S≤0.035, Ni≤0.30, Cr≤0.15, Cu≤0.25

No. 50 steel equivalent grades: Chinese GB standard steel No. 50; Japanese JIS standard steel No. S50C/S53C; German DIN standard material steel No. 1.1213; German DIN standard steel No. CF53; British BS standard steel No. 060A52; French AFNOR standard steel No. XC48TS; French NF standard steel number C50; Italian UNI standard steel number C53; Belgium NBN standard steel number C53; Sweden SS standard steel number 1674; Spanish standard steel number F.112; American AISI/SAE standard steel number 1050; No. C50E4.

No. 50 steel has medium machinability, low cold deformation plasticity, poor weldability, no temper brittleness during heat treatment, but low hardenability. The critical diameter in water is 13-30mm, and there is a tendency to crack during water quenching. No. 50 steel is usually used after heat treatment such as normalizing, quenching and tempering, or high frequency surface quenching.

No. 50 steel process specification: critical point temperature
Approximate values: Ac1=725℃, Ac3=760℃, Ar3=721℃, Ar1=690℃.

No. 50 steel normalizing specification: 830±10℃, air cooling.

Normal quenching temperature is 830±10℃, cooled by water and oil; tempering temperature is 600±10℃, cooled by water and oil.