SCM420 42CrMo Alloy Steel Round Bar for High-Pressure Pipes

Grade Introduction:
SCM420 are alloy steel with high hardenability, temper brittleness, well weldability, less cold cracking tendency, good machinability, and great cold plastic strain. SCM420 generally is used for the parts which need high wear resistance, such as gears, shafts, high-pressure pipes, all kinds of fasteners, and so on. Carburizing structural steel.

Grade Application:
SCM420 case hardening alloy steels are widely used as gear components of all kinds and cogwheels. Open die steel forgings for general engineering purposes. Steel is available to supply different sizes of SCM420 steel and is able to supply modified SCM420 steel composition according to different requirements.

Equivalent grades:
GB 20CrMo, JIS SCM420, ASTM 4118, DIN 25CrMo4.

Chemical composition:
The following table shows the chemical composition of SCM 420 steel:

Mechanical Properties:
Tensile strength σb (MPa): ≥ 885 (90) Yield strength σs (MPa): ≥ 685 (70) Elongation rate δ5 (%): ≥12 Section shrinkage ψ (%): ≥50 Impact energy Akv (J): ≥78 Impact toughness value αkv (J / cm²): ≥98 (10) Hardness: ≤ 197HB

 Finishing rolling process: 

Finishing rolling is a process to obtain higher precision and better surface quality by rolling the heat-treated seamless steel pipe multiple times. The specific steps include: heat treatment - pickling - cooling - finishing rolling - sizing - cutting - length - inspection - packaging. Finishing rolling can improve the precision, surface quality and mechanical properties of steel pipe.

Cold drawing process: 

Cold drawing is a process of drawing the heat-treated seamless steel pipe one by one in a cold state to obtain high precision, high surface quality and high mechanical properties. The specific steps include: heat treatment - pickling - cooling - cold drawing - deoxygenation - wet pickling - cold water washing - leveling - straightening - pickling - cold water washing - oxide skin - cold drawing - sizing - straightening - pickling - cold water washing - deoxygenation - polishing - inspection - packaging. Cold drawing can significantly improve the dimensional accuracy, surface quality and mechanical properties of steel pipes.

Hot rolling production process: 

Hot rolling is the process of heating the blank to a certain temperature, and then forming it into seamless steel pipe through multiple rolls. The specific steps include: heating - rolling - roll probe - sizing - cooling - trimming - rod breaking - inspection - packaging. Hot rolling can produce seamless steel pipes with large diameters and wall thickness, but the accuracy and surface quality are not as good as fine rolling and cold drawing.

These three processes have different applications in the production of seamless precision steel pipes, and the specific choice depends on the required dimensional accuracy, surface quality and mechanical properties.