40Cr steel Pipe is a kind of Chinese GB standard alloy steel for engineering and machinery purpose, and one of the most widely used steel grades.

After quenching and tempering treatment, 40Cr steel pipe has good comprehensive mechanical properties, low temperature impact toughness, low notch sensitivity, good hardenability, and high fatigue strength in cold oil. When water cooling, the complicated shape of the parts is prone to cracks, the cold bending plasticity is medium, and the cutting workability after normalizing is good, but the weldability is poor, should be preheated before welding, and is generally used in the state of quenching and tempering.