40# flat steel has high strength and good machinability, moderate cold deformation plasticity, poor weldability. This material can be welded after quenching and tempering, no tempering brittleness during heat treatment, but low hardenability.
Chemical Composition of 40# Flat Steel (%)
Carbon : 0.37 to 0.45
Silicon: 0.17 ～ 0.37
Manganese: 0.50 ～ 0.80
Sulfur: ≤0.035
Phosphorus: ≤0.035
Cr: ≤0.25
Nickel: ≤0.25
Copper: ≤0.25
40# steel application:40# flat steel has high strength and good machinability, moderate cold deformation plasticity, poor weldability, can be welded after quenching and tempering, no tempering brittleness during heat treatment, but low hardenability. 40# flat steel can be used as a small-section quenched and tempered part with a large load or a large normalized part with less stress, as well as a surface hardened part that does not require high core strength and wear resistance on the surface, and 40# steel product is used to manufacture moving parts such as rollers, shafts, Connecting rods, discs, etc. As well as train axles, it can also be used for cold drawing, steel plates, steel strips, seamless pipes, etc.
