what material is 4140

First of all, we need to understand what material is 4140.

The common antirust elements are Cr and Ni. The Cr content of 42CrMo is only 0.9-12.0; The requirement of Ni is less than 0.3, the general antirust CR at least to reach 12.5 above, Ni to reach 5.00 above to have the basic antirust ability.

42CrMo steel belongs to high strength low alloy steel

with high strength and toughness, good hardenability, no obvious temper brittleness, high fatigue limit and multiple impact resistance after quenching and tempering treatment, and good low temperature impact toughness. The steel is suitable for manufacturing large and medium-sized plastic moulds requiring certain strength and toughness.

what material is 4140?

This kind of steel has no anti-corrosion performance, of course, it is easy to rust. It can’t be said that it’s easy to rust. It mainly depends on preservation.
To prevent rust, it is necessary to carry out surface anti-corrosion treatment. If the surface is oiled, it is not easy to rust. The most commonly used is the surface blackening treatment