4130 Steel is a low alloy steel that contains chromium and molybdenum as strengthening agents. With a nominal carbon content of 0.30% this alloy is excellent for fusion weldability. 4130 can also be hardened through heat treatment. 4130 can increase its wear quality through nitriding. 8630 and 4130 have similar properties. 4130 is known as a Chrome-Moly alloy. In addition alloy 4130 is stocked in a normalized, quench and tempered conditions. 4140 and 4130 are similar but 4130 has better weldability due to the smaller amount of Carbon but does give up through thickness strength based on that Carbon content as well.