General Information about 4150 Steel and 4150 Round Bar

4150 steel is part of the SAE (Society of Automotive Engineers) family of steel grades. 4150 round bar is a higher carbon variation of the chromium, manganese, molybdenum 4100 series of low alloy steels. It is considered a low alloy steel because its percentage of metals is low in proportion to its main component, iron.

4150 round bar is noted for increased hardenabilty. 4150 steel may be selected when slightly higher mechanical properties are required. Machinabilty of 4150 round bar is better in the annealed or normalized condition.  It is ideal to machine 4150 steel in the annealed form and then heat treat it to harden the steel; as heat treatment can make it very hard and 1difficult to work. Tempering may be done to restore some of the ductility after heat treatment and quench.

4150 round bar may be forged as well as hot and cold worked. 4150 steel has common alloying elements as 4140 but differs in the amount of carbon. Both are commonly known as chromium molybdenum steels as they contain .80 to 1.10 percent chromium and.15 to .25 percent molybdenum. These elements make 4150 steel stronger and harder than standard carbon steel.

4150 round bar may be supplied as hot rolled, cold drawn, rough turned or turned and polished. A typical length for 4150 round bar is 20′, although many mills have the capacity to roll a variety of lengths depending on the application. It is also supplied in a wide range of diameters. 4150 steel may also be supplied in wire rod form, with a typical package weighing around 4,000#.


4150 steel consists of carbon, .48/.53, manganese, .75/1.00, phosphorus, .035 (max.), sulfur, .04 (max.), silicon, .15/35, chromium, .80/1.10 and molybdenum, .15/.25.