Steel 4150

Aging Procedure

Not applicable to this alloy.

Annealing Procedure

Anneal at 1650 F and slow furnace cool.

Cold Workability

4150 may be cold worked by conventional methods with the alloy in the annealed condition. After heat treatment the alloy is very hard and difficult to work.

Forgeability

Forging may be accomplished at 2200 F down to 1800 F.

Formability

Ductility and formability in the annealed condition is good. Forming after heat treatment is difficult.

Hardening Procedure

See "Heat Treatment" and "Tempering" -- also hardens due to cold working.

Heat Treatability

It is best to normalize the alloy at 1650 F before heat treatment. Then heat treat at 1500 F and water quench to harden the alloy.

Hot Workability

The alloy can be hot worked in the range of 1900 F to 1600 F.

Machinability

Machinability of 4150 is good in the annealed condition, or in the normalized condition. After heat treatment the alloy can be very hard and it is best to limit machining at that point to grinding.

Principle Design Features

This is a higher carbon variation of the chromium, manganese, molybdenum 4100 series of low alloy steels.

Tempering Procedure

Temper at temperatures ranging from 400 F to 1200 F depending upon the hardness level desired. Higher tempering temperatures result in lower hardness values. For example tempering at 600 F gives a tensile strength of 255 ksi while tempering at 1000 F gives 170 ksi.

Weldability

The alloy may be welded by conventional methods. Welding the alloy in the hardened (heat treated) condition may affect the mechanical properties due to welding heat input. A post-weld heat treatment may be needed. Follow an approved weld procedure.