4140 AISI 4140 SAE 4140 Alloy Steel - Equivalent Steel-Steel Overview - 1010|1015|1020|1025|1045|1018|1117|1035|1040|1050|1215|4140|4150

4140/4150 - Widely used general purpose alloys, low in cost. A broad range of strength and toughness is attainable through variations in heat treatment. Used for forgings, tubing and fitting.

4140 is an alloy steel that is supplied in either the annealed or prehardened condition. The prehardened condition is heat treated to a medium hardness (HRC 28/32) and is designated as 4140 HT. 4140 annealing is supplied in the soft condition and can be hardened to RC 54. 4140 annealing is designated as 4140 Ann or simply 4140. 4140 HT is supplied in many forms such as hot rolled or turned, ground and polished rounds and block or DCF plate to be used as a holder material for high strength structural components.

Alloy 4140 is an oil-hardening steel of relatively high hardenability. Its chromium content provides good hardness penetration, and the molybdenum imparts uniformity of hardness and high strength. C4140 responds well to heat-treatment and is comparatively easily machined in the heat-treated condition. With a combination of such highly desirable properties as good strength and wear resistance, excellent toughness, coupled with good ductility, and the ability to resist stress at elevated temperatures.

AISI 4140 is a chromium molybdenum quality alloy steel. AISI 4140 is primarily supplied in the hardened and tempered condition to 18-22HRc range. AISI 4140 offers good ductility, shock resisting characteristics combined with resistancee to wear. AISI 4140 is suitable for a variety of applications in the oil and gas sector. This material can be supplied to AISI steel standards.

A829-4140 steel plate is structural quality alloy steel plate with specific chemical composition requirements given in detail below. Tensile properties may also be specified for A829-4140 steel plate. When tensile properties are required, the specific requirements must be compatible with the chemical composition, condition, and plate thickness.

This is one of the chromium, molybdenum, manganese low alloy steels noted for toughness, good torsional strength and good fatigue strength.

Applications

4140 is used in a tremendous variety of applications, too numerous to mention here.

Machinability

Machinability of this alloy is good in the annealed condition. In the heat treated and quenched condition machining is best limited to finish grinding.

Forming

As with all the low alloy steels forming may be done by conventional methods with the alloy in the annealed condition. These alloys have good ductility, but are tougher than plain carbon steel and thus usually require more force, or pressure, for forming.

Welding

Weldable by all of the conventional methods. Note that welding with the alloy in the heat treated condition will affect the mechanical properties and a post weld heat treatment may be needed.

Heat Treatment

This alloy is hardened by heating to 1550 F and quenching in oil. It is best to normalize the alloy by heating at 1675 F for a long enough time to permit thorough heating, followed by air cooling, prior to the hardening treatment.

Forging
4140 may be forged at 2200 F down to 1700 F.

Hot Working

Hot working, if required, may be done in the range of 1900 F to 1500 F.

Cold Working

The alloy readily cold works in the annealed condition by conventional methods.

Annealing

Annealing is done at 1600 F followed by slow furnace cooling.

Aging

Not applicable to this alloy.

Tempering

Tempering temperatures range from 400 F to 1200 F depending upon the hardness level desired. The lower the tempering temperature the greater the hardness of the alloy. For example tempering at 600 F gives a tensile strength of 225 ksi while tempering at 1000 F will give 130 ksi.

Hardening
Hardens by cold working, or heating and quenching - also see "Heat Treatment" and "Tempering".