home / Cold Drawn Steel Bar

4140 Steel

AISI 4140 steel is a building composite steel containing chromium and molybdenum. It falls in a class of low amalgam steel. It has high weariness quality, scraped area and effect obstruction, sturdiness, and torsional quality. It tends to be warm treated in various approaches to give it a mix of properties.

We can provide you 4140 steel in the following forms

  1. Rounds (As rolled) – 23.5mm to 80mm
  2. Hexagons (As rolled) – 23.5mm to 52.5mm
  3. Round Cornered Square (RCS) – 55mm to 75mm
  4. Bright Bars (Rounds)- 22mm to 63.5mm

We are supplier of 4140 steel to a number of companies in Mumbai, Pune (eg Chakan, Bhosari, Ranjangaon, etc), Aurangabad, Ahmednagar, Rajkot, Thane, Nagpur, etc. All our 4140 supplied is Ultrasound and MPI inspected.

The following datasheet gives an overview of AISI 4140 steel.

Chemical Composition
The following table shows the chemical composition of AISI 4140 steel.

  • Element
  • Iron, Fe
  • Chromium, Cr
  • Manganese, Mn
  • Carbon, C
  • Silicon, Si
  • Molybdenum, Mo
  • Sulfur, S
  • Phosphorous, P
  • Content (%)
  • 96.785 – 97.77
  • 0.80 – 1.10
  • 0.75 – 1.0
  • 0.380 – 0.430
  • 0.15 – 0.30
  • 0.15 – 0.25
  • 0.040
  • 0.035

Material Properties of SAE4140 steel for Fabrication and Heat Treatment

4140 steel has the following properties

AISI 4140 alloy steel has good machinability in the annealed condition.

AISI 4140 alloy steel has high ductility. It can be formed using conventional techniques in the annealed condition. It requires more pressure or force for forming because it is tougher than plain carbon steels.

AISI 4140 steel can be welded using all conventional techniques. However, the mechanical properties of this steel will be affected if it is welded in the heat treated condition, and post weld heat treatment should be performed.

Heat Treatment
AISI 4140 steel is heated at 845°C followed by quenching in oil. Before hardening, it can be normalized by heating at 913°C for a long period of time followed by air cooling.

AISI 4140 steel is forged at 926 to 1205°C.

Hot Working
AISI 4140 steel can be hot worked at 816 to 1038°C.

Cold Working
AISI 4140 alloy steel can be cold worked using conventional methods in the annealed condition.

AISI 4140 steel is annealed at 872°C followed by slowly cooling in the furnace.

AISI 4140 alloy steel can be tempered at 205 to 649°C depending upon the desired hardness level. The hardness of the steel can be increased if it has lower tempering temperature. For example, tensile strength of 225 ksi cab be achieved by tempering at 316°C (600°F), and a tensile strength of 130 ksi can be achieved by tempering at 538°C (1000°F).

AISI 4140 alloy steel can be hardened by cold working, or heating and quenching.