Alloy steels are designated by AISI four-digit numbers and comprise different kinds of steels, each with a composition which exceeds the limitations of B, C, Mn, Mo, Ni, Si, Cr, and Va set for carbon steels.
GENERAL CHARACTERISTICS OF 4140 ALLOY STEEL
4AISI 140 alloy steel is a chromium-, molybdenum-, and manganese-containing low alloy steel. It has high fatigue strength, abrasion and impact resistance, toughness, and torsional strength.
Forming
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.
APPLICATIONS
This alloy finds many applications as forgings for the aerospace and oil and gas industries, along with myriad uses in the automotive, agricultural and defense industries, Typical uses are forged gears and shafts, spindles, fixtures, jigs and collars.
Bar Specification
| UNS | Type | AMS | ASTM |
|---|---|---|---|
G41400 | AISI 4140 | 6349 | A193 |
Chemical Composition
| Grade | Cr | Mn | C | Si | Mo | S | P | Fe |
|---|---|---|---|---|---|---|---|---|
AISI 4140 | 0.80 - 1.10 | 0.75 - 1.0 | 0.380 - 0.430 | 0.15 - 0.30 | 0.15 - 0.25 | 0.040 | 0.035 | Balance |
Mechanical Properties
| Grade | Tensile strength (Mpa) | Yield strength (Mpa) | Elongation at break (in 50 mm) | Hardness (Rockwell B) max | Hardness (Brinell) max |
|---|---|---|---|---|---|
AISI 4140 | 655 | 415 | 140 | 92 | 197 |