The following are typical values for the general chemical composition and mechanical properties of 4140 seamless pipe, but please note that these values may vary depending on the specific standard and manufacturer:
chemical composition:
Carbon (C): 0.38-0.43%
Manganese (Mn): 0.75-1.00%
Silicon (Si): 0.15-0.35%
Phosphorus (P): ≤ 0.035%
Sulfur (S): ≤ 0.040%
Chromium (Cr): 0.80-1.10%
Nickel (Ni): ≤ 0.25%
Molybdenum (Mo): 0.15-0.25%
Mechanical properties (typ., after heat treatment):
Yield strength (YS): ≥ 655 MPa (95,000 psi)
Tensile strength (UTS): ≥ 850 MPa (125,000 psi)
Elongation (EL): ≥ 20%
Impact Toughness (Charpy V-notch): ≥ 54 J (40 ft-lb) (usually in quenched and tempered condition)
Heat treatment is a key step that affects the properties of 4140 steel. Typically, 4140 seamless pipe is quenched and tempered to achieve the required hardness and strength. Quenching is usually done in water or oil, followed by a tempering process to reduce hardness and increase toughness.
