Chemical composition and mechanical properties of 5140 seamless steel pipe

Hit：72026-03-07 16:26:29　

Chemical composition and mechanical properties of 5140 seamless steel pipe
Mechanical properties (heat treatment state: quenched and tempered, i.e. quenched+high-temperature tempered)
The typical mechanical performance indicators are as follows:
Tensile strength (σ b): ≥ 980 MPa
Yield strength (σ s): ≥ 785 MPa
Elongation rate (δ 5): ≥ 9%
Shrinkage rate of cross-section (ψ): ≥ 45%
Impact energy (Akv): ≥ 47 J
Hardness: ≤ 207 HB (annealed or high-temperature tempered state)
Heat treatment suggestions
Quenching temperature: 850 ℃± 10 ℃, oil cooled
Tempering temperature: 520 ℃± 10 ℃, water-cooled, oil cooled or air-cooled
Applicable processes: quenching and tempering, surface quenching, nitriding, carbonitriding, etc
Chemical composition (mass fraction%)
According to multiple authoritative standards (ASTM A29/A29M, SAE J404, GB/T 3077, etc.), the typical chemical composition of 5140 seamless steel pipe is as follows:
Carbon (C): 0.38% -0.43%
Silicon (Si): 0.15% -0.35%
Manganese (Mn): 0.70% -0.90%
Chromium (Cr): 0.70% -0.90% (some standards such as JIS SCr440 allow up to 1.20%)
Phosphorus (P): ≤ 0.035%
Sulfur (S): ≤ 0.040%
Nickel (Ni), copper (Cu): usually residual elements with low content (≤ 0.30%)
5140 seamless steel pipe (corresponding grades such as AISI 5140, SAE 5140, UNS G51400, GB 40Cr, JIS SCr440, DIN 1.7035/41Cr4) is a chromium molybdenum alloy structural steel widely used in the manufacture of mechanical parts that can withstand high loads, moderate impacts, and wear resistance, such as gears, shafts, connecting rods, and main shafts.