SNCM439 is a kind of nickel - chromium - molybdenum tempered, alloy structure steel. It has a higher strength, hardness, wear resistance and good toughness, its hardenability is slightly higher than 40Cr, critical quenching diameter in oil up to 18 ~ 33mm, can be considered to ideal replacement of 40Cr steel. After normalizing, it has good machinability, cold drawing, rolling, tapping, forging and heat treatment. At high temperature, the decarburization tendency and quenching deformation tendency are small, but the tempering property is not as good as that of 40Cr steel. SNCM439 steel rod is generally used in the condition of tempering and the service temperature range is -20 ~ 425℃.
Standards: JIS G4051/4053
Type: Round bar
Size: 16-320 mm
Finish: Peeled, Cold Drawn or Hot Rolled, Turned and Polished, Centreless Ground.
The Equivalent Standards:
The Chemical Composition of JIS G4051 SNCM439:
The Mechanical Properties of JIS G4051 SNCM439:
Yield Strength 0.2% (kgf/mm²)
Elongation -% in 50 mm (min.)
• Annealing: high temperature annealing at 820℃, low temperature annealing at 670℃
• Normalization: air cooling at room temperature 820~870℃
• Quenching: 820~870℃ oil cooling
• Tempering: water cooling at 580~680℃
4140 is used extensively in most industry sectors for a wide range of applications such as: Screws, nuts, gears, pistons or automotive semi-shafts, steering shafts, worm shafts, spline shafts and machine tool spindles.
World iron&steel is a professional supplier of alloy steel rods and bars. We manufacture and distribute high quality SNCM439 Gear steel round bar in accordance with JIS G4051 standards, specified delivery conditions and final customer specifications for industrial and commercial applications. Special sizes of steel bars and delivery issues can be further negotiated and we provide a wide range of solutions for purchasing departments to select alternative grades, contact us for the datails!