Alloy Steel 38XC Round Bar 38XC Bars 38XC Rods

Product Description

38XC (also written as 38KhS or 38 in Cyrillic) is a high-strength, chromium-silicon ($\text{Cr-Si}$) alloy structural steel designated under the GOST 4543 standard. Thanks to the unique synergy between chromium and high silicon levels, this grade exhibits remarkable fatigue life, exceptional wear resistance, elasticity, and high torsion limits.

It is primarily supplied as hot-rolled or forged round bars, rods, and flats for heavy-duty machinery.

Technical Specifications

1. Chemical Composition (GOST 4543)

The high silicon content ($\approx 1.00\% - 1.40\%$) acts as a solid-solution strengthener, preventing softening during tempering and lending the alloy some characteristics shared with high-performance spring steels.

2. Global Material Equivalents

If you are cross-referencing across international standards to source or substitute this grade, the nearest equivalent materials include:

• China (GB/T): 38CrSi (A21382)

• Germany / Europe (DIN, EN): 37HS / 38CrSi

• Czech Republic (SN): 14 341 (14341)

• USA (AISI/SAE): No exact direct ASTM match due to the high Si + high Cr combination, but it sits functionally between the 92xx spring series and 51xx/41xx structural series for heavy-duty shaft and gear work.

Mechanical Properties (Typical Heat-Treated State)

When quenched (typically in oil at around $880^\circ\text{C} - 900^\circ\text{C}$) and tempered, 38XC yields deep hardenability and uniform cross-sectional strength:

• Tensile Strength ($R_m$): $\ge 930\text{ MPa}$

• Yield Strength ($R_e$): $\ge 740\text{ MPa}$

• Elongation ($A_5$): $\ge 12\%$

• Reduction of Area ($Z$): $\ge 50\%$

• Impact Toughness ($KU_2$): $\ge 30\text{ J}$

• Annealed Supply Hardness: $\le 255\text{ HBW}$

Typical Applications

Because 38XC withstands severe cyclic stresses, high variable loads, and frictional wear, it is standard for components requiring deep core toughness and surface endurance:

• Power Generation: Turbine fasteners, high-stress studs, and boiler support rods.

• Automotive & Heavy Machinery: Camshafts, multi-diameter transmission shafts, heavy-duty axles, and connecting rods.

• Drivetrain Components: Mechanical gears, pinions, clutch plates, and friction discs.

• Machine Tool Parts: High-wear valve rods, main axes, and spindle drives.

Processing & Fabrication Notes

  Welding Warning: 38XC is categorized as difficult to weld due to its carbon and silicon levels, which elevate the risk of cold cracking.

• Preheating: If welding or thermal cutting (oxy-acetylene/plasma) is mandatory, the stock must be preheated uniformly to $250^\circ\text{C} - 350^\circ\text{C}$ depending on the cross-sectional bar diameter.

• Post-Heat Treatment: Slow cooling in calm air or insulation blankets following hot work is essential to prevent thermal shock and structural stress cracking.