38KHS Alloy Steel Bar 38KHS Round Bars 38KHS Rods

Product Description

38KHS (or 38KhS / 38ХС) is a high-performance, low-alloy structural steel originating from the GOST standard system. It is specifically categorized as a Chromium-Silicon steel.

The "38" indicates a carbon content of approximately 0.38%, "KH" (Kh) stands for Chromium, and "S" stands for Silicon. This combination makes the steel particularly effective for parts that need high fatigue strength and resistance to vibration and impact.

1. Chemical Composition

The high Silicon content is the standout feature of this grade, providing superior elastic limits.

2. Mechanical Properties (After Quenching & Tempering)

When heat treated (usually oil quenched at 900°C and tempered at 500–600°C), 38KHS round bars achieve high structural integrity.

• Tensile Strength ($\sigma_b$):$\ge$ 930 MPa

• Yield Strength ($\sigma_s$):$\ge$ 735 MPa

• Elongation ($\delta_5$):$\ge$ 12%

• Reduction of Area ($\psi$):$\ge$ 45%

• Impact Toughness ($KCU$):$\ge$ 590 $kJ/m^2$

• Hardness (Brinell):$\le$ 255 HB (in the annealed state)

3. Key Characteristics

• Elasticity: The Chromium-Silicon pairing creates a high "yield-to-tensile" ratio. This means the steel can take significant stress before permanently deforming, making it ideal for spring-loaded or reciprocating parts.

• Hardenability: It has excellent through-hardening depth, ensuring that even large-diameter rods maintain consistent strength from the surface to the core.

• Sensitivity to Flakes: Like many high-strength alloy steels, it requires controlled cooling after forging or hot rolling to prevent internal "flaking" or micro-cracking.

• Weldability:Poor. It is not intended for welded constructions. If welding is necessary, extensive pre-heating and immediate post-weld heat treatment are required to avoid brittle fractures.

4. Global Equivalents

This grade is very common in Eastern Europe and Central Asia. If you are sourcing it internationally, look for these equivalents:

5. Applications

38KHS round bars and rods are the preferred choice for components subject to high alternating loads and friction:

• Engine Parts: Camshafts, crankshafts, and connecting rods.

• Transmission: High-load gears, transmission shafts, and splined shafts.

• Heavy Fasteners: High-tensile studs and bolts for industrial machinery.

• Valves: Suction valves and parts for compressors.

• Agricultural Machinery: Axles and power-take-off (PTO) shafts.

Available Stock Forms

• Round Bars: Typically found from 10mm to 300mm diameters.

• Rods: Often available in hot-rolled or cold-drawn finishes.

• Condition: Usually supplied in Annealed (for easier machining) or Normalized condition. Some suppliers offer them pre-Quenched & Tempered (QT) to your hardness specifications.