BDS 38ChS Alloy Steel Bar 38ChS Round Bars 38ChS Rods

Product Description

BDS 38ChS (Bulgarian: 38ХС) is a high-strength, chromium-silicon alloy structural steel regulated by the Bulgarian standard BDS 6354. It is designed for heavy-duty components that require high fatigue strength, excellent wear resistance, and significant elastic properties.

It is the direct Bulgarian equivalent of the Soviet/Russian GOST 38KhS (38ХС) and the Polish 37HS.

1. Chemical Composition

The "38" indicates approximately 0.38% Carbon, while "ChS" (or KhS) stands for Chromium (Х) and Silicon (С).

2. Mechanical Properties (Typical for $\varnothing$ 25mm)

After a standard heat treatment cycle (Oil Quenching at ~900°C and Tempering at ~600°C):

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

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

• Elongation ($A_5$): $\ge$ 12%

• Impact Strength (KCU): $\ge$ 690 $kJ/m^2$

• Hardness (Annealed): $\le$ 255 HB

3. Key Technical Characteristics

• Elasticity: Similar to the PN 37HS, the high silicon content makes this steel excellent for parts that must resist permanent deformation (spring-like behavior).

• Deep Hardenability: Chromium and Silicon together allow for uniform hardness even in larger cross-sections.

• Weldability: Difficult. This steel is sensitive to cold cracking. Welding is generally not recommended, but if unavoidable, it requires preheating to 250–300°C and immediate post-weld stress relief.

• Wear Resistance: It performs exceptionally well in friction environments, especially when oil-quenched.

4. Global Equivalents

BDS 38ChS is part of a specific family of Cr-Si steels common in Eastern and Central Europe:

5. Common Applications

38ChS round bars and rods are utilized for parts operating under high alternating loads and intense friction:

• Automotive & Heavy Machinery: Camshafts, crankshafts, and drive axles.

• Transmission Components: High-load gears, clutch discs, and friction plates.

• Fasteners: High-tensile studs, heavy-duty bolts, and specialized screws.

• Tools: Suction valves, cams, and shafts for excavators and tractors.

Available Forms

• Round Bars: Usually available in diameters ranging from 20mm to 300mm.

• Delivery Condition: Often supplied in the Annealed state to simplify machining, or Quenched & Tempered (+QT) for immediate use in high-strength applications.

• Finish: Black (hot-rolled), peeled, or bright-drawn.