PN 37HS Alloy Steel Bar 37HS Round Bars 37HS Rods

Product Description

PN 37HS is a Polish standard (PN-H-84030) high-strength silicon-manganese alloy steel. It is categorized as a quenching and tempering steel, specifically valued for its high elastic limit and fatigue resistance. It is often used in applications where a balance of toughness and hardness is required, particularly in heavy machinery and spring-like mechanical components.

1. Chemical Composition

The "37" indicates a carbon content of approximately 0.37%, while "HS" points to the primary alloying elements: Silicon (S) and Manganese (H).

2. Mechanical Properties (Quenched & Tempered)

When properly heat treated (typically oil quenched at 860°C and tempered at 540°C), 37HS achieves impressive structural stats:

• Tensile Strength ($R_m$): $\ge$ 980 MPa

• Yield Strength ($R_e$): $\ge$ 785 MPa

• Elongation ($A_5$): $\ge$ 10%

• Impact Energy (KV): $\ge$ 39 J

• Hardness: Highly dependent on tempering, but generally high for structural parts.

3. Key Characteristics

• High Elasticity: Due to the high Silicon content, this grade has excellent spring-back properties and resistance to permanent deformation.

• Hardenability: The Manganese addition ensures deep hardening, making it suitable for medium-to-large diameter round bars.

• Weldability: Poor. Like most high-silicon/manganese steels, it is prone to cracking. Welding should generally be avoided; if necessary, it requires significant preheating and immediate stress relieving.

• Wear Resistance: Good resistance to surface abrasion, especially compared to standard carbon steels.

4. Global Equivalents

Finding an exact match for 37HS can be tricky as silicon-manganese structural steels are a specialty of certain European standards, but these are the closest matches:

5. Common Applications

37HS round bars and rods are typically found in heavy-duty mechanical engineering:

• Heavy Machinery: Highly stressed bolts, studs, and specialized fasteners.

• Shafts & Axles: Drive shafts and axles for agricultural or mining equipment that face high torque.

• Connecting Elements: Levers, rods, and pins subjected to alternating loads.

• Spring-like Components: Heavy-duty clips or supports requiring high yield strength.

Available Stock Conditions

• Hot Rolled: Common for rods and larger bars.

• Forged: Used for very large diameters to ensure a refined grain structure.

• Heat Treatment: Usually supplied in the Annealed (+A) state for machining, though it can be ordered Quenched and Tempered (+QT) to your specific strength requirements.