GOST 35 Alloy Steel Bar GOST 40 Round Bars GOST 35 Rods

Product Description

GOST 35 & GOST 40 (Steel 35 & Steel 40)

GOST 35 and GOST 40 are high-quality structural carbon steels defined under the GOST 1050 standard. These are medium-carbon steels widely used in mechanical engineering for components that require higher strength than mild steel (like GOST 20) but still maintain good ductility and machinability.

1. Chemical Composition

The numbers "35" and "40" represent the average carbon content in hundredths of a percentage point.

2. Mechanical Properties

These grades are typically used in the Normalized or Quenched and Tempered (QT) condition. Steel 40 offers slightly higher strength and hardness but slightly lower elongation than Steel 35.

3. Key Technical Characteristics

• Hardenability: Both grades have limited through-hardenability. They are excellent candidates for Surface Hardening (induction or flame hardening) to create a wear-resistant skin with a tough core.

• Weldability: Limited. Because of the higher carbon content, these steels are prone to cracking if welded without precautions. Preheating to 150–200°C and post-weld heat treatment are generally recommended.

• Machinability: Very good. These grades are favorite materials for high-volume turning, milling, and drilling operations.

• Forging: They have excellent hot-forming characteristics, typically forged at temperatures between 1280°C and 750°C.

4. Global Equivalents

If you are sourcing these materials outside the CIS region, the following grades are the closest matches:

5. Common Applications

GOST 35 (Steel 35):

Used for parts experiencing low-to-medium stress where toughness is critical:

• Small axles, levers, and rods.

• Low-load crankshafts and tie rods.

• Fasteners (bolts and nuts) of medium strength classes.

GOST 40 (Steel 40):

Used for components requiring higher surface hardness and strength:

• Gears, pinions, and shafts.

• Piston rods and spindles.

• Crankshafts for medium-sized machinery.

• Tool holders and structural hardware.

Available Stock

• Round Bars: Available from 6mm to over 400mm in diameter.

• Rods: Often supplied as hot-rolled or cold-drawn (calibrated) for precision machining.

• Delivery Condition: Usually supplied As Rolled or Normalized.