DIN 35CrMo7 1.2302 Alloy Cold Tool Steel

35CrMo7 / 1.2302 is a widely used chromium-molybdenum alloy steel compliant with the European standards EN 17350. With a carbon content of 0.30–0.40% and additions of chromium and molybdenum, this medium-carbon steel achieves an exceptional combination of high tensile strength, excellent toughness, and good fatigue resistance after quenching and tempering heat treatment.

Its superior hardenability, high-temperature strength, and good weldability make it a preferred choice for highly stressed and high-load applications. Commonly employed in heavy-duty machinery, power transmission systems, the petroleum industry, and automotive components (such as shafts, connecting rods, and gears).

1: Steel equivalent

2: Chemical composition

3: Surface hardness and hardenability.

4: Supply size & Tolerance & Stock size

For 1.2302 steel, because we don’t use them in domestic market, so there is no stocks for that material.

5: Ultrasonic Test    

EN10228-3 class III or Sep 1921-84 D/D

6：Steel making & Forging processing

1): Steel making process:

  EF+LF+VD

  EAF+LF+VD

  EF+LF+VD+ESR

  EAF+LF+VD+ESR

2): Forging processing:  

Initial temperature: 1150-1200℃

Final temperature: ≥850℃

Cooling in the furnace

7: Heat treatment

1): Annealed:

Heat 1.2302 steel to 830-860℃

Cooling in the furnace slowly

2): Quenching and tempering:  

Heat 1.2302 steel to 830-860℃ in the furnace

Quench in the oil

Temper steel at 540-660℃ in the furnace

Cooling in the air

Above curve in figure is a rough guide to the tempering behaviour of steels.

8：Application

35CrMo7 is widely used in critical components demanding high performance and reliability due to its excellent comprehensive mechanical properties, including high strength, high fatigue limit, good impact toughness, and relatively high high-temperature strength. Its primary application fields and specific uses are as follows:

1. Heavy machinery and equipment manufacturing

1) Gears: Large heavy-duty gears in heavy trucks, construction machinery, mining equipment, and wind turbine gearboxes.

2) Shaft Components: Machine tool spindles, engine crankshafts, heavy-duty vehicle half-shafts, turbine rotor shafts, compressor main shafts, etc.

3) Connecting Rods: Large connecting rods in diesel engines and compressors, subjected to both tensile/compressive loads and fatigue stresses.

4) High-Strength Bolts/Fasteners: High-strength preload bolts for pressure vessels, pipeline flanges, and heavy-duty structural connections.

2. Petroleum and Chemical Industry

1) Petroleum drilling and production equipment: drill pipe joints, sucker rods, pump shafts, blowout preventer components, etc.

2) Pressure vessels: Containers and pipelines subjected to medium-to-high temperatures and pressures.

3) Compressor components: Piston rods, valve plates, crankshafts, etc.

3. Automotive and Transportation

1) Engine components: Engine crankshafts, camshafts, connecting rods, gear shafts, etc.

2) Transmission systems: Transmission gears, drive shafts, rear axle differential gears, etc.

3) Steering and suspension: Steering knuckles, universal joints for heavy-duty vehicles, etc.

4. Power and Energy Industry

1) Wind power industry: Gear ring, main shaft, high-speed shaft in wind turbine gearboxes.

2) Hydroelectric and Thermal Power: Turbine main shafts, turbine blades, generator rotor shafts, etc.

5. Molds and Tools

1) Plastic Molds: Used for manufacturing large, high-durability injection molds, where its excellent strength and toughness withstand immense clamping forces.

2) Die-Casting Molds: Pins, slides, and other components for aluminum and magnesium alloy die-casting molds.