SEM430

SEM430 Alloy Steel Product Overview

SEM430, equivalent to AISI 4130, SAE 4130, or DIN 25CrMo4 (1.7218), is a medium-carbon, low-alloy chromium-molybdenum steel under the JIS G4105 and ASTM A29 standards. Renowned for its excellent strength-to-weight ratio, high toughness, and superior weldability, SEM430 is widely used in applications requiring high tensile strength and fatigue resistance. Typically supplied in the annealed condition (max 229 HB) or hardened and tempered (22–30 HRC), it offers good machinability, ductility, and atmospheric corrosion resistance. It is suitable for high-stress, high-temperature applications up to 315°C (600°F).

Applications

SCM430 (AISI 4130) is used in industries requiring robust, durable components:

Aerospace:

• Aircraft structural components, such as fuselage frames, landing gear, and wing spars.
• Engine mounts and roll cages.

Automotive:

• Chassis components, roll bars, and suspension parts.
• Crankshafts, axles, and high-performance gears.

Oil and Gas:

• Drill collars, valves, and fittings for high-pressure environments.
• Tubing and piping for exploration and production equipment.

Other Uses:

• Bicycle frames and motorcycle components.
• High-strength bolts, studs, and fasteners.
• Tool holders and shafts in general engineering.

Chemical Composition

The chemical composition of SEM430 (AISI 4130) ensures its strength, toughness, and hardenability:

• Chromium (Cr): Enhances hardenability, wear resistance, and corrosion resistance.
• Molybdenum (Mo): Improves strength, toughness, and resistance to tempering.
• Manganese (Mn): Contributes to hardenability and tensile strength.
• Carbon (C): Provides hardness while maintaining weldability.

Supply Size

SEM430 (AISI 4130) is available in various forms and sizes to meet industrial requirements:

• Round Bars:
  Diameter 16 mm to 700 mm.
• Flat Bars:
  Minimum: 10 mm thickness x 80 mm width.
  Maximum: 500 mm thickness x 2000 mm width.