SEM440

SEM440 Alloy Steel Product Overview

SEM440 is a medium-carbon, chromium-molybdenum alloy steel standardised under JIS G4105, equivalent to AISI 4140, DIN 1.7225, and 42CrMo4. It is renowned for its high tensile strength, excellent toughness, and good hardenability, making it ideal for applications requiring robust mechanical properties. SEM440 is typically supplied in the annealed or normalised condition (max 229 HB) or hardened and tempered (18–22 HRC), offering a balance of strength, wear resistance, and machinability. Its chromium and molybdenum content enhances hardness penetration and high-temperature strength, while its stable composition ensures low harmful elements and high purity. This steel is widely used in engineering and automotive applications for components subjected to high stress and wear.

Applications

SEM440 is used in a wide range of engineering and industrial applications requiring high strength and durability:

Automotive:

• Gears, pinions, and gear shafts for transmissions and differentials.
• Crankshafts, camshafts, and connecting rods.
• Axle shafts, steering components, and drive shafts.

Industrial:

• Heavy-duty bushings, bearings, and sprockets.
• Machine tool spindles, arbours, and rollers.
• Forged components like couplings, hydraulic shafts, and pump shafts.

Other Uses:

• Oil and gas industry components, such as collets, connection rods, and conveyor pins.
• Agricultural and construction machinery parts.
• High-strength fasteners, bolts, and torsion bars.

Chemical Composition

The chemical composition of SEM440 ensures its high strength, toughness, and hardenability:

• Chromium (Cr): Enhances hardenability, wear resistance, and corrosion resistance.
• Molybdenum (Mo): Improves high-temperature strength, toughness, and temper resistance.
• Manganese (Mn): Contributes to hardenability and tensile strength.
• Carbon (C): Provides hardness and strength, optimized for heat treatment.

Supply Size

SEM440 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.