JIS G4105 SCM440 Alloy Steel Seameless Pipes: High-Temperature Chromium-Molybdenum Tubes

SCM440 alloy steel seamless pipes, specified under JIS G4105, are chromium-molybdenum medium-carbon structural steel tubes designed for high-temperature service. These pipes combine excellent strength, toughness, and fatigue resistance after quenching and tempering, making them equivalent to international grades such as AISI 4140 and EN 42CrMo4.

【Material】 

SCM440 (JIS G4105) is a medium-carbon, chromium-molybdenum alloy structural steel. Delivered in a quenched and tempered condition (typically 18–22 HRC), SCM440 offers high tensile strength, good toughness, and excellent fatigue resistance at elevated temperatures, making it ideal for components subjected to cyclic loading and thermal stress.

【Specifications】

• Standard: JIS G4105

• Diameter range: Φ16 mm to Φ350 mm (cold drawn) and up to Φ1000 mm (hot forged)

• Wall thickness tolerance: H11 (cold drawn), black ±0/+1 mm (hot rolled)

• Delivery condition: Quenched and tempered, hardness 18–22 HRC

【Chemical Composition】

【Mechanical Performance】

【Key Features】

• High strength-to-weight ratio: Superior tensile and yield strengths for heavy-duty components.

• Excellent fatigue resistance: Quenched and tempered microstructure sustains cyclic loads.

• Good ductility and toughness: Maintains impact resistance at elevated temperatures.

• Heat resistance: Retains mechanical properties in high-temperature environments up to 350 °C.

• Machinability and weldability: Suitable for complex shapes; pre- and post-heat treatment recommended.

【Standards Compliance】

• JIS: G4105 “Chromium-Molybdenum Machine Structural Steel Tubes”

• GB/T: 9711.1 Grade 35CrMo / GB/T 3077 40CrMo

• EN: 10216-4 Grade 42CrMo4; EN 10083-3

• ASTM: A519 Grade 4140 (seamless alloy steel tubing)

• GOST: GOST 8732-78; GOST 9941

• JIS (plate): G4053 SCM440 plate equivalent

【Application Fields】

General Industries

• Automotive: Drive shafts, axles, transmission gears.

• Mechanical engineering: Spindles, tooling holders, hydraulic cylinder tubes.

• Oil & gas: Pump components, valve stems, compressor shafts.

• Power generation: Turbine rotors, boiler tubes, piping in high-temperature zones.

• Aerospace: Landing gear struts, actuator rods, structural tubing.

Specific Uses per Field

• Automotive: Crankshafts and camshafts where high fatigue strength is essential.

• Mechanical: Hydraulic pistons and jigs requiring precise heat treatment.

• Oil & Gas: Downhole tool mandrels and couplings exposed to cyclic pressure.

• Power: Boiler superheater tubes demanding creep resistance.

• Aerospace: Flight control rods subject to dynamic loading.

Q: Are you trading company or manufacturer ?

A: manufacturer,also can do trading.

Q: How long is your delivery time?

A: Generally speaking,it is 10-15 days if the goods are in stock,or it is 30-40 days if the goods are not in stock,

it is according to quantity.

Q: Do you provide samples? is it free or extra ?

A: Yes, we could offer the sample for free charge but need pay the cost of freight.

Q: What is your terms of payment ?

A: Payment<=2000USD, 100% in advance. Payment>=2000USD, 30% T/T in advance ,balance before shippment.

If you have another question, pls feel free to contact with me.