Material Specifications & International Equivalents

As a premium chromium-molybdenum steel grade within the SAE/ASTM system, 4140 seamless tubes maintain precise correspondence with international standards including:

  • China: 42CrMo alloy structural steel (GB/T 3077)

  • Germany: 42CrMo4 (DIN standards)

  • Japan: SCM440 (JIS G4053)

  • Europe: X42CrMo4 (EN standards)

  • United Kingdom: EN24T (BS standards)

The designation "41" identifies chromium-molybdenum alloy series within SAE standards, while "40" corresponds to approximately 0.40% carbon content, clearly defining its medium-carbon chromium-molybdenum composite alloy characteristics for heavy-duty mechanical applications requiring maximum performance reliability.

Mechanical Properties & Performance Characteristics

These high-strength alloy tubes demonstrate excellent mechanical capabilities in annealed condition with tensile strength ≥650MPa, yield strength ≥400MPa, and elongation ≥12%. Through proper quenching and tempering processes, the mechanical properties can be significantly enhanced to achieve tensile strength of 900-1100MPa and hardness reaching HRC32-40, substantially outperforming carbon steels and single-alloy chromium steels in both fatigue strength and impact toughness.

The specialized performance characteristics include exceptional high-temperature stability with reliable mechanical properties maintained below 450°C environment, and improved corrosion resistance against neutral media including water, air, and lubricating oils. The enhanced processing characteristics include excellent hardenability through chromium-molybdenum synergy, suitable for through-hardening of medium-to-large cross-sectional components. Medium machinability after annealing requires carbide tooling selection, while welding necessitates preheating to 250-300°C with controlled cooling to prevent cracking.

Technical Advantages: 

• Optimal balance between ultra-high strength and impact toughness

• Superior fatigue resistance under heavy alternating loads

• Enhanced high-temperature stability below 450°C

• Improved wear resistance and deformation resistance

• 3-5 times longer service life compared to carbon steels

• Reliable performance in extreme heavy-duty conditions

Applications & Industrial Solutions  

4140 chromium-molybdenum alloy seamless tubes serve critical applications across multiple heavy-duty sectors:

  • Mechanical Manufacturing  

  • High-precision machine tool spindles

  • Heavy-duty transmission shafts and gear shafts

  • Connecting rods and crankshafts

  • High-strength fasteners and mold blanks

  • Measuring instrument bases 

  • Machinery components requiring fatigue resistance and dimensional stability

Petrochemical Industry 

  • Medium-high pressure petroleum transmission pipelines

  • Chemical reactor accompanying pipelines

  • High-temperature medium transfer pipes

  • Oil and gas drilling equipment components

  • High-temperature applications below 450°C operating conditions

Automotive & Engineering Machinery

  • Heavy truck transmission gears and axle shafts

  • Engineering machinery hydraulic supports

  • Excavator transmission shafts and crane structural components

  • Heavy equipment components withstanding high-frequency vibration and impact

Aerospace Industry 

  • Aircraft engine auxiliary structural components

  • Hydraulic system pipelines

  • Aerospace component forging blanks

  • Aerospace applications requiring strength and lightweight combination

Specialized Applications

  • High-pressure hydraulic system pipelines

  • Offshore platform heavy-duty structural members

  • Racing vehicle core components

  • Imported high-end equipment localization

  • Replacement applications for 42CrMo and 42CrMo4 material components

Customization & Delivery Options 

4140 tubes are typically supplied in annealed condition (GBK/+A) to facilitate subsequent machining and welding operations. The recommended delivery condition is quenched & tempered (Q&T) providing pre-enhanced high-strength and high-toughness properties that reduce customer heat treatment requirements and associated costs. For precision machining applications, we provide stress-relieved condition (BKS/+SR) with straightness within 0.3mm/m to ensure assembly precision. High-temperature applications can be served with normalized condition (NBK/+N) to optimize microstructural homogeneity and high-temperature stability.

Tenjan Advantage & Quality Commitment 

Supported by 25 years of specialized experience in alloy steel tube manufacturing and comprehensive production capabilities, Tenjan delivers reliable 4140 chromium-molybdenum tubular solutions through advanced quality management systems and technical expertise. Our custom alloy steel capability enables production of various domestic and international alloy steel grades tailored to your specific application requirements, including specialized chromium-molybdenum alloys for extreme heavy-duty applications. With full-process manufacturing control and professional technical support, we ensure consistent material quality and performance reliability for your most demanding heavy-load and high-temperature applications. Our flexible order quantities and responsive customer service guarantee seamless project integration and ongoing technical support throughout your operation lifecycle, maintaining our commitment to delivering premium chromium-molybdenum alloy solutions that exceed customer expectations for strength, durability, and reliability in the most challenging operational environments.