Material Specifications & International Equivalents

As a specialized chromium-alloy steel grade within the SAE/ASTM system, 5120 seamless tubes maintain precise correspondence with international standards including:

  • China: 20Cr alloy structural steel (GB/T 3077)

  • Germany: 16Cr4 (DIN standards)

  • Japan: SCr420 (JIS G4053)

  • Europe: X20Cr13 (EN standards)

The designation "51" identifies chromium-alloy series within SAE standards, while "20" corresponds to approximately 0.20% carbon content, clearly defining its low-carbon chromium alloy characteristics for mechanical applications requiring enhanced surface properties through carburizing treatment.

Mechanical Properties & Performance Characteristics

These case-hardening alloy tubes demonstrate excellent mechanical capabilities in annealed condition with tensile strength ≥470MPa, yield strength ≥315MPa, and elongation ≥22%. Through proper carburizing + quenching + low-temperature tempering processes, the surface hardness can achieve HRC55-60 with significantly enhanced wear resistance while maintaining core hardness of HRC25-35 for reliable impact resistance.

The enhanced processing characteristics include superior machinability in annealed condition with minimal tool wear and high surface finish quality. Good weldability with preheating to 150-200°C prevents cold cracking, while excellent response to carburizing treatment ensures uniform case depth and controlled surface carbon concentration. The improved hardenability compared to carbon steels enables more effective through-hardening for enhanced mechanical properties.

Technical Advantages:

  • Optimal "hard surface + tough core" properties after carburizing

  • Enhanced wear resistance and strength compared to carbon steels

  • Superior processability and plasticity versus medium-carbon alloy steels

  • Cost-effective performance for budget-conscious applications

  • Reliable performance under medium-low load conditions

  • Excellent fatigue resistance in repeated friction environments

Applications & Industrial Solutions

5120 alloy seamless tubes serve various applications across multiple sectors requiring surface hardness and core toughness:

Mechanical Manufacturing

  • Carburized gears and gear shafts

  • Spline shafts and bearing sleeves

  • Clutch plates and high-precision pin shafts

  • Precision components requiring surface wear resistance

Automotive Industry

  • Transmission auxiliary gears and drive shaft splines

  • Steering system linkages and brake system components

  • Automotive applications with medium-low load conditions

General Machinery

  • Power tool gears and hydraulic pump components

  • Textile machinery precision parts

  • Machine tool auxiliary transmission components

  • Industrial equipment requiring reliability and processability

Structural Applications

  • Light engineering machinery links and supports

  • Medium-strength structural components after quenching and tempering

  • Structural elements requiring enhanced durability

Localization Replacement

  • Import equipment maintenance parts replacement

  • Domestic adaptation for imported 20Cr equivalent components

  • International standard compatibility applications

Customization & Delivery Options

5120 tubes are typically supplied in annealed condition (GBK/+A) to facilitate subsequent machining, welding, and carburizing operations. For precision engineering scenarios, we provide stress-relieved condition (BKS/+SR) to ensure long-term dimensional stability. Applications requiring enhanced microstructural homogeneity can be served with normalized condition (NBK/+N) to optimize uniformity for critical structural applications. Tenjan's manufacturing flexibility enables customized solutions in dimensions, surface quality, and mechanical properties to meet specific application requirements.

Tenjan Advantage & Quality Commitment

Supported by 21 years of specialized experience in alloy steel tube manufacturing and comprehensive production capabilities, Tenjan delivers reliable 5120 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-alloy steels for cost-effective case hardening applications. With full-process manufacturing control and professional technical support, we ensure consistent material quality and performance reliability for your most demanding mechanical 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 high-performance alloy solutions that exceed customer expectations for durability, processability, and reliability in challenging operational environments while optimizing cost efficiency for medium-duty applications.