SUS420J1/J2 – Dual-Variant Martensitic Alloys For Balanced Hardness & Corrosion Protection

Overview

SUS420J1 and SUS420J2 are two closely related martensitic stainless steels under JIS G 4303, differing primarily in carbon content to meet diverse hardness and toughness requirements. Both grades contain 12.00-14.00% chromium for basic corrosion resistance and are magnetic, heat-treatable, and suitable for cutting tools and precision components. SUS420J1 (medium carbon: 0.16-0.25%) offers better toughness, while SUS420J2 (higher carbon: 0.20-0.30%) delivers higher hardness and wear resistance after heat treatment. Both are cost-effective alternatives to high-carbon martensitic grades, with good machinability in the annealed state.

Chemical Composition (wt%)

SUS420J1: C: 0.16-0.25, Cr: 12.00-14.00, Mn ≤ 1.00, Si ≤ 1.00, P ≤ 0.040, S ≤ 0.030, Ni ≤ 0.60 SUS420J2: C: 0.20-0.30, Cr: 12.00-14.00, Mn ≤ 1.00, Si ≤ 1.00, P ≤ 0.040, S ≤ 0.030, Ni ≤ 0.60

Typical Mechanical Properties (Quenched & Tempered Condition)

SUS420J1: Tensile Strength (Rm) ≥ 850 MPa; Yield Strength (Rp0.2) ≥ 550 MPa; Elongation (A) ≥ 10%; Hardness (HRC): 50-53 SUS420J2: Tensile Strength (Rm) ≥ 900 MPa; Yield Strength (Rp0.2) ≥ 600 MPa; Elongation (A) ≥ 8%; Hardness (HRC): 52-55

Core Advantages

SUS420J1: Balanced hardness and toughness; good corrosion resistance in mild environments; easy heat treatment; excellent polishability. SUS420J2: Higher wear resistance and hardness than J1; good machinability in annealed state; cost-effective for high-wear applications. Both: Magnetic; good formability; suitable for precision components and cutting tools.

Applications

SUS420J1: Valve components, pump shafts, surgical instruments, kitchen knives, plastic molds. SUS420J2: Heavy-duty knives, scissors, bearing parts, high-wear machine components, mold inserts.

Equivalent Grades

SUS420J1: EN 1.4021, UNS S42000, GB 20Cr13, AISI 420 SUS420J2: EN 1.4028, UNS S42020, GB 30Cr13, AISI 420F

Stainless Steel Suppliers

If you have project requirements for stainless steel, we welcome your order. GNEE has a large inventory of popular products for you to choose from. It can be processed into various practical product forms, including plates, coils, tubes, bars, wires, etc. For detailed chemical composition information and free samples, please contact our factory immediately. We offer competitive prices and excellent service.Email: info@gneestainless.com

 

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