When sourcing SUS 420J2 and SUS 420J1 stainless steel, understanding the differences between them is crucial for purchasing professionals to select the most suitable material for cutting tools, industrial inserts, and wear-resistant components.
Within this series of steels, 420J1 and 420J2 are two main grades, which achieve the desired hardness through high-temperature heating followed by quenching in oil or air. The carbon content largely determines the maximum hardness these steels can achieve after quenching.
What is 420J1 Stainless Steel?
420J1 stainless steel is a martensitic stainless steel with excellent wear resistance, hardness, and certain corrosion resistance, making it suitable for manufacturing parts and tools requiring high hardness. Its hardness can be increased through quenching and tempering heat treatment, and it is commonly used in the manufacture of cutting tools, bearings, valves, turbine blades, etc.
What is 420J2 Stainless Steel?
420J2 stainless steel conforms to the American ASTM standard, with the common standard being SUS420J2, and also meets the newer national standard 30Cr13. 420J2 stainless steel is a martensitic stainless steel whose main characteristics are high hardness and strength, good corrosion resistance, and high polishability after heat treatment (quenching and tempering). It is commonly used in the manufacture of cutting tools, medical devices, bearings, and plastic molds, etc.
Stainless Steel 420 / 420J1 / 420J2 Sheets & Plates Equivalent Grades:
| STANDARD | JIS | WERKSTOFF NR. | BS | AFNOR | SIS | UNS | AISI |
| SS 420 | SUS 420 | 1.4021 | 420S29 | - | 2303 | S42000 | 420 |
| SS 420J1 | SUS 420J1 | 1.4021 | 420S29 | Z20C13 | 2303 | S42010 | 420L |
| SS 420J2 | SUS 420J2 | 1.4028 | 420S37 | Z20C13 | 2304 | S42010 | 420M |
SS420 vsSUS 420J1 vs SUS420J2 stainless steel Chemical composition：
| Grade | C | Mn | Si | P | S | Cr | Ni | Mo |
| SUS 420 | 0.15 max | 1.0 max | 1.0 max | 0.040 max | 0.030 max | 12.0-14.0 | - | - |
| SUS 420J1 | 0.16-0.25 | 1.0 max | 1.0 max | 0.040 max | 0.030 max | 12.0-14.0 | - | - |
| SUS 420J2 | 0.26-0.40 | 1.0 max | 1.0 max | 0.040 max | 0.030 max | 12.0-14.0 | - | - |
SUS 420J1 vs SUS420J2 stainless steel Physical properties
| Performance Category | parameter | SUS420J1 | SUS420J2 |
|---|---|---|---|
| Physical properties | (Density) | 7.75 g/cm³ | 7.75-7.76 g/cm³ |
| (Elastic Modulus) | 200-210 GPa | 219 GPa (approx.) | |
| (Thermal Conductivity) | 25-30 W/(m·K) | 25.1 W/(m·K) at 100℃ | |
| (Thermal Expansion Coefficient) | ~11-12 × 10⁻⁶/K | 10.5 × 10⁻⁶/K (0~100℃) | |
| Mechanical properties | (Yield Strength) | ≥225 N/mm² | |
| (Tensile Strength) | ≥440 N/mm² | ||
| (Reduction of Area) | ≥50% | ||
| (Hardness) | HRC 50-55 | ||
| (Elongation) | ≥12% / ≥50% |
Strength and Durability of 420J1 Stainless Steel vs. 420J2 Stainless Steel
Tensile Strength:
The tensile strength of 420J2 exceeds that of 420J1 due to its higher carbon content. With superior strength and corrosion resistance, 420J2 stainless steel is often the go-to material for situations that demand these properties.
Hardness:
Post-quenching, 420J2 stainless steel shows a noticeable increase in hardness compared to 420J1 stainless steel. The hardening process involves heating 420J2 steel to 950–1020°C (1742–1868°F) until the temperature is uniform throughout the material.
Yield Strength:
Yield strength signifies the transition from elastic deformation to plastic deformation. Hard metals typically exhibit a higher yield strength. At a 0.2% offset, 420J1 stainless steel has a yield strength of 440 MPa, while 420J2 stainless steel stands higher at 540 MPa.
SUS 420J1 vs. SUS 420J2: Prices
The price range for SUS 420J1 stainless steel is US$2.00 to US$2.20 per kilogram, while SUS 420J2 is slightly more expensive, ranging from US$2.20 to US$2.50 per kilogram, reflecting its higher carbon content and superior hardness. Price fluctuations are influenced by global steel market trends, order volumes, and surface treatment processes.If you are interested in our products and services, please feel free to contact me. Our team is always ready to support and assist you!
Is 420J2 stainless steel good?
Yes, 420J2 stainless steel is known for its strength, hardness, and corrosion resistance. It is widely used in conditions where hardened and tempered material is required.
Is 420J2 steel good for knives?
420J2 stainless steel is preferred for manufacturing low-cost, durable knives commonly used in kitchens. The grade is also suitable for axe heads due to its hardening capability.