420 1.2083 SUS420J2 Stainless Steel
420 tool steel boasts high hardness, excellent corrosion resistance and superior mirror polishability, ideal for molds processing aggressive plastics and precision optical & medical components.
- Standard: AISI 420，DIN 1.2083，JIS SUS420J2，GB 4Cr13
- Technique: Hot Rolled，Hot Forged
- Shape: Plate，Flat，Block，Round
- Heat treatment: Annealed / Q+T
- Surface Treatment: Black，Rough Machined， Fully Machined，Ground Finish
- Tolerance: +/-1%
- MOQ: 1 Ton
We supply AISI 420 in various custom sizes
plate
flat
block
round
Chemical Composition (%)
Grade | C | Si | Mn | P | S | Cr |
1.2083 | 0.36-0.42 | ≤1.00 | ≤1.00 | ≤0.030 | ≤0.030 | 12.50-14.50 |
420 | 0.15-0.40 | ≤1.00 | ≤1.00 | ≤0.030 | ≤0.030 | 12.00-14.00 |
4Cr13 | 0.36-0.45 | ≤0.60 | ≤0.80 | ≤0.030 | ≤0.030 | 12.00-14.00 |
SUS420J2 | 0.26-0.40 | ≤1.00 | ≤1.00 | ≤0.040 | ≤0.030 | 12.00-14.00 |
Main characteristics of 420 tool steel
- Excellent corrosion resistance – high chromium resists rust & mild chemicals
- High hardness & wear resistance – ensures long service wear life
- Good dimensional stability – low deformation in heat treatment
- Superior polishability – achieves smooth mirror finish
420 | 1.2083 | SUS420J2 tool steel applications
420 steel Used for making Mould plates and inserts for working with chemically aggressive plastics
420 steel delivers excellent corrosion resistance and stable high hardness, making it an optimal material for mold plates and inserts processing chemically aggressive plastic materials in industrial production.
420 steel suitable for optical and medical products
420 steel delivers superior mirror polishability and precise dimensional stability, perfectly applicable to fabricating high-precision parts for optical and medical product manufacturing.
Our production technology for 420 Stainless Steel
- EAF
- LF
- VD/VOD
- ESR
- Forged
- Soft Annealed
- Machined surface
- UT 100% SEP1921 Class 3 D/d or E/e
- Soft annealed microstructure with hardness max 230 HB (or 225 HB)
- Macrostructure, microstructure, grain size, and non-metallic inclusions shall meet the standards specified in DIN EN ISO 4957 / ASTM A681, ensuring superior mirror polishability (up to SPI A1 / A2).
mechanical properties & heat treatment of 420 steel
| Heat temperature | Start forging temperature | Finish forging temperature | Cooling method |
| 1050°C – 1100°C | 1050°C | 850°C | Slow cooling in furnace or sand |
Annealing
- 840 to 870°C
- Slow controlled cooling in furnace at a rate of 10 to 20°C/hr down to approx. 600°C, further cooling in air.
- Hardness after annealing: max. 229 HB.
Hardening
- 1000 to 1050°C / Oil, air
- Holding time after temperature equalization: 15 to 30 minutes.
- Obtainable hardness: 53-56 HRC
Stress relieving
- Approx. 650°C
- Slow cooling in furnace; intended to relieve stresses set up by extensive machining, or in complex shapes.
- After through heating, hold in neutral atmosphere for 1 - 2 hours.
Tempering
- 100 to 200°C (212 to 392°F)
- Slow heating to tempering temperature immediately after hardening / time in furnace
- 1 hour for each 20 mm of work piece thickness but at least 2 hours / cooling in air.
- For average hardness figures to be obtained please refer to the tempering chart.
Why Choose NSPM as Your 420 Tool Steel Supplier
Source Direct
Direct mill cooperation ensures stable supply, competitive pricing, and consistent quality. Global resource integration and strong supply chain management guarantee reliable material sourcing and long-term availability.
Stock Ready
50,000+ tons inventory across 11 warehouses enables fast delivery. Flexible cutting, short lead times, and ready stock support urgent demands and improve customers’ production efficiency.
Expert Team
600+ professionals, including R&D specialists and technical engineers, provide application-driven support. Fast response and deep tooling knowledge ensure accurate solutions for diverse industrial needs.
Fully Inspected
Strict quality control system with full traceability, UT testing, and heat treatment records. Certified standards (ISO, CE) ensure every material meets high-performance and reliability requirements.
Full-Chain Machining
From steel supply to precision machining, heat treatment, and equipment manufacturing, NSPM offers integrated solutions that enhance accuracy, efficiency, and overall tooling performance.
