S1 1.2550 SKD41 Cold Work Tool Steel
S1 Cold Work Tool Steel provide high impact resistance, toughness, and wear resistance. With moderate hardenability and excellent shock absorption, ideal for chisels, shear blades, and punches.
- Standard: AISI S1, DIN 1.2550（60WCrV7）, JIS SKD41, GB 6CrW2Si, EN 60WCrV8
- Technique: EAF + LF + VD or ESR, forged, multi-directional forging ratio ≥4, spheroidized annealed
- Shape: Round, Flat, Plates, Blocks
- Heat treatment: Supplied in annealed condition, hardness ≤248 HBW; pre-hardened to 54–58 HRC (quenched and tempered) available on request
- Surface Treatment: Black (hot-rolled / forged surface), turned, milled / ground, sawn ends
- Tolerance: flat bars & plates thickness: +0.5/-0.0 mm (turned); forged blocks: ±0.2 mm
- MOQ: 1 Ton
We supply AISI S1 in various custom sizes
flat size range
- Thickness: 6-100 mm
- Width: 40-610 mm
block size range
- Thickness: 100-300 mm
- Width: 200-610 mm
round size range
- Diameter: φ10-400 mm
Chemical Composition (%)
Grade | C | Si | Mn | P ≤ | S ≤ | Cr | Mo | Ni | V | W |
1.2550 (60WCrV7) | 0.55-0.65 | 0.50-0.80 | ≤0.40 | ≤0.030 | ≤0.030 | 1.00-1.30 | — | — | — | 2.00-2.70 |
AISI S1 (1.2550) | 0.45-0.55 | 0.15-1.20 | 0.10-0.40 | ≤0.030 | ≤0.030 | 1.00-1.80 | ≤0.40 | ≤0.30 | 0.15-0.30 | 1.50-3.00 |
GB 6CrW2Si | 0.55-0.65 | 0.50-0.80 | ≤0.40 | ≤0.030 | ≤0.030 | 1.00-1.30 | — | 允许残余≤0.25 | — | 2.00-2.70 |
60WCrV8 (1.2550) | 0.55-0.65 | 0.70-1.00 | 0.15-0.45 | ≤0.030 | ≤0.030 | 0.90-1.20 | — | — | 0.10-0.20 | 1.70-2.20 |
Main characteristics of S1 tool steel
- High impact resistance – withstands heavy shock loads
- Excellent toughness – resists cracking and chipping
- Good wear resistance – extends tool service life
- Moderate hardenability – suitable for large-section tools
S1 | 1.2550 | SKD41 tool steel applications
S1 steel for Hot Shear Blade
High tungsten content provides 1.2550 with excellent hot hardness and edge stability, ensuring clean cuts and long service life in hot shearing of bars and billets.
S1 steel for Hot Forming Punch
Superior shock resistance and temper stability allow the punch to withstand repeated high-temperature impacts in hot forging and extrusion operations.
S1 steel for Heavy-Duty Cold Heading Die
Exceptional toughness combined with good wear resistance makes it ideal for cold heading dies subjected to extreme mechanical shock, reducing early fracture risks.
Our Production Technology For 1.2550 (60WCrV7 / S1 / 6CrW2Si) Shock Resisting Tool Steel
- EAF
- LF
- VD
- ESR
- Forged or Hot Rolled
- Spheroidizing Annealed
- Machined surface / Peeled
- Ultrasonic testing (UT) 100% as per SEP 1921, ASTM A388, or EN 10228-3 (upon request)
- Micro Cleanliness as per ASTM E45 or DIN 50602
- Spheroidized microstructure as per relevant tool steel standards
- Macrostructure, microstructure, grain size, and mechanical properties shall meet the standards specified in GB/T 1299 for Tool and Die Steels
- Delivery condition: Soft annealed, hardness max. 229–230 HB
mechanical properties & heat treatment of S1 steel
| Heat temperature | Start forging temperature | Finish forging temperature | Cooling method |
| 1050 – 1100 °C | 1050 – 1000 °C | ≥ 850 – 800 °C | Pit, sand, or furnace cooling |
Annealing
- Heat slowly and uniformly to 710 – 750°C (approx. 1310 – 1382°F).
- Hold at temperature for 2 – 5 hours, depending on section thickness
- Cool slowly in the furnace to room temperature
- Hardness after annealing: max. 225 – 230 HB (approx. 21–22 HRC)
Hardening
- 1.2550 (60WCrV7 / S1) is an oil-hardening shock resisting tool steel. It contains tungsten (1.70–2.20%), which confers excellent fatigue resistance, and chromium (0.90–1.20%), which provides depth of hardness and abrasion resistance. Oil is the preferred quenching medium for most applications. Temper immediately after quenching
- Pre-heating (recommended):Primary preheat: 550 – 600°C, hold for 30–45 minutes.Secondary preheat: 800 – 820°C, hold for 30–40 minutes
- Austenitizing temperature: 860 – 900°C (with an upper alternative of 900–950°C for thicker sections)
- Holding time: After temperature equalization, hold for 20 – 30 minutes (or 30 minutes per 25mm of section thickness)
- Quenching media:Oil (preferred for most sections) — quench immediately after holding.Hot bath at 180 – 220°C (martempering) as an alternative hardening procedure when suitable salt bath equipment is available
- Hardness after quenching: 60 HRC (approx. 58–62 HRC range)
Stress relieving
- Perform after rough machining or heavy stock removal, especially for tools with complex shapes or unbalanced cross-sections, to reduce the risk of distortion during final heat treatment
- Heat carefully to 650 – 700°C (650°C per SIJ, 700°C per other sources)
- Hold at temperature for 1 – 2 hours (2 hours for larger sections)
- Air cool after holding
- This operation is performed to reduce distortion during hardening
Tempering
- Temper immediately after the workpiece cools to hand-warm temperature (approx. 50–70°C). Delayed tempering may cause cracking
- Number of tempers: Minimum 2 times. Double tempering is recommended to improve toughness and ensure complete transformation of retained austenite
- Holding time: Soak for at least 1 hour per 20mm of section thickness (minimum 2 hours per cycle)
- Cooling method: Air cool after each tempering cycle (must cool to room temperature before the next tempering)
- Tempering temperature ranges:Low-temperature tempering (150 – 250°C): For maximum hardness (58–62 HRC) with excellent wear resistance — suitable for cold cutting tools, shear blades, and blanking dies.Medium-temperature tempering (300 – 400°C): For balanced hardness and toughness (52–58 HRC) — suitable for hot work tools and cold piercing punches.Do not exceed 400°C for wear-critical applications; tempering above 500°C significantly reduces hardness (48–43 HRC) and is used only when toughness is the primary requirement
Why Choose NSPM as Your S1 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.
