Huaxia Steel — Professional Shock-Resisting Tool Steel Supplier
15+ years of experience | ISO 9001 & SGS Certified | Factory-direct pricing | Custom sizes available | Worldwide shipping
What is S7 TOOL STEEL?
AISI S7 is a shock-resisting, air-hardening tool steel that offers the highest impact toughness of any tool steel grade. Its unique formulation—medium carbon with chromium and molybdenum—provides an exceptional combination of toughness, compressive strength, and moderate wear resistance. S7 maintains its toughness even at high hardness levels (up to 58 HRC), making it irreplaceable in applications where tool steels like O1 or D2 would fracture under repeated impact.
At Huaxia Steel, we supply S7 tool steel conforming to ASTM A681 and DIN 1.2357 standards. Available as hot-rolled bars, forged rounds, and plates, our S7 is fully certified and can be supplied in custom sizes to minimize your machining time.
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Chemical Composition (wt%)
| Element | Min (%) | Max (%) |
|---|---|---|
| Carbon (C) | 0.45 | 0.55 |
| Silicon (Si) | 0.20 | 1.00 |
| Manganese (Mn) | 0.20 | 0.80 |
| Phosphorus (P) | — | 0.030 |
| Sulfur (S) | — | 0.030 |
| Chromium (Cr) | 3.00 | 3.50 |
| Molybdenum (Mo) | 1.30 | 1.80 |
| Vanadium (V) | 0.20 | 0.30 |
Data per ASTM A681 / equivalent standards (2025/2026 Reference).
Mechanical & Physical Properties
- Hardness (Annealed): 197-229 HB
- Hardness (Hardened + Tempered): 54-58 HRC
- Tensile Strength: ~1,800 MPa (261 ksi)
- Yield Strength: ~1,450 MPa (210 ksi)
- Impact Toughness (Charpy V-notch): 14-18 J (at 56 HRC)
- Density: 7.83 g/cm³ (0.283 lb/in³)
- Elastic Modulus: 207 GPa (30,000 ksi)
Heat Treatment Guide
| Process | Temperature | Details |
|---|---|---|
| Annealing | 815-845°C (1500-1550°F) | Furnace cool slowly; hardness 197-229 HB |
| Preheating | 650-705°C (1200-1300°F) | Equalize before ramping to hardening temperature |
| Austenitizing | 940-955°C (1725-1750°F) | Soak 30-45 min after reaching temperature |
| Quenching | Air cool (or oil for large sections) | Achieves 58-60 HRC as-quenched |
| Tempering | 200-540°C (400-1000°F) | Double temper recommended; 200°C→58 HRC, 315°C→54 HRC, 540°C→48 HRC |
Need Custom Heat Treatment Advice?
Our engineers can recommend optimal heat treatment parameters for your specific application.
Common Applications
- Pneumatic chisels & jackhammer bits
- Heavy-duty blanking & punching dies
- Shear blades (plate & structural steel)
- Cold & hot forging punches
- Battering tools & rivet sets
- Master hobs for cold hubbing operations
- Swaging dies & gripper dies
- Heavy-duty snap rings & retaining rings
International Equivalent Grades
| Standard / Country | Grade Designation | Details |
|---|---|---|
| USA (AISI/SAE) | S7 | UNS T41907, ASTM A681 |
| Germany (DIN) | 1.2357 / 1.2355 | 50CrMoV13-1 |
| EU (EN ISO) | 50CrMoV13-1 | EN ISO 4957 |
| Japan (JIS) | — | No direct JIS equivalent (custom order) |
| China (GB) | 5Cr3MnSiMoV | GB/T 1299 (approximate) |
| UK (BS) | BS7 | BS 4659 |
Available Forms & Dimensions
Round bars (dia 12-500mm), Flat bars (thickness 6-120mm), Forged blocks up to 800x400mm, Custom-cut sections available
Custom sizes: Available upon request. Contact us with your specifications for a tailored quotation.
Why Choose Huaxia Steel as Your S7 TOOL STEEL Supplier?
Factory-Direct Pricing
Eliminate middlemen. Our direct mill partnerships ensure competitive pricing on every order, from small prototype quantities to container loads.
Certified Quality
Every shipment includes full mill test certificates (MTC/EN 10204 3.1). ISO 9001 certified. Third-party SGS inspection available on request.
Custom Processing
Cut-to-size, precision sawing, surface grinding, and heat treatment services. We deliver material ready for your production line.
Fast Global Logistics
Efficient shipping to North America, Europe, Middle East, Southeast Asia, and beyond. Standard lead time 7-15 days for stock items.
Frequently Asked Questions
Q: What is the maximum hardness achievable with S7 tool steel?
The maximum hardness depends on the specific grade. After proper heat treatment, typical maximum hardness ranges from 58-67 HRC. Refer to the heat treatment table above for specific tempering curves.
Q: Can S7 tool steel be welded?
Most tool steels can be welded for repair purposes, but it requires proper preheating, low-hydrogen electrodes, and post-weld heat treatment. For high-chromium grades like D2, welding is generally not recommended for structural applications. Always consult the manufacturer’s welding guidelines.
Q: What is the difference between S7 and other tool steel grades?
Each tool steel grade is optimized for specific applications. The key differentiators are wear resistance, toughness, hot hardness, and heat treatment method (air/oil/water). Compare grades based on your specific requirements: wear resistance (D2 > A2 > O1), toughness (S7 > H13 > A2), and hot hardness (M2 > H13 > D2).
Q: How do I order S7 tool steel from Huaxia Steel?
Simply contact us via the form on this page, email, or phone. Provide the grade, dimensions (thickness x width x length or diameter x length), quantity, and any special requirements such as surface finish or heat treatment condition. Our team will respond with a tailored quotation within 12 hours.
Q: What certifications do your tool steel products carry?
All Huaxia Steel tool steel products are supplied with full Mill Test Certificates (MTC/EN 10204 3.1) showing chemical composition and mechanical properties. We are ISO 9001:2015 certified, and third-party inspection (SGS, BV, TUV) is available upon request at no extra charge for orders above 5 tons.
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Factory-direct pricing. ISO & SGS certified quality. Fast global logistics. Get your quote in 12 hours.
