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Aobo Steel | Global Tool Steel Supplier in China
AISI S7 Tool Steel Supplier | DIN 1.2355 | Bulk Shock-Resisting Tool Steel
Reliable Bulk Supply of Annealed S7 for Impact-Resistant Tooling Applications
✓100% UT Tested (SEP 1921-82 Class D/d)
✓Delivered in Fully Annealed Condition
✓MOQ 5 Tons | FCL Recommended (~26 Tons)
✓Round Bar / Flat Bar / Forged Block
S7 tool steel is a shock-resisting tool steel classified in the “S” series under the AISI system. It is designed for applications exposed to high impact and repeated shock loading. International equivalents include UNS T41907, DIN 1.2355 (50CrMoV13-15), JIS SKS93, and the Chinese grade 5Cr3Mn1SiMo1V.
Supply Overview
| Item | Details |
|---|---|
| Grade | AISI S7 / DIN 1.2355 |
| Delivery Condition | Fully Annealed (Soft Machining Condition) |
| Available Forms | Round Bar / Flat Bar / Forged Block |
| Monthly Output | Stable rolling production for distributor replenishment |
| Recommended Export Model | Full 20GP container (~26 tons) |
| MOQ | 5 tons |
| Lead Time (Ingot Stock) | Approx. 20 days |
| Lead Time (Fresh Melt) | 30–45 days |
| Lead Time (ESR Grade) | Approx. 60 days |
| Inspection | In-house UT team + Third-party inspection available |
| Documentation | EN 10204 3.1 MTC + UT report |
Supply Stability for Distributor Inventory
- Continuous production cycle to support repeat container shipments
- Stable alloy sourcing to reduce raw material price fluctuation risk
- ESR grade available upon request for premium market positioning
- Full batch traceability linked to the original heat number
- Dedicated inspection before shipment
Packaging and Shipping
- Seaworthy wooden packing with anti-rust protection
- 20GP loading optimized up to ~26 tons
- Mixed sizes and mixed items allowed within one container
- Container loading photos available before shipment
For international distributors, full-container shipments ensure better freight control and smoother customs clearance.
S7 Tool Steel Applications
- Punches
- Blanking Dies
- Cold Forming Dies
- Coining Dies
- Mandrels
- Structural Component Parts
- Trimming Dies
S7 Steel Composition
| Carbon | Manganese | Silicon | Chromium | Molybdenum | Vanadium |
| 0.45 – 0.55% | 0.20 – 0.90% | 0.20 – 1.00% | 3.00 – 3.50% | 1.30 – 1.80% | 0.20 – 0.35% |
Properties
Physical Properties
| Density | 7.80−7.83 g/cm3 |
| Specific Gravity | 7.83 |
| Modulus of Elasticity | 205−207 GPa |
| Thermal Conductivity | 28.5 W/(m⋅K) (at 95∘C) |
| Thermal Expansion (Linear) | |
| 20−100∘C | 12.5 μm/(m⋅K) |
| 20−250∘C | 13.3 μm/(m⋅K) |
| 20−500∘C | 14.27 μm/(m⋅K) |
| Specific Heat Capacity | ∼0.46 J/(g⋅K) |
| Electrical Resistivity | ∼0.75 μΩ⋅m |
| Critical Temperature (Ac1) | 793∘C |
| Critical Temperature (Ac3) | 838∘C |
| Transformation Temperature | 785−800∘C |
Mechanical Properties
| Tensile Strength | ∼1517−2151 MPa |
| Yield Strength | ∼1310−1999 MPa |
| Hardness (Annealed) | Max 223−250 HBW |
| Hardness (Heat Treated) | Up to 60−61 HRC |
| Hardness (Tempering Range) | 45−57 HRC (depending on temp) |
| Elongation at Break | ∼7−15% |
| Poisson’s Ratio | 0.27−0.30 |
| Modulus of Elasticity | 207 GPa |
Other Properties
- Shock Resistance: Very high, a primary and defining characteristic of S7.
- Wear Resistance: Good, though generally lower than high-carbon, high-chromium cold-worked steels like O6 or D2 tool steel.
- Dimensional Stability: Good stability throughout the correct heat-treating process. Dimensional growth of +0.001 inches per inch (0.001 mm per mm) when S7 is air quenched from the correct hardening temperature.
- Air Hardening Benefit: S7’s air-hardening capability provides a significant margin of safety during hardening, reducing the risk of distortion and cracking compared to liquid-quenching steels.
- Elevated Temperature Performance: S7 exhibits good resistance to softening at moderately elevated temperatures, making it suitable for medium-temperature hot work applications.
- Surface Hardening: Through processes such as carbonitriding or nitriding, the surface hardness of S7 tool steel can be further improved to approximately 64 HRC. However, such surface treatments can affect S7 steel’s inherent shock resistance and should be carefully considered based on application requirements.
Heat Treatment of S7 Tool Steel
S7 is an air-hardening shock-resisting tool steel designed to maintain high toughness under impact loading. Typical heat treatment parameters are:
- Preheating: 650–700 °C
- Austenitizing: 925–955 °C
- Quenching: Air cooling
- Tempering: 200–540 °C (double tempering recommended)
After proper heat treatment, S7 typically achieves a hardness range of 54–58 HRC, depending on section size and tempering temperature.
For detailed temperature charts, soaking times, and practical recommendations, please refer to our dedicated S7 Heat Treatment Guide.