S7 Tool Steel Overview
Shock-Resistant Air-Hardening Tool Steel
S7 is a high-impact tool steel designed for applications where repeated shock, impact, and mechanical stress are expected. As an air-hardening steel with excellent toughness and moderate wear resistance, S7 is a top choice for large choppers, throwing blades, hammers, and sword tangs that demand maximum durability and minimal risk of breakage.
It is widely used in both industrial tooling and high-impact knife or sword applications, especially where edge stability and structural strength are more important than wear resistance.
Performance Overview
| Key Feature | Rating | Remarks |
| Chipping Resistance | ★★★★☆ | Highly resistant to edge failure under shock or lateral force |
| Toughness | ★★★★★ | One of the highest among conventional tool steels |
| Wear Resistance | ★★☆☆☆ | Moderate – not ideal for abrasion-dominant applications |
| Grindability | ★★★☆☆ | Easier than high-carbide steels like D2 or CPM M4 |
| Dimensional Stability | ★★★★☆ | Excellent due to air-hardening – especially for long or flat parts |
| Corrosion Resistance | ★★☆☆☆ | Not stainless – requires oil or coating for rust prevention |
| Heat Treat Forgiveness | ★★★★☆ | Air-quenching reduces risk of warping; responds well to press tempering |
| Weldability | ★★☆☆☆ | Limited – mechanical joining preferred over welding |
Heat Treatment Guidelines
S7 benefits from air-hardening behavior, which reduces distortion and makes it a good choice for long or flat parts.
Recommended process:
Austenitizing: 950–980°C (1740–1800°F), hold for 20–30 minutes
Quenching: Air (recommended) or oil (for thick sections)
Tempering: 200–550°C (390–1020°F), 2–3 cycles, 1–2 hours per cycle
→ Lower temper = higher hardness; higher temper = increased toughnessFinal Hardness: HRC 54–58
Normalization: Optional before forging
Cryo: Optional, not usually required
S7 responds well to press tempering or jig tempering to correct flatness after hardening.
Chemical Composition
S7 features a carefully balanced composition designed to enhance toughness, shock resistance, and thermal stability:
Carbon (C): 0.45%
Contributes to strength and hardness without brittleness.Chromium (Cr): 3.25%
Improves hardenability and adds depth to heat treatment response.Molybdenum (Mo): 1.40%
Increases toughness and high-temperature strength.Vanadium (V): 0.25%
Helps refine grain structure and toughness.Manganese (Mn): 0.70%
Supports hardenability and strength.Silicon (Si): 0.35%
Enhances oxidation resistance and strength at temperature.
S7 does not contain large amounts of wear-resistant carbides, which allows it to absorb shock without cracking.
Processing Notes
S7 can be forged or stock removed, and works well for flat stock, forged tangs, and tool-style blade geometries.
Best forged at 1000–1100°C (1850–2000°F)
Requires slow, controlled cooldown or normalization before hardening
Air quenching allows excellent dimensional control
Can be jig-tempered to preserve straightness in long blades
Best suited for rough-use designs, not for high-wear slicers or fine-edged tools.
Ideal Applications
Thanks to its exceptional shock tolerance, S7 excels in:
⚔️ Throwing knives and tomahawks
🔪 Large chopping knives and cleavers
🛡️ Structural sword components (tangs, spines)
🪓 Hammers and impact tools
🧰 Training blades requiring safety and toughness
🎯 Tools subject to repeated impact or mechanical stress
Material Options
We offer S7 in the following configurations:
✅ Annealed flat bar stock (ready for forging or machining)
✅ Precision-cut plates available on request
✅ Optional heat treatment (air-hardened + tempered)
✅ Custom dimensions by order
✅ Ideal for long blades, training tools, or high-impact blade parts
Why Choose Us?
We’re more than just a steel supplier—we understand bladesmithing from the inside out. Every material we offer is carefully selected, professionally handled, and backed by real technical support.
We understand the real-world needs of sword makers and custom bladesmiths. From steel behavior during forging and quenching to EDM and final finishing, we speak your language—because we’re craftsmen too.
We stock carefully selected steels like CPM 3V, CPM 1V, and more—known for their toughness, edge retention, and dimensional stability. Whether treated or annealed, every batch is chosen for serious work.
Need specific dimensions for your blade profile? We offer custom cutting, stock thickness options, and surface prep to suit forging or grinding—saving you time and material waste.
We focus on long-term value—offering premium materials at fair prices. Whether you’re a one-blade-at-a-time maker or a growing workshop, we’ll work with your budget.
We understand that your build schedule depends on material arriving when promised. We ship on time, provide tracking, and follow up—so you can plan with confidence.
Have questions about heat treatment, material choice, or blade geometry? We’re here to help—not just before the sale, but anytime you need practical advice.
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Would you like to start a project with us?
Whether you’re crafting a single custom blade or building a full line of swords, we’re here to support your vision with the right materials and reliable service. Tell us what you’re making—we’ll help you choose the steel, prepare it, and get it to you on time. Let’s build something sharp together.