Purohit Steel is a leading Grade S7 Stockist and Exporter in India, supplying premium air-hardening, shock-resisting tool steel with verified chemical composition, mechanical properties and full traceability for tool rooms, die makers and manufacturers of impact-duty tooling.
As an ISO-certified company established in 1965, we maintain ready stock of Grade S7 in round bar and flat bar form, with in-house bandsaw cutting, machining, grinding and EDM support for fast turnaround across India and export markets.
Table of Contents
- 1. What is Grade S7 Steel
- 2. Why Purohit Steel for S7
- 3. Comparison: S7 vs S1 vs A2
- 4. Chemical Composition
- 5. Mechanical Properties
- 6. Physical & Thermal Properties
- 7. Equivalent International Grades
- 8. Heat Treatment Guidelines
- 9. Available Forms & Sizes
- 10. Machining & Selection Notes
- 11. Applications & Uses
- 12. Industries We Serve
- 13. Related Products
- 14. Authorized Stockist Brands
- 15. Cities We Supply in India
- 16. Our Services
- 17. Frequently Asked Questions
- 18. About Purohit Steel
- Our Certifications
- Countries We Export Worldwide
- Export Packaging & Shipping
- Quality Inspection & Testing
- Latest Price List
- MOQ & Payment Terms
- People Also Search For
What is Grade S7 Steel?
Grade S7 (AISI/SAE, UNS T41907) is an air-hardening, chromium-molybdenum shock-resisting tool steel developed for applications involving extreme impact and heavy shock loading. It is widely regarded as the highest-hardenability grade in the ASTM S-series, offering a superior balance of toughness, strength and wear resistance compared to S1, O1 and even some D-series grades in high-impact service.
Because S7 is air-hardening, it minimises distortion and warping during heat treatment, making it well suited to precision tools and components that must hold tight tolerances after hardening. After heat treatment, S7 typically reaches 54-58 HRC while retaining excellent ductility, and it also offers good softening resistance at moderately elevated temperatures.
S7 has no exact DIN/Werkstoffnummer equivalent; the closest related European grade is 1.2542 (45WCrV7), though not identical — see the comparison table below for how S7 compares with S1 and A2.
Why Purohit Steel for Grade S7
- Ready Stock: Round bar and flat bar sizes held in inventory for immediate dispatch
- ISO-Certified Quality: Documented quality management since 1965
- Authorized Stockist: Sourced through globally reputed manufacturers, including NLMK Verona and SeAH CSS
- Value-Added Machining: In-house bandsaw cutting, precision machining, grinding, drilling, gun drilling, EDM and wire-cut
- Technical Support: Assistance with grade selection, heat treatment guidance and equivalence mapping
- Pan-India & Export Supply: Warehousing in Vasai with a sales outlet in Mumbai, serving customers across India and international markets
- Export-Ready Packaging: Palletised, moisture-protected packing suitable for both domestic transport and export shipment
Comparison: S7 vs S1 vs A2
Buyers often need to choose between related shock-resisting and general-purpose cold work grades. The table below compares S7 against two other grades Purohit Steel stocks, to help select the right material for the application.
| Factor | S7 | S1 / 1.2550 | A2 |
|---|---|---|---|
| Alloy family | Cr-Mo, air-hardening | Tungsten-Cr-V, oil-hardening | Cr-Mo-V, air-hardening |
| Working hardness | 54-58 HRC | 56-60 HRC | 56-62 HRC |
| Shock / impact resistance | Best in class among cold work grades | Excellent | Good, less than S1/S7 |
| Hardenability / distortion in heat treatment | Excellent, air-hardening minimises distortion | Good, oil quench needed | Excellent, air-hardening minimises distortion |
| Wear resistance | Good | Moderate | Good, better than S1/S7 |
| Best suited for | Large punches, dies and precision tooling under heavy shock | Hand and pneumatic impact tools such as chisels and punches | General-purpose stamping, forming and cutting dies |
Grade S7 Chemical Composition
Composition as per ASTM A681 (typical mill range, weight %):
| Element | Symbol | Composition (%) |
|---|---|---|
| Carbon | C | 0.45 - 0.55 |
| Silicon | Si | 0.20 - 1.00 |
| Manganese | Mn | 0.20 - 0.90 |
| Chromium | Cr | 3.00 - 3.50 |
| Molybdenum | Mo | 1.30 - 1.80 |
| Vanadium | V | 0.20 - 0.30 |
| Phosphorus | P | 0.030 max |
| Sulphur | S | 0.030 max |
| Iron | Fe | Balance |
Mechanical Properties of Grade S7
Typical values; supplied soft-annealed and hardened by the customer or on request:
| Property | Typical Value |
|---|---|
| Supply hardness (annealed) | ≤229 HB (typ. 192-212 HB) |
| Hardness (hardened & tempered) | 54 - 58 HRC (usable up to ~60-61 HRC) |
| Impact Toughness | Excellent — among the highest of all cold work tool steels |
| Wear Resistance | Good |
| Hardenability | Excellent (highest of the S-series, deep-hardening in air) |
| Dimensional Stability | Excellent, aided by air-hardening response |
| Softening Resistance | Good at moderately elevated temperature |
| Modulus of Elasticity (E) | ~200-210 GPa |
Values are typical and vary with section size, tempering temperature and mill batch. Mill test certificates (EN 10204 2.2 / 3.1) are available on request.
Physical & Thermal Properties
| Property | Value |
|---|---|
| Density | ~7.76-7.80 g/cm³ |
| Thermal Conductivity (room temp.) | ~22-25 W/(m·K) |
| Coefficient of Thermal Expansion (20-200°C) | ~11-12 × 10-6 /K |
| Specific Heat Capacity | ~460 J/(kg·K) |
| Modulus of Elasticity | ~200-210 GPa |
Equivalent International Grades
| Country / Standard | Designation |
|---|---|
| USA (AISI / SAE, ASTM A681) | S7 |
| USA (UNS) | T41907 |
| Europe (closest, not identical) | 1.2542 / 45WCrV7 |
S7 has no exact DIN/Werkstoffnummer equivalent — refer to the comparison table above before substituting grades.
Heat Treatment Guidelines
| Process | Guideline |
|---|---|
| Supply condition | Soft-annealed, ≤229 HB — ready to machine before hardening |
| Preheating | Two-stage: approx. 500-600°C, then 800-850°C before quenching |
| Hardening (austenitizing) | 940-1010°C, hold 30-60 min depending on section size |
| Quenching | Air cool for sections up to approx. 65 mm; oil quench for heavier sections |
| Tempering | 425-650°C for 2-3 hrs; approx. 400°F (~205°C) for ~57-58 HRC, 600°F (~315°C) for ~55-56 HRC, 1000°F (~540°C) for ~50-52 HRC |
| Resulting hardness range | Approx. 48-61 HRC depending on tempering temperature; working range typically 54-58 HRC |
Available Forms & Sizes
- Round Bars
- Flat Bars
- Custom sizes cut to drawing via in-house bandsaw cutting
Material is machined, ground, drilled and finished in-house through our precision machining, grinding, drilling, gun drilling, EDM and wire-cut facilities.
Machining & Selection Notes
- Machinability: S7 machines readily in the annealed condition with standard HSS or carbide tooling.
- Air-hardening advantage: Because S7 hardens in air, complex or precision components hold their dimensions well through heat treatment, reducing the need for post-hardening grinding.
- Tempering for application: Lower tempering temperatures give higher hardness and wear resistance; higher tempering temperatures trade some hardness for maximum toughness under heavy shock.
- Welding / repair: Limited weldability; preheat and stress-relieve after any weld repair.
- Grade selection: Choose S7 for larger punches, dies and precision tooling under heavy shock where minimal heat-treatment distortion matters; choose S1 for smaller hand and pneumatic impact tools, or A2 where wear resistance is more important than maximum shock resistance — see the comparison table above.
Applications of Grade S7 Steel
S7's exceptional combination of toughness, hardness and dimensional stability makes it a preferred choice across forging, automotive, construction and heavy manufacturing industries.
- Punches, dies and stamping tools
- Air chisels and pneumatic tool components
- Cold-work tools exposed to heavy shock
- Shear blades for high-impact cutting
- Jackhammer bits
- Riveting and punching tools
- Forming dies
- Hammers and impact tools
Punches, Dies & Forming Tools
S7's high hardenability and shock resistance make it a strong choice for punches, blanking dies and forming tools that must survive continuous impact without chipping or cracking.
Construction & Heavy Equipment Tools
Jackhammer bits, breaker points and similar tools benefit from S7's ability to withstand repeated heavy blows while resisting brittle failure.
Industries We Serve
- Forging industry
- Tool room industry
- Automotive industry
- Construction & heavy equipment manufacturing
- Die & mould manufacturing
- General engineering & industrial manufacturing
Authorized Stockist
Grade S7 Supply Locations Across India
We supply Grade S7 steel across major industrial cities including Mumbai, Pune, Khopoli, Nashik, Aurangabad, Navi Mumbai, Palghar, Umbergaon, Vapi, Valsad, Daman, Vadodara, Ahmedabad, Rajkot, Hyderabad, Bangalore, Chennai, Cochin, Delhi, Gurgaon, Manesar and Sonipat — as well as to export markets.
Our Steel Products
Our Services
Frequently Asked Questions
About Purohit Steel
Purohit Steel was established in 1965 by Shree Bherumalji Rajpurohit, a visionary in metallurgy. Over the decades, we have built a strong reputation as a trusted stockist and exporter of tool steel, plastic mould steel and engineering steel products across India.
As an ISO-certified company, we source premium materials from globally reputed manufacturers and operate a modern warehousing facility in Vasai along with a sales outlet in Mumbai, enabling efficient storage, fast processing and timely delivery across India and export markets.
With decades of relationships with tool & die manufacturers and a customer-focused approach, Purohit Steel continues to deliver reliable, technically supported steel solutions for the tooling industry.
Read more about Purohit Steel, view our certifications, or get in touch with our technical sales team.
Our Certifications
Purohit Steel operates as an ISO-certified company, backed by documented quality management, safety and compliance certifications that support reliable supply to domestic and export customers.
View all certificates in detail on our Certifications page.
Countries We Export Worldwide
Beyond India, Purohit Steel exports tool & mould steel grades to customers across the following countries and regions:
| Export Destinations | |||||
|---|---|---|---|---|---|
| UAE | Saudi Arabia | Oman | Bangladesh | Sri Lanka | Nepal |
| Vietnam | Thailand | Indonesia | Kenya | Nigeria | South Africa |
For export enquiries and destination-specific documentation, please contact our sales team.
Export Packaging & Shipping
Bars, flats and blocks are packed to withstand handling, transit and marine shipment, whether for domestic dispatch or export orders.
- Palletised and strapped packing for round bars, flat bars and blocks
- Moisture-protected wrapping to prevent surface corrosion in transit
- Seaworthy export packing with clear shipping marks and material identification
- Documentation support including packing lists, invoices and mill test certificates for customs clearance
- Shipment by road, rail or sea freight as per order requirement and destination
Quality Inspection & Testing
Every batch held in our stock is checked through documented inspection procedures before dispatch, so mould makers and OEMs receive material with verified, traceable quality.
- Chemical composition verification against mill certificates
- Hardness testing (Brinell / Rockwell) on received stock
- Dimensional inspection as per standard bar and block tolerances
- Visual and surface defect inspection
- EN 10204 2.2 / 3.1 mill test certificates provided on request
- Third-party inspection coordination available for export orders
Full material traceability is maintained from incoming stock through to dispatch for every order.
Latest Price List
Pricing depends on section size, quantity, form (round bar / flat bar / block) and current raw material rates. Indicative guidance is below — contact us for a firm, up-to-date quotation.
| Form | Typical Price Basis |
|---|---|
| Round Bar | Per Kg, based on diameter & length — contact for latest rate |
| Flat Bar / Plate | Per Kg, based on thickness & size — contact for latest rate |
| Block (cut to size) | Per Kg / Per Piece, based on drawing — contact for latest rate |
Prices are subject to change with raw material and freight costs. Share your required size and quantity via the quotation form or WhatsApp for the latest price.
MOQ & Payment Terms
Minimum Order Quantity: Flexible MOQ depending on size and form — from small trial quantities for tooling houses up to bulk orders for OEMs, subject to confirmation at enquiry stage.
Payment Terms: Advance payment / part-advance with balance before dispatch for domestic orders; T/T (bank transfer) or Letter of Credit (LC) for export orders, depending on order value and destination.