Extrusion dies see a very different kind of stress compared to forging or die-casting tooling: instead of a sudden impact or a rapid injection shot, hot billet material is pushed continuously through the die orifice, holding the bearing surface at sustained elevated temperature for the length of each production run. Purohit Steel stocks the H11 and H13 hot-work tool steel grades used across Indian extrusion die shops for aluminium and brass extrusion tooling.
This guide focuses on the failure modes that matter most for extrusion dies — steady-state hot wear and thermal fatigue from cyclic billet loading — which is a different engineering problem from the shock-impact loading covered in our forging dies guide.
Table of Contents
- 1. Steady-State Wear vs Impact Shock
- 2. Thermal Fatigue from Cyclic Billet Loading
- 3. Hot-Hardness & Bearing-Surface Temperature
- 4. Which Grade Should You Choose
- 5. Why Purohit Steel for Extrusion Die Steel
- 6. Applications & Industries
- 7. Related Products
- 8. Authorized Stockist Brands
- 9. Cities We Supply in India
- 10. Our Services
- 11. Frequently Asked Questions
- 12. 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
Steady-State Wear vs Impact Shock
In forging, the die takes a sudden, discrete blow and then largely cools before the next stroke. In extrusion, by contrast, the die bearing surface stays in near-continuous contact with hot metal for the full length of the billet as it is pushed through the die orifice under sustained pressure. There is no single shock event to absorb — instead, the bearing surface is worked by constant sliding contact and abrasive friction at temperature, for minutes at a stretch, run after run.
This changes the priority order for grade selection: where forging die steel is chosen mainly for toughness against impact, extrusion die steel is chosen mainly for hot-wear resistance and dimensional stability of the bearing surface under sustained thermal and frictional load.
Thermal Fatigue from Cyclic Billet Loading
Although contact is continuous within a single extrusion run, the die still sees thermal cycling billet-to-billet: it heats up as each new billet is pushed through, then cools somewhat during die changes, handling and idle time between runs. Over thousands of cycles, this repeated heating and cooling opens fine surface cracks at the bearing edge — the same underlying thermal-fatigue mechanism seen in die casting and forging, but driven here by production cadence rather than by a single hammer blow or injection shot.
H13's documented thermal-fatigue resistance and dimensional stability through heat treatment is a large part of why it is the default choice for extrusion tooling worldwide, not just in die casting.
Hot-Hardness & Bearing-Surface Temperature
H11 and H13 both retain useful hardness and strength at service temperatures up to roughly 600-650°C, which comfortably covers standard aluminium extrusion, where billet and die temperatures typically run in the 400-500°C range. For extrusion work that runs the bearing surface consistently hotter — certain brass extrusion processes, high-speed aluminium lines, or mandrels and bridge-die components that see extended direct contact — H21's superior red-hardness above 650°C becomes relevant, provided its quench-sensitive heat treatment is managed carefully.
This is the opposite trade-off from forging: in forging, H21's lower toughness rules it out of most impact- loaded cavities; in extrusion, where impact is not the issue and sustained heat is, H21 earns a place in the grade line-up for the hottest-running tooling.
Which Grade Should You Choose
| Extrusion Duty | Recommended Grade | Why |
|---|---|---|
| General aluminium extrusion dies (most common) | H13 / 1.2344 | Best-proven hot-wear resistance and thermal-fatigue resistance for continuous elevated-temperature contact |
| Large die blocks / die holders needing extra toughness or deep hardenability | H11 / 1.2343 ESR | Very good toughness with excellent, even hardening through thick sections |
| Mandrels, bridge dies or brass extrusion running at sustained temperature above 650°C | H21 | Superior red-hardness for the hottest-running bearing surfaces; requires careful, controlled heat treatment |
H13 remains the default recommendation for the large majority of aluminium extrusion dies; H11 and H21 are selected for specific toughness or sustained-temperature requirements. Confirm final selection against the detailed data on each grade page.
Why Purohit Steel for Extrusion Die Steel
- Ready Stock: H11, H13 and H21 held in round bar, flat bar and block sizes 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 — including fine EDM work needed for extrusion die orifice profiles
- Technical Support: Grade-selection and heat-treatment guidance for extrusion tooling
- Pan-India & Export Supply: Warehousing in Vasai with a sales outlet in Mumbai
Applications & Industries
- Aluminium extrusion dies and die rings
- Brass and copper-alloy extrusion tooling
- Extrusion mandrels and bridge dies
- Extrusion die holders and backer plates
- Profile, tube and section extrusion tooling
Industries We Serve
- Aluminium extrusion industry
- Brass & non-ferrous extrusion industry
- Architectural & building products manufacturing
- Automotive component manufacturing
- Tool & die industry
Authorized Stockist
Extrusion Die Tool Steel Supply Locations Across India
We supply H11, H13 and H21 extrusion die tool 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.
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.