Choosing the right tool steel for mould making is a trade-off between hardness, polishability, machinability and corrosion resistance — and no single grade wins on all four at once. Purohit Steel stocks the full range of mould-making steel used across Indian tool rooms, from general-purpose P20 to corrosion-resistant stainless mould steels, so mould makers can match the grade to the job rather than the job to whatever grade happens to be on the shelf.
This guide explains what actually matters when selecting mould-making tool steel and gives a straight decision table mapping mould type to the recommended Purohit Steel grade, with links through to full technical data on each grade page.
Table of Contents
- 1. What Matters When Choosing Mould-Making Steel
- 2. Why Purohit Steel for Mould-Making Tool Steel
- 3. Which Grade Should You Choose
- 4. Hardness & Hardenability
- 5. Polishability & Surface Finish
- 6. Corrosion Resistance by Plastic Type
- 7. Machinability & Lead Time
- 8. Beyond Plastic Moulds
- 9. Applications & Industries
- 10. Related Products
- 11. Authorized Stockist Brands
- 12. Cities We Supply in India
- 13. Our Services
- 14. Frequently Asked Questions
- 15. 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 Matters When Choosing Mould-Making Tool Steel
Mould-making tool steel has to satisfy four requirements at once, and the relative weight of each depends on the mould, the plastic and the production run:
- Hardness & hardenability: The cavity must resist wear from repeated injection cycles, and large blocks need that hardness to stay uniform from surface to core, not just on the outer skin.
- Polishability: Cosmetic and optical parts need a mirror or near-mirror cavity finish, which depends on a clean, inclusion-free microstructure — ESR-refined grades polish more consistently than conventionally melted steel.
- Machinability: Pre-hardened steels let mould makers machine cavities directly without a separate heat-treatment cycle, shortening lead time and avoiding hardening distortion on finished cavities.
- Thermal & corrosion resistance: Some resins (PVC, flame-retardant grades, certain engineering plastics) release corrosive by-products during moulding; water-cooled tooling and humid plant environments add further corrosion risk that a base Cr-Mn-Mo steel is not designed to resist.
Getting this balance wrong shows up later as short mould life, poor surface finish, rust pitting in cooling channels, or unnecessary tooling cost from over-specifying a stainless grade where a standard P20 would do.
Why Purohit Steel for Mould-Making Tool Steel
- Full Range, One Supplier: General-purpose, deep-hardening and corrosion-resistant mould steel grades all stocked under one roof
- Ready Stock: Round bar, flat bar and block 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: Grade-selection guidance based on mould size, plastic type and finish requirement
- Pan-India & Export Supply: Warehousing in Vasai with a sales outlet in Mumbai, serving customers across India and international markets
Which Grade Should You Choose — Mould Type to Recommended Grade
Use the table below as a starting point, then confirm against the specific plastic and part requirements on each grade's full technical page.
| Mould Type / Requirement | Recommended Grade | Why This Grade |
|---|---|---|
| General-purpose injection & blow moulds, small-medium runs | 1.2311 (P20) | Pre-hardened 280-325 HB, good machinability, lowest cost of the mould steel range |
| Large mould blocks needing deep, uniform core hardness | 1.2738 (P20+Ni) | Nickel addition gives excellent hardenability through thick sections |
| Water-cooled tooling, humid plant environment, moderate corrosion risk | 1.2085 | 15-17% Cr martensitic stainless, pre-hardened 280-325 HB |
| High-gloss, transparent, food-contact or medical moulds | 1.2083 ESR | ESR-refined ~13% Cr stainless-type steel, cleanest microstructure, best polish and corrosion resistance |
| Large blocks needing uniform surface finish / texture through thick section (up to 700mm) | VR300 | Cr-Mn-Mo-Ni grade engineered for uniform hardness distribution through heavy sections |
| PVC or other corrosive-resin moulds, household appliance moulds | VR16 | Stainless martensitic Cr-Mo (~14% Cr), corrosion resistant, pre-hardened |
This is a general guide, not a substitute for reviewing the full chemical composition and mechanical property data on each grade page before finalising a specification.
Hardness & Hardenability
Every grade Purohit Steel stocks for mould making — 1.2311, 1.2738, 1.2085, 1.2083 ESR, VR300 and VR16 — is supplied pre-hardened (quenched and tempered) at roughly 280-330 HB, so the mould base or cavity block can be machined directly without a separate hardening cycle. The difference between grades is how uniformly that hardness holds through the section: base 1.2311 is suited to small and medium sections, 1.2738 adds nickel for deeper hardenability in larger blocks, and VR300 is specifically engineered for uniform hardness through sections up to 700mm.
For localised wear resistance on cavity and core surfaces, 1.2311 and 1.2738 both respond well to gas or plasma nitriding, raising surface hardness to roughly 55-60 HRC while keeping the core tough.
Polishability & Surface Finish
Cosmetic, optical and transparent-part moulds demand a clean, inclusion-free microstructure that polishes to a consistent, defect-free finish. This is where ESR (Electro-Slag Remelting) refining matters: the process removes non-metallic inclusions and produces a more homogeneous structure than conventionally melted steel, which is why 1.2083 ESR is the preferred choice for high-gloss and transparent plastic moulds. Standard 1.2311 and 1.2738 take a good working polish and are perfectly adequate for functional and textured parts where mirror-grade finish is not required.
Corrosion Resistance by Plastic Type
Base Cr-Mn-Mo mould steels such as 1.2311 and 1.2738 have low inherent corrosion resistance. This is fine for benign commodity resins (PP, PE, ABS, PS) processed in a dry environment, but becomes a real risk with:
- PVC and other halogenated resins, which can release corrosive by-products (such as HCl) during processing that attack unprotected tool steel surfaces over repeated cycles.
- Water-cooled mould systems, where cooling channels in a base steel are prone to rust and scale build-up over time.
- Food-contact, medical and cosmetic moulds, which are cleaned and sterilised frequently with chemicals that also attack unprotected steel.
For these situations, step up to a corrosion-resistant grade: 1.2085 (15-17% Cr) for moderate corrosion risk, VR16 (~14% Cr stainless martensitic) specifically for corrosive plastics such as PVC, or 1.2083 ESR where maximum corrosion resistance and polish are both required. For a resin-by-resin breakdown, see our dedicated guide to tool steel for plastic moulds.
Machinability & Lead Time
Because 1.2311, 1.2738, 1.2085, 1.2083 ESR, VR300 and VR16 all arrive pre-hardened, mould makers can rough and finish-machine cavities directly, without waiting on a heat-treatment cycle or managing the distortion risk that comes with post-machining hardening. This keeps project lead times predictable, which is often as important to a tool room as the steel's raw material cost.
Standard HSS or coated carbide tooling at moderate cutting speeds works well across this hardness range; adequate coolant is recommended to avoid locally tempering the pre-hardened surface during heavy cuts.
Beyond Plastic Moulds
While this guide is centred on plastic-mould tooling, some of the same pre-hardened grades — particularly 1.2311 — are also used for low-pressure die-casting dies, tooling plates and extrusion dies where moderate service temperature and a pre-hardened, machinable steel are acceptable. For moulds and dies that see sustained high temperature, thermal cycling or impact loading — gravity or pressure die casting, forging, and aluminium extrusion — a dedicated hot-work tool steel is the correct choice instead. See our guides to tool steel for die casting, tool steel for forging dies and tool steel for extrusion dies for H11 / H13 / H21 selection.
Applications & Industries
- Plastic injection mould cavities, cores and bases
- Blow moulds and compression moulding tools
- Automotive interior and exterior plastic component moulds
- Packaging, household and consumer product moulds
- Medical, cosmetic and food-contact packaging moulds
- Textured and high-gloss cosmetic-part cavities
- Mould bases, plates and general tooling components
Industries We Serve
- Plastic injection moulding industry
- Automotive industry
- Packaging manufacturing
- Consumer goods production
- Medical & pharmaceutical packaging
- Engineering & tooling workshops
Authorized Stockist
Mould-Making Tool Steel Supply Locations Across India
We supply mould-making 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.