1. Confirm the Exact Steel Designation
Do not rely only on a generic family name or assumed equivalence. Confirm the supplier designation, specification, supply condition and any customer-controlled material requirement before release.
CNC Machining & Injection Molding — DFM/Moldflow Support, CMM Inspection, Prototype to Production Solutions.
Mold Steel Quick Reference
Use this chart to compare common injection mold steels side by side, including P20, 718, NAK80, H13, S7 and stainless mold-steel routes. The table is intended as a quick engineering reference for hardness route, wear resistance, corrosion behavior, polishability, typical use and key limitations.
Chart Usage
Use the chart as a quick comparison reference before RFQ review, steel purchase or tooling specification release. Start with the actual supplier grade and project conditions, then compare the relevant hardness route, wear behavior, corrosion resistance, polishability and known limitations.
Do not rely only on a generic family name or assumed equivalence. Confirm the supplier designation, specification, supply condition and any customer-controlled material requirement before release.
Distinguish pre-hardened supply conditions from steels that require later heat treatment. Final hardness should follow the approved material, component function and project specification rather than a universal chart value.
Use the wear, corrosion and polishability columns to identify which steel families deserve closer review. A single chart rating should not be treated as the complete reason for choosing a grade.
The limitation column is as important as the typical-use column. Repairability, finish requirements, local wear, corrosion exposure and supplier-specific conditions can change the final decision.
Reading the Chart
The chart below compares common mold steels across several engineering characteristics. Use the ratings as relative screening references, then verify the exact supplier grade, condition and project requirements before releasing a final steel specification.
Check whether the steel is normally supplied in a pre-hardened condition or requires a later hardening route. The chart may show a typical reference range, but the final hardness should follow the actual grade, heat treatment and approved component requirement.
Use the wear column to compare relative suitability where abrasion, repeated contact or localized tooling wear may matter. Wear should still be evaluated together with resin reinforcement, feature geometry and the location of the exposed mold component.
Review corrosion behavior when the resin, additives, moisture, process environment or maintenance conditions can expose tooling surfaces to corrosive attack. A higher chart rating does not replace grade-specific corrosion data.
Use this column to screen steels for cosmetic or high-polish surfaces. Final polish capability also depends on steel cleanliness, supplier quality, heat treatment, machining history, repair areas and the required surface specification.
Read the limitation column before treating any grade as a default. Toughness, weld-repair behavior, local impact loading, dimensional stability and maintenance strategy can change whether a steel is appropriate for a specific mold component.
Main Comparison Matrix
Compare common mold steels by supply and hardness route, relative wear behavior, corrosion resistance, polishability, typical review use and key limitations. These values are screening references; the exact supplier grade and approved condition remain the controlling specification.
| Steel / Designation | Typical Supply / Hardness Route | Typical Hardness Reference | Wear | Corrosion | Polishability | Typical Review Use | Key Limitation |
|---|---|---|---|---|---|---|---|
| P20 / 1.2311 Common pre-hardened mold-steel route | Usually supplied pre-hardened; additional hardening is not normally the primary route for general mold use. | Common supplier conditions are often around the upper-20s to low-30s HRC; verify the purchased grade. | Moderate for general, lower-abrasion molding conditions. | Low relative to stainless mold-steel routes. | General-purpose ; actual finish capability depends on steel cleanliness and supplier quality. | General cavity, core or mold-component review where severe wear, corrosion or premium polish is not the dominant requirement. | Not a default choice for strongly abrasive, corrosion-sensitive or demanding mirror-polish conditions. |
| 718 / 1.2738-type P20-family pre-hardened mold steel with improved through-section use | Generally supplied pre-hardened and commonly reviewed for larger mold sections where hardness uniformity matters. | Often supplied in the low-to-mid 30 HRC range; actual condition is supplier and grade dependent. | Moderate for general mold service. | Low compared with stainless mold steels. | Good general polishability when the grade and material quality are suitable. | Larger cavity or core blocks and general-purpose molds where a pre-hardened route and through-section consistency are useful. | Abrasive fillers, corrosion-sensitive resins and demanding optical polish may require a different steel route. |
| NAK80 Pre-hardened precipitation-hardening mold steel | Supplied pre-hardened; normally used without a conventional final through-hardening step. | Common supplier conditions are typically around the upper-30s to low-40s HRC; verify the exact supplier datasheet. | Moderate ; not normally treated as the primary severe-abrasion route. | Moderate-to-low ; it is not a stainless substitute. | Strong for polished and cosmetic mold surfaces when material and finishing controls are appropriate. | Cosmetic cavities, polished surfaces and applications where a stable pre-hardened machining route is useful. | Severe abrasion, aggressive corrosion exposure or impact-loaded tooling may justify another steel family. |
| H13 / 1.2344 Hot-work tool steel | Normally machined in a softer condition and subsequently hardened and tempered to the approved component requirement. | Mold applications commonly use hardened conditions around the high-40s to low-50s HRC, subject to supplier and heat-treatment specification. | High relative to common pre-hardened mold-steel routes. | Moderate-to-low ; not a stainless corrosion-control solution. | Good , but premium cosmetic or optical requirements need grade-specific review. | Wear-sensitive inserts, gates, shut-offs and selected tooling components where higher hardness and wear resistance are required. | Heat-treatment distortion, EDM condition, toughness and repair strategy must be controlled for the actual component. |
| S7 Shock-resistant tool steel | Usually hardened and tempered after machining according to the component's impact and toughness requirement. | Final hardness varies with toughness requirements and heat-treatment route; use the approved supplier and component specification. | Good where impact resistance and edge toughness matter. | Low relative to stainless tooling routes. | Functional rather than a default premium mirror-polish choice. | Impact-loaded inserts, shut-offs and tooling features where toughness or resistance to chipping is a dominant concern. | Not the natural first choice when corrosion resistance or premium polishability dominates the requirement. |
| 420-type / 1.2083 Martensitic stainless mold-steel route; verify exact equivalence | Generally hardened and tempered after machining; exact treatment depends on the selected grade and required component condition. | Common mold applications use hardened conditions in the upper-40s to low-50s HRC range, depending on grade and treatment. | Moderate-to-high depending on grade and hardness condition. | High compared with common non-stainless mold steels. | Strong for polished or corrosion-sensitive cavity surfaces when the steel quality supports the required finish. | Corrosion-sensitive tooling, polished cavity surfaces and projects where stainless mold-steel behavior is an important review factor. | Actual polishability, corrosion resistance and repair behavior vary by grade, metallurgy and treatment; do not treat all 420-type grades as identical. |
| 1.2316 Corrosion-resistant chromium-moly mold steel | Supplied or heat treated according to the selected commercial grade and final mold-component requirement. | Hardness condition varies materially by supplier route and end use; confirm the purchased specification rather than applying a universal value. | Moderate to grade-dependent. | High relative to common non-stainless pre-hardened steels. | Good where corrosion resistance and controlled cavity finish are both important. | Corrosion-sensitive mold components and applications where a corrosion-resistant mold-steel route is required. | Do not automatically treat 1.2316 as interchangeable with AISI 420 or 1.2083; chemistry, condition and supplier specification must be verified. |
On mobile, swipe horizontally to compare all steel properties.
Application Screening
Use this matrix to identify which steel route deserves closer review for a given project condition. It is intentionally a screening tool—not a rule that assigns one steel grade automatically to each resin, mold type or component.
| Project Condition | Steel Route to Review | Why It Deserves Review | What Still Needs Verification |
|---|---|---|---|
| General molding with lower abrasion and limited corrosion exposure | Pre-hardened general-purpose mold-steel route | Can simplify machining and tool construction where severe wear, corrosion or premium surface demands are not dominant. | Verify supplier grade, required finish, local component loading, lifecycle expectation and any customer-controlled material callout. |
| Glass-, mineral- or carbon-fiber reinforced resin with abrasive exposure | Hardened or localized wear-resistant route | Reinforcement can increase local abrasion at gates, flow restrictions, shut-offs and other concentrated wear regions. | Confirm the actual wear zone, filler formulation, geometry and whether local hardened or replaceable tooling is more practical than upgrading the entire mold. |
| Corrosion-sensitive resin, additive or tooling environment | Corrosion-resistant stainless mold-steel route | Corrosion resistance may become more important where resin chemistry, decomposition products, moisture or maintenance conditions attack exposed tooling surfaces. | Verify the exact resin grade, supplier steel chemistry, required hardness condition, polish demand and maintenance environment. |
| High-polish, transparent or appearance-critical cavity surface | Polish-grade or high-cleanliness mold-steel route | Metallurgical cleanliness, polishing response and surface stability become more important where cosmetic approval or optical appearance is critical. | Verify steel quality, supplier route, heat treatment, repair history, machining condition and the actual required surface specification. |
| Impact-loaded shut-off, insert or mechanically stressed tooling feature | Toughness-focused tool-steel route | Chipping resistance and toughness may matter more than maximum hardness where repeated impact, edge loading or mechanical shock is present. | Confirm geometry, contact condition, heat-treatment route, hardness target, support condition and repair strategy. |
| Sliding or repeatedly contacting mold interface | Compatible wear-pair and surface-engineering route | Galling, scoring and seizure depend on more than one steel grade; hardness pairing, surface condition, lubrication and clearance also matter. | Verify both contacting materials, surface treatment, lubrication, load, motion, clearance and maintenance approach. |
On mobile, swipe horizontally to review all application columns.
Resin Risk Cross-Check
Resin family alone should not assign the mold steel grade, but it can reveal which tooling risks deserve closer review. Use this section to cross-check abrasion, corrosion, surface demand and resin-specific processing exposure before a steel reference becomes a final project specification.
Resin Check 01
Glass, mineral and carbon-fiber reinforcement can increase abrasive tooling exposure, especially around gates, restrictions, shut-offs and other localized high-flow features.
Resin Check 02
Some resin systems, additives or decomposition products can increase corrosion risk under particular processing, venting, moisture and maintenance conditions.
Resin Check 03
Clear or appearance-critical molded parts place more emphasis on steel cleanliness, surface condition, polishing response and stability after machining or repair.
Resin Check 04
High-temperature or demanding polymers can change the tooling environment, but processing temperature alone should not be converted into an automatic mold-steel grade rule.
| Resin / Program Condition | Main Tooling Risk to Review | Chart Property to Recheck | What Still Needs Verification |
|---|---|---|---|
| Unfilled general-purpose resin | General tooling suitability, surface requirement and lifecycle fit | Hardness route, polishability and key limitations | Confirm the exact commercial grade, geometry, finish requirement and whether local wear or corrosion conditions are actually absent. |
| Glass-, mineral- or carbon-fiber reinforced resin | Localized abrasion at gates, flow restrictions, shut-offs and selected cavity or core features | Wear resistance and local tooling strategy | Verify filler type, loading, flow path, wear-zone location and whether replaceable or localized hardened tooling is required. |
| Corrosion-sensitive resin or additive system | Corrosion at exposed cavity surfaces, vents, inserts or other affected mold regions | Corrosion resistance, hardness route and limitation notes | Verify the exact resin formulation, processing environment, supplier steel grade and maintenance requirement. |
| Transparent, glossy or appearance-critical resin program | Surface defects, polish stability and visible repair sensitivity | Polishability and material-quality notes | Confirm the actual surface specification, steel cleanliness, supplier route, machining history and repair condition. |
| High-temperature or high-performance polymer | Combined thermal, wear, corrosion and processing exposure | Full chart comparison rather than one-property selection | Verify the exact supplier resin grade and separate temperature requirement from abrasion, corrosion, surface and component-duty risks. |
On mobile, swipe horizontally to review all resin-risk columns.
Engineering Boundary
Use the chart to compare steel routes and identify where further review is needed. Do not treat the chart as a final tool-life, component-design or material-release decision.
Component-Level Cross-Check
The main comparison chart describes steel families, but mold components operate under different local conditions. Recheck the chart by component duty before applying one mold-wide material callout.
| Mold Area | Main Local Duty | Chart Property to Recheck | Risk of One Mold-Wide Callout |
|---|---|---|---|
| Cavity / Core | Surface quality, resin exposure and dimensional support | Wear, corrosion, polishability and hardness route | Local inserts or surface-critical regions may need different requirements. |
| Gate / Shut-Off / Local Insert | Concentrated abrasion, sealing contact and replaceability | Wear resistance, toughness and limitation notes | A general cavity material may not address a localized wear or service-critical zone. |
| Slide / Lifter / Moving Pair | Sliding contact, friction, impact and repeated motion | Toughness, hardness route and service condition | Material alone does not resolve galling, clearance or lubrication requirements. |
| Ejector System | Repeated sliding, clearance retention and molded-part contact | Wear, surface condition and maintenance needs | Ejection components should not automatically inherit the cavity specification. |
| Mold Base / Structural Plate | Support, rigidity, flatness and dimensional stability | Supply condition and structural suitability | Cavity-grade material can add cost without solving the actual structural requirement. |
On mobile, swipe horizontally to review all component-level columns.
Release & Supplier Verification
A comparison chart can narrow the steel route, but the final purchase decision still requires the exact grade, material condition, component scope, project-specific requirements and supporting evidence to be confirmed before the tooling specification is released.
Confirm the supplier designation, material standard and approved commercial grade rather than relying on assumed equivalence.
Record the supplied condition and whether later heat treatment or another approved final condition is required.
Identify exactly which cavity, core, insert, slide or other mold component the callout applies to.
Define relevant resin, wear, corrosion, surface, treatment and repair requirements separately from the base steel name.
Confirm which material certificate, treatment record or customer approval is required before release.
| Verification Field | What to Record or Confirm | Release Question | Risk if Unclear |
|---|---|---|---|
| Steel Grade | Exact supplier grade, applicable standard and approved commercial designation | Does the material being purchased match the steel route actually reviewed? | Similar steel families may be treated as equivalent when they are not. |
| Supply / Hardness Condition | Pre-hardened, annealed or other supplied condition, plus any required later treatment | Is the delivered condition compatible with machining and the approved final component requirement? | Supplier and buyer may interpret the same steel designation differently. |
| Component Scope | Drawing, BOM or mold specification identifying where the callout applies | Is it clear which mold components use this material and which do not? | One mold-wide callout may be copied to components with different local duty. |
| Additional Requirements | Resin and filler context, surface target, treatment, repair restriction or replacement requirement | Have project-specific requirements been documented separately from the steel name? | The base steel may be correct while the actual tooling condition remains undefined. |
| Evidence / Approval | Material certificate, project-required treatment record or agreed customer approval | Is the required evidence defined before steel purchase and machining? | Verification may be requested too late to resolve a material or treatment mismatch efficiently. |
On mobile, swipe horizontally to review all release and verification fields.
Downloadable Reference
Keep a compact comparison reference for RFQ review, supplier discussion and mold-specification checks without reopening the full technical guide.
Quick Reference FAQ
Short answers to common questions about using mold-steel comparison data during RFQ, specification and supplier review.
An injection mold steel selection chart is a comparison and screening reference. It helps engineers compare steel families by supply condition, hardness route, relative wear resistance, corrosion resistance, polishability, typical use and key limitations before moving to a project-specific material specification.
No. Hardness ranges in a comparison chart should be treated as typical engineering references. The final requirement depends on the exact supplier grade, supply condition, heat-treatment route, component geometry and approved project specification.
P20- and 718-type steels are commonly associated with pre-hardened general-purpose tooling routes. H13 is a hardenable tool-steel route often reviewed where higher wear or local tooling duty matters. Stainless mold-steel routes place more emphasis on corrosion resistance and, depending on grade quality, polished cavity requirements. The final grade still depends on the actual project conditions.
They should not be treated as automatically interchangeable. AISI 420-type steels, DIN 1.2083 and DIN 1.2316 can all appear in corrosion-resistant mold-steel discussions, but their chemistry, supplier variants, supply condition, hardness response and polishability can differ. Verify the actual supplier specification before using any cross-reference as a purchase callout.
Sometimes a common baseline material is practical, but it should not be assumed automatically. Cavities, local inserts, gates, shut-offs, moving interfaces, ejector components and structural plates can have different wear, corrosion, polish, toughness and service requirements.
No. A higher-hardness or more expensive steel can still be a poor fit if the dominant requirement is different. Mold performance also depends on component duty, heat treatment, geometry, surface condition, corrosion exposure, repair strategy and maintenance. The chart should therefore be used to compare trade-offs rather than rank steels from “best” to “worst.”
Project-Specific Review
If the comparison chart does not fully resolve your project, send the CAD or 2D drawing, resin grade and key tooling requirements. We can review the steel direction together with the relevant wear, corrosion, surface and component-duty risks before tooling release.
Request a DFM & Mold Steel Review
Use the review to clarify unresolved steel-route questions before RFQ alignment, mold specification release or steel purchase.
Request Free DFM Review →Review scope: project-specific recommendations depend on the supplied drawing, resin information, tool design and agreed requirements. The comparison chart itself remains a reference tool rather than a final material release.