Mold Steel 2311 vs H13 vs 2344 — A Complete Comparison
Selecting the right mold steel is one of the most critical decisions in mold making. Use the wrong steel, and you risk premature wear, cracking, or poor surface finish — all of which translate to costly downtime and scrap.
This guide compares DIN 1.2311 (P20 modified), DIN 1.2344 (H13), and DIN 1.2343 (similar to H13) — three of the most widely used mold steels in injection molding, die casting, and hot stamping. We'll cover chemical composition, mechanical properties, heat treatment, pricing, and when to choose each.
The Three Steels at a Glance
| Property | 1.2311 (P20 Modified) | H13 (1.2344) | 1.2343 (Modified H13) |
|---|---|---|---|
| **Type** | Pre-hardened plastic mold steel | Hot work tool steel | Hot work tool steel |
| **Hardness (delivered)** | 28–32 HRC | 180–220 HB (annealed) | 180–220 HB (annealed) |
| **Max working hardness** | 32 HRC | 48–52 HRC | 48–52 HRC |
| **Toughness** | Good | Excellent | Excellent |
| **Wear resistance** | Moderate | High | High |
| **Polishing grade** | SPI A-2 (high gloss) | SPI B-1 (moderate) | SPI B-1 (moderate) |
| **Max service temp** | ~300°C (570°F) | ~600°C (1110°F) | ~600°C (1110°F) |
| **Typical price** | $ | $$$ | $$ |
| **Common applications** | Injection mold cores/cavities, automotive interior panels | Die casting dies, extrusion dies, hot forging | Die casting (aluminum), hot stamping |
Chemical Composition Comparison
The chemical makeup drives the performance differences:
| Element | 1.2311 (P20 mod) | H13 (1.2344) | 1.2343 (mod H13) |
|---|---|---|---|
| Carbon (C) | 0.35–0.45% | 0.32–0.45% | 0.35–0.42% |
| Chromium (Cr) | 1.80–2.20% | 4.75–5.50% | 4.80–5.50% |
| Molybdenum (Mo) | 0.15–0.25% | 1.10–1.50% | 1.20–1.60% |
| Vanadium (V) | — | 0.80–1.20% | 0.60–1.00% |
| Silicon (Si) | 0.20–0.40% | 0.80–1.20% | 0.30–0.60% |
| Manganese (Mn) | 1.30–1.60% | 0.20–0.50% | 0.20–0.50% |
| Sulfur (S) | ≤0.03% | ≤0.03% | ≤0.03% |
Key differences:
- **1.2311** has higher manganese (1.3-1.6%) for through-hardening at moderate hardness. Chromium at ~2% gives moderate wear resistance.
- **H13** has much higher chromium (5%), vanadium (1%), and molybdenum (1.5%) — the trio that gives it hot hardness and wear resistance at elevated temperatures.
- **1.2343** is similar to H13 but with slightly lower vanadium and silicon, making it slightly more cost-effective for less demanding hot work applications.
Physical Properties (Heat Treated to Working Hardness)
| Property | 1.2311 (30 HRC) | H13 (48 HRC) | 1.2343 (48 HRC) |
|---|---|---|---|
| **Tensile strength** | ~980 MPa (142 ksi) | ~1,450 MPa (210 ksi) | ~1,400 MPa (203 ksi) |
| **Yield strength** | ~830 MPa (120 ksi) | ~1,250 MPa (181 ksi) | ~1,200 MPa (174 ksi) |
| **Elongation** | 12–15% | 8–10% | 9–12% |
| **Impact toughness (Charpy V)** | 15–20 J | 25–35 J | 30–40 J |
| **Thermal conductivity** | ~29 W/m·K | ~25 W/m·K | ~26 W/m·K |
| **Density** | 7.85 g/cm³ | 7.80 g/cm³ | 7.80 g/cm³ |
> Note: 1.2311 has better elongation (ductility) at its working hardness, while H13 has superior impact toughness when properly heat treated.
Heat Treatment Parameters
1.2311 (Pre-hardened — no additional heat treatment needed)
1.2311 is typically delivered pre-hardened to 28–32 HRC. For most injection molding applications, no post-machining heat treatment is required.
If higher hardness is needed:
- **Austenitizing**: 840–870°C (1545–1600°F)
- **Quenching**: Oil or polymer
- **Tempering**: 540–650°C (1000–1200°F) to achieve 28–36 HRC
H13 (1.2344)
- **Preheating**: 650–700°C (1200–1290°F)
- **Austenitizing**: 1020–1050°C (1870–1920°F)
- **Quenching**: Air or oil — air cooling is preferred for complex geometries to avoid cracking
- **Tempering**: Two cycles at 540–600°C (1000–1110°F)
- **Typical hardness**: 48–52 HRC
1.2343
- Similar to H13 but with slightly broader tempering window
- **Austenitizing**: 1000–1040°C (1830–1900°F)
- **Tempering**: Two cycles at 540–580°C (1000–1075°F)
- **Typical hardness**: 46–50 HRC
> ⚠️ Important: Never skip double tempering for H13 or 1.2343. A single temper cycle leaves retained austenite that will cause premature failure under thermal cycling.
Polishing Performance
For visible parts (textured or high-gloss), polishing capability matters:
| Criteria | 1.2311 | H13 | 1.2343 |
|---|---|---|---|
| **Polishing grade achievable** | SPI A-2 (high gloss) | SPI B-1 (good) | SPI B-1 (good) |
| **Texture etching** | Excellent | Good | Good |
| **Photo-etching (chemical)** | Very good | Fair (high Cr resists) | Fair |
| **EDM surface integrity** | Good | Fair (recast layer risk) | Fair |
Real-world tip: For high-gloss automotive parts (e.g., headlamp lenses), 1.2311 is still the preferred choice due to its excellent polishing characteristics and P20-class inclusion cleanliness.
Application Selection Guide
Choose 1.2311 (P20 Modified) when...
✅ Injection molds for non-abrasive plastics: ABS, PP, PE, PS, PC/ABS blends — 1.2311 handles these beautifully at 28–32 HRC.
✅ Thin-wall parts: The good ductility of 1.2311 reduces cracking risk in delicate core details.
✅ High-gloss or textured finishes: Excellent polishing grade and texture etching compatibility.
✅ Medium production runs: 200,000–500,000 shots typical, up to 1M depending on plastic type.
✅ Cost-sensitive projects: 1.2311 is approximately 40–50% cheaper than H13 raw material.
❌ Not suitable for: — Abrasive plastics (glass-filled nylon, PBT-GF30) — High-temperature applications (300°C+) — Aluminum die casting (too soft)
Choose H13 (1.2344) when...
✅ Aluminum die casting dies: H13 is the industry standard for aluminum die casting molds. Its hot hardness resists thermal fatigue and heat checking.
✅ Extrusion dies: For aluminum and brass extrusion.
✅ Hot forging dies: Where mechanical shock at elevated temperature is a factor.
✅ High-cavity-pressure injection molds: For abrasive, glass-filled, or high-temperature engineering resins (PEEK, PEI, LCP).
✅ Long production runs: 1M+ shots in abrasive plastics.
❌ Not suitable for: — Low-budget projects where 1.2311 suffices — High-gloss optical parts (better to use 1.2311 or NAK80)
Choose 1.2343 when...
✅ Less demanding hot work: Lower-temperature die casting, or where budget is between 1.2311 and H13.
✅ Complex die casting cores: Better toughness than H13 in thin sections.
✅ Hot stamping dies: For steel stamping at controlled temperatures.
✅ Budget-conscious hot work: 1.2343 costs about 15–20% less than H13 but performs adequately for many hot work applications.
Price Comparison (2026 market estimate)
| Steel | Price per kg (USD) | Price relative to 1.2311 |
|---|---|---|
| 1.2311 (P20 mod) | $2.50–3.50 | 1x (baseline) |
| 1.2343 | $3.50–5.00 | 1.3–1.5x |
| H13 (1.2344) | $5.00–6.50 | 1.7–2.0x |
Block prices vary by size, surface finish requirements, and heat treatment included. Pre-hardened 1.2311 includes heat treatment cost in the material price. H13 requires additional heat treatment after machining.
Supplier Considerations
- **China (main source)**: 1.2311 widely available from 50+ mills. H13 quality varies — specify AISI H13 or NADCA #207 standard to ensure quality.
- **Europe**: ThyssenKrupp, Böhler, Stora — premium quality but 20–40% higher prices.
- **Japan/NAK**: Hitachi, Daido — NAK80 and HPM38 are direct competitors in the injection mold steel space.
- **LSS (LKM)**: Standard duty mold base steel (less consistent than 1.2311, around 26–30 HRC).
Decision Framework
Ask these three questions:
- **What is the mold's operating temperature?**
- < 300°C → 1.2311 is sufficient
- > 300°C or thermal cycling → H13 or 1.2343
- **What plastic material?**
- Non-abrasive (PP, PE, ABS, PC) → 1.2311
- Glass-filled, high-temperature (PA66-GF30, PEEK, LCP) → H13
- **What is the expected production volume?**
- < 500,000 shots → 1.2311
- 500K–1M+ shots → H13
- Die casting or extrusion → H13 or 1.2343
Quick Summary
| Your situation | Recommended steel | Why |
|---|---|---|
| Injection mold, ABS/PP parts, 300K shots | 1.2311 | Lowest cost, good polish, pre-hardened |
| Injection mold, glass-filled nylon, 800K shots | H13 | Wear resistance at the cavity surface |
| Aluminum die casting, any volume | H13 | Thermal fatigue resistance is mandatory |
| High-gloss automotive lens mold | 1.2311 | Superior polishing grade |
| Extrusion die, aluminum section | H13 | Hot hardness at 500°C+ |
| Budget die casting, low volume | 1.2343 | 20% cheaper than H13, still capable |
Frequently Asked Questions
Q: Can I use 1.2311 for die casting?
No. 1.2311 max service temperature is ~300°C. Die casting involves molten aluminum at 650–700°C. The steel will soften and heat-check within the first few shots.
Q: Is H13 the same as P20?
No. P20 (1.2311) is a pre-hardened plastic mold steel. H13 is a hot work tool steel designed for high-temperature applications. They differ significantly in chemistry, heat treatment, and application.
Q: Which steel is best for glass-filled plastic molds?
H13 (or coated H13) is the best choice. The glass fibers act as abrasives that wear down softer steels. H13's higher hardness and vanadium carbides resist this wear.
Q: Can I polish H13 to a mirror finish?
H13 can be polished to a high finish, but requires more effort than 1.2311. The higher hardness (48+ HRC vs 30 HRC) means longer polishing time. For extremely high-gloss parts, 1.2311 or NAK80 is preferred.
Q: What steel do most Chinese mold factories recommend?
For standard injection molds, 1.2311 (often called "P20 modified" or simply "718H"). For die casting and demanding applications, H13. LSS/LKM standard P20 is the budget option.
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This guide is based on industry experience and material supplier specifications. Actual properties vary by supplier, heat treatment, and specific alloy chemistry. Always confirm with your material supplier before making a final selection.
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