NM400
NM400 and NM500 are both high-performance wear resistant steel plates within the NM series.
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NM400 provides excellent balance between wear resistance, toughness, and workability.
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NM500 offers significantly higher hardness and abrasion strength for demanding environments.
Material selection should be based on abrasion severity, impact load, fabrication requirements, and expected service life to ensure optimal performance and cost efficiency.
- Description
NM400 is a high-strength abrasion resistant steel plate widely used in mining, construction, cement, and heavy machinery industries. It is produced through quenching and tempering processes to obtain a martensitic microstructure, providing a balanced combination of hardness, toughness, and weldability.
NM500 belongs to the same wear resistant steel series but offers higher hardness and stronger abrasion resistance. Below is a detailed comparison between NM400 and NM500 in terms of chemical composition and wear strength.
1. Chemical Composition Comparison (Typical Range, %)
The exact composition varies slightly depending on thickness and production process, but the typical ranges are:
| Element | NM400 (%) | NM500 (%) | Function in Steel |
|---|---|---|---|
| Carbon (C) | 0.17–0.24 | 0.20–0.28 | Increases hardness and strength |
| Manganese (Mn) | 0.70–1.60 | 0.70–1.60 | Improves hardenability and toughness |
| Silicon (Si) | ≤0.50 | ≤0.50 | Strengthens matrix |
| Chromium (Cr) | 0.30–1.00 | 0.40–1.20 | Enhances wear resistance |
| Nickel (Ni) | ≤1.00 | ≤1.00 | Improves impact toughness |
| Molybdenum (Mo) | ≤0.50 | ≤0.70 | Increases hardenability |
| Boron (B) | Trace | Trace | Significantly improves hardenability |
Key Composition Differences:
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NM500 generally has slightly higher carbon and alloy content.
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Higher alloying improves hardenability and final hardness.
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Both grades maintain low impurity levels for better toughness and weldability.
2. Hardness and Wear Resistance Comparison
Hardness is the primary indicator of abrasion resistance.
| Property | NM400 | NM500 |
|---|---|---|
| Brinell Hardness (HBW) | 370–430 | 470–540 |
| Yield Strength (MPa, approx.) | ≥1000 | ≥1250 |
| Tensile Strength (MPa, approx.) | 1200–1600 | 1400–1800 |
| Impact Toughness | Good | Moderate to good |
| Relative Wear Resistance | 1.0 (baseline) | ~1.2–1.5 times NM400 |
Wear Strength Comparison
NM500 offers approximately 20–50% higher abrasion resistance than NM400 under similar working conditions.
This improvement comes from:
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Higher hardness
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More stable martensitic structure
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Improved alloy hardenability
However, higher hardness slightly reduces ductility and increases forming difficulty compared to NM400.
3. Application Comparison
NM400 – Balanced Performance
Suitable for:
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Loader buckets
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Dump truck bodies
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Conveyor liners
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Hoppers
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Moderate impact + abrasion environments
Advantages:
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Good weldability
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Easier bending and processing
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Cost-effective solution
NM500 – Severe Abrasion Environments
Suitable for:
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Crusher liners
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Mining wear plates
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High-wear chutes
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Heavy-duty earthmoving equipment
Advantages:
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Longer service life in sliding abrasion
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Reduced replacement frequency
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Better performance in high-wear conditions
4. Processing Considerations
| Factor | NM400 | NM500 |
|---|---|---|
| Cutting | Easier | Requires more power |
| Bending | Good formability | Limited bending radius required |
| Welding | Standard preheat control | Stricter preheat recommended |
| Machining | Moderate difficulty | Higher tool wear |
NM400 is more fabrication-friendly, while NM500 prioritizes maximum wear resistance.
5. Selection Guidelines
Choose NM400 when:
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Balanced wear and toughness are required
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Forming and welding are important
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Moderate abrasion dominates
Choose NM500 when:
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Severe sliding abrasion is the main wear mechanism
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Longer service life is critical
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Fabrication complexity is acceptable
