NM400 and Hardox 400 are both high-strength, abrasion-resistant steel plates with nominal hardness around 400 HBW, commonly used in heavy-duty and mining applications.
NM400
While they serve similar functions, there are key differences in standards, chemical composition, toughness, and cost, which can influence the choice for specific equipment and production environments.
Standard and Origin of NM400 and Hardox 40
| Steel Grade | Standard | Origin |
|---|---|---|
| NM400 | GB/T 24186 | China |
| Hardox 400 | EN 10 163 / SSAB | Sweden |
Hardness Comparison of NM400 and Hardox 40
| Steel Grade | Hardness (HBW) | Notes |
|---|---|---|
| NM400 | 360 – 440 | Typical Chinese range |
| Hardox 400 | 390 – 430 | Guaranteed by SSAB, tighter control |
Insight:
Both plates provide similar abrasion resistance, but Hardox 400 generally has a more consistent hardness range, verified by supplier certification.
Chemical Composition of NM400 and Hardox 40
| Element | NM400 (%) | Hardox 400 (%) |
|---|---|---|
| C (Carbon) | 0.12 – 0.20 | 0.27 (max) |
| Mn (Manganese) | 1.20 – 1.70 | 1.20 – 1.60 |
| Si (Silicon) | 0.80 – 1.20 | 0.70 – 1.00 |
| Cr (Chromium) | ≤ 0.30 | 0.30 (typical) |
| Ni (Nickel) | ≤ 0.30 | 0.30 (typical) |
| P (Phosphorus) | ≤ 0.025 | ≤ 0.025 |
| S (Sulfur) | ≤ 0.015 | ≤ 0.005 |
Mechanical Properties of NM400 and Hardox 40
| Property | NM400 | Hardox 400 |
|---|---|---|
| Hardness (HBW) | 360 – 440 | 390 – 430 |
| Yield Strength (MPa) | ≥ 400 | 1000 – 1250 (typical, EN 10 163) |
| Tensile Strength (MPa) | 950 – 1100 | 1200 – 1400 |
| Elongation (%) | ≥ 12 | 10 – 15 |
Hardox 400 tends to have higher tensile and yield strength, giving better impact and wear performance in extreme conditions.
NM400 is more weld-friendly and easier to process in domestic fabrication.
Applications Comparison of NM400 and Hardox 40
| Application | NM400 | Hardox 400 |
|---|---|---|
| Mining buckets & liners | ok | ok |
| Construction machinery | ok | ok |
| Crusher & conveyor parts | ok | ok |
| Dump truck beds / trailers | ok | ok |
| Extreme wear or abrasive environments | Moderate | Preferred |
Cost and Availability of NM400 and Hardox 40
NM400: Generally cheaper and widely available in China and Asia.
Hardox 400: Higher price due to brand, certification, and guaranteed mechanical performance.
For domestic equipment or moderate wear, NM400 is ideal. For export projects, certified equipment, or extreme abrasion environments, Hardox 400 provides higher confidence and durability.
| Factor | Best Choice |
|---|---|
| Cost-sensitive projects | NM400 |
| High-impact & long-life | Hardox 400 |
| Welding & forming ease | NM400 |
| Guaranteed wear performance | Hardox 400 |
Both NM400 and Hardox 400 provide excellent abrasion resistance around 400 HBW, but NM400 is better for cost-effectiveness and weldability, while Hardox 400 excels in extreme wear, impact resistance, and certified applications.
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What is NM400 steel?
NM400 Steel is a high-strength, wear-resistant steel known for its superior durability and toughness. NM400 is a Chinese GB standard steel grade. The NM 400 material is widely used in industries where resistance to abrasion is important, such as in the construction and mining sectors.
What is the difference between Hardox 400 and NM400?
Hardox 400 generally contains a higher chromium (Cr) and nickel (Ni) content, which contributes to better hardness and toughness, while NM400 maintains a balance between cost and performance.
What is the difference between AR 400 and NM400?
NM400 offers cost-effectiveness and low-temperature toughness, making it ideal for budget-conscious projects in moderate wear environments. AR400, with its superior impact resistance and formability, excels in high-impact applications requiring complex fabrication.
Can NM400 be reheated or heat-treated during processing?
This is one of the most critical warnings for first-time users.
NM400 steel plate must not undergo secondary high-temperature heat treatment. The material achieves its wear resistance through a quenched and tempered (Q+T) process. If reheated to high temperatures-such as flame heating for easier bending-the internal microstructure will be altered, resulting in a permanent loss of hardness and wear resistance.
Additionally, the recommended service temperature for NM400 is generally below 250°C–300°C. Exceeding this range may reduce its mechanical properties unless specially alloyed grades (with elements like Mo or V) are used.