NM400 and NM450 are two of the most widely used abrasion-resistant steel plates in mining, construction, and heavy equipment industries. While both belong to the same wear-resistant steel family, the key difference lies in hardness level, wear life, and fabrication performance.
NM400
Choosing the right grade directly affects service life, maintenance cost, and production efficiency-so understanding their differences is critical for engineers and buyers.
NM400 vs NM450 Mechanical Properties Comparison
| Property | NM400 Steel Plate | NM450 Steel Plate |
|---|---|---|
| Hardness | 360–440 HB | 420–480 HB |
| Yield Strength | ≥900 MPa | ≥1000 MPa |
| Tensile Strength | 1100–1300 MPa | 1200–1500 MPa |
| Elongation | Better | Slightly lower |
| Impact Toughness | More balanced | Lower (if hardness maximized) |
Higher hardness in NM450 = better wear resistance, but reduced ductility.
Typical Applications of NM400 and NM450
| NM400 (common uses) | NM450 (common uses) |
|---|---|
| Truck and loader bucket liners where impact and moderate abrasion occur | High-wear liners, chutes, and screens subjected to severe abrasive wear where service life is prioritized |
| Conveyor skids, wear plates in moderate abrasion environments | Grinding mill liners, heavy-duty crusher jaws, and applications where cutting/grinding abrasion dominates |
| Parts requiring better balance of toughness and wear (e.g., rock-breakers) | Parts where maximum abrasion resistance is required and replacement intervals must be minimized |
When selecting between NM400 and NM450, the decision should be based on actual working conditions and cost priorities. NM400 is a better option for applications exposed to both impact and abrasion, especially where higher ductility, easier welding, and simpler fabrication are required.
It is also ideal when controlling initial material costs is important, even if it means accepting more frequent maintenance or replacement.
On the other hand, NM450 is more suitable for environments where abrasive wear is the primary cause of failure. Its higher hardness allows for a longer service life, making it the preferred choice when reducing downtime and extending replacement intervals is more critical than higher upfront material and processing costs.
Cost and Availability of NM400 and NM450
In terms of pricing, NM450 generally comes at a higher cost than NM400, mainly due to its increased alloy content, stricter production processes, and tighter quality control requirements. However, the actual price difference can fluctuate depending on factors such as market conditions, plate thickness, and the supplying mill.
Regarding availability, both NM400 and NM450 are commonly manufactured by major steel producers in forms such as plates and wear liners. That said, NM400 is usually easier to source across a wider range of thicknesses and specifications, while NM450 is more often supplied in standard sizes and limited thickness ranges depending on stock conditions.
NM400
From a product perspective, both grades can be delivered as raw plates, precision-cut liners, or fully fabricated components. It's important to note that lead times tend to increase as processing complexity rises, especially when custom cutting, welding, or specialized heat treatment is required.
When comparing NM400 and NM450, the differences mainly come down to weldability, mechanical balance, and cost. NM400 offers better weldability due to its lower hardenability, making it easier to process and more suitable for general fabrication.
It also provides a well-balanced combination of strength, ductility, and toughness. In contrast, NM450 delivers higher strength and hardness, but requires more careful control during welding and processing to maintain adequate toughness. From a cost perspective, NM400 is typically more economical, while NM450 involves a higher initial investment.
NM400 is the preferred choice when:
- Components are exposed to both impact and abrasion
- Good ductility and weldability are needed to simplify fabrication and repairs
- Lower material cost and easier on-site welding are key considerations
NM450 is more suitable when:
- Abrasive wear is the primary failure factor
- Extending service life is more important than upfront cost
- The manufacturing process can handle stricter welding procedures and heat treatment control
- Parts are replaceable wear components where higher hardness reduces maintenance frequency
Before making a final decision, it is essential to verify mill certificates to confirm the actual chemical composition and mechanical properties.
For critical applications, requesting additional data such as hardness distribution, heat treatment records, and impact toughness at service temperature is highly recommended.
In many cases, real-world testing-such as pilot runs or field trials-provides the most reliable basis for selecting the optimal grade and minimizing total cost of ownership.
Contact now to get NM400 Abrasion Steel Quote
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.