NM450 and NM500 are two widely used wear-resistant steel grades encountered in mining, earth-moving, bulk-handling, and aggregate-processing equipment. Engineers, procurement managers, and manufacturing planners commonly weigh trade-offs between wear life, toughness, weldability, and cost when selecting between them. Typical decision contexts include whether to prioritize in-service abrasion resistance (longer wear life) at the expense of ductility and repairability, or to prioritize easier fabrication and improved impact tolerance at a lower hardness.
Standards and Designations
Common regional designations and standards:
- China: GB/T wear-resistant steels commonly referenced as NM (e.g., NM450, NM500). NM is a Chinese designation for quench-and-tempered wear-resistant steels.
- Europe: EN standards use different designations (e.g., AR400/450 equivalents or proprietary AR grades).
- Japan: JIS has wear-resistant steels but nomenclature differs.
- U.S.: ASTM/ASME do not define NM grades directly; producers often supply AR (abrasion-resistant) steels or proprietary brands.
Classification:
Both NM450 and NM500 are high-strength, low-alloy / quenched and tempered abrasion-resistant carbon steels (not stainless). They are best classified as wear-resistant quenched-and-tempered steels (a subcategory of HSLA-like engineering steels with controlled alloying and heat treatment).
Chemical Composition Comparison
NM450 and NM500 are low-carbon alloy steels, but their alloy design reflects different performance priorities.
- NM450 typically features slightly lower carbon equivalent, emphasizing better toughness and weldability
- NM500 may contain optimized alloy content (Mn, Cr, Mo, B) to achieve higher hardenability and surface hardness
Engineering Insight:
The controlled chemical composition of NM500 enables higher hardness, while NM450 prioritizes resistance to cracking under impact.
Mechanical Properties
| Property | NM450 (typical behavior) | NM500 (typical behavior) |
|---|---|---|
| Hardness | ≈450 HB nominal in the delivered condition (designed for high abrasion resistance) | ≈500 HB nominal in the delivered condition (higher abrasion resistance) |
| Tensile strength | Elevated compared with mild steel; generally lower than NM500 at delivered hardness | Generally higher tensile strength correlated with higher hardness |
| Yield strength | High for structural steels; lower than NM500 for comparable sections | Higher yield/strength values at given thickness due to higher hardness/hardenability |
| Elongation | Higher ductility than NM500 at equal thickness due to lower hardness | Reduced ductility compared with NM450 (trade-off for hardness) |
| Impact toughness | Typically better than NM500 when both are delivered at nominal hardness, especially at low temperatures | Generally lower impact energy than NM450 when compared at nominal delivered hardness; can be improved by process control but remains a trade-off |
Heat Treatment Process
Both NM450 and NM500 are produced using quenching and tempering technology.
NM450 Heat Treatment
Optimized quenching intensity
Tempering focused on maintaining toughness
Produces a hardness range of approximately 430–480 HBW
NM500 Heat Treatment
More aggressive quenching
Tempering designed to retain high hardness
Produces a hardness range of approximately 480–540 HBW
The heat treatment process directly determines their wear resistance and impact behavior in service.
Fabrication, Machinability, and Formability
- Cutting:
Both grades can be oxy-fuel cut, plasma cut, or laser cut, but harder nominal grade (NM500) is more abrasive to cutting consumables.
- Machinability:
Hardened surface condition reduces machinability; cutting resistances increase with hardness. Machining of finished pieces is generally minimized; components are often fabricated and then machined locally.
- Formability and bending:
Lower hardness grades (NM450) accept cold forming better than NM500. Bending of hardened plate is limited; bending should be performed prior to final quench/temper or by controlled processes with tooling designed for high-strength plate.
- Finishing:
Grinding and dressing of wear surfaces are more time-consuming on NM500; abrasive wheel wear is higher.
Typical Applications
| NM450 | NM500 |
|---|---|
| Bucket lips, liners, screens, chutes where a balance of abrasion resistance and impact toughness is required; works well in moderately abrasive soils and ores. | High-wear liners, crusher wear parts, impact-prone apron feeders where maximum abrasion resistance and extended wear life are prioritized over ductility. |
| Truck bed liners, skip liners where fabrication and repairability are frequent. | High-abrasion, sliding-wear environments such as high-throughput crushing circuits and fixed liners where minimizing replacement frequency matters. |
| Ground-engaging tools subject to combined impact and abrasion (if impact dominates, choose tougher variants or thicker sections). | Applications where long service life under severe abrasion justifies increased fabrication controls and potential increased material cost. |
NM450 vs NM500: How to Choose?
Choose NM450 if:
Impact resistance is critical
Components require bending or forming
Welding reliability is a priority
Choose NM500 if:
Abrasion is severe and continuous
Maximum service life is required
Equipment operates under stable load conditions
In many projects, a combination of NM450 and NM500 is used in different wear zones to optimize performance and cost.
Request a Quote or Technical Support
If you are comparing NM450 vs NM500 steel plates for your project, GNEE Steel is ready to assist.
👉 Contact GNEE Steel today for datasheets, application guidance, and competitive quotations.
Let our expertise help you reduce wear costs and extend equipment life.
What are the properties of NM450 steel?
Mechanical Properties: Yield strength ≥1000 MPa, tensile strength 1250-1400 MPa, and elongation ≥10%. These values ensure NM450 can endure extreme conditions. Thickness and Dimensions: Available in plates from 3-80mm thick, with widths up to 3000mm and lengths up to 12000mm, customizable for specific needs.
What is NM500 steel?
NM500 is a wear-resistant steel known for its high hardness and toughness. The "NM" stands for "wear-resistant" and the "500" indicates its Brinell hardness. Originating in China, NM500 is used in industries requiring extreme abrasion resistance. It is similar to ASTM A514 steel.
Is NM500 the same as AR500 steel?
Key implication: AR500 is preferred in North America for compliance with ASTM certifications, while NM500 dominates Asian markets . Both steels exceed 500 HBW surface hardness, but AR500 shows marginally higher tensile/yield strength and better low-temperature toughness .
| Other steel plate by GNEE | ||||
| Name | Material | Specification (mm) | Tons | Remark |
| Clad steel plate | P265GH+410,S355JR+410,A516Gr70+316, A537CL1+304L,Q235B+304L,Q345B+304, A516Gr70(NACE)+410,A537CL1+904L, A537CL1+316L,A516Gr70+304L,A537CL1+304 ,A516Gr70+410,A516Gr70+904L |
2-300mm(Based plate),1-50mm(Composited plate) | / | UT, AR, TMCP.Normalized, Quenched and Tempered,Z Direction Test, Charpy V-Notch impact TestThe Third Party Test , Coated or Shot Blasting and Painting. |
| Low Alloy | Q345A, Q345B, Q345C, Q345D, Q345E, Q390, Q420, Q460C, ST52-3, S355J2+N, SS400, SA302GrC, S275NL, 35CrMo | 6 - 350 | 5788.56 | Normalizing, tempered ,controlled rolling, hot rolling , Hot rolling,1st inspection, 2nd inspection, 3rd inspection |
| Pressure Vessel Plate | A204 Grade B,A515 Grade 70,A537 Class 1,SA387 Grade 11 Class 1,P265GH,S537 Class 2,P355Q,P275N,P355N,P690Q,Q345R, | 3 - 300 | 8650 | Normalizing, tempered ,controlled rolling, hot rolling , Hot rolling,1st inspection, 2nd inspection, 3rd inspection |
| High-Strength Plate | A514 Grade F, A572 Grade 50, A588 Grade A, S355JR, S690Q, SS400, S690QL, Q345B, Q345E | 8 - 120 | 3086.352 | Quenched and tempered |
| Wear-Resistant Plate | NM360, NM400, NM450, NM500 | 6 - 150 | 3866.297 | Quenched and tempered |
| Ship Plate | ABS AH32,ABS DH32,ABS EH32,ABS FH36,ASTM A131 A, ASTM A131 EH32,ASTM A131 AH36,CCS A,CCS AH32,LR AH32, DNV A36,BV AH32 |
8 - 200 | 2853.621 | Hot rolling, normalized ,hot rolling controlled rolling, quenched and tempered + toughness and brittleness |
