NM450 is a high-strength wear-resistant steel plate. Its designation follows the internationally recognized naming system for wear-resistant steels and primarily complies with the performance requirements specified in the European standard EN 13242:2022 "Aggregates for Unbound and Hydraulically Bound Mixtures for Construction Works – Specifications". It is also widely referenced against national industry standards, such as China's GB/T 24186-2019 "High-Strength Wear-Resistant Steel Plates for Construction Machinery". This standard clearly defines the chemical composition, mechanical properties, hardness, and testing methods for NM-series wear-resistant steels and serves as a widely accepted technical basis for production and trade globally. As a high-hardness grade within the wear-resistant steel family, NM450 delivers outstanding performance under extreme wear conditions and is a key material for replacing ordinary steel to significantly extend equipment service life.

The designation "NM450" has a clear meaning:

? ? "NM" stands for "Nai Mo", the pinyin abbreviation of the Chinese term for "Wear-Resistant". This naming convention is widely used in China and markets influenced by Chinese standards to identify high-strength low-alloy wear-resistant steels, distinguishing them from ordinary structural steels.
? ? "450" indicates the average Brinell hardness of the steel after quenching and tempering heat treatment is 450 HBW. According to relevant standards (e.g., EN ISO 6506-1), its actual hardness typically ranges from 420 to 480 HBW. This level is significantly higher than NM400 (370–430 HBW) and belongs to the high-wear-resistance category, effectively resisting extremely severe abrasive wear. While demanding higher requirements for toughness, weldability, and processability, it represents an advanced-grade wear-resistant steel that achieves an optimized balance between wear resistance and toughness.

The primary application of NM450 steel plate is in manufacturing critical components operating under extreme wear and high-impact conditions, especially where resistance to intense abrasive wear, high-stress impact wear, and gouging wear is required. Typical applications include:

? ? Mining and Quarry Equipment: High-wear areas of jaw crushers, cone crushers, and impact crushers, such as moving/fixed jaw plates, crushing mantles, concaves, and impact plates, which are in constant contact with hard rock and ore.
? ? Construction Machinery: Bucket teeth, front cutting edges, base plates, and side plates of large excavators and loaders—parts subjected to high impact and severe wear.
? ? Dump Trucks and Haulage Vehicles: Floor and side panels of heavy-duty mining trucks and dumper trucks transporting highly abrasive materials like iron ore, granite, and construction demolition debris.
? ? Cement and Building Materials Industry: Critical components such as rollers, mill liners, classifier rotors, and pipeline elbows in vertical mills, ball mills, and conveying systems exposed to high-speed particle erosion.
? ? Power and Metallurgical Industries: Coal chute pipes, raw coal bunkers, and ash hoppers in dust collectors—areas prone to severe wear.

Its main characteristics include:

? ? Extremely High Surface Hardness and Outstanding Wear Resistance: A hardness of 450 HBW provides exceptional resistance to abrasive wear, offering a service life far exceeding that of ordinary steel and medium-hardness wear-resistant steels, significantly reducing maintenance costs.
? ? Optimized Toughness and Impact Resistance: Through advanced alloy design and precise quenching & tempering processes, NM450 maintains sufficient toughness despite its ultra-high hardness, enabling it to withstand moderate-to-high impact loads and reducing the risk of cracking.
? ? Limited Weldability: Welding is challenging and must strictly follow welding procedures, including thorough preheating (typically 200–250°C), use of specialized wear-resistant filler materials, control of interpass temperature, and post-weld slow cooling to prevent cold cracking.
? ? Poor Cold Formability: Due to its extremely high hardness, cold forming capability is very limited. Only small-angle bends or large-radius bending are permitted, and cold working is generally not recommended.
? ? High Cost-Effectiveness (for Specific Applications): Although more expensive than NM400, its much longer service life in extreme wear conditions drastically reduces downtime and replacement frequency, resulting in significant overall economic benefits.

Therefore, NM450 is a high-performance, purpose-built wear-resistant steel, making it an ideal choice for combating the most severe wear challenges.