NM450 material equivalent

By Gary J. McDowell
    
    The steel grade NM450 (also known as Abrasion-Resistant Steel Plate) is a steel alloy made from mainly Iron, Chromium, and Nickel. This steel is known for its excellent strength and ability to withstand abrasion and wear.
    
    NM450 material is predominantly used in the construction sector and mining industry, being especially useful due to its enhanced resistance against surface wear. Its existence is necessary to combat corrosion in much more extreme environments than would be encountered in more traditional implementations.
    
    NM450 holds an impressive level of denotation as it holds a Brinell hardness value of between 327 HBW to 538 HBW. The use of the HBW scale is defined as the ‘hardness of hard materials to soft materials tested using a hard and soft calibrated cylinder pressed into the material’. The values provided give an impressive overview of the wear characteristics of the material and its composition.
    
    Composition
    
    The composition of the NM450 alloy is predominately iron, but also consists of Chromium and Nickel, as well as a little Carbon, Silicon and Manganese. The mixture of Chromium and Nickel serve to give the material added abrasion resistance, as well as very high levels of needed strength.
    
    Carbon is also needed in this alloy to add more immediate strength and resistance to ‘volume wear’, but it needs to be below the 0.5% level, else the corrosive properties increase drastically, to the point of being unusable in any practical way.
    
    (C 0.30-0.45%)(Si 0.35-0.9%) (Mn 1.00-1.6%)(Cr 1.50-2.00%)(Ni 0.45-0.9%)
    
    Characteristics
    
    NM450 is an incredibly durable material, being resistant to Hardness Notching, Corrosion, and the like. As previously mentioned, it has excellent wear resistance and carbon content, which gives the plate an increased resistance to wear, as well as an improved level of strength. As indicated by its hardness, it stands to reason that it is also retained its structure and shape very well too.
    
    This steel can be welded with ease, despite its rather strict composition list, thanks to the use of Low-Hydrogen Electrodes. This welding process has to be done with care, however, due to the critical low-heat input that is needed. Welding with Arc Air or Oxy-Acetylene should be avoided completely, as the heat input can easily exceed the limits of the material, leading to the weakening of the structure.
    
    Summary
    
    NM450 is an incredibly strong, durable and resistant material, perfect for use in industries that require strength and resistance in extreme environments. Its composition of Iron, Chromium, Carbon, Silicon, and Nickel gives it a Brinell hardness of between 327 HBW to 538 HBW. The use of Low-Hydrogen electrodes is needed for the welding of the material, as well as taking a much less than usual heat input when compared to other materials.