The welding of NM 500

    
    NM 500 and NM 750 are two of the most renown wear resistant steel grades available on the market today. They are widely used in the construction and manufacturing industries due to their superior strength and wear resistance, making them an ideal choice for high abrasion environment applications where other steel grades may fail.
    
    The optimal welding process for NM 500 and NM 750 depends on the specific application at hand. For both NM 500 and NM 750, arc welding is the preferred technique and the two most widely used methods are Manual Metal Arc Welding (MMAW) and Metal Active Gas Welding (MAG). The correct choice of electrode and welding parameters is extremely important for high quality welding; too high a temperature can damage the material and is likely to lead to welding problems, including lack of fusion and brittle welds.
    
    When welding NM 500 and NM 750, preheating of the joint is essential. This reduces internal stress in the material, which helps to reduce the risk of cracking during welding, and also increases weldability. Preheating should be done at a temperature of around 500°C, and should not exceed 650°C. It is also important to keep the inter-pass temperature to a minimum of 250°C, as too high a temperature reduces the strength of the weld.
    
    After the welding is complete, a post weld heat treatment (PWHT) is recommended, as this relieves welding stresses, improves resistance to hardening, and helps to make the weld more ductile. The PWHT should be done at a temperature between 550°C and 650°C for up to 10 minutes, with an end result of equipment temperature of no more than 450°C.
    
    Welding of NM 500 and NM 750 is a highly specialised task and should only be attempted by an experienced welder, in accordance with instructions from the steel manufacturer. An appropriate welding procedure should always be tested before it is used in production in order to ensure the highest quality welds.