Introduction of welding process of wear-resistant steel NM360

Wear-resistant steel NM360 is a kind of medium wear-resisting steel. It has a strong volatility and is widely used in the manufacture of wear-resistant and abrasion-resistant components with the advantages of high wear resistance, good impact resistance and reliable performance. Wear-resistant steel NM360 is mainly used for components subjected to strong wear and forming cutters, building materials, mining machinery and other equipment components. So how is wear-resistant steel NM360 welded?
    
1. Pre-welding treatment   
1.1 Remove oil
Before welding, the oil on the surface of wear-resistant steel NM360 should be removed to avoid embrittlement at high temperature, which will reduce the welding quality. If necessary, the surface of the component should be ground off to remove adsorbed oil. If necessary, the component can also be degreased using an appropriate degreaser to prevent oxidation during welding.
    
1.2 Preheat
Preheating is one of the important measures to ensure the quality of welding. When welding wear-resistant steel NM360 often need to use preheating, preheating can reduce crack formation and reduce the chance of structure segregation. Preheating temperature is generally between 50℃ to 150℃, when preheating, should keep uniform preheat temperature, Pay attention to temperature rise, when temperature reach preheating temperature, should keep temperature and time, otherwise partial layer temperature is too high.
    
2. Selection of welding parameters
    
    The selection of welding parameters should be based on the background materials, thickness and size of the material components. Table 1 shows the general welding parameters for wear-resistant steel NM360.
    
    Metal type | Argon (fillet welding) |Copper-coated electrode (butt welding)
    |
    Current (A) |100-150 | 140-190 |
    Voltage (V) | 18-20 |22-24 |
    Welding Method | Uphill welding | Short arc welding |
    
Table 1 Welding Parameters of Wear Resistant Steel NM360
    
3. Welding
3.1 Argon Welding
When welding wear-resistant steel NM360, argon Arc welding can be used. Argon arc welding should use 100% argon (5.0 grade) as the protective gas to avoid oxidation at high temperature. The current and voltage of argon Arc welding should be selected in accordance with the parameters in Table 1.
    
In order to make the welding joint meet the strength requirements, the welding should be welded in three layers. When welding, the highest angle should be at least 65°. When welding, it is necessary to pay attention to the distance from the heat affected zone, which should be within 4 times the weld width.
    
3.2 Copper-coated electrode welding (butt welding)
When welding wear-resistant steel NM360, copper-coated electrode welding can also be used. Copper-coated electrode welding should use argon-oxygen protective gas or argon. The current and voltage should be selected in accordance with the parameters in table 1.
    
In order to make the welding joint meet the strength requirements, the welding should be welded in three layers. The joint should be well grinded. And the arc should be consistent, the welding speed should also be uniform.
    
4. Post-welding treatment
After welding, it is necessary to pay attention to cooling, normalizing and stress relief. And the welding seam should be inspected by magnetic particle inspection or ray inspection.
    
The above is the welding process of wear-resistant steel NM360. In the welding process, it is necessary to pay attention to the pre-welding treatment, the selection of welding parameters and the post-welding processing. The right process is the guarantee of welding quality.

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