Research on the technology of low-strength matching welding of EH400 wear-resistant steel

    
    Introduction
    
    Wear-resistant steel EH400 is specially developed for the wear parts of the equipment used in harsh working environments. It is a kind of steel with high thermal performance and wear-resistance, which is suitable for all kinds of wear parts whose stress is large and temperature changes obviously. As a low-strength matching welding, EH400 wear-resistant steel technology is widely applied in many fields due to its significant economic, environmental and safety benefits.
    
    Characteristics
    
    EH400 wear-resistant steel features good mechanical properties, including high toughness, low impact toughness and high hardness, combined with excellent weldability and metallurgical stability. This steel has excellent performance of high wear resistance, fatigue strength and impact toughness, and superior corrosion and oxidation resistance. The high strength and low ductility of EH400 steel requires special treatment and welding process safeguards to achieve good mechanical properties while maintains its good corrosion and oxidation resistance.
    
    Low-strength Matching Welding Technique
    
    Low-strength matching welding is one of the most common welding process for EH400 wear-resistant steel. It is a type of welding process that uses lower power than normal welding power for welding EH400 steel without causing any considerable effect on the metallurgical structures of the welded EH400 steel part. This process utilizes less heat and distortion will, therefore, be kept to minimum thaning traditional welding process. Additionally, the overall efficiency of the welding process is improved from low power consumption and faster welding speed. The specific procedure for low-strength matching welding has been listed as follows.
    
    Step 1: The surface of the EH400 steel should be swept off before applying the welding process, to ensure effective oxidation by removing contaminants.
    
    Step 2: Select the appropriate low-strength matching welding power based on the thickness and size of the workpiece to be welded. The welding current should then be adjusted to the appropriate heat.
    
    Step 3: The welding device should be fitted with a ceramic insulation board, in order to prevent welding discoloration and defects.
    
    Step 4: Use a brush to brush the welding surface of the workpiece. By doing so, the welding surface will be more uniform and the welding quality will be better.
    
    Step 5: Use welding machine to spray welding arc while controlling the shape of the welding arc. Ensure the area of the surface that contacted the welding arc is not more than ¾ of the steel plate.
    
    Step 6: After the welding process is completed, the surface of the workpiece should be cleaned and the welding surface should be polished.
    
    Step 7: Inspect the welding surface with a testing instrument to check for any defects in the welded workpiece.
    
    Applications of Low-strength Matching Welding
    
    Low-strength matching welding technique is widely applicable in welding EH400 series wear-resistant steel. It is extensively used to construct hull plates, pipe lining and conveyer systems in the offshore industry, and many parts of mining machinery and general metal fabrication. The low power welding process is also popular in the manufacturing of small parts and components, and it is becoming increasingly popular in the automobile industry as well.
    
    Conclusion
    
    EH400 wear-resistant steel is a modern material that is highly resistant to wear and corrosion, allowing it to be used in many everyday applications. Low-strength matching welding is a reliable welding process for EH400 steel which offers economic, environmental and safety benefits. This welding process can achieve good mechanical properties while maintaining its corrosion and oxidation resistance, and is especially applicable in the offshore industry, small parts manufacturing, automotive industry and general metal fabrication.

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