Comprehensive Analysis of Surfacing Welding Technology: Technical Characteristics, Application Fields, and Implementation Key Points

 

Surfacing welding is a process that uses electric welding, gas welding, or other welding methods to deposit metal materials on the surface of workpieces. Its purpose is to repair worn or cracked parts and endow the base material with a strengthened layer with special properties such as wear resistance, heat resistance, and corrosion resistance. This technology is not used for connecting components but can significantly improve the service life and performance of equipment through surface modification. Therefore, it plays an irreplaceable role in the manufacturing and maintenance fields.

 

Core Technical Elements of Surfacing Welding

1. Selection of Surfacing Welding Metal

The surfacing welding metal needs to be comprehensively selected according to the working environment of the workpiece, the requirements for mechanical properties, and the surfacing welding method. For example, high - carbon steel is suitable for scenarios requiring high hardness and wear resistance, while austenitic stainless steel is used in corrosion - resistant or high - temperature environments. Reasonable alloy matching can maximize the functions of the deposited layer. For instance, adding elements such as chromium and nickel can improve the corrosion resistance.

2. Precise Control of Welding Parameters

Parameters such as welding current, voltage, and speed directly affect the quality of the surfacing welding layer. Excessively high current may cause excessive dilution of the base metal, affecting the performance of the deposited layer. Too high a welding speed may easily result in defects such as porosity or lack of fusion. Usually, the parameters need to be optimized through experiments to ensure the balance between penetration depth and dilution rate.

3. Performance Optimization of the Surfacing Welding Layer

Post - welding heat treatment is a key step to improve the inter - layer bonding force and eliminate stress. For example, tempering the high - carbon alloy surfacing welding layer can improve toughness and crack resistance. In addition, when using multi - layer surfacing welding, the temperature of each layer needs to be controlled to avoid the accumulation of thermal stress.

 

Mainstream Surfacing Welding Process Methods

- Shielded Metal Arc Surfacing Welding: It has flexible operation and is suitable for small - batch or workpieces with complex shapes. However, it has low efficiency and requires high skills of welders.

- Submerged Arc Surfacing Welding: It has a high degree of automation and excellent deposition efficiency, and is suitable for the repair of large - area flat or curved surfaces. It is often used for the strengthening of large components such as rolls and mining machinery.

- Plasma Arc Surfacing Welding: It has high energy density and low dilution rate and can achieve precise surfacing welding. It is especially suitable for the repair of high - melting - point alloys or thin - walled workpieces.

 

Industrial Application Value of Surfacing Welding

Surfacing welding technology is widely used in multiple industries to achieve cost reduction and efficiency improvement:

- Metallurgy and Mining Equipment: It can repair the hammer heads of crushers and the surfaces of rolls to improve wear resistance.

- Energy and Chemical Industry: It can enhance the corrosion resistance of pipes and valves and extend their service life in high - temperature and high - pressure environments.

- Agricultural Machinery: It can renovate agricultural machinery cutters and gears to reduce the cost of frequent replacement.

- Manufacturing and Repair: By surfacing welding precious alloy layers on ordinary steel substrates, high - performance composite structures can be obtained at extremely low cost.

 

Common Problems and Countermeasures in Implementation

- Cracking Risk Control: Measures such as pre - heating before welding (the temperature is calculated according to the carbon equivalent formula Ceq = C+1/6Mn+1/24Si+1/5Cr+1/4Mo+1/15Ni), controlling the inter - layer temperature, and slow cooling after welding can be taken to reduce thermal stress. High - alloy steels need to be pre - heated to above 400 °C, while austenitic stainless steels usually do not require pre - heating.

- Compatibility between the Base Metal and the Surfacing Welding Layer: For high - hardness surfacing welding layers, it is recommended to use low - carbon steel with good toughness as a transition layer to relieve stress concentration.

- Balance between Efficiency and Quality: Automated surfacing welding equipment can improve consistency and production efficiency, especially suitable for batch repair scenarios.