WPS/PQR Knowledge Sharing

Welding method

- Such as manual arc welding, gas shielded welding, submerged arc welding, etc. Different welding methods are suitable for different materials, weldment thickness and welding positions. For example, manual arc welding equipment is simple, flexible to operate, and suitable for welding in various positions; gas shielded welding can obtain high-quality welds and is often used in occasions with high requirements for weld quality.

Parent Base material

- Specify the type and model of the parent material, because different parent materials (such as carbon steel, alloy steel, aluminum alloy, etc.) have different welding properties. For example, carbon steel has good weldability, while aluminum alloy is easy to oxidize during welding, and special welding processes are required to ensure quality.

Welding materials

- Include welding rods, welding wires, flux, etc. Its model and specifications should be selected according to the parent material and welding method. For example, when welding A234WPB carbon steel, E43 series welding rods can be selected when manual arc welding is used.

Welding equipment

- Indicate the equipment used for welding, such as the model, power and other parameters of the welding machine. Appropriate equipment is the basis for ensuring a stable welding process.

Welding parameters

- Welding current, voltage and welding speed are key parameters. For example, excessive current may cause defects such as weld undercut and overheating; too fast speed may cause incomplete penetration. For manual arc welding, the welding current is generally selected according to the diameter of the electrode. Generally, the larger the diameter of the electrode, the greater the current.

Welding position

- Such as flat welding, vertical welding, horizontal welding, and overhead welding. The welding difficulty of different positions is different, and the welding process will also be adjusted. Flat welding is the most convenient operation and the weld quality is easier to ensure; overhead welding is the most difficult position and requires high operating skills of the welder.

Preheating and post-heating

- Some materials need to be preheated before welding to reduce welding stress and prevent cracks. Post-heating is mainly to improve the structure and performance of the weld and eliminate residual stress. For example, for thick-walled high-strength alloy steel, preheating treatment is often required before welding.