What Are The Differences between Solid-phase Welding And Fusion Welding in Steel Pipe Welding

Solid phase welding and fusion welding are two common steel pipe welding methods. There are some obvious differences between them, mainly including the following points:

1. Steel pipe welding principle:
- Solid phase welding: In solid phase welding, the workpiece itself does not melt during the welding process, and the welding is achieved by solid phase diffusion. Welding materials are usually made under solid-state conditions through the action of pressure and/or temperature, causing the grain structure of the raw material to diffuse and form a weld.
- Fusion welding: Fusion welding means that during the welding process, the welding material or workpiece is heated to a molten state to form a molten pool, and then cools and solidifies to form a weld. Common fusion welding includes arc welding, gas-shielded welding, laser welding, etc.

2. Steel pipe temperature requirements:
- Solid phase welding: Solid phase welding generally requires higher temperatures and/or pressures to achieve solid-state diffusion, but has lower welding temperature requirements relative to fusion welding.
- Fusion welding: Fusion welding requires heating the welding material or workpiece to the melting temperature, usually requiring a higher temperature to melt the welding material.

3. Welding material selection:
- Solid phase welding: Solid phase welding is usually suitable for materials with high melting points or that are difficult to melt, such as metal alloys, etc.
- Fusion welding: Fusion welding is more suitable for materials that are easily melted, such as metals, plastics, etc.

4. Steel pipe welding quality:
- Solid phase welding: Solid phase welding usually enables high-strength welding because there is no liquid metal during the welding process, reducing the occurrence of pores and cracks.
- Fusion welding: Because fusion welding involves melting and condensation processes, there may be welding defects such as pores and thermal cracks. Special attention must be paid to the welding quality.

In general, solid phase welding and fusion welding each have their own applicable occasions, advantages, and disadvantages. Choosing the appropriate welding method depends on the specific materials, requirements, and welding conditions.