What is the appropriate temperature for welding straight seam steel pipes during industrial processing

Welding, also known as fusion welding, is a manufacturing process and technique that joins metals or other thermoplastic composite materials (such as plastics) by heating, applying high temperature, or applying high pressure. There are three welding methods:
1. Fusion welding: The workpiece is heated to form a molten pool. After cooling and solidification, the molten pool can remain connected, and filler material can be added if necessary. Suitable for pressureless welding of various metals and alloys.
2. Pressure welding: Pressure must be applied to the welded parts during the welding process. Suitable for various metal materials and certain metal processing.
3. Brazing: Using a metal structural material with a melting point lower than the base metal as a filler metal, the liquid filler metal wets the base metal, fills the joint gap, diffuses into the base metal, and achieves the welding of the joint. Suitable for welding various active materials and welding different or non-uniform metals.

The welding temperature for low-carbon steel straight seam steel pipes is controlled between 1250°C and 1460°C, which can meet the requirements of 3 to 5 mm pipe wall thickness. When the input heat resources are insufficient, the weld edge of the heated straight seam steel pipe cannot reach the required welding temperature, and the metal structure can remain firm, forming a non-melting or fully penetrated joint. When the input heat is excessive, the weld edge is heated above the welding ambient temperature, leading to weld overheating or the formation of molten droplets.

A common feature of various pressure welding methods is the use of pressure without filler material during the welding process. Most pressure welding methods, such as diffusion welding, high-frequency welding, and cold pressure welding, do not involve a melting process. Therefore, there is no problem of alloy element combustion loss or harmful element intrusion into the weld, simplifying the welding process and improving welding safety and hygiene. Simultaneously, due to the relatively low heating temperature and short heating time, the heat-affected zone is small. Many materials that are difficult to weld by fusion welding can often be pressure welded into high-quality joints with the same strength as the base material.