Joint efficiency of welded steel pipe

The joint coefficient of the welded steel pipe is divided into two zones, one is the weld zone and the other is the fusion zone.

Weld area
After the joint metal and the metal to be filled are melted, it is cooled at the fastest speed. The weld arrangement is an as-cast arrangement of liquid metal crystallization, and the composition is segregated, the crystal grains are coarse, and the arrangement is not fine. However, due to the small weld pool, rapid cooling, strict chemical composition control, carbon, sulfur, and phosphorus are low, and the weld chemical composition is adjusted by the alloy to make it rich in certain alloying elements. Therefore, the weld metal The functional problem is not big enough to be able to satisfy the function pleading, especially the strength is simple to arrive.

2. Melting zone
A transition between the melt zone and the non-melting zone. The chemical composition of the fusion zone is not uniform, and the arrangement is coarse, often a coarse overheating arrangement or a coarse hardening arrangement. Its function is often the worst of the welded joints. The superheating zone (or quenching zone) in the fusion zone and the heat-affected zone is the thintest part of the mechanical function of the welded joint. The calculation formula of the internal pressure cylinder thickness is derived according to the strength of the circumferential (initial) film stress in the cylinder. Therefore, the corresponding weld coefficient should be the longitudinal seam weld coefficient of the cylinder.