Q235 welded pipe is carbon structural steel (GB/700-1999), Q--yield, 235--the minimum yield point (σs) value of this grade. This type of steel is generally smelted in a converter or an open hearth. Its main raw materials are molten iron and scrap steel. The sulfur and phosphorus content in the steel is higher than that of high-quality carbon structural steel. Generally, sulfur is ≤0.050% and phosphorus is ≤0.045%. The content of other alloying elements brought into the steel from raw materials, such as chromium, nickel, and copper, generally does not exceed 0.30%. According to the composition and performance requirements, the grades of this type of steel include Q195, Q215A, B, Q235A, B, C, and D. Q255A, B, Q275 and other steel grades are represented.
Can be divided into straight seam welded pipe and spiral welded pipe
Straight seam welded pipe: The production process is simple, the production efficiency is high, the cost is low, and the development is rapid.
Spiral welded pipe: The strength is generally higher than that of straight seam welded pipe. It can use narrower billets to produce welded pipes with larger diameters, and can also use billets of the same width to produce welded pipes with different diameters. However, compared with straight seam pipes of the same length, the weld length is increased by 30~100%, and the production speed is lower. Therefore, smaller diameter welded pipes mostly use straight seam welding, while large diameter welded pipes mostly use spiral welding.
Spiral seam welded steel pipes are divided into two types: automatic submerged arc welded steel pipes and high-frequency welded steel pipes.
