What are the main manufacturing processes for Q195 steel pipe?
The production process of Q195 steel pipe includes hot rolling, cold rolling, welding and seamless pipe manufacturing. Hot rolling process is suitable for large-diameter thick-walled pipes, while cold rolling is used for high-precision thin-walled pipes. Welded pipes (such as ERW high-frequency welded pipes) have low cost and high production efficiency, while seamless pipes (such as hot rolling or cold drawing) have higher strength but are more expensive. Different processes affect the dimensional accuracy, surface quality and mechanical properties of steel pipes.
What is the production process of Q195 welded steel pipe?
The production process of Q195 welded steel pipe includes steel strip unwinding, leveling, forming, high-frequency welding, deburring, sizing and cutting. The steel strip is rolled into a tube shape, and then heated by high-frequency current to fuse the edges. After welding, water cooling or air cooling is required, and non-destructive testing (such as ultrasonic testing) is performed to ensure the quality of the weld. Finally, the steel pipe is straightened, coded and packaged before leaving the factory.
How is Q195 seamless steel pipe manufactured?
Q195 seamless steel pipes are usually hot rolled or cold drawn. During hot rolling, the steel billet is heated and perforated, and then formed by a rolling mill, which is suitable for large-diameter thick-walled pipes. The cold drawing process is to draw the hot-rolled pipe to a smaller size at room temperature to improve the surface finish and dimensional accuracy. The strength of the cold-drawn pipe is slightly higher than that of the hot-rolled pipe, but the production cost is higher, and it is suitable for precision mechanical structures.
What are the heat treatment processes for Q195 steel pipes?
Q195 steel pipes are generally not subjected to complex heat treatment because their low carbon composition determines good cold working properties. However, in some cases, annealing may be performed to eliminate cold working stress and improve plasticity. The annealing temperature is usually 600~700℃, and the heat preservation is followed by slow cooling. If used for special purposes, normalizing may be performed to refine the grains, but the cost is higher.
What are the surface treatment methods for Q195 steel pipes?
Common surface treatments for Q195 steel pipes include galvanizing, painting, plastic spraying, and black pipes (uncoated). Galvanizing (hot-dip or electroplating) can significantly improve corrosion resistance and is suitable for outdoor environments. Spray painting and plastic spraying are mainly used for decoration or rust prevention, and come in a variety of colors. Black pipes (untreated) are the cheapest, but are prone to rust and need to be used in a dry environment.
