Analysis of pressure grade of carbon steel spiral steel pipe

The pressure ratio of the spiral steel pipe on the gas pipeline also tends to decrease gradually. For pipe diameter, pressure, and pressure ratio, optimization calculation and comparison are required. When the output is determined and the pipe diameter, pressure, and pressure ratio are determined through optimization, if a higher pressure is selected but the steel strength grade is too low, the wall thickness will be too large, which will bring problems to many links such as pipe making, on-site welding, and transportation. It is difficult, even impossible to achieve.

Nowadays, thick-walled spiral pipes are mostly used for fluid-conveying pipelines, and the conveying pressure of pipeline media has gradually increased in recent years, especially on gas pipelines. This is because increasing the delivery pressure within a certain range will increase economic benefits. Taking gas pipelines as an example, under the condition of constant delivery, as the delivery pressure increases, the gas density increases, and the flow rate decreases, so friction Resistance to drops.

The demands of production have driven the increase in steel grades. The so-called pressure ratio refers to the ratio of the inbound pressure to the outbound pressure. A reduction in the pressure ratio means that the entire line is operating at a higher pressure, which can also reduce energy consumption. In the early days, the pressure was mostly 1.6 and later dropped to 1.4. In recent years, the pressure ratio of some foreign gas pipelines is 1.25. Of course, if the pressure ratio decreases, the number of compressor stations will increase, thus increasing the investment.