Analysis of pressure grade of carbon steel spiral steel pipe

the online pressure ratio of spiral steel pipes in gas transmission pipelines also has a gradually decreasing trend. pipe diameter, pressure, and pressure ratio must be optimized and compared. when the transmission volume is determined and the pipe diameter, pressure, and pressure ratio are determined through optimization, if a higher pressure is selected and the steel strength grade is too low, the wall thickness will be too large, which will bring problems to many aspects such as pipe making, on-site welding, and transportation. difficult, even difficult to achieve.

nowadays, thick-walled spiral pipes are mostly used in fluid transportation pipelines. the transmission pressure of pipeline media has gradually increased in recent years, especially on gas transmission lines. increasing the transmission pressure within a certain range will increase economic benefits. taking gas transmission pipelines as an example, under the condition that the transmission volume remains unchanged, as the transmission pressure increases, the density of the gas increases and the flow rate decreases, thus causing the friction resistance drop.

the demand for production has promoted the improvement of steel grades. the so-called pressure ratio refers to the ratio of the incoming station pressure to the outgoing station 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, some foreign gas pipelines have a pressure ratio of 1.25. of course, as the pressure ratio decreases, the number of compressor stations will increase, resulting in increased investment.