Which Steel Pipe Is Best Suited For High Pressure And Long-Distance Transmission?

In major projects such as "West-East Gas Transmission" and "Central Asia Energy Cooperation", high-pressure long-distance pipeline is the "lifeline" of energy transmission. This kind of pipeline needs to bear the pressure exceeding 10 MPa (equivalent to 1000 meters water depth pressure), and the transmission distance often reaches hundreds of kilometers, which puts forward the extreme requirements for the strength, toughness and stability of steel pipe. As an enterprise that has been deeply involved in this field for 20 years, Hebei Huayang Steel Pipe has an annual production capacity of 2 million tons. The steel pipes supplied by Hebei Huayang Steel Pipe have helped Uzbekistan Oilfield, West-East Gas Transmission Branch Line and other domestic and foreign projects. What kind of steel pipe can be competent for such a harsh scene? The answer lies in performance data and engineering practice.

The dual nature of high pressure and long distance transportation determines that steel pipes must break through three technical barriers. One is high strength, which needs to meet both high tensile strength and yield strength, and the ratio of the two needs to be controlled within a reasonable range to avoid uneven stress; Secondly, it has high toughness. In complex environments such as -20℃ and low temperature, the impact toughness should be above 30J to prevent brittle fracture. The third is corrosion resistance and fatigue resistance, which need to resist soil sulfide erosion and long-term pressure impact.

Huayang steel pipe stressed: "This kind of steel pipe is by no means an ordinary pipe, and each pipe has to pass 12 tests such as hydrostatic test and X-ray flaw detection. The steel pipes customized by us for the Central Asia project adopt the double standard of' ultrasonic + X-ray' only for weld inspection, and the defect rate is controlled below 0.3%. "

In the core area of high pressure scene, longitudinal submerged arc welded pipe (LSAW) has become the first choice because of its characteristics of "single steel plate forming+longitudinal seam welding". It adopts JCOE forming process to gradually press the steel plate into a J-C-O-shaped tube blank, and then it is welded by double-wire submerged arc welding, and the weld is parallel to the axis of the steel tube, which can evenly transmit the axial pressure.

The practical experience of Huayang confirms this point. The 50 km customized LSAW pipe sent to Uzbekistan in 2025 is made of X70 pipeline steel, with tensile strength of 570MPa and impact toughness of 42J at -20℃, which successfully meets the transportation needs of local 10MPa high-pressure oil fields. The 3PE anti-corrosion treatment of the outer layer and the anti-rust treatment of the inner wall of this batch of steel pipes are all completed by Huayang's own production line, and the whole process is traced back to ensure the quality. In the domestic Bohai Oilfield project, Huayang LSAW pipe also passed the rigorous test with the pressure bearing capacity of 10MPa and became the "safety center" of the high pressure section.

For hundreds of kilometers of long-distance transmission, spiral submerged arc welded pipe (SSAW) stands out for its stress dispersion advantage and cost-effectiveness. The continuous steel strip is used as raw material, and is formed and welded according to the spiral angle of 30-45 degrees, so that the weld can disperse the pressure in different directions and meet the fatigue stress demand of long-distance transportation.

Three SSAW production lines in Huayang have an annual production capacity of 500,000 tons, and once supplied 30,000 tons of DN1200 steel pipes for a branch line of the West-East Gas Pipeline. AI vision inspection system is used to monitor the weld quality of this batch of steel pipes. Although the axial tensile strength is slightly lower than that of LSAW pipes (about 500MPa), it fully meets the working pressure requirement of 4MPa, and the cost per ton is 15% lower than that of LSAW pipes. "The long-distance transmission lines pays more attention to the overall economy and fatigue resistance, and the spiral weld of SSAW pipe just meets this demand." Huayang production director explained.

Seamless pipe has excellent pressure-bearing performance in theory because of its advantage of no weld seam, but its high cost limits its application. Huayang data shows that the price of seamless pipe with the same specification is more than 40% higher than that of LSAW pipe, and it is only used in special short scenes such as extreme cold and ultra-high pressure (> ＞12MPa). Although the cost of ERW (High Frequency Longitudinal Welded Pipe) is low, its maximum diameter is usually less than 660mm, and its strength is insufficient, so it is only suitable for medium and low pressure short-distance transportation.

"A client once considered building a high-pressure transmission line with seamless pipes. According to our calculation, the cost of a 100-kilometer pipeline will increase by 230 million yuan. Finally, the combination scheme of Huayang LSAW + SSAW was chosen to ensure safety and control the budget." Huayang sales manager revealed.

In the high-pressure long-distance transmission scenario, it is difficult for a single steel pipe type to cover the whole process. Huayang typically adopts a "LSAW for core sections + SSAW for transmission lines" combination strategy: LSAW pipe is used in the core sections such as high-pressure wellheads and hub stations, and SSAW pipe is used in the long-distance transmission line.

This strategy has been verified in several projects. In a Central Asia energy project, LSAW pipe supplied by Huayang is used in the high-pressure wellhead section of 10MPa, and SSAW pipe is used in the subsequent 80-kilometer transmission line. By unifying the anti-corrosion standard and detection system, the 20-year design life guarantee of the whole pipeline is realized. Relying on 45 automatic production lines, Huayang can control the whole process from steel plate forming to anti-corrosion shipment to ensure the performance matching of different types of steel pipes.