Possibilities of using X80, X100, X120 high-strength steels for onshore gas transmission pipelines

• There are significant differences between mass of pipes made of X70M, X80M, X100M and X120M steel respectively.
• Deviations from average amount of capital expenditures on pipes DN 700, X70-X100 steel grade varies in the range of ±10%.
• Using high-strength steel for onshore pipeline results in less labor, lower logistics costs and smaller extent of welding.

Some of the reasons for increasing the operating pressures of onshore gas transmission pipelines and using pipes with thinner wall thicknesses are given in this paper. High-strength materials with yield strengths above 600 MPa for pipelines in the pressure range between 8.0 and 10.0 MPa are described. The mechanical properties of the steel according to PN-EN ISO 3183:2013(E) Petroleum and natural gas industries – Steel pipe for pipeline transportation systems are given. Based on other publications, the chemical composition of the steel for gas pipelines is presented and the manufacturing process for producing steel of grades X80, X100, X120 is described. Wall-thickness calculations for DN 700 MOP 8.4 MPa pipe according to the Polish technical standard are given, and a comparison of the wall thicknesses of DN 700 gas pipelines of different steel grades and design factors are presented, based on the Polish Technical Regulation. Finally, the estimated capital expenditures for 1 km of DN 700 pipeline of steel grades with yield strengths of Rt0.5 > 555 MPa are analysed. A summary of the limitations on world-wide use of high-strength steel for gas transmission pipelines is also provided.

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