According to the latest news, a little batch of X90 steel pipe have been used in the third phase west-east gas project construction site.
In china ‘s oil and gas transmission pipeline construction,only in Ⅲ and Ⅳclass areas using longitudinal submerged arc welding pipe(LSAW pipes), but inⅠandⅡareas,spiral submerged arc welded pipe(SSAW pipes) have been used widely.
In the first and second phase of west to east gas pipeline project,According to the design requirements of 10 million Mpa delivery pressure and X70 grade of steel,the largest diameter of spiral welded pipe made of 15.9 mm thick plate can be up to 1067 mm in diameter.
But with the advancing of west to east gas pipeline project and increasing gas pressure, the properties of pipeline crack prevention requirements in our country has also been on rise.
We consider not only steel ductile and brittle transition temperature,improving ductile-brittle crack arrest property is very important.therefore,high-strength and large-diameter welded pipe have been required a higher impact toughness.
In the fourth and fifth west to east gas pipeline projects, high-pressure and large-diameter pipeline has become the main development direction of oil and gas transmission pipeline.
In pipeline construction,It has been measured that when raising a steel grade,in the same throughput,we can save 7% ~ 8% steel usage and pipeline construction cost by 3% ~ 5%.
therefore, X90 grade steel pipe not only conforms to the trend of the development of high strength and weight loss, also feasible on the implementation and production.
At present, X90 grade pipeline have completed correlation research that how the key element such as molybdenum,niobium elements influence the structure, realized low-carbon, high niobium and molybdenum pipeline steel basic alloy steel designation;Finished finishing reduction, finish rolling temperature, cooling rate and final cooling temperature on the structure and hardness of the steel product;Finished weld evaluation tests with different contents of niobium ring.
In December 2016, china petroleum group completed X90 pipeline blasting successfully for the first time and realize the crack arrest, which laid the foundation for the X90 pipeline steel industry application.
X90 line pipes,namely API 5L x90 according American petrol institute. More information,see WORLDIRON STEELOr call me on 86-029-83526770