Assorted Difficulties We May Encounter In The Research of 120X Pipeline Steel

Jun 2
09:55

2015

tracy chen

tracy chen

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Mainly list the six kinds of difficulties we may encounter in the research of 120X pipeline steel.

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In the steel pipeline series used in oilfield,Assorted Difficulties We May Encounter In The Research of 120X Pipeline Steel Articles X120 steel pipeline, due to its safety and reliability, large throughput, cost reduction and other advantages, has been a new development trend at current stage.X120 steel pipeline will be widely used in natural gas pipeline industry.X120 steel typical microstructure is bainite steel. The difficulties in the research and development are as below:1, X120 technical requirements higher than X65 and X80.Carry on the strict technical control of the system in the material design, steelmaking, casting, steel production and steel pipe production (seamless steel pipe or welded steel pipe).2, X120 must has low yield ratio.The higher the yield ratio, the higher the utilization rate of the materials. While with the increase of the yield ratio, the amount of plastic deformation of materials before rupture gets smaller, namely the small plastic reserves, poor reliability, once overload easy to suddenly fracture.3, X120 steel pipeline is large diameter steel for high pressure conveying, which can improve the efficiency of delivery, and thin-walled steel pipe can also reduce piping construction cost at the same time. But with the thinning of wall thickness and increase of pressure, it requires a higher crack arrest toughness. Therefore X120 advanced steel pipeline must optimize the relationship between the crack arrest toughness and the wall thickness thinning.4, for X120 high strength steel pipeline, plate specimen due to the yield strength reduction in the process of pressing, it turns inaccurate; Ring expansion test, due to time consuming and high cost, is not suitable for industrial production; Round bar specimens can prevent the Bauschinger effect, but the size is too small, not enough to represent dimension performance of the steel pipe. The yield strength of the accurate measurement also need further research.5, compared with the ordinary steel pipeline, X120 has higher requirements of the welding material, welding material should have match the parent metal outside also should have enough toughness, strength and weld strength and toughness is inversely proportional general relationship, the higher the intensity, the lower the toughness. So to develop good weldability of high strength, high toughness of welding metal wire and flux is urgent.6, in the welding process of X120 steel pipeline, both considering the strength and toughness of weld metal, making smaller matching. For X120, the weldability of the base metal, HAZ softening, weld metal performance all need further research.