| It is quite clear that the general development tendency for pipeline steel exploration is to develop high grade and large-diameter sized steel.High anti-crack performance of acicular ferrite X70 pipeline steel has been commercialized in applications in "West-to-East Gas Pipeline Project".Gas pipeline steel generally becomes the first choice in industrial developed countries in 21st century.The requirement of this X80 grade steel keeps increasing.Pure steel smelting,inclusion morphology control,HAZ microstructure control,reduce slab center segregation,slab reheating temperature control,controlled rolling,texture controlling and accelerated cooling on behalf of the mainstream on the production process of pipeline steel,which makes X80 pipeline steel component design and metallurgical technology to a higher level,so its production become the comprehensive embodiment of the technology and equipment level of iron and steel enterprises.The trial production of X80 pipeline steel hot rolled coil by steel 1750mm hot strip mill.Steelmaking plant by low carbon Nb-V-Ti microalloyed composition system,alloying elements Mo,Cr,Cu,Ni low alloy;Hot rolled take controlled rolling,mandatory accelerated cooling process to control the organization of the final product,with high strength and high toughness low carbon acicular ferrite ferrite structure.The X80 hot-rolled coil steel which was used in spiral submerged arc welding pipe of natural gas pipeline project were successfully trial-produced.The testing results showed that the products have particularly pure and homogeneous tiny structure.The microstructure is just as the typical needle-like ferrite pipeline steel which possess high strength and high toughness at low temperature and high temperature dynamic tear resistance but with band structure of Pearlite-phase-free.The size of 11 ×1550×C mm adapted to the X80 hot-rolled coil technology match the requirements of spiral submerged arc welded pipe which is used in Tarim oil field pipeline construction.it can achieve a large number of supply.The size of the specification 18.4×1550×C mm of the X80 hot-rolled coil steel satisfy the technical demand of the "West-to-East Gas Pipeline Project".The performance of 1219 mm spiral submerged arc welded pipe which is made by tube mill could meet the spiral welded pipe specification requirements of the second-pipeline-engineering of"West-to-East Gas Pipeline Project".We will be succeeding in producing X80 pipeline steel in 1750 hot rolling unit in Xinjiang Bagang Iron and Steel Company. |
