论文部分内容阅读
Hot-rolled wide strip for production of large diameter,heavy gauged(up to 19 mm) helical line pipe grade X80 was a priority development over the last three years.Microstructure,texture and mechanical properties of strips have been characterised.Also the welding conditions have been simulated.The favourable microstructure is achieved by the proper selection of an appropriate chemical composition of low carbon content and increased niobium micro alloying in combination with suitable strictly controlled hot-rolling parameters.The addition of niobium in combination with the adjustment of other alloying elements increases the recrystallisation stop temperature and thus makes it possible to apply a high temperature processing(HTP) concept.The homogeneous bainitic microstructure across the strip gauge is then formed during accelerated cooling on the run-out table of the hot-rolling mill.All results indicated excellent properties of these hot strips which make it suitable for spiral pipes of grade X80 for example 18.9mm×Φ1 220 mm at dimension.
Hot-rolled wide strip for production of large diameter, heavy gauged (up to 19 mm) helical line pipe grade X80 was a priority development over the last three years. Microstructure, texture and mechanical properties of strips have been characterized. Als the welding conditions has been simulated. The favourable microstructure is achieved by the proper selection of an appropriate chemical composition of low carbon content and increased niobium micro alloying in combination with suitable strictly controlled hot-rolling parameters. The addition of niobium in combination with the adjustment of other alloying elements increases the recrystallization stop temperature and thus makes it possible to apply a high temperature processing (HTP) concept. The homogeneous bainitic microstructure is then formed during accelerated cooling on the run-out table of the hot-rolling mill. All results indicated excellent properties of these hot strips which make it suitable for spiral pipes of g rade X80 for example 18.9mm × Φ1 220 mm at dimension.