中文摘要：

采用热模拟试验方法、力学性能测试技术及显微分析技术研究了加热温度对X80钢级热煨弯管组织性能的影响规律。结果表明，随着加热温度的升高，X80热煨弯管强度升高，塑韧性降低。加热温度为950℃时．组织形态以粒状贝氏体及贝氏体铁素体为主，辅之少量的软相组织，其优良强韧性的获得归因于细小的有效晶粒尺寸及多相分布的混杂组织单元；加热温度高于1050℃时，横贯奥氏体晶界的粗大贝氏体铁素体板条结构的存在可导致韧性的严重恶化；处于两相区加热温度为850℃时．多边形铁素体的存在不利于强度水平的提高。

英文摘要：

The effects of heating temperature on microstructures and properties of X80 grade heating bending were studied through thermal simulation, mechanical property test and microscopic analysis. The results showed that the strength of X80 grade hot-bending bends increases while plasticity and toughness decrease with the heating temperature increasing. When the heating temperature is 950 ~C, the microstructures of the experimental steel mainly consist of granular bainite and bainitic ferrite, including some soft-plastic mixture microstructure, and a better combination of strength and toughness can be obtained due to the fine effective grains and the mixed multiphase mierostructare. The coarse BF laths traversing the austenite grain boundary can lead to a severe deterioration of the toughness when heating temperature is above 1 050 ℃. The PF is not in favor of the strength improvement when heated at 850 ℃ in the two-phase region.