T91锅炉热强钢管焊接性能的试验研究

以国产焊接用T91锅炉热强钢管为主要研究对象,根据焊接线能量、焊前预热和焊后热处理等条件对焊接的影响设计了试验的正交方案,并用硬度试验、断口扫描、电镜观察等多种试验和分析方法对其焊接成品进行了焊接性和冷裂敏感性等方面的研究。结果表明：采用焊前预热150℃以上、小热输入多层焊、焊后（770±10）℃、1 h高温回火工艺能降低T91钢焊接热影响区的淬硬倾向及焊接接头中的扩散氢含量,使得马氏体中的碳得到充分的扩散以形成回火索氏体,改善了T91钢管接头的韧塑性。

Test and Research on Welding Performance of T91 Refractory Steel Tube of Boiler

Domestic T91 refractory steel tube of boiler for welding is mainly studied. According to the influence of weld line energy, pre-welding warming and post-welding heat treatment, etc. on welding, orthogonal test plan is designed; such aspects as weldability and cold crack sensitivity of the welded part are studied by multiple testing and analyzing methods including hardness test, fracture scanning and observation based on scanning electron microscope（SEM）. The findings show that adopting a pre-welding warming temperature above 150 ℃ , multi-layer welding with little welding heat input, （770 ± 10 ℃ ）after welding and high-temperature tempering for 1 h can reduce the quench hardening tendency of the T91 steel heataffected zone（HAZ）and the diffusible hydrogen content in weld joint, thus enabling sufficient carbon diffusion in martensite to form tempering sorbite, improving the toughness and ductility of T91 steel tube joint.