异种钢水下摩擦柱/锥塞焊接头组织及性能

应用X65、Q235C、Q345C和316L塞棒与X65母材塞孔配合对异种钢水下摩擦柱/锥塞焊过程进行试验研究,探讨塞焊缝区微观组织、显微硬度及力学性能变化规律。试验表明:在转速7 000 r/min、塞棒消耗量14 mm、焊接压力分别为30~50 k N和20~40 k N范围内,用X65和Q345C塞棒可获得无缺陷异种钢水下摩擦柱/锥塞焊接头。异种钢塞焊缝组织均与原始组织有明显差异,塞焊缝区域主要为贝氏体或马氏体或其混合组织特征;X65和Q345C塞棒均形成有效扩散冶金连接,结合界面处具有带状细小铁素体组织特征;316L塞棒与X65塞孔很难形成无缺陷摩擦柱/锥塞焊接头。异种钢塞焊缝区硬度普遍高于其母材,这种高匹配摩擦柱/锥塞焊缝接头有利于抗拉强度的提高,但塞焊缝附近的高硬化倾向将降低异种钢塞焊接头的塑性。研究结果为开发基于等静压摩擦柱/锥塞焊接技术的海底管线修复技术提供重要试验依据。

Study on the Microstructures and Properties of Underwater Friction Hydro Pillar/Taper-Pillar Welded Joints for Dissimilar Steels

The testing investigations of underwater friction hydro pillar/taper-pillar welded joints for dissimilar steels are performed by using the X65,Q235C,Q345C and 316L steel pillar combined with X65 base metal,and the varying regularities of microstructures,microhardness and mechanical properties for plug welded joints are discussed.It is found that the dissimilar steel underwater friction hydro pillar/taper-pillar welded joints with free defects can be obtained by using the X65 and Q345C steel pillar under the welding conditions of rotational speed 7 000 r/min,pillar consuming length 14 mm,welding axial forces in 30-50 kN and 20-40 kN ranges respectively.The microstructures of dissimilar steel plug welds are obviously different from that of original materials,the plug welds are composed of bainite or Martensite or their mixture structures;The effectively diffusing metallurgical bonding have been produced by using X65 and Q345C steel pillar and the bonding interfaces are possessed of the features of fine banded ferrite microstructures;but the plug welded joint of 316L steel pillar and X65 plug hole with defect free are hardly obtained.The microhardness values of plug weld zones are generally higher than that of base metal,and these high matching welded joints are beneficial to the increase of tensile strength,however the high hardening tendency around the plug welds should obviously reduce the plasticity of dissimilar steel plug welded joints.The testing results should provide the important testing data to develop the repairing techniques of marine pipeline based on the friction hydro pillar/taper-pillar welding technologies.