NiCrBSi粉末火焰喷焊钢管的抗拉强度研究

采用氧乙炔火焰喷焊工艺在耐热钢管表面制备了镍基合金喷焊层,分别利用OM、SEM、EDS、TEM等方法分析了喷焊管表面与横截面的显微组织、形貌、元素分布及物相结构.通过拉伸实验测定了喷焊管的抗拉强度,观察了喷焊管的拉伸变形规律.结果表明,在实验工艺参数下,喷焊层内部形成了以γ-Ni固溶体为基体,呈弥散分布的富Cr针状第二相,以及硼硅酸盐玻璃相,在第二相粒子周围,γ-Ni固溶体内有大量位错缠绕.喷焊层与基体形成了冶金结合,整体抗拉强度高达522 MPa.拉伸后,钢管基体产生了延性裂纹,喷焊层发生了半脆性断裂.喷焊管同时具备了外层耐蚀耐磨性能与基材的良好韧性,综合性能有较大改善.

Investigation on tensile strength of steel tube covered with NiCrBSi spray weld coating

NiCrBSi alloy coatings were produced on refractory steel tube substrate by oxyacetylene flame spray welding.OM,SEM,EDS,TEM were used to character the coatings in terms of macrostructure,distribution of element phase structure.The tensile strength of the coatings was measured by tensile testing and the extending deformation was observed.Results made it clear that the coatings were composed of γ-Ni solid solution,dispersion distributing Cr-riched second phase and borosilicate glass phase.Abundance dislocations winding around second phase particles.The coatings and the substrate formed metallurgy bonding,so the tensile strength got 522 MPa.Ductility cracks were found in steel tube substrate and quasi-brittle fractures were observed in alloy coatings.Refractory steel tube with Ni based alloy coatings presented high intensity and nice toughness properties at the same time,then whole capabilities were improved greatly.