镍基涂层钢管金相分析与弯曲强度测试

Metallurgical Analysis and Bending Strength Test of Steel Tubes Covered with Ni-based Coatings

在锅炉钢管表面制备了镍基合金喷焊防护层,利用OM、SEM、EDS、TEM等仪器观察分析,结果表明:涂层与基材形成冶金结合,涂层内基体相为γ-Ni固溶体,针状Cr的碳化物周围有大量位错组织,针状相在γ-Ni固溶体内形成弥散强化,喷焊层弯曲强度高达675MPa左右,弯曲后喷焊层脆性断裂,锅炉钢管基材及结合层没有裂纹。

Ni-based alloy spray welding coatings were prepared to protect boiler steel tubes. Results got by many instruments such as OM, SEM, EDS and TEM showed that metallurgical bonding was formed between the steel tube and the coating, matrix phase in coatings was y-Ni solid solution, and needle shaped Cr carbide second phases surrounded with dislocation loops were found in y-Ni solid solution. Dispersion strengthening in coatings of the second phases made bending strength of the coatings as high as 675 MPa. Brittle fracture occurred in the coatings and no crack took place in boiler steel tubes.