摘要
在镍基自熔合金粉末中添加质量百分比为2%的Cu、3%的Mo元素,利用氧乙炔火焰喷焊工艺在锅炉钢管表面制备镍基合金喷焊层,分别应用OM、SEM、EDS、TEM等方法分析喷焊管表面与横截面的显微组织、形貌、元素分布及喷焊层的物相结构。通过压弯实验测定喷焊管的弯曲强度,观察喷焊管的弯曲变形规律。结果表明,喷焊层内的基体相为γ-Ni固溶体,基体相内有针状Cr、Mo碳化物第二相弥散分布,Cu、Mo在γ-Ni基体相内有固溶分布,Mo对针状第二相也有明显的强化,第二相很细,很长,分布很均匀。在第二相粒子周围,γ-Ni基体相内有大量的位错环组织,第二相弥散强化效果与合金元素固溶强化效果明显,喷焊层弯曲强度高达788MPa。弯曲试验后,喷焊层脆性断裂,钢管基材发生弯曲而没有裂纹。
2% Cu and 3% Mo in weight were added in Ni-based self-fluxing alloy powder. This powder was used to produce refractory steel tube covered with coatings by oxyacetylene flame spray welding techniques. Many instruments such as OM, SEM, EDS and TEM were applied to observe microstructure and analyze distributions of elements, phases in coatings. The deformations of the steel tube were studied, after the bending strength was determined by three-points bending tests. Results showed that the matrix phase of spray welding coatings was γ-Ni solid solution, and in the matrix phase there were needle shaped Cr, Mo carbide second phases. Cu Mo distributed in γ-Ni solid solution, while Mo had influence on second phases. Second phases were very thin, long and distributed uniformly in γ-Ni solid solution. Around second phase particles, large amount of dislocation loops formed in the γ-Ni matrix phase. Dispersion strengthening by second phases and solution strengthening for alloy element had a visible effect, bending strength of the specimens get 788 MPa. After bending test, brittle fractures occurred in spray welding coatings, but no fracture in substrate tubes.
出处
《黑龙江大学工程学报》
2013年第3期108-112,共5页
Journal of Engineering of Heilongjiang University
基金
黑龙江省教育厅科学技术研究项目(12511427)
关键词
氧乙炔火焰喷焊
镍基合金粉末
弥散强化
弯曲试验
oxyacetylene flame spray welding
Ni-based alloy powder
dispersion strengthening~ bending test
