激光熔覆TiB-TiC/Co基复合涂层宏观形貌研究

Study of the Macro Form of the TiB-TiC/Co-Based Composite Coatings by Laser Cladding

为了改善Q235钢表面合金涂层的成形质量,利用激光熔覆技术在Q235钢试样表面制备了TiB-TiC/Co基复合涂层,研究了工艺参数对激光熔覆TiB-TiC/Co基复合涂层宏观形貌的影响。结果表明:随着预置粉末层厚度增加,熔覆材料在基体表面的润湿性逐渐降低,基体对熔覆层的稀释率逐渐减小;随着熔覆层搭接率增加,熔覆层表面平整度逐渐增加,搭接区域均熔合良好,未出现气孔、夹杂等明显缺陷,但搭接区微观组织明显粗化;随着扫描速度增加,熔覆层表面平整度逐渐变差,润湿角和稀释率明显减小;随着激光输出功率增加,熔覆层的表面形貌、润湿角和稀释率变化规律正好相反。通过对试验结果的综合分析,使熔覆层能获得良好宏观形貌的工艺参数为:光斑尺寸为5 mm;搭接率为50%;激光输出功率为2.3 kW;扫描速度为4 mm/s。

In order to improve the forming quality of the alloy coatings, TiB-TiC/Co-based composite coatings was fabricated by laser cladding on Q235 steel.The effect of the processing parameter on the macro-forming of the TiB-TiC/Co-based composite coatings was studied.The results showed that, with the increase of the thickness of the preset powder, the wettability of the cladding coatings material on the substrate surface was gradually reduced, and the dilution effect of the substrate to the cladding coatings was gradually reduced as well.With the increase of the overlap rate of the cladding coatings, the surface flatness of the cladding coatings was gradually increased, and the fusion of the overlap area was good and no obvious defects such as pores and inclusions were observed.However, the microstructure of the overlap area was obviously coarsened.With the increase of the scanning speed, the surface smoothness of the cladding coatings was decreased, and the wetting angle and dilution rate were obviously decreased accordingly.With the increase of the laser output power, the surface morphology, wetting angle and dilution rate of the cladding coatings were changing to the opposite.Based on the comprehensive analysis of the test results, good macro forms of the cladding coatings could be obtained with the process parameters of the spot size of 5 mm, the overlap rate of 50 %,the laser output power of 2.3 kW and the scanning speed of 4 mm/s.