激光-感应复合熔覆Ni基WC复合层的工艺研究

为了提高熔覆效率与消除熔覆层的裂纹,采用激光-感应复合熔覆的方法在A3表面获得了无气孔与裂纹的Ni基WC复合层。研究了不同的加工参量对复合层质量的影响,结果表明,随着激光比能的增加,粉末面密度增加;在相同的激光比能条件下,随着粉末面密度增加,熔覆层的高度增加,稀释率减小;在相同的粉末面密度条件下,随着激光比能的增加,熔覆层的宽度略有增加。此外,相对于单纯的激光熔覆技术,激光-感应复合熔覆的效率约可以提高5倍。在激光-感应复合熔覆过程中,熔覆层与基材间的温度梯度大大降低,这是Ni基WC复合层无裂纹的关键原因。

Process study of Ni-based WC composite coatings by means of laser-induction hybrid cladding

To increase the cladding efficiency and eliminate the cracks in the cladding layer,laser-induction hybrid cladding was adopted to obtain Ni-based WC composite coatings without porosities and cracks.The influence of processing parameters on the composite coatings by means of laser-induction hybrid cladding was investigated.The results showed that the area density of deposition powder had an increase with increasing laser specific energy.At the same laser specific energy, the cladding height increased and the dilution decreased with increasing area density of deposition powder.When the area density of deposition powder kept constant, the cladding width slightly increased and the contact angle decreased with increasing laser specific energy.Moreover,due to introduction of induction heater,the efficiency of laser-induction hybrid cladding was increased about five times higher than that of the individual laser cladding.As a result,the temperature gradient during laser-induction hybrid cladding was much lower than that during the general laser cladding, which was the main reason that no cracks appeared in Ni-based WC composite coatings.