Effect of Laser Metal Deposition Parameters on the Characteristics of Stellite 6 Deposited Layers on Precipitation-Hardened Stainless Steel

Laser metal deposition (LMD) is one of the manufacturing processes in the industries, which is used to enhance the properties of components besides producing and repairing important engineering components. In this study, Stellite 6 was deposited on precipitation-hardened martensitic stainless steel (17-4 PH) by using the LMD process, which employed a pulsed Nd:YAG laser. To realize a favor deposited sample, the effects of three LMD parameters (focal length, scanning speed, and frequency) were investigated, as well as microstructure studies and the results of a microhardness test. Some cracks were observed in the deposited layers with a low scanning speed, which were eliminated by an augment of the scanning speed. Furthermore, some defects were found in the deposited layers with a high scanning speed and a low frequency, which can be related to the insufficient laser energy density and a low overlapping factor. Moreover, various morphologies were observed within the microstructure of the samples, which can be attributed to the differences in the stability criterion and cooling rate across the layer. In the long run, a defect-free sample (S-120-5.5-25) possessing suitable geometrical attributes (wetting angle of 57 degrees and dilution of 25.1%) and a better microhardness property at the surface (approximate to 335 Hv) has been introduced as a desirable LMDed sample.

Automated summary

In this study, Stellite 6 was deposited on precipitation-hardened martensitic stainless steel (17-4 PH) using the LMD process with a pulsed Nd:YAG laser. The effects of focal length, scanning speed, and frequency on the sample properties were investigated to eliminate cracks and defects, leading to the introduction of a defect-free desirable sample with improved microhardness properties.