Influence of Laser Beam Power and Scanning Speed on the Macrostructural Characteristics of AISI 316L and AISI 431 Stainless Steel Depositions Produced by Laser Cladding Process

Abstract

In the laser cladding process, control of the process parameters and knowledge of the characteristics of the materials used are essential for obtaining depositions with excellent metallurgical union, satisfactory dilution values, absence of defects, and acceptable geometric characteristics. Without such precautions, depositions can exhibit low or excess dilution, low wettability, and the presence of pores, consequently reducing the performance of the materials. The aim of the present work was to evaluate the effects of the laser beam power, with maximum power of 4000 W and continuous wave mode, and scanning speed in laser cladding processes employing the AISI 316L austenitic stainless steel and the AISI 431 martensitic stainless steel, considering the geometric characteristics, dilution, and structural defects of the depositions. It was found that the laser power had a greater effect on the width and dilution of the depositions, while the scanning speed influenced the deposition height. The depositions of AISI 431 steel presented dilution values between 9 and 25%, using power settings between 1400 and 1600 W. The depositions of AISI 316L steel required higher power values between 1900 and 2600 W to achieve dilution values between 15 and 41%. The existence of pores and satisfactory hardness values were observed for both materials, with the average of microhardness of 522 HV0.5/15 and 356 HV0.5/15 on the AISI 431 and AISI 316L depositions. It was also found that the different characteristics of the addition metals, considering their morphology, particle size distribution, and flow rate, led to significant changes in the geometric features of the depositions.