Extreme High -Speed Laser Cladding (EHLA) is a new process category of laser cladding. In this study, EH-LA layer was characterized by comparing with conventional laser cladding (LC) layer. Basic SUS316L layers, as well as WC-reinforced SUS316L layers, were formed on SUS304 substrates using both LC and EHLA processes. The macroscopic morphology, microstructure, microhardness, wear resistance, and residual stress of the four types of layers were evaluated. As a result, EHLA layers exhibited slightly higher micro-hardness and less wear loss than that of LC layers, despite the presence of more micropores. This can be due to their finer dendritic structures. Furthermore, residual stress of EHLA layer was lower than that of LC layer due to those micropores. Additionally, EHLA can add up to 45 wt.% WC into SUS316L layer without crack formation, resulting in higher wear resistance than that of LC where crack formation occurred at 25 wt.% WC. This enhanced crack resistance in EHLA is believed to be due to the less heat input during deposition.

In Laser Cladding, a differentiation must be made between cladding by brazing and cladding by welding regarding process parameters and the resulting material properties. Results of investigations of bronze cladding on steel parts produced by Laser Deposition Brazing will be presented. This means that a strong metallurgical bond is realized by diffusion processes by Laser Deposition Brazing, but the steel base material is not molten. The coatings were characterized by hardness distribution measurements from the bronze cladding to the steel substrate, by measuring the size of the heat-affected zone and by porosity measurements. This combination of a steel substrate and a local bronze coating is used industrially in many tribological applications, such as plain bearings or hydraulic pumps etc. The bronze offers excellent tribological properties. In some cases, the bronze is used as a complete solid part. However, applying the bronze locally to a steel base body instead of using a complete solid bronze component, offers the advantage of the higher modulus of elasticity of the steel, which provides greater stability of shape with regard to possible elastic deformations as these coated parts are exposed to high mechanical loads, it is essential that a high coating quality is achieved by laser cladding and that the properties are extensively and purposefully characterized. The production technology, the characterization and the industrial applications of such bronze coated steel parts are presented and explained in this contribution.

Laser cladding shows an increasing interest to apply high-quality tailored surface coatings, as well as 3D-deposits for repair and additive manufacturing of metallic parts. The industry is requesting powerful technologies that maintain the quality advantages of the laser technology, but also make the process more productive, as well as time and cost efficient. At Fraunhofer IWS a Laserline fiber-coupled diode laser of 20 kW power has been employed for over a decade to develop competitive coating solutions. The deposition rates achieved with this technology are comparable to those of common PTA technique, while at the same time bringing significant advantages in terms of reduced heat affected zone, distortion and savings in material resources.

In this study, pure spherical Ta powders made by induced plasma sphero technique were used in the laser cladding process. The powders were sent into high-energy laser zone and were melted at the surface of a steel substrate to create a Ta layer. The microstructure development in the Ta layer was investigated in a scanning electron microscope. The results showed that the layer was basically dense with some pore/crack defects. In the layer, typical dendritic crystalline structures were formed. With the help of an energy dispersive spectroscope, Fe was detected in the Ta layer. The top surface had about 5% Fe while at the bottom of the cladded layer 15% Fe was detected. So, the diffusion of Fe upwards occurred. With the participant of Fe, the microstructure of the Ta layer was changed. Thermocalc software was used to simulate the phase constitution at different Ta-Fe compositions. The results by the simulation basically agreed with the experimental observations.

Laser cladding is a technology that uses high-energy-density lasers to quickly melt and solidify alloy powder on the surface of the metal substrate to form a cladding layer with good performance. The alloy powder composition has a significant impact on the cladding layer performance, including hardness, wear resistance and corrosion resistance. In this work, the effect of Nb content on the microstructure types and phase precipitation rules in the martensitic stainless steel laser cladding layers was investigated through the thermodynamics software. The martensitic stainless steel cladding layers with different Nb content was fabricated on the 45# steel substrate by the laser cladding. The microstructure and element composition of the cladding layers were analysed by the scanning electron microscope (SEM) and the energy spectrum analyser (EDS). The hardness, wear resistance and corrosion resistance of the cladding layers were also discussed. The results show that the amount of Cr element in carbide (boride) gradually decreases, while the amount of Nb element in carbide (boride) gradually increases, with the increasing Nb element content from 0.6 wt.% to 2.2 wt.%. For the performance of the cladding layer, the increase in the content of Nb makes the hardness and wear resistance of the cladding layer increase first and then decrease, but the corrosion resistance gradually increases. Generally speaking, the comprehensive performance is better when the Nb element content in the cladding layer is about 1.4 wt.%. At this time, the microhardness of the cladding layer is about 780.00 HV 0.2 , and the self-corrosion potential is -350.87 mV.

In order to improve the quality of coating, the causes of defect are analyzed in this paper. The research innovative uses single factor experiment combined with MATLAB to fit out the relationship between porosity and laser power, scanning speed, thickness, overlap rate. The multivariate quadratic equation is derived in this paper. It provides a solution to avoid defects in the aspect of laser cladding process.