Wear Resistance Of Clad Layer Research Articles

Elucidating the microstructure and wear behavior of tungsten carbide multi-pass cladding on AISI 1050 steel

In this work, tungsten carbide powder was clad on AISI 1050 medium carbon steel by multi-pass gas tungsten arc welding (GTAW) method. The microstructure and wear performance of the multi-pass clad layers were characterized by micro-analysis rigs and reciprocating tribometer. A local alloying process was used to synthesize a vein-like phase in the microstructure of multi-pass clad layers. The vein-like phase was identified by X-ray diffraction as Fe 3W 3C. Both the hardness and the wear performance of the multi-pass clad layers exceeded that of AISI 1050 medium carbon steel. However, under specific wear test conditions, wear loss was higher in the multi-pass clad layers than in the substrate. Further wear tests and micro-analyses were conducted to clarify the peculiar phenomenon. Experimental results suggest that some metastable phases are transformed in situ to a stable phase, which reduces the wear resistance of clad layer during the dry rubbing process.

Characteristics of multilayer laser cladding using powder mixture of Co based alloy and vanadium carbide

The powder mixture of Co based alloy (Stellite 6) and vanadium carbide (VC) in the range of 0–56 wt-%VC fraction with a constant chemical composition multilayer cladding (CCCMLC) and functionally gradient material multilayer cladding (FGMMLC) were deposited on stainless steel (SUS304) by a 2·4 kW CW CO2 laser and powder feeder. In the CCCMLC, the VC weight fractions at each layer are constant. In the FGMMLC, the VC weight fractions at each layer are varied by controlling the disc rotation speed of the powder feeder. To decrease crack sensitivity of the clad layer, influence of preheating temperature and VC weight fraction using the CCCMLC and FGMMLC on the crack sensitivity was investigated comparatively. As a result, in the FGMMLC with gradual increase in VC particles, clad at three subsequent layers shifts the critical amount of VC at which cracking appears to be the highest level, or it reduces the required preheating temperature, namely, the crack sensitivity of the clad layer using FGMMLC is lower than that using CCCMLC. On the other hand, the microstructure, Vickers hardness and wear resistance of the clad layer were investigated by an X-ray diffractometer, energy dispersion spectroscopy (EDS), scanning electron microscope (SEM), laser microscope, wear tester and hardness tester. Microstructures of the clad layer were classified into two types, hypoeutectic structure and hypereutectic structure. The wear resistance of clad layer made by CCCMLC and FGMMLC has been almost the same.

Abrasive wear performance and microstructure of laser clad WC/Ni layers

WC/Ni clad layers were produced on H13 tool steel substrates with a pulsed Nd:YAG laser and optical fibres using the injected powder technique. The effects of parameters, such as laser beam profile, WC powder shape and substrate pre-heat temperature on the clad layer microstructure and wear properties were investigated. The microhardness of the clad layers was measured using a Vickers microhardness tester. The microstructure of the clad layers was assessed by optical and scanning electron microscopy. The results show that up to 1 mm thick, fully dense and crack-free of WC/Ni clad layers can be formed on H13 substrates. The results further show that the higher is the microhardness of the clad layers, the higher is its wear resistance. Average surface microhardness values of the clad layers were as high as 650 HV. WC particle shape influences the microstructure and wear resistance of clad layer with crushed particles producing more wear resistant surfaces. The clad layers’ abrasive wear resistance was a factor of 5–10 times higher than that of unclad H13 tool steel.

Microstructure and wear resistance of NiCrBSi laser clad layer on titanium alloy substrate

Laser cladding of NiCrBSi powders on Ti-6Al-4V alloy substrate was performed, and microstructure, microhardness and wear resistance of the clad layers were evaluated. Results show that the laser clad layer is divided into three regions: the clad, the dilution and the heat-affected zones. In the clad zone, fine particles of TiB 2, TiC and M 23(CB) 6 are distributed in the matrix of the primary γ-Ni and the multi-phase eutectics consisting of γ-Ni, Ni 3B and silicides. Microhardness of the clad zone is very high, being approximately HV 1000. The dilution zone is a mixture of melted Ni-base and Ti-base alloys, and possesses a characteristic of directional crystallization. The heat-affected zone has an acicular martensitic structure, and the microhardness is HV 360–380. Compared to titanium alloy, the wear resistance of clad layer is improved. The mechanism of wearing of clad layer is a mixed type of slight peeling-off and abrasion.