Optimization of Process Parameters, Microstructure, and Properties of Laser Cladding Fe-Based Alloy on 42CrMo Steel Roller

Abstract

The mould foot roller is a key component of a continuous casting machine. In order to investigate the possibility of using laser cladding to repair mould foot roller, Fe-based powders and 42CrMo steel are used in this work. The laser cladding process parameters were optimized by orthogonal experiments. The chemical compositions, microstructure, properties of the cladding layer under the optimum process parameters, and substrate were systematically investigated by using optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), microhardness test, wear test, and salt spray corrosion test. The results indicate that the primary factor affecting the width and depth of the cladding layer is laser power. The scanning speed also has a significant effect on the height of the cladding layer. The optimum process parameters for repairing the mould foot roller are 2 kW laser power, 4 mm/s scanning speed, and 15 g/min feeding rate of powder. Along the depth direction of the cladding layer, the microstructure of the coating gradually transforms from plane crystal, cell grains, or dendrites to equiaxed grains. The matrix is mainly martensite with retained austenite; the eutectic phase is composed of netlike M2B, particulate M23(C,B)6, and M7(C,B)3 phase. The hardness of the cladding layer is significantly improved, about three times that of the substrate. The weight loss of the cladding layer is just half that of the substrate. Its wear resistance and corrosion resistance have been significantly improved. The work period of the laser cladding-repaired foot roller is much longer than for the surfacing welding-repaired one. In summary, laser cladding technology can increase the life of mould foot rollers.

Numerical Simulation of Thermal Conductivity of Foam Glass Based on the Steady-State Method

“…Orthogonal experiment design is used to study multi-factor and multi-level methods. According to the orthogonality, some representative factors can be selected from the experiment for testing [28]. These representative factors are characterized by features like uniformly dispersed, neat and comparable.…”

Investigation on the Microstructure and Wear Behavior of Laser-Cladded High Aluminum and Chromium Fe-B-C Coating

“…The interface bonding zone is a thick planar crystal, which gradually develops into columnar crystal and dendritic crystal of the cladding layer. The microstructure of coating mainly depends on the ratio value of temperature gradient G to the solidification rate R [23]. There is a large temperature gradient at the interface between the substrate and the molten pool, the solidification rate R tends to zero, this makes the G/R value tends to infinity.…”

Surfacing – Technologies and Layer Properties (A Review)

“…When the aim is to obtain intermetallic compounds with the metal of the substrate in the coating, this can be achieved by adding the second metal in the form of a powder [23]. High cooling rates using heat sources with high energy concentration such as electron beam surfacing (EBS) [25], [26], [27], [28] and [29] or laser surfacing (LS) [30] - [39] creates conditions for modifying the surface layer even without the use of filler materials [25] or after a surfacing process has been performed [3], [26]. The electron beam process is also used for sintering [27] of powder mixture to form layers.…”