Study On The Laser Cladding Of Tire Mold

The rubber tire is processing under extreme environmental conditions of a high temperature oxidation and acid-corrosion. This means that the tire mold needs to require a very high performance in tire vulcanization process. Generally, electroplating method is employed in order to improve the high temperature oxidation resistance of tire mold, but the coating prone to peeling in this procession. As an advanced surface modification technology, with the powder coating and the thin surface layer of substrate melting, laser cladding is to form a good metallurgical combine between the coating and substrate in a quick cooling condition. The dilution rate is controllable to ensure the excellent performance of coating is not changed. Due to the nice performance, the self-fluxing alloy powder of nickel-based and JG-2iron-based austenitic stainless steel is widely used now. They both possess high temperature oxidation resistance, corrosion resistance, moderate hardness, a good wettability between the coating and substrate and many other excellent properties.In this paper, Ni25, JG-2, NiCrAlY, NiCrAlYBSi is prepared on the35#steel substrate by laser cladding to improve the oxidation resistance of the substrate surface. We study the similarities and difference between the nickel and iron-based material in improving the oxidation resistance property. Meanwhile, we also study the effect of B, Si addition on the microstructure and properties. We study phase composition, microstructure morphology, micro-ingredients, microhardness distribution, oxidation resistance properties by X-ray diffraction, scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), micro-hardness, thermal gravimetric analysis (TGA) systematically.The results of the study show that both nickel-based and JG-2iron-based austenitic stainless steel can improve the oxidation resistance greatly. Primary phase γ-Ni and eutectic composition Ni3B, Ni3Al is existed in the nickel-based alloy coating. However, single phase austenite is existed in the iron-based alloy coating. They are very similar in the microstructure. Both form the plane crystal in the interfacial binding region. The microstructure gradually developed into columnar crystals (thick dendrites or cellular dendrite) upwards vertically. Difference between the cooling rate and temperature gradient promote the occurrence of this phenomenon. NiCrAlYBSi coating has a much smaller microstructure than NiCrAlY coating. Certainly,NiCrAlYBSi coating has a higher hardness and oxidation resistance than NiCrAlY coating.