Effect of Different Heat Source Heating on Microstructure and Wear Resistance of Iron-Based Alloy Layer
Surface engineering technology has become an indispensable multi-disciplinary technology in industrial production. It is the most economical and effective way to change the surface of materials to obtain the desired performance. Among them, the self-fluxing alloy powder thermal spray welding technology is easy to obtain, and it is easy to obtain a high-performance spray-welded layer which is different from the substrate but forms a metallurgical bond with the substrate, and has been manufactured and repaired in industrial parts with special performance requirements. Widely used on the topic. At present, the widely used self-fluxing alloy powders are classified into iron-based, cobalt-based, and nickel-based. Iron-based self-fluxing alloy powders are characterized by relatively low cost, but have a higher melting point and a lower self-fluxing and oxidation resistance than nickel-based and cobalt-based ones. In this experiment, based on the different heating characteristics and mode of the heat source, the intermediate frequency induction heat source and the arc heat source are used to find a heating method more suitable for the Fe55 self-fluxing alloy, so that the microstructure of the deposited layer is well improved, and the hardness and resistance can be further improved. Grindability, resulting in better performance.
The base material is 45 steel, and the surfacing material is Fe55 self-fluxing alloy powder. Its chemical composition (mass fraction, the same below, %) is: 0.8C, 18Cr, 4Si, 14Ni, 3B, the rest is Fe; particle size 75μm (200 Project). Fe55 was uniformly mixed with 5% WC and 3% SiC by mechanical mixing, and dried at 150 ° C for 2 h. The uniformly mixed alloy powder is bonded and pressed with water glass to a thickness of 2 mm, and the carbon dioxide gas protection welding process parameters are: welding current 260 A, welding voltage 24 V, welding speed 80 mm/min, and protective gas flow rate 10 L/min. The mixed deposited powder was preliminarily placed on the surface of the base sample by a bonding preset method, and the thickness was set to 1.5 mm and dried at 150 ° C. The medium frequency induction heating current-time is 75A-2min, 85A-4min, and the powder is melted uniformly and the slag is removed, the heating is stopped, and the air is cooled.
The microstructure of the deposited layer obtained by arc welding is mainly martensite, and there are also reinforcing phases such as Cr23C6, Fe23 (C, B) 6, and W3Cr12Si5. In terms of wear resistance of Fe55 self-fluxing alloy powder, the wear layer obtained by arc welding is better than induction welding, and the wear resistance of the former is more than twice that of the latter.
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