The important factors for structure and mechanical properties in the repair of iron base metal component by thermal spray and welding processes

Cast iron is widely used in the manufacturing industry due to its high strength and wear resistance properties. However, cast iron's brittle nature results in frequent failure of cracks during formation or use. Among the repair methods that can be used are thermal spray and the welding process. Even though both welding and thermal spray have been implemented for various metal repairs processes, however very limited technical reports as well as scientific papers are found for this topic. Therefore, the optimum condition of metal repair by both processes is still needed to be explored. The present works focus on the comparison between thermal spray and welding method for cast iron repairs purposes. In the experiment of thermal spray process focus has been given in optimizing spraying distance on microstructure and hardness properties. On the other hand, in the welding experimental works focus has been given on the influence of groove design on microstructure and hardness. Each research variable is carried out to obtain optimal crack repair results. It was observed that thermal spray process produces less Heat Affected Zone (HAZ) area compared to the welding process therefore having less critical area. The highest hardness value of thermal spray method is 101.33 shown by 30 cm spraying distance. Meanwhile, the highest hardness value of HAZ area of welding method is 600 HV shown by specimen A. It was obtained that from the present experimental works, thermal spray process produces better results than welding process. However, the value of the specimen hardness produced by the welding and thermal spray method depends on the type of coating material used