Abstract:
Heat treatment is an important method for modifying the properties of metallic materials. It enhances the material loading support during operational process. Therefore, heat treatment was applied in industries to efficiently improve microstructure properties, the hardness and the strength of the welded joints. This paper aimed to investigate the influence of the solution treatment parameters on mechanical properties and microstructure properties of welding aluminum on SS400 carbon steel surface.
The specimens for heat treatment, mechanically cut into the identified dimensions, was the weld of aluminum on SS400 steel plate produced by GTAW process with the welding current of 250 A and the welding speed of 100 mm/min. The parameters of solution treatment process included the heating temperature of 350-740 degree Celsius the holding time of 1-3 hours, and the ageing time of 5-15 hours. After the solution treatment, the specimens were mechanically sheared, grounded, polished, and then the hardness, the strength and the microstructure properties were examined.
The research revealed that with the solution treatment temperature of 350-740 degree Celsius for 3 hours, the hardness of welds was 305, 263, and 234 HV, respectively. The increase in the temperature and heating time during the solution treatment resulted in a higher thickness but lower hardness of intermetallic compound layer of the joint interface. The minimum hardness of the improved joint was 202 HV when the joint was treated at solution-heated temperature of 740 degree Celsius for 3 hours.