| With the development of society, the traditional hydro power and thermal power can not meet the demands of contemporary society’s development, therefore, the study of new power generation methods is imminent. Tidal power is taken more and more seriously by humans as a clean energy because of its highly reliability, low loss, etc. However, tidal power station hydroelectric generating component has to dip in the sea or in the air filled with salt spray and eroded by the tide for long time, So, the material of the component has to be high quality metal material. It not only needs to have high strength and toughness, but also a strong resistance to pitting, crevice corrosion and stress corrosion. Duplex stainless steel(DSS), due to its higher mechanical properties (high strength,toughness and ductility) and excellent resistance to chloride corrosion and pitting resistance, as well as low cost, Duplex stainless steel conforms the performance requirement of the material of tidal power station hydroelectric generating component. Because welding is one of the main processing methods of such material’s structure,so it is very important to research the duplex stainless steel welding performance and properties of welded joints.In this paper, the study has adopted welding thermal simulation method to reproduce welding thermal cycle in heat affect zone(HAZ) of as-rolled and as-cast 2205 duplex stainless steel by using thermal/mechanical simulation. Using optical microscopy,scanning electron microscopy(sem),impact testing machine and electrochemical workstation to study the different welding thermal cycle’s effect of the microstructure and mechanical properties of as-rolled and as-cast 2205 duplex stainless steel. According to the result to get the available parameters of welding process, implement the welding experiment for the as-rolled and as-cast 2205 duplex stainless steel. Study effects of the solution treatment temperature and aging treatment of microstructure and mechanical properties of as-rolled and as-cast 2205 duplex stainless steel, by doing the thermal treatment to the welding joint after welding.Experimental results show that the peak temperature has little effect on microstructure and mechanical properties of 2205 DSS welding HAZ and so does cooling rates between 800-500℃(t8/5), while, if the t8/5 is slower than 10℃/s, the impact toughness and corrosion resistance of duplex stainless steel heat affected zone can significantly reduce. The cooling rates between 1350-800℃(t800)have great effect on microstructure and mechanical properties of 2205 DSS welding HAZ. When the t800 is 80℃/s, the hardness of HAZ of duplex stainless steel is the highest, worst impact toughness; when the t800 is 20℃/s, The corrosion resistance of duplex stainless steel heat affected zone is the best. After the actual welding,when the solution temperature is about 1050-1000℃,the welding joints have good impact toughness and microstructure. While the aging treatment temperature has little effect on welding joints. |
