A Study Of Cast Steels And Heat Treatment For Trough Walls Of Scraper Conveyors

Central groove ledge, as the major part of the central groove which is one of most significant component of the scraper conveyor undertakes its main loading force in the coal-mining process, and plays a great role in the daily operation. This paper mainly focuses on improving the mechanical and welding properties by adjusting composition ratio as well as heat treatment process to make a better understanding of the ledge material, which is easily worn out and corrosive under the working conditions.The experimental steel based on ZG30 Si Mn is investigated by reducing carbon content and adding a certain amount of alloy elements like Cr,Mo and V, as well as some rare earth elements. Low alloy casting steel and RE casting steel were treated by quenching, tempering, normalizing, Q-P and Q-P-T respectively. And then the mechanical properties and weldability of samples are tested and the test results are as follows:(1) the alloying elements, as Cr, Mo and V, have a strengthening effect on the tested steel;(2) Among the five quenched and tempered casting steel, ZG26 Si Mn Mo V performs the best mechanical properties after being quenched and tempered at 920℃ and 580℃, respectively, and the strength could be reaching 1000 MPa, elongation at least 18% and impacting energy over 40 J at room temperature;(3)The strength and hardness of RE steel quenched and tempered and normalized have a certain degree of improvement, but the ductility and toughness relatively decrease due to the inclusions found in the microstructure of the fracture;(4)Three of the five casting steels treated by Q-P and Q-P-T process do not obtain the expected results. The strength and hardness are relatively improved, but the ductility and toughness are getting rather low, which mainly due to the content of Si or Al, resulting in failure to sufficiently suppress the precipitation of Fe3 C and formation of stable carbides.(5) ZG26 Si Mn performs the best weldability among the three casting steel, but adding alloying elements is harmful to improve the weldability of casting steels. In this paper, the chemical composition and heat treatment process was investigated to further improve the mechanical properties and weldability of middle groove ledge material of scraper conveyor, and further improve the production efficiency of scraper conveyors.