Research Of Welding Speciality And Mechanism Of New-style Wearing Resistant Cast Steel And 20 Steel

The new-style mild alloy wearing resistant cast steel combines the advantages of high hardness and good wearing resistant capability and has wide application in fields of architecture and mechanism etc. But ,at the same time , it's mechanical properties are worse , and it's very difficult to manufacture and assure dimension precision for the damageable workpiece when machining. For the sake of broadening the applied range of such wearing resistant material, this paper is about the work on solving the above-mentioned mechanical difficult problem with the method of weld-compound according to the principium of heterogeneous-steels-welding. In this paper, we roundly tested and researched the welding methods, electrodes, programme and parameters employed on wearing resistant cast steel and 20 steel, and, we made some innovations and acquired many instructional returns which have their applied cost: rationally designed weld tie-in can avoid or abate the flaws of heterogeneous-steels-weiding; avoiding small and irregular weld gaps in design and manufacture to the best of our abilities; selecting alkaline and low-hydrogen welding-rods and direct-current reverse-connection and slowly cooling after welding. These measures can effectively prevent the weld flaws. Simultaneously, we expatiated that the later-heat-treatment(slowly cooling down to 200-250C after welding and then keep temperature for 2~4 hours) is in the favor of abating and eliminating the weld flaws, and this is very important to improve the weld microstructure and the mechanical properties of weld tie-in. In addition, we detailedly analyzed and demonstrated the generation and growing mechanism of the heterogeneous-steels-welding flaws and the restraining measures; we discussed the way to modify weld microstructure and then- influence on the mechanicalproperties. The weld tie-in acquired in this research is equal or close to the wearing resistant cast steel in tensile strength( o b=400 MPa) and precede in impact ductility(ak=25J.cm-2). We have manufactured forty or more abrasion-plates and these plates have been applied in ten or more factories for two years. As a result, such abrasion-plates can work well and economically and remarkably course economic benefit which is 5~7 times of the imported concrete conveying pump abrasion-plate, and even part of them can substitute the imported ones.