Firstly, the basic process flow of trial production of coupler products, the main process equipment and process methods used by each work department are introduced; After comparing the original process scheme and the improved process scheme, the casting process scheme of 17 coupler body and 16 coupler tongue is determined after continuous adjustment (serving mass production); The coupler body and tongue parts produced by the final process scheme have passed the appraisal at all levels, and the quality inspection items meet the standard requirements. The factory has the batch production capacity of 17 coupler body and 16 coupler tongue.
Secondly, the key casting defects left in the trial production of coupler are analyzed. The casting defects of coupler production are mainly cracks. The cracks are mainly hot cracks, which can be solved by increasing the transition fillet radius of sensitive parts, setting anti crack ribs, adjusting the formed cold iron, improving smelting, pouring, controlling sand falling and heat treatment process. Cold cracks can not be ignored, and the sand falling and cleaning, pouring and riser cutting process need to be strictly controlled; Air hole, sand inclusion, mechanical sand sticking and other defects are natural crack sources. Cracks are easy to occur under the action of alternating stress during the use of the hook tongue of the hook body. They need to be solved through the above corresponding measures, which can greatly save man hours and expenses, improve the qualified rate of products and reduce the occurrence of fatigue cracks.
Finally, the quality of coupler body and tongue products produced in batch in the early stage is analyzed. The results of an initial inspection showed that except for the scrapping of the steel castings caused by the penetration of sand, the steel castings have no obvious surface defects. The main reason for the penetration of sand is that during the molding of sand, the sand mold strength at the gate and the corner of complex curved surface is not enough or the sand box is not properly shaped, resulting in a large amount of loose sand. During pouring, due to the scouring and enrichment of liquid steel, serious sand inclusion is formed, resulting in penetration and scrapping of steel castings. The crack flaw detection results of the casting workshop and finishing workshop show that the hot crack, cold crack, heat treatment crack and welding crack of the hook tongue of the hook body still exist, and the number of cracks in the casting workshop is still large. On the one hand, the cracks are due to the objective reasons such as high thermal sensitivity and poor weldability of Grade E steel, and more importantly, the riser cutting, air gouging welding repair, pre normalizing, tempering, surface quenching and A considerable number of crack defects were produced in the process of quenching and tempering. Therefore, it is necessary to further standardize the machining and heat treatment process operation of steel castings and carry out corresponding worker operation training.