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Виконано обґрунтування технологічної схеми формоутворення поверхонь шестигранної порожнини пуансонів гарячого пресування головок болтів, способом розмірної обробки електричною дугою з урахуванням особливостей фізичних механізмів їх утворення та гідродинамічних явищ в міжелектродному проміжку. Встановлені аналітичні зв’язки технологічних характеристик процесу розмірної обробки електричною дугою сталі 5ХНМ з режимами обробки і геометричними параметрами. The article is dedicated to the development of technology and accessories of the method for processing of hexagonal cavities of hot-pressing punches by electrical arc, as high-performance alternative to traditional processing methods. An important factor in increasing the carrying capacity of heavy duty bolts is the increasing of the elasticity of the bolt head. This condition is fully met by the high-strength bolts with hexagon head produced by the method of hot pressing. The use of an elastic flange ensures continuous operation under alternating loadings without loss of pre-tightening efforts. When developing equipment and tools, it is necessary to take into account the conditions which ensure the formation of the bolt head. The most important parameter for pressing is the dimensional accuracy, hot impact resistance of the tool, material ductility, burr tool cavity walls, since the pressure force on the transmission side surface is proportional to the pressure in the longitudinal direction. It is found that the optimum parameters hex hot pressing punch cavity walls during the processing performance of M = 610 mm³ / min. by electrical arc, is the roughness Ra = 2,5..6,3 mkm that provides frictional force required to fill the cavity of the bolt head. It is suggested to get the hexagonal cavities of hot pressing punches by dimension electrical arc with the set roughness Ra = 2,5..6,3 mkm of side walls, which allows you to take great allowances material at the lowest cost to the processing time. At the same time the cycle of processing is decreased 2-4,5 times. The objectivation of technological scheme of formation of hexagonal cavities of hot pressing punches by dimension electrical arc was made taking into account features of the physical mechanism of formation and hydrodynamic phenomena in the electrode gap. The analytical processing characteristics of process of sizing by electric arc of steel 5HNM with treatment regimes and geometrical parameters were established. |
