Study On New Process Of Oversize Head Forging

Nuclear power industry and petrol-chemical industry developed very quickly, in order to content the need of high quality large-scale head which require to be forged in whole, these quality can make the head bare the the inclement circumstance include: high strength and toughness, impact property, low temperature performance, anti-corrosion and radiation ability and so on.The paper studied the follow subject:(1)study part top anvil revolve forging large whole head process which is the technology of the Cast Steel Company of Japan(2)put forward double sector top anvil revolve forging process(3)the finishing revolve forging processBy simulation to analysis and grasp the essential of the process, and found the failure of the process is that the thickness of head bottom reduced in unacceptable amount. In the paper, the cause of the reduce was discussed from the angular of the plastic forming theory. Through simulating the forming process with different size and shape top anvil, the stress and the steel flow state during the forming process can be seen, then by compare all those variables, the cause can be concluded as follow:(1)affix tense has enforce the bottom region by the end region of the head blank during the forging process(2)during the process the flank region of the head blank led the bottom region rise as a whole bodyThe paper analyzed the effect of different friction coefficientμand press quantity△T simulated a great number of the forging process use vary breadth b sphere-faced top die and the differentθdouble sector top anvil. Through simulation it can be found that the frication coefficient is the key factor which effect the forming process, as it raises the forging force raise, while the thickness reduction reduced. At the same time, forging with different press quantity also effect the result, when forging with smaller press quantity the thickness reduction of the bottom will reduced, but the forging time raise, and vice versa. That against the object of this paper, and finally we found that the flat-bottomed double sectors anvil can satisfy the need, for its flat bottom and the head blank formed a space it can retain some steel, after revolve forging using a whole sphere face top anvil press down these steel, then the steel flowed away from bottom be compensated, as a result the thickness reduction be completely eliminated.