Abstract:This paper defined misunderstanding of the straightening technology,emphasized on the straighte-ning process analytical theory,three step of anti bending straightening theory,quadrature phase straightening theory,the optimum elastic core theory,triple straightening theory,sectional curvature bending straightening theory,elastic flattening and plastic bending straightening theory of balance,rolling and anti-bending synthetic straightening theory,the size of section of the straightening effect theory,etc.It put forword that double staggered roll system straightening is of great development.

Abstract:The multi-ram forging is a die forging method that can apply loads from two or more directions to forming the billet in the separable die cavity.It can produce a hollow forgings with outside bosses or complex forgings with shoot protruding to different directions.The final shapes and dimensions of the forgings are close to the parts.Therefore higher material utilization rate is achieved,less machining needed.Further,complete in-ternal flow line of the forgings brings good stress erosion resistance and fatigue strength.All these advantages enable forgings produced using multi-ram forging method to better meet the forgings' requirements in different fields such as machinery,electric equipment,petrochemical equipment,aerospace equipment,ship and car manufacturing,national defense.Multi-ram forging has become a promising and widely-used branch in forging technology.Since the beginning of 1950s,the US company Cameron started to use multi-ram forging,multi-ram forging press and process have gained continuous development.To satisfy ever-increasing technical require-ments,five aspects such multi-ram forging presses and technology that can pierce holes in different and change-able directions should be further studied and improved.