外文翻译--锻造工艺不当产生的缺陷.doc

Forging craft not when produces flaw Big crystal grain hyperpyrexia and the distortion degree insufficiency, or the end hammers the hyperpyrexia, or the distortion degree falls the human critical deformation range to cause. Aluminum alloy distortion degree oversized, forms the texture; Also the heat-resisting alloy distortion temperature excessively is low, forms when the mix distortion organization possibly causes the thick crystal grain The crystal grain is non-uniform The crystal grain non-uniform is refers to forging certain spots the crystal grain to be specially thick, certain spots are actually small. Has the crystal grain non-uniform primary cause is semifinished materials each place distortion causes the crystal grain stave degree non-uniform not one, either the partial region distortion degree falls the human critical deformation range, either heat-resisting alloy partial work hardening, either when quenching heating the partial crystal grain is thick. High-temperature steel and heat-resisting alloy to crystal grain non-uniform specially sensitive. The crystal grain non-uniform will cause the forging the lasting performance, the weary performance to drop obviously. 3.Chilling phenomenon When distortion because the temperature somewhat low or the distortion speed too is quick, as well as hammers the after-cooling excessively quickly, possibly causes the conditioning which the recrystallization causes not to be able to follow the strengthening which the distortion causes (hardening), after thus caused the hot forging the forging interior still the part retention cold-work organization. This kind of organizations existence enhanced the forging intensity and degree of hardness, but reduced the plasticity and toughness. The serious chilling phenomenon possibly causes the forging crack, sees example 78, 79, 83, 84. 4.Crack The crack is usually when forging has the big tensile stress, the shear stress or the additional tensile stress causes. The crack occ