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单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,机械工程专业英语,课文分析,The above considerations provide the basis for classification of forging temperature ranges,namely,hot working(hot forging)and cold working(cold forging).Hot working is considered to be plastic deformation that is accomplished above the,recrystallization,temperature.The use of the term“hot working”usually implies that the material is heatedbut not always.For example,the,recrystallization,of lead takes place at very low temperatures.By the above definition,lead forged at room temperature is being hot worked.,Lesson 8 Cold Working and Hot Working,课文分析,上述考虑因素提供了锻造温度系列的分类基础，换句话说，分热加工（热锻）和冷加工（冷锻）。,The above considerations provide the basis for classification of forging temperature ranges,namely,hot working(hot forging)and cold working(cold forging).,在再结晶温度以上才能完成塑性变形加工的就是热加工。,n.,再结晶,Lesson 8 Cold Working and Hot Working,Hot working is considered to be plastic deformation that is accomplished above the,recrystallization,temperature.,课文分析,使用,“,热加工,”,这一术语通常意味着,材料一般要加热，但并不总是要加热。,例如，铅的再结晶就是在很低的温度下进行。,The use of the term“hot working”usually implies that the material is heatedbut not always.For example,the,recrystallization,of lead takes place at very low temperatures.,根据以上定义，在室温条件下铅的锻造也是热加工。,Lesson 8 Cold Working and Hot Working,By the above definition,lead forged at room temperature is being hot worked.,机械工程专业英语,课文分析,Cold working is defined as plastic deformation below the,recrystallization,temperature.Several common metals,or their alloys,have,recrystallization,temperatures in the order of 750C900C.To improve properties,several of these alloys are strain hardened by forging in the range of 550C700C.Although by definition,this is truly“cold work”,it is often referred to as“warm work”.,Lesson 8 Cold Working and Hot Working,课文分析,在再结晶温度以下的塑性变形被定义为冷加工。,Cold working is defined as plastic deformation below the,recrystallization,temperature.,几种常用金属或他们的合金，其再结晶温度大约在,750C900C,大约,约等于,Lesson 8 Cold Working and Hot Working,Several common metals,or their alloys,have,recrystallization,temperatures,in the order of,750C900C.,课文分析,为了改善性能，这些合金中的某些合金是在,550C700C,温度范围内通过锻造来进行硬化处理的。,To improve properties,several of these alloys are strain hardened by forging in the range of 550C700C.,尽管按照定义，这确实是“冷加工”，但它常常被称作是“热加工”。,Lesson 8 Cold Working and Hot Working,Although by definition,this is truly“cold work”,it is often referred to as“warm work”.,机械工程专业英语,课文分析,The heating is done mainly to reduce the flow stress and thereby the forging force required.“Warm working”operations must be very closely controlled if the ultimate improvement in properties is to be obtained.The operation is normally followed by stress relieving at a temperature below the temperature.The temperature of,recrystallization,for austenitic stainless steels,higher temperature alloys,and many non-ferrous alloys can vary over a considerable range.Factors influencing this temperature include the degree of strain hardening present,the time of annealing,the prior grain size and the solute atomic concentration in solid solution.,Lesson 8 Cold Working and Hot Working,机械工程专业英语,课文分析,The heating is done mainly to reduce the flow stress and thereby the forging force required.,Lesson 8 Cold Working and Hot Working,“,Warm working”operations must be very closely controlled if the ultimate improvement in properties is to be obtained.,如果材料性质最终要获得改善，就必须非常严密地控制所谓“热加工”操作。,加热主要是为了减少流动应力，进而减少所需的锻造力。,机械工程专业英语,课文分析,The operation is normally followed by stress relieving at a temperature below the forging temperature.,Lesson 8 Cold Working and Hot Working,The temperature of,recrystallization,for austenitic stainless steels,higher temperature alloys,and many non-ferrous alloys can vary over a considerable range.,对于奥氏体不锈钢、高温合金钢和许多有色金属合金的再结晶温度可在超出相当大的范围内变化。,实行以上操作工艺之后接着就要在低于锻造温度以下的温度中进行消除应力处理。,机械工程专业英语,课文分析,Factors influencing this temperature include the degree of strain hardening present,the time of annealing,the prior grain size and the solute atomic,concentration,in solid solution.,Lesson 8 Cold Working and Hot Working,影响再结晶温度的因素包括：目前的应变硬化程度、退火时间，变形前的晶粒度，以及固溶体中溶质原子的浓度。,knsentrein,n.,集中，专心,化,提浓,浓缩,浓度；,采矿,汰选,集中物，密集,机械工程专业英语,课文分析,The,recrystallized,grain size at the instant of,recrystallization,is inversely,proportional,to the degree of deformation.,Lesson 8 Cold Working and Hot Working,This fact leads to the possibility of grain size refinement by a combination of controlled deformation and,recrystallization,.,在再结晶瞬间，再结晶晶粒度与变形程度成反比。,这一事实导致依靠控制再结晶和控制变形的相结合来使晶粒晶粒度细化的可能。,prp:nladj,.,比例的,成比例的,机械工程专业英语,课文分析,Refinement of grain size by means of controlled deformation is regularly practiced by the forging industry.However,there is hazard inherent to this method.Nearly all the alloys are sensitive to a combination of strain hardening and temperature where very rapid grain growth(called“abnormal grain growth”)occurs.The combination is normally referred to as critical strain and usually occurs when the alloy is subjected to relatively small strains,although th
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