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Forging craft not when produces flaw1. Big crystal grainhyperpyrexia 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 grain2. The crystal grain is non-uniformThe 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 phenomenonWhen 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.CrackThe crack is usually when forging has the big tensile stress, the shear stress or the additional tensile stress causes. The crack occurs the spot usually is biggest in the semifinished materials stress, the thickness thinnest spot. If the semifinished materials surface and the interior have the micro crack, or in the semifinished materials have the organization flaw, either hot-working temperature not when causes the material plasticity to reduce, either distortion speed excessively quickly, distortion degree oversized, surpasses the material permission the plastic indicator and so on, then in removes thick, pulls out long, the punch holes, the broaching, curving and working procedures and so on in extrusion all possibly produces the crack. 5.ChapThe chap is presents the shallow turtle shape crack in the forging surface. In the forging forming the tension stress surface (e.g., fill has not protruded part or curving part) easiest to produce this kind of flaw. Causes the chap internal cause possibly is various:Raw material gathers fusible elements and so on the Cu, Sn excessively are many.When high temperature long time heating, the steel materials surface has the copper to separate out the surface which, the superficial crystal grain thick, the decarbonization, or passes through heats up many times.The fuel measures including the sulfur excessively high, has the sulfur to infiltrate the human steel materials surface.6.Edge crackThe edge crack is when the drop forging and the cutting edge produces the crack in a minute modular surface place. The edge crack produces the reason possibly is:In drop forging operation because hits hard causes the metal intense flowing to produce puts on the muscle phenomenon.The magnesium alloy die forged item cutting edge temperature excessively is low; Copper alloy die forged item cutting edge hyperpyrexia. 7.Minute modular surface crackThe minute modular surface crack refers to the crack which produces along a forging minute modular surface. Raw material mixes with nonmetallic many, when drop forging to divides the modular surface flowing and the centralism or the pipe remaining after the drop forging pushes the human edge often the shape ingredient modular surface crack. 8.FoldThe fold was in the flow of metal process has oxidized the surface layer metal converged to form together. It may be (or multi-stocks) the metal convection convergence forms by two; Also might be the massive flowing is close to the part rapidly by a metal the surface layer strap flowing, both convergence will form; Also may be because the distortion metal has, the backflow curving forms; Also may be the partial metal local distortion, is oppressed others in another part of metals to form. Folding and raw material and semifinished materials shape, mold design, formed working procedure arrangement, lubrication situation and forging actual operation and so on related Not only the fold reduced the components load bearing area, when works because here stress concentration often becomes the weary source9.Puts on the classPuts on the class is the streamline distributes the improper one form. Is putting on flows the area, has certain angle distribution the streamline to converge originally to form together puts on the class, possibly and causes to put on flows the area inside and outside grain size difference to be disparate. Puts on the reason which the class produces with the fold to be similar, is by two metals or strap, but puts on flows the part which another metal affluxes form the metal still was a whole puts on the class to cause the forging mechanics performance to reduce, when puts on especially flows the belt both sides crystal grain difference is disparate, the performance reduces obviously. 10.The forging streamline distribution is not suitableThe forging streamline distribution along is not refers on forging low time has streamline disorder phenomena and so on streamline cut-off, backflow, turbulent flow. If the mold design does not work as or the forging method choice is unreasonable, prefabricated semifinished materials streamline disorder; The worker does not operate when and the mold wears causes the metal to produce the non-uniform flowing, all may cause the forging streamline distribution not to be suitable. The streamline along cannot cause each mechanics performance to reduce, therefore regarding the important forging, all has the request which the streamline distributes.11.The casting organization remainsThe casting organization remains mainly appears in uses the ingot casting to make the semifinished materials in the forging. The cast condition organization mainly remains in the forging difficult deformation range. Forging compared to insufficient and forging method not when is the primary cause casting organization which the casting organizationremains produces remains can cause the forging the performance drop, attacks the tenacity and the weary performance in particular and so on. 12.Carbide segregation rank not symbol requestThe carbide segregation rank symbol request mainly does not appear in the Lai body labor molding tool steel. Mainly is in the forging carbide distributes non-uniform, assumes the greatly massive centralism distribution or assumes the netted distribution. Creates this kind of flaw the primary cause is raw material carbide segregation rank is bad, adds it changes hammers when hammers compared to insufficient or the forging method not when has this kind of flaw forging, when heat treatment quenching easy partial superheat and quenches the crack. Makes the cutting tool and the mold use when easy breaking and so on.13.Banded structureThe banded structure is the ferrite and the pearlyte, the ferrite and the austenite, the ferrite and the bainite as well as the ferrite and the martensite assumes the belt-shaped distribution in the forging one kind of organization, they appear in Asia altogether fold in the steel, the austenite steel and half martensite steel. This kind of organization, is when which the banded structure which two coexists in the situation forges distortion produces to be able to reduce the material the crosswise plastic indicator, specially resilience. Often is easy in forging either the components work along the lines of ferrite or two intersection point dehiscence.14.Partial backfill insufficiencyThe partial backfill insufficient mainly occurs in the muscle rib, the convex angle, the corner, the fillet spot, the size does not conform to the pattern requirement. Produces the reason possibly is:The forging temperature is low, the metal fluidity is bad;The equipment tonnage insufficient or the hammer strength is insufficient;The system molds the design not to be unreasonable, the semifinished materials volume or the section size are unqualified;In the mold chest cavity piles up the oxide skin or the welded together distortion metal. 15.Owes the pressureOwes the pressure to refer is vertical increases, the reason to the minute modular surface direction size which produces possibly is generally:The forging temperature is low.The equipment tonnage is insufficient, hammer strength insufficiency or hammer number of times insufficient16.Wrong movesWrong moves is the forging is opposite along the minute modular surface upper half in the lower part has the displacement. Produces the reason possibly is:Slide (hammer head) and between guide rail gap oversized;The forging die design is unreasonable, lacks eliminates wrong moves the strength to close up an opening or the guide pillar;Mold installment not good17.The spool thread is curvingThe forging spool thread is curving, has the error with the plane geometry position. Produces the reason possibly is:The forging leaves when the mold does not pay attention;When cutting edge the stress is uneven;The forging cools when various part of temperature decrease speed not one;The cleaning up and the heat treatment improper锻造工艺不当产生的缺陷1.大晶粒大晶粒通常是由于始锻温度过高和变形程度不足、或终锻温度过高、或变形程度落人临界变形区引起的。铝合金变形程度过大，形成织构；高温合金变形温度过低，形成混合变形组织时也可能引起粗大晶粒2.晶粒不均匀晶粒不均匀是指锻件某些部位的晶粒特别粗大，某些部位却较小。产生晶粒不均匀的主要原因是坯料各处的变形不均匀使晶粒破碎程度不一，或局部区域的变形程度落人临界变形区，或高温合金局部加工硬化，或淬火加热时局部晶粒粗大。耐热钢及高温合金对晶粒不均匀特别敏感。晶粒不均匀将使锻件的持久性能、疲劳性能明显下降。3.冷硬现象变形时由于温度偏低或变形速度太快，以及锻后冷却过快，均可能使再结晶引起的软化跟不上变形引起的强化（硬化） ，从而使热锻后锻件内部仍部分保留冷变形组织。这种组织的存在提高了锻件的强度和硬度，但降低了塑性和韧性。严重的冷硬现象可能引起锻裂，见实例 78、79、83、84。4.裂纹裂纹通常是锻造时存在较大的拉应力、切应力或附加拉应力引起的。裂纹发生的部位通常是在坯料应力最大、厚度最薄的部位。如果坯料表面和内部有微裂纹、或坯料内存在组织缺陷，或热加工温度不当使材料塑性降低，或变形速度过快、变形程度过大，超过材料允许的塑性指针等，则在撤粗、拔长、冲孔、扩孔、弯曲和挤压等工序中都可能产生裂纹。5.龟裂龟裂是在锻件表面呈现较浅的龟状裂纹。在锻件成形中受拉应力的表面（例如，未充满的凸出部分或受弯曲的部分）最容易产生这种缺陷。引起龟裂的内因可能是多方面的：原材料合 Cu、Sn 等易熔元素过多。高温长时间加热时，钢料表面有铜析出、表面晶粒粗大、脱碳、或经过多次加热的表面。燃料含硫量过高，有硫渗人钢料表面。6.飞边裂纹飞边裂纹是模锻及切边时在分模面处产生的裂纹。飞边裂纹产生的原因可能是：在模锻操作中由于重击使金属强烈流动产生穿筋现象。镁合金模锻件切边温度过低；铜合金模锻件切边温度过高。7.分模面裂纹分模面裂纹是指沿锻件分模面产生的裂纹。原材料非金属夹杂多，模锻时向分模面流动与集中或缩管残余在模锻时挤人飞边后常形成分模面裂纹。8.折叠折叠是金属变形过程中已氧化过的表层金属汇合到一起而形成的。它可以是由两股（或多股）金属对流汇合而形成；也可以是由一股金属的急速大量流动将邻近部分的表层金属带着流动，两者汇合而形成的；也可以是由于变形金属发生弯曲、回流而形成；还可以是部分金属局部变形，被压人另一部分金属内而形成。折叠与原材料和坯料的形状、模具的设计、成形工序的安排、润滑情况及锻造的实际操作等有关折叠不仅减少了零件的承载面积，而且工作时由于此处的应力集中往往成为疲劳源9.穿流穿流是流线分布不当的一种形式。在穿流区，原先成一定角度分布的流线汇合在一起形成穿流，并可能使穿流区内、外的晶粒大小相差较为悬殊。穿流产生的原因与折叠相似，是由两股金属或一股金属带着另一股金属汇流而形成的，但穿流部分的金属仍是一整体穿流使锻件的力学性能降低，尤其当穿流带两侧晶粒相差较悬殊时，性能降低较明显。10.锻件流线分布不顺锻件流线分布不顺是指在锻件低倍上发生流线切断、回流、涡流等流线紊乱现象。如果模具设计不当或锻造方法选择不合理，预制毛坯流线紊乱；工人操作不当及模具磨损而使金属产生不均匀流动，都可以使锻件流线分布不顺。流线不顺会使各种力学性能降低，因此对于重要锻件，都有流线分布的要求。11.铸造组织残留铸造组织残留主要出现在用铸锭作坯料的锻件中。铸态组织主要残留在锻件的困难变形区。锻造比不够和锻造方法不当是铸造组织残留产生的主要原因铸造组织残留会使锻件的性能下降，尤其是冲击韧度和疲劳性能等。12.碳化物偏析级别不符要求碳化物偏析级别不符要求主要出现于莱氏体工模具钢中。主要是锻件中的碳化物分布不均匀，呈大块状集中分布或呈网状分布。造成这种缺陷的主要原因是原材料碳化物偏析级别差，加之改锻时锻比不够或锻造方法不当具有这种缺陷的锻件，热处理淬火时容易局部过热和淬裂。制成的刃具和模具使用时易崩刃等。13.带状组织带状组织是铁素体和珠光体、铁素体和奥氏体、铁素体和贝氏体以及铁素体和马氏体在锻件中呈带状分布的一种组织，它们多出现在亚共折钢、奥氏体钢和半马氏体钢中。这种组织，是在两相共存的情况下锻造变形时产生的带状组织能降低材料的横向塑性指针，特别是冲击韧性。在锻造或零件工作时常易沿铁素体带或两相的交界处开裂。14.局部充填不足局部充填不足主要发生在筋肋、凸角、转角、圆角部位，尺寸不符合图样要求。产生的原因可能是：锻造温度低，金属流动性差；设备吨位不够或锤击力不足；制坯模设计不合理，坯料体积或截面尺寸不合格；模膛中堆积氧化皮或焊合变形金属。15.欠压欠压指垂直于分模面方向的尺寸普遍增大，产生的原因可能是：锻造温度低。设备吨位不足，锤击力不足或锤击次数不足16.错移错移是锻件沿分模面的上半部相对于下半部产生位移。产生的原因可能是：滑块（锤头）与导轨之间的间隙过大；锻模设计不合理，缺少消除错移力的锁口或导柱；模具安装不良17.轴线弯曲锻件轴线弯曲，与平面的几何位置有误差。产生的原因可能是：锻件出模时不注意；切边时受力不均；锻件冷却时各部分降温速度不一；清理与热处理不当
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