工藝夾具-差速器殼,工藝,夾具,差速器 Forging craft not when produces flaw 1. 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 2. 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 organization's 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 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.Chap The 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:①Raw material gathers fusible elements and so on the Cu, Sn excessively are many.②When 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.③The fuel measures including the sulfur excessively high, has the sulfur to infiltrate the human steel materials surface. 6.Edge crack The 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:①In drop forging operation because hits hard causes the metal intense flowing to produce puts on the muscle phenomenon.②The magnesium alloy die forged item cutting edge temperature excessively is low; Copper alloy die forged item cutting edge hyperpyrexia. 7.Minute modular surface crack The 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.Fold The 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 source 9.Puts on the class Puts 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 suitable The 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 remains The 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 organization remains 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 request The 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 structure The 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 insufficiency The 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:①The forging temperature is low, the metal fluidity is bad;②The equipment tonnage insufficient or the hammer strength is insufficient;③The system molds the design not to be unreasonable, the semifinished materials volume or the section size are unqualified;④In the mold chest cavity piles up the oxide skin or the welded together distortion metal. 15.Owes the pressure Owes the pressure to refer is vertical increases, the reason to the minute modular surface direction size which produces possibly is generally:①The forging temperature is low.②The equipment tonnage is insufficient, hammer strength insufficiency or hammer number of times insufficient 16.Wrong moves Wrong 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:①Slide (hammer head) and between guide rail gap oversized;②The forging die design is unreasonable, lacks eliminates wrong moves the strength to close up an opening or the guide pillar;③Mold installment not good 17.The spool thread is curving The forging spool thread is curving, has the error with the plane geometry position. Produces the reason possibly is:①The forging leaves when the mold does not pay attention;②When cutting edge the stress is uneven;③The forging cools when various part of temperature decrease speed not one;④The cleaning up and the heat treatment improper 鍛造工藝不當(dāng)產(chǎn)生的缺陷 1.大晶粒 大晶粒通常是由于始鍛溫度過高和變形程度不足、或終鍛溫度過高、或變形程度落人臨界變形區(qū)引起的。鋁合金變形程度過大，形成織構(gòu)；高溫合金變形溫度過低，形成混合變形組織時(shí)也可能引起粗大晶粒 2.晶粒不均勻 晶粒不均勻是指鍛件某些部位的晶粒特別粗大，某些部位卻較小。產(chǎn)生晶粒不均勻的主要原因是坯料各處的變形不均勻使晶粒破碎程度不一，或局部區(qū)域的變形程度落人臨界變形區(qū)，或高溫合金局部加工硬化，或淬火加熱時(shí)局部晶粒粗大。耐熱鋼及高溫合金對晶粒不均勻特別敏感。晶粒不均勻?qū)⑹瑰懠某志眯阅?、疲勞性能明顯下降。 3.冷硬現(xiàn)象 變形時(shí)由于溫度偏低或變形速度太快，以及鍛后冷卻過快，均可能使再結(jié)晶引起的軟化跟不上變形引起的強(qiáng)化（硬化），從而使熱鍛后鍛件內(nèi)部仍部分保留冷變形組織。這種組織的存在提高了鍛件的強(qiáng)度和硬度，但降低了塑性和韌性。嚴(yán)重的冷硬現(xiàn)象可能引起鍛裂，見實(shí)例78、79、83、84。 4.裂紋 裂紋通常是鍛造時(shí)存在較大的拉應(yīng)力、切應(yīng)力或附加拉應(yīng)力引起的。裂紋發(fā)生的部位通常是在坯料應(yīng)力最大、厚度最薄的部位。如果坯料表面和內(nèi)部有微裂紋、或坯料內(nèi)存在組織缺陷，或熱加工溫度不當(dāng)使材料塑性降低，或變形速度過快、變形程度過大，超過材料允許的塑性指針等，則在撤粗、拔長、沖孔、擴(kuò)孔、彎曲和擠壓等工序中都可能產(chǎn)生裂紋。 5.龜裂 龜裂是在鍛件表面呈現(xiàn)較淺的龜狀裂紋。在鍛件成形中受拉應(yīng)力的表面（例如，未充滿的凸出部分或受彎曲的部分）最容易產(chǎn)生這種缺陷。引起龜裂的內(nèi)因可能是多方面的：①原材料合Cu、Sn等易熔元素過多。②高溫長時(shí)間加熱時(shí)，鋼料表面有銅析出、表面晶粒粗大、脫碳、或經(jīng)過多次加熱的表面。③燃料含硫量過高，有硫滲人鋼料表面。 6.飛邊裂紋 飛邊裂紋是模鍛及切邊時(shí)在分模面處產(chǎn)生的裂紋。飛邊裂紋產(chǎn)生的原因可能是：①在模鍛操作中由于重?fù)羰菇饘購?qiáng)烈流動產(chǎn)生穿筋現(xiàn)象。②鎂合金模鍛件切邊溫度過低；銅合金模鍛件切邊溫度過高。 7.分模面裂紋 分模面裂紋是指沿鍛件分模面產(chǎn)生的裂紋。原材料非金屬夾雜多，模鍛時(shí)向分模面流動與集中或縮管殘余在模鍛時(shí)擠人飛邊后常形成分模面裂紋。 8.折疊 折疊是金屬變形過程中已氧化過的表層金屬匯合到一起而形成的。它可以是由兩股（或多股）金屬對流匯合而形成；也可以是由一股金屬的急速大量流動將鄰近部分的表層金屬帶著流動，兩者匯合而形成的；也可以是由于變形金屬發(fā)生彎曲、回流而形成；還可以是部分金屬局部變形，被壓人另一部分金屬內(nèi)而形成。折疊與原材料和坯料的形狀、模具的設(shè)計(jì)、成形工序的安排、潤滑情況及鍛造的實(shí)際操作等有關(guān) 折疊不僅減少了零件的承載面積，而且工作時(shí)由于此處的應(yīng)力集中往往成為疲勞源 9.穿流 穿流是流線分布不當(dāng)?shù)囊环N形式。在穿流區(qū)，原先成一定角度分布的流線匯合在一起形成穿流，并可能使穿流區(qū)內(nèi)、外的晶粒大小相差較為懸殊。穿流產(chǎn)生的原因與折疊相似，是由兩股金屬或一股金屬帶著另一股金屬匯流而形成的，但穿流部分的金屬仍是一整體穿流使鍛件的力學(xué)性能降低，尤其當(dāng)穿流帶兩側(cè)晶粒相差較懸殊時(shí)，性能降低較明顯。 10.鍛件流線分布不順 鍛件流線分布不順是指在鍛件低倍上發(fā)生流線切斷、回流、渦流等流線紊亂現(xiàn)象。如果模具設(shè)計(jì)不當(dāng)或鍛造方法選擇不合理，預(yù)制毛坯流線紊亂；工人操作不當(dāng)及模具磨損而使金屬產(chǎn)生不均勻流動，都可以使鍛件流線分布不順。流線不順會使各種力學(xué)性能降低，因此對于重要鍛件，都有流線分布的要求。 11.鑄造組織殘留 鑄造組織殘留主要出現(xiàn)在用鑄錠作坯料的鍛件中。鑄態(tài)組織主要?dú)埩粼阱懠睦щy變形區(qū)。鍛造比不夠和鍛造方法不當(dāng)是鑄造組織殘留產(chǎn)生的主要原因 鑄造組織殘留會使鍛件的性能下降，尤其是沖擊韌度和疲勞性能等。 12.碳化物偏析級別不符要求 碳化物偏析級別不符要求主要出現(xiàn)于萊氏體工模具鋼中。主要是鍛件中的碳化物分布不均勻，呈大塊狀集中分布或呈網(wǎng)狀分布。造成這種缺陷的主要原因是原材料碳化物偏析級別差，加之改鍛時(shí)鍛比不夠或鍛造方法不當(dāng)具有這種缺陷的鍛件，熱處理淬火時(shí)容易局部過熱和淬裂。制成的刃具和模具使用時(shí)易崩刃等。 13.帶狀組織 帶狀組織是鐵素體和珠光體、鐵素體和奧氏體、鐵素體和貝氏體以及鐵素體和馬氏體在鍛件中呈帶狀分布的一種組織，它們多出現(xiàn)在亞共折鋼、奧氏體鋼和半馬氏體鋼中。這種組織，是在兩相共存的情況下鍛造變形時(shí)產(chǎn)生的帶狀組織能降低材料的橫向塑性指針，特別是沖擊韌性。在鍛造或零件工作時(shí)常易沿鐵素體帶或兩相的交界處開裂。 14.局部充填不足 局部充填不足主要發(fā)生在筋肋、凸角、轉(zhuǎn)角、圓角部位，尺寸不符合圖樣要求。產(chǎn)生的原因可能是：①鍛造溫度低，金屬流動性差；②設(shè)備噸位不夠或錘擊力不足；③制坯模設(shè)計(jì)不合理，坯料體積或截面尺寸不合格；④模膛中堆積氧化皮或焊合變形金屬。 15.欠壓 欠壓指垂直于分模面方向的尺寸普遍增大，產(chǎn)生的原因可能是：①鍛造溫度低。②設(shè)備噸位不足，錘擊力不足或錘擊次數(shù)不足 16.錯(cuò)移 錯(cuò)移是鍛件沿分模面的上半部相對于下半部產(chǎn)生位移。產(chǎn)生的原因可能是：①滑塊（錘頭）與導(dǎo)軌之間的間隙過大；②鍛模設(shè)計(jì)不合理，缺少消除錯(cuò)移力的鎖口或?qū)е?；③模具安裝不良 17.軸線彎曲 鍛件軸線彎曲，與平面的幾何位置有誤差。產(chǎn)生的原因可能是：①鍛件出模時(shí)不注意；②切邊時(shí)受力不均；③鍛件冷卻時(shí)各部分降溫速度不一；④清理與熱處理不當(dāng)