【正文】 2. Microstructure after quenching should be fine lamellar pearlier and granular sorbets organizations, such organizations in the rapid heating, can lower the heating temperature in the austenite position to improve uniformity. If the crosssectional area larger gear, and the quenching properties of materials are inadequate to achieve the above two requirements, you can rough out the alveolar stage after quenching and tempering treatment. Carburized gear blank preparatory heat treatmentSuch gear blank are forging, heat treatment aims to improve the preparation coarse or uneven after carburizing forging organizations to create favorable conditions and to improve the cutting performance. Carburizing steel more plex, Tianjin elements and their content and the quenching properties of steel are greatly different. Low harden ability carburizing preparation of rough treatment, normalizing or hardening plus tempering. Middle and high harden ability carburizing actinium preparation heat treatment, after first normalizing rough forging and tempering, quenching and tempering line after roughing. Its principles and form quenched quenching process is basically the same gear blank, the difference can be improved only when the tempering temperature of quenched and tempered (or even up to the critical steel near). This is because the casehardened steel gear blank only for the purpose of quenching after carburizing to create favorable conditions, rather than adjust its mechanical properties.3. The final heat treatment heavyduty gear Softhardened gear tooth surface or in the final heat treatment Such gears are quenched and final heat treatment, that is, after roughing in the shape of gear, for quenching and tempering at different temperatures to ensure that all parts of the mechanical properties of gear to meet the requirement. Quenched and generally not open before the alveolar, but the modulus of more than 10 line slot Gear quenched and preceded to ensure the tooth part of the performance requirements. The final surface hardening heat treatment hardened gearsSurface hardening of gears basically divided into two modes:(1) Gear tooth all round the table。 soft and the hard surface with the tooth surface, the small gear hardness HB280 ~ 320, large gear for the HB240 ~ 280 in the hardened and hardened with time, a small gear strengthened by the surface hardness HRC45 ~ 50, a large gear for the HB280 ~ 320 or higher. Overall, the soft and the hardened tooth require a good robust performance, contact fatigue performance and certain antiwear properties. To this end, be selected according to the size of quenching crosssection equivalent or higher performance materials, appropriate to increase Cr, Ni, Man, Mo and other alloying elements content in order to improve the performance of its quenching by adding an appropriate amount of Si, Man, etc. Tianjin element to strengthen the ferrite. After appropriate heat treatment, hardness and strength not only to ensure that the requirements, but also to guarantee access to the fine pearlier lamellar or granular, round the fire sorbet organizations, to minimize eutectoid ferrite, and the distribution to be uniform.(2) Quench hardened surface of the quenching properties of gears materials: body heat treatment requirements of this gear has a certain bination of properties, while the tooth surface after quenching with the corresponding surface hardness, hardened layer depth and good hardness gradient. Therefore, the selected materials, spare parts need to ensure that the appropriate crosssection size of the subsidized through performance, to affect the harden ability of carbon and Tianjin element content control to the extent appropriate, to minimize carbon and strong carbide elements, play alloying elements Man, The role of Ni。(2) Control the size of the original grain size within a certain range。從加工工藝上看，在滿足機(jī)械性能和強(qiáng)度要求的前提下，要保證零件加工尤其齒輪部分表面質(zhì)量，滿足傳動平穩(wěn)平順的要求。結(jié) 論重型汽車驅(qū)動橋主動錐齒輪的加工流程長，工藝過程復(fù)雜，幾何尺寸和內(nèi)在金相組織及性能要求高，材料選擇要滿足大扭矩軸類零件的要求，也要滿足大模數(shù)齒輪零件的要求；機(jī)械加工工藝過程要滿足齒形、齒向、齒面的加工要求，保證主被動齒輪副的嚙合要求，滿足高精度軸類零件的加工要求；熱處理工藝過程要滿足高強(qiáng)度、大扭矩軸類零件和高轉(zhuǎn)速、大傳動比齒輪零件的要求。選用數(shù)控嚙合檢查機(jī)，由嚙合檢查機(jī)自動測得齒輪最佳嚙合狀態(tài)下安裝距修正量△A，保證裝配質(zhì)量。在檢查機(jī)上與配偶齒輪有隙嚙合時觀察接觸斑點(diǎn)。將檢驗(yàn)結(jié)果與零件圖樣進(jìn)行對比，從而判斷零件是否合格的過程叫做檢驗(yàn)或終檢。磨削加工過程如下：磨外圓由Ф75處→磨外圓Ф60處→磨花鍵底徑→磨花鍵兩側(cè)→過螺紋磨削階段的加工工序卡片有：磨外圓（Ф75處），磨外圓（Ф60處）。以提高尺寸精度和形位精度。對于切削加工后又經(jīng)淬火等熱處理及表面處理的工件的最后加工，通常采用磨削加工。根據(jù)工件被加工的表面形狀和砂輪與工件之間的相對運(yùn)動，磨削分為外圓磨削、內(nèi)圓磨削、平面磨削和無心磨削等幾種主要加工類型。設(shè)備：電磁感應(yīng)；工藝：加熱溫度880℃，空冷。 （3）噴砂噴砂是采用壓縮空氣為動力，以形成高速噴射束將噴料（銅礦砂、石英砂、金剛砂、鐵砂、海南砂）高速噴射到需要處理的工件表面，使工件表面的外表面的外表或形狀發(fā)生變化，由于磨削對工件表面的沖擊和切削作用，使工件的表面獲得一定的清潔度和不同的粗糙度，使工件表面的機(jī)械性能得到改善，因此提高了工件的抗疲勞性，增加了它和涂層之間的附著力，延長了涂膜的耐久性，也有利于涂料的流平和裝飾。低溫回火：對要求具有高的強(qiáng)度、硬度、耐磨性及一定韌性的淬火零件，通常進(jìn)行低溫回火，獲得揮霍馬氏體為主的組織，淬火內(nèi)應(yīng)力得到部分消除，淬火時產(chǎn)生的微裂紋也大部分得到愈合。第二次淬火加熱至Ac1+30～50℃，進(jìn)行不完全淬火，目的是細(xì)化表層組織，使表層獲得細(xì)小的隱晶馬氏體加均勻細(xì)小的顆粒狀碳化物組織，并減少殘余奧氏體量。滲碳二次淬火工藝：對于性能要求很高的零件，或是由本質(zhì)粗晶粒鋼制成的零件，滲碳后應(yīng)采用二次淬火法。淬火后還需低溫回火(160～200℃)，以消除淬火應(yīng)力，降低脆性。淬火后還需低溫回火(160～200℃)，以消除淬火應(yīng)力，降低脆性。在實(shí)際生產(chǎn)過程中，我們根據(jù)自身的經(jīng)驗(yàn)及現(xiàn)有設(shè)備條件摸索出以下三種可行性滲碳淬火工藝：滲碳一次淬火工藝：工件經(jīng)過滲碳后冷卻至一定溫度保溫一段時間，速度快的話，在高碳的滲碳層中只有少量的碳化物析出，降低奧氏體的含碳量，提高M(jìn)s點(diǎn)，使淬火下來的殘余奧氏體量減少，提高淬火硬度。、淬火是將鋼加熱至臨界點(diǎn)（Ac3或Ac1）以上，保持一定時間后快速冷卻，使過冷奧氏體轉(zhuǎn)變?yōu)轳R氏體或貝氏體組織的工藝方法。加工件放入連續(xù)推盤式密閉滲碳爐內(nèi)，在高溫900～950℃下加熱、保溫，使其表面層增碳。氣體滲碳可分為吸熱式氣氛滲碳、滴注式氣氛滲碳與氮基氣氛滲碳。與淬火相比，滲碳主要用于那些對表面耐磨性要求較高，并承受較大沖擊載荷的零件。所謂碳勢，是指滲碳?xì)夥张c鋼件表面達(dá)到動態(tài)平衡時鋼表面的含碳量。擴(kuò)散是指滲入原子在金屬基本體中由表面向內(nèi)部的擴(kuò)散，這是化學(xué)熱處理得以不斷進(jìn)行并獲得一定深度滲層的保證。吸收是指活性原子被金屬表面吸收的過程，其基本條件是滲入元素要與基本金屬形成一定溶解度的固體，否則吸收過程不能進(jìn)行?；瘜W(xué)熱處理過程分為分解、吸收和擴(kuò)散三個基本過程。通常在進(jìn)行化學(xué)滲的前后均需采用其他合適的熱處理，以便最大限度地發(fā)揮滲層的潛力，并達(dá)到工件心部與表層在組織結(jié)構(gòu)、性能等的最佳配合。工業(yè)上應(yīng)用最多的為感應(yīng)加熱和火焰加熱表面淬火。為了達(dá)到只加熱工件表層的目的，要求所用熱源具有較高的能量密度。表面熱處理分為表面淬火和化學(xué)熱處理兩大類。它不改變零件心部的組織和性能 。