【正文】 (2) Heat treatment process a. Improved conventional heating process. Air heating will be vacuum heated, controlled atmosphere or protective atmosphere heating, as well as vacuum and controlled atmosphere heating joint will replace air heating. With the vacuum technology progress, vacuum heat treatment towards furnace temperature increased and the automation. Induction heating treatment, tend to increasing power and frequency range direction. b. expansion of the surface heat treatment and various types of chemical treatment instead of the whole heat treatment. Heat treatment equipment and heat treatment technology abroad status (Ⅰ ) in the early 1970s, American Society for Metals (ASM), British Wolf Morrison heat treatment center (Wolfson Heat Treatment Center) and the former Yugoslavia (now Croatia) have established the material and Heat Treatment, did it may, according to the database of mechanical performance requirements after heattreatment of puteraided material selection, or known material and Heat Treatment process foresee the organization and performance last. Then Europe, Japan and other advanced industrial countries to develop puter autocalculating on all kinds of heat treatment process control technology, began the process parameters under puter control, and analog control technology in production gained in application. The international wellknown anufacturers of many successive and cycle type heat treatment line adopted by programmable Controller (Programable) or microprocessor Controller of single control or group control. Foreign heat treatment factory attaches great importance to the cooling heating process. According to the product technology and process requirement, can undertake rapid cooling, oil quenching cooling, disposable gas quenching cooling, etc. By gas quenching way before the quenching cooling nitrogen and helium gas, and now the use of air jet, the strong in fast speed, quenching cooling after only extremely thin surface oxidation, are pale, parts, and still beautiful color saved a great deal of nitrogen and inert gas, so that treatment costs will decline further. Vacuum lowpressure carburizing bined with highpressure gas quenching is an advanced carburizing today, it has carburizing speed, excellent carbide organization ,quenching cracking and little deformation, saving energy and carburizing agent raw materials, carburized parts surface quality is good, be helpful for environmental protection etc. (Ⅱ ) heat treatment equipment: The trend of foreign heat treatment furnace development: (1) stove based on the power is increasing, oil for heat treatment furnace ratio decreasing. (2) To product surface quality request more strictly controlled atmosphere heat treatment furnace, this occupies an important position still. (3) Lining tends to use of lightweight materials, the application in resistance furnace with heatresistant ponent and nonmetallic furnace the proportion of heating elements increase gradually. (4) The microputer and PLC accelerates the development of heat, and have with the other automation line of automatic heat treatment process of trend. eccentric shaft failure forms and preventing measures Shaft loading: fatigue, impact, tensile, pression, bending, twisting, cutting, wear, surface changes, size changes, etching, corrosion and other failure modes. (1) eccentric shaft under heavy load at work, subject to bending stress, wear and tear in the neck, by the main have occurred wear fracture and axial crack two circumstances parts (2) axial crack, axial crack is eccentric shaft parts mon failure form, this crack except material adverse outside, main is caused by excessive heat surface tension stress caused by its quenchhardening ability, due to merger part weeks than axial tensile stress surface , and material surface tensile stress of lateral performance under longitudinal, prevent such hardening layer, and promptl y tempering. (3) Axis failure form: There are insufficient due to fatigue resulting fatigue fracture, static strength due to lack of plastic deformation or brittle fracture, wear, and exceed the allowable range of deformation and vibration. (4) axial fracture is mainly reverse fatigue fracture. Chapter II Theoretical analysis Heat Treatment of eccentric shaft Unified Digital Code: A20202 【 Chemical Composition】 ⑷ (mass fraction) (%) C: ~ Si: ~ M n: ~ Cr: ~ 【 Mechanical properties 】 Sample blank size (mm): 15 Heat buried: The first quenching temperature: 880 ℃ 。 steel, plastic strain of cold high in the cold state The following drawing。 910 \ 920 ℃ , 30 minutes, the amount of kerosene drops of 180200 drops / min。確定了材料為 20Cr 的偏心軸的最佳熱處理工藝參數(shù)和最佳滲碳淬火方式（鹽浴、直接淬火、低溫回火）后進行對滲碳后滲層深度、金相組織及力學件能的檢測與分析。偏心軸是電動工具電錘的重要傳動零件。 偏心軸結(jié)構(gòu)示意圖 偏心軸的用途及性能要求 偏心軸在采礦、機電、水利等方面的應(yīng)用極為廣泛，隨著這些 成品產(chǎn)量的增加以及消費人群要求的不斷提高，偏心軸質(zhì)量的提髙也迫在眉睫。所以要求偏心軸表面具有髙的硬度、耐磨性及疲勞強度，而心部則具有一定的強度和良好的塑性、韌性等的特殊性能。 （ 2） 在基礎(chǔ)理論方面不斷取得成就。大多數(shù)加熱爐和熱處理設(shè)備要實現(xiàn)自動化及數(shù)字控制，這不僅可以減少勞動力，而且是提 高熱處理質(zhì)量的前提。感應(yīng)加熱熱處理，趨向與增大功率及擴大頻率范圍方向發(fā)展。目前國際知名廠家的許多連續(xù)式和周期式熱處理生產(chǎn)線都采取了用可編程控制器(Programable Controller)或微處理機的單控或群控。 真空低壓滲碳與高壓氣淬相結(jié)合是當今一種先進的滲碳淬火工藝，它具有滲碳速度快、碳化物組織優(yōu)良、淬火開裂和變形小、節(jié)約能源和滲碳劑原料、滲碳零件表面質(zhì)量好、有利于環(huán)保等特點。 （ 4） 微機和可編程序控制器的發(fā)展加速了熱處理自動化，并有與其它工序組成全自動熱處理線的趨勢。 （ 4） 軸類的斷裂主要是扭轉(zhuǎn)疲勞斷裂。 第三章實驗材料及實驗方法 材料： 本文研究的是材料為 20Cr 的偏心軸， 20Cr 是碳含量為 %的低碳鋼適合進行滲碳處理， 20Cr 鋼比相同含碳量的碳素鋼的強度和淬透性都明顯地高，油淬到半馬氏體硬度的淬透性為 φ 20~23mm。 這種鋼淬火低溫回火后具有良好的綜合力學性能，低溫沖擊韌性良好，回火脆性不明顯。將裝好工件的料筐衣次吊入爐內(nèi)，關(guān)閉爐蓋，擰緊爐蓋螺栓，滴甲醇，開風扇，送電升溫，進入排氣期。 出爐風冷。然后用 180℃ 、 240℃ 、 300℃ 和 600℃ 的粗砂布磨光，再換用 800℃ 、 1500℃ 的金相砂紙逐級細磨，一直磨到 2020℃ 砂紙方可進行粗拋光和細拋光。 拋光 細磨的式樣還需進行拋光。拋光液是由 Cr203 或 Mg0 等極細粒度的磨料加水而形成的懸浮液，依靠拋光液中極細的拋光粉末與式樣磨面間產(chǎn)生的相對磨削和滾壓作用來消除磨痕。如果浸蝕不足重復(fù)浸蝕。測讀硬度是通過升降顯微硬度計 的調(diào)焦機構(gòu)、測量顯微鏡、加荷機構(gòu)，正確選擇負荷、加荷速度進行全自動加卸 試驗力及正確控制試驗力保持時間，通過顯微硬度計光學放大 ,測出在一定試驗 力下金剛石角錐體壓頭壓入被測物后所殘留壓痕的對角線長度，來求出被測物硬