【正文】 紓緩壓力的主要目的是減輕壓力已經(jīng)從這些進(jìn)程傳授到工件的 成形，軋制，加工或焊接。盡管這三個(gè)過(guò)程的時(shí)間和溫度周期可能是相同的，這些材料被處理的條件和目標(biāo)可能會(huì)有所不同。在黑色金屬熱處理合金，回火加熱爐的奧氏體和淬火硬化鋼或鐵的一些預(yù)選的溫度低于下轉(zhuǎn)變溫度 （一般低于 1300℃或 705℃）組成。 上述淬火介質(zhì)的冷卻能力相差很大。這個(gè)周期可能有很大的不同，這取決于具體的組成和合金的特點(diǎn)。這種變化的目的可能是，但不僅限于，改善可加工性，促進(jìn)工作的冷（如進(jìn)程退火已知），機(jī)械或電氣性能的提高，或增加尺寸穩(wěn)定性。 規(guī)范通常被用作調(diào)理治療，特別是用于提煉已受到鍛造或其他熱工操作，高溫鋼的晶粒。 分類處理過(guò)程中的熱 在某些情況下，熱處理程序是明確的技術(shù)條款和應(yīng)用 .否則在其他情況下，簡(jiǎn)單的解釋說(shuō)明或削減是不夠的，因?yàn)橥瑯拥姆椒ń?jīng)?？梢杂脕?lái)獲得不同物體 .例如，壓力正在緩解，回火往往具有相同的設(shè)備和相同的時(shí)間和溫度使用旋回目標(biāo)完成，然而，對(duì)于不同的兩個(gè)過(guò)程。 轉(zhuǎn)變曲線 對(duì)熱治療的基礎(chǔ)是時(shí)間溫度曲線或傾斜試驗(yàn)曲線改造的 地方，在一個(gè)圖所有三個(gè)參數(shù)是該曲線的形狀。 F to 100176。 this is followed by cooling at a relatively slow rate to avoid creation of new stresses. The generally accepted definition for heat treating metals and metal alloys is “ heating and cooling a solid metal or alloy in a way so as to obtain specific conditions or properties.” Heating for the sole purpose of hot working (as in fing operations) is excluded from this definition． Likewise，the types of heat treatment that are sometimes used for products such as glass or plastics are also excluded from coverage by this definition． Transformation Curves The basis for heat treatment is the timetemperaturetransformation curves or TTT curves where，in a single diagram all the three parameters are plotted． Because of the shape of the curves， they are also sometimes called Ccurves or Scurves． To plot TTT curves， the particular steel is held at a given temperature and the structure is examined at predetermined intervals to record the amount of transformation taken place． It is known that the eutectoid steel (T80) under equilibrium conditions contains， all austenite above 723℃，whereas below， it is pearlite． To form pearlite， the carbon atoms should diffuse to form cementite． The diffusion being a rate process， would require sufficient time for plete transformation of austenite to pearlite． From different samples， it is possible to note the amount of the transformation taking place at any temperature． These points are then plotted on a graph with time and temperature as the axes． Through these points， transformation curves can be plotted as shown in for eutectoid steel． The curve at extreme left represents the time required for the transformation of austenite to pearlite to start at any given temperature． Similarly， the curve at extreme right represents the time required for pleting the transformation． Between the two curves are the points representing partial transformation. The horizontal lines Ms and Mf represent the start and finish of martensitic transformation. Classification of Heat Treating Processes In some instances， heat treatment procedures are clearcut in terms of technique and application． whereas in other instances， descriptions or simple explanations are insufficient because the same technique frequently may be used to obtain different objectives． For example, stress relieving and tempering are often acplished with the same equipment and by use of identical time and temperature cycles． The objectives， however， are different for the two processes． The following descriptions of the principal heat treating processes are generally arranged according to their interrelationships． Normalizing consists of heating a ferrous alloy to a suitable temperature (usually 50176。湖南工 院 畢業(yè)設(shè)計(jì) (論文 ) 外文翻譯 外 文 題 目 Heat treatment of metal 譯 文 題 目 金屬熱處理 系部 機(jī)械工程系 專 業(yè) 班 級(jí) 機(jī)械設(shè)計(jì)制造及其自動(dòng)化 機(jī)本 0807 班 學(xué) 生 姓 名 曹 然 指 導(dǎo) 教 師 陳平、鄧興貴 完 成 時(shí) 間 202105 原文 Heat treatment of metal The generally accepted definition for heat treating metals and metal alloys is “ heating and cooling a solid metal or alloy in a way so as to obtain specific conditions or properties.” Heating for the sole purpose of hot working (as in fing operations) is excluded from this definition． Likewise，the types of heat treatment that are sometimes used for products such as glass or plastics are also excluded from coverage by this definition． Transformation Curves The basis for heat treatment is the timetemperaturetransformation curves or TTT curves where，in a single diagram all the three parameters are plotted． Because of the shape of the curves， they are also sometimes called Ccurves or Scurves． To plot TTT curves， the particular steel is held at a given temperature and the structure is examined at predetermined intervals to record the amount of transformation taken place． It is known that the eutectoid steel (T80) under equilibrium condition