高錳鋼具有高硬度與高強度的鋼材，也有很強的抗擠壓、抗衝擊以及抗磨損等能力。本論文主要在探討成分為Fe-8 Mn-0.8 C (wt.%)的高錳鋼，於1100℃固溶處理後、固溶處理後再經深冷處理、與經由固溶處理後再於1000至500℃的溫度區間進行恆溫處理後的組成相與其對應的相變化情形。本高錳鋼經1100℃高溫水淬或空冷方式冷卻至室溫的組成相為沃斯田體。將經1100固溶處理水淬後的高錳鋼再進行淬入液態氮的深冷處理，發現其靠近試片邊緣側為麻田散體，靠近中心處為沃斯田體晶粒組織。由此可知於本高錳鋼試片的周圍處形成麻田散體相起始溫度介於零下176℃至室溫間，而本高錳鋼形成麻田散體相起始溫度是低於零下176℃。經1100固溶處理後再經低溫熱處理後，於晶界處有初析碳化物出現，隨著溫度降低，晶界碳化物隨之增加，形貌會從顆粒狀而變成連續晶粒層，且基地內魏德曼組織有增多之趨勢，並有麻田散體組織的形成；由於添加錳元素，推測共析溫度降低至介於600℃與650℃之間，並且在該溫度區間觀察到晶粒內部同時具有麻田散體組織與殘留沃斯田體分佈。波來體析出的鼻部溫度為550℃。

The high manganese steel has extremely high hardness strength property, impact resistance as well as wear resistance. We studied thigh manganese steel alloy with composition Fe-8Mn-0.8C which was treated by solution treatment at 1100C for 1-hour, cryogenic treatment and isothermal heat treatment in the temperature range of 1000C to 500C after solution treatment. The metallographic microstructure of the samples was studied to explore the effect of temperature and composition on the microstructure, and the resultant phase change. After the solution treatment of the alloy and water or air cooling to room temperature, the metallographic microstructure was preliminarily observed as a single austenite phase. The specimen done by cryogenic treatment after solution treatment and water quenched was found the martensitic phase at the edge and austenite at the center of the specimen. Study of the initial temperature of the phase change of the martensitic dispersion can be presumed between -179C and room temperature or the specimen cooled with liquid nitrogen. The martensite start temperature of high manganese steel in this paper can be under -179C. The carbides precipitates found beside grain boundary after solution treatment at 1100C and isothermal treatment. When the temperature of isothermal getting lower, carbides precipitates increased, and the morphology will change from granular to continuous grain layer. Also, we found the Widmanstätten structures in the base tends to increase and the formation of martensite phase. Due to the addition of manganese, the eutectoid temperature decreased to between 600°C and 650°C, and the grains were observed to have both martensite structure and residual austenite distribution in this temperature range. The nose of the temperature at which the pearlite were precipitated was 550°C.

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