本文關(guān)鍵詞： Cr17Mn17Mo3NiN奧氏體不銹鋼 熱變形行為 微觀組織演變 熱加工圖　出處：《江蘇大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：奧氏體不銹鋼因?yàn)榫邆淞己玫哪透g性和無磁性,而被廣泛地應(yīng)用到眾多行業(yè)之中。高氮奧氏體不銹鋼中氮含量比較高,氮在提高鋼的強(qiáng)度和耐蝕性能的同時(shí)還會阻滯回復(fù),熱加工工藝不合理將導(dǎo)致鋼在熱軋時(shí)容易出現(xiàn)應(yīng)變集中,使產(chǎn)品的成型性變差。因此有必要對其熱變形行為進(jìn)行深入研究,為高氮奧氏體不銹鋼熱加工工藝優(yōu)化提供理論依據(jù)。本文利用Gleeble-3500熱力模擬試驗(yàn)機(jī)對Cr17Mn17Mo3NiN奧氏體不銹鋼(代號H1)在不同變形參數(shù)(T:950-1100℃,(?)·0.01-1 s-1)下進(jìn)行高溫壓縮試驗(yàn)。分析不同變形參數(shù)對其流變應(yīng)力曲線的影響;借助金相顯微鏡(OM)、透射電鏡(TEM)等表征手段揭示了其高溫微觀組織的演變規(guī)律;基于雙曲正弦函數(shù)構(gòu)建了高溫本構(gòu)模型;以動(dòng)態(tài)材料模型理論(DMM)為基礎(chǔ),繪制其熱加工圖,研究其可加工安全區(qū)間,為這類不銹鋼的推廣和應(yīng)用提供重要的科學(xué)理論基礎(chǔ)。研究結(jié)果表明:當(dāng)應(yīng)變速率一定時(shí),流變應(yīng)力隨著溫度的升高降低,而當(dāng)變形溫度一定時(shí),流變應(yīng)力隨著應(yīng)變速率的減小降低;Cr17Mn17Mo3NiN奧氏體不銹鋼在高溫低應(yīng)變速率下的主要軟化機(jī)制為動(dòng)態(tài)再結(jié)晶,且動(dòng)態(tài)再結(jié)晶的程度和再結(jié)晶的晶粒尺寸都會增加,而在高溫高應(yīng)變速率下為動(dòng)態(tài)回復(fù);原始奧氏體晶粒的晶界弓出是Cr17Mn17Mo3NiN奧氏體不銹鋼發(fā)生動(dòng)態(tài)再結(jié)晶的主要形核機(jī)制,晶界附近亞晶的旋轉(zhuǎn)機(jī)制對再結(jié)晶的形核有輔佐作用。Cr17Mn17Mo3NiN奧氏體不銹鋼的熱變形激活能為551.36 kJ/mol;最優(yōu)的熱加工工藝窗口是變形溫度為1000-1050℃,應(yīng)變速率為0.01-0.1 s-1的區(qū)域。
[Abstract]:Austenitic stainless steel is widely used in many industries because of its good corrosion resistance and non-magnetic properties. The nitrogen content of high nitrogen austenitic stainless steel is relatively high. Nitrogen can not only improve the strength and corrosion resistance of steel, but also delay the recovery of steel. The unreasonable hot working technology will lead to strain concentration in hot rolling. So it is necessary to study the thermal deformation behavior of the product. This paper provides a theoretical basis for the optimization of hot working process of high nitrogen austenitic stainless steel. In this paper, Cr17Mn17Mo3NiN austenitic stainless steel (Cr17Mn17Mo3NiN) was tested by Gleeble-3500 thermal simulation machine. Under different deformation parameters: t: 950-1100 鈩，

本文編號：1443194