本文選題：17-4PH不銹鋼 + 高溫塑性變形　； 參考：《江蘇大學(xué)》2017年碩士論文

【摘要】：17-4PH不銹鋼作為重要的核反應(yīng)堆結(jié)構(gòu)材料,被西方大國(guó)廣泛應(yīng)用于如輕水反應(yīng)堆(LWR)和壓水反應(yīng)堆(PWR)的閥桿等核電站結(jié)構(gòu)材料。近年來對(duì)其的研究主要集中在17-4PH不銹鋼的熱處理工藝方面,在熱變形行為方面的研究鮮有報(bào)道。本文采用Gleeble-3500熱力模擬試驗(yàn)機(jī)對(duì)該鋼進(jìn)行熱壓縮實(shí)驗(yàn),采集相關(guān)實(shí)驗(yàn)數(shù)據(jù),通過回歸擬合等數(shù)學(xué)計(jì)算了17-4PH不銹鋼高溫塑性變形過程中的流變應(yīng)力、應(yīng)變速率、形變溫度之間的定量關(guān)系。并通過OM、TEM等手段對(duì)材料在熱壓縮過程中的組織進(jìn)行了研究,最后基于實(shí)驗(yàn)結(jié)果并利用材料動(dòng)態(tài)模型建立17-4PH不銹鋼的熱加工圖,根據(jù)對(duì)該熱加工圖提出合理的熱加工工藝參數(shù)區(qū)域,研究主要結(jié)論如下:(1)17-4PH不銹鋼在高溫壓縮過程中,流變應(yīng)力隨應(yīng)變速率的降低而降低,表明17-4PH不銹鋼為正應(yīng)變速率敏感材料。當(dāng)溫度的升高時(shí),流變應(yīng)力也會(huì)降低。同為T=1000℃,ps從e·=0.01s-1時(shí)113.42MPa增長(zhǎng)至e·=5s-1時(shí)的232.04MPa;同為e0.01s1·-(28),ps從T=1100℃的140.57MPa增高至T=950℃的249.49MPa。溫度和應(yīng)變速率的共同作用可以通過lnZ值進(jìn)行反映。(2)在熱變形過程中,當(dāng)T=1100℃、e·=0.01s-1和T=1050℃、e·=0.01s-1時(shí),出現(xiàn)明顯的峰值應(yīng)力特征,此時(shí)動(dòng)態(tài)再結(jié)晶軟化機(jī)制占據(jù)主導(dǎo)作用,而在T≤1100℃、·-1ε≤5s其他大部分條件下,材料的動(dòng)態(tài)回復(fù)作為主導(dǎo)作用的情況居多。(3)當(dāng)變形溫度恒定時(shí),不同的應(yīng)變速率下的17-PH不銹鋼熱壓縮試樣微觀組織形態(tài)存在顯著差異,隨著應(yīng)變速率的提高,加工硬化作用越來越明顯,晶粒沿流變方向拉長(zhǎng),動(dòng)態(tài)軟化程度降低。當(dāng)應(yīng)變速率恒定時(shí),隨著溫度的升高,再結(jié)晶程度變大,晶�；兂潭冉档�,動(dòng)態(tài)再結(jié)晶晶粒的體積分?jǐn)?shù)相應(yīng)增加。(4)17-4PH不銹鋼峰值應(yīng)力本構(gòu)方程為:其與實(shí)際測(cè)量平均誤差為5.62%,在誤差允許范圍內(nèi)。(5)根據(jù)動(dòng)態(tài)再結(jié)晶理論,建立起了動(dòng)態(tài)再結(jié)晶的臨界應(yīng)變模型,當(dāng)ce3e,材料在熱壓縮過程中開始發(fā)生動(dòng)態(tài)再結(jié)晶:30.154exp(47474.95 9.04 / 8.314)X10pe eT-·(28)0.8c pe(28)e(6)基于動(dòng)態(tài)材料模型繪制了17-4PH不銹鋼的熱加工圖。變形初期材料容易發(fā)生失穩(wěn)。當(dāng)e=0.3、0.6,熱加工圖特征變化不顯著,流變失穩(wěn)區(qū)所對(duì)應(yīng)的功率耗散效率均迅速下降,當(dāng)e=0.1時(shí),失穩(wěn)區(qū)域所對(duì)應(yīng)功率耗散效率小于0.16,低于耗散峰值的一半,同樣,e=0.3、0.6時(shí),失穩(wěn)區(qū)耗散效率分別小于0.12和0.15,均遠(yuǎn)遠(yuǎn)低于峰值耗散效率。(7)當(dāng)e=0.6時(shí),17-4PH不銹鋼適宜的加工參數(shù)區(qū)間為T=1062℃~1100℃、e·≤0.023s-1。不宜進(jìn)行加工的參數(shù)區(qū)間為T=950℃~1028℃、e·=0.27s-1~5s-1。
[Abstract]:As an important structural material for nuclear reactor, 17-4PH stainless steel has been widely used in the western countries as the structural materials of the stem of the valve stem such as the light water reactor (LWR) and the pressurized water reactor (PWR). In recent years, the research on the thermal treatment of 17-4PH stainless steel is mainly concentrated on the thermal deformation behavior, and the research on the thermal deformation behavior is rarely reported. The hot compression test of the steel was carried out by the Gleeble-3500 thermal simulation test machine, and the relevant experimental data were collected. The quantitative relationship between the rheological stress, the strain rate and the deformation temperature in the high temperature plastic deformation process of the 17-4PH stainless steel was calculated by regression fitting and so on. The microstructure of the material in the process of thermal compression was carried out by means of OM and TEM. In the end, based on the experimental results and using the dynamic model of the material to establish the hot working diagram of 17-4PH stainless steel, the main conclusions are as follows: (1) in the process of high temperature compression, the flow strain of 17-4PH stainless steel decreases with the decrease of the strain rate, indicating that 17-4PH is not. Rust steel is a positive strain rate sensitive material. When the temperature rises, the rheological stress will also decrease. The same is the 232.04MPa at T=1000 C, PS from e to =0.01s-1 to e. =5s-1, and the same as e0.01s1. (28), the common effect of PS from T=1100 to the temperature and the strain rate can be carried out through the values. (2) (2) during the process of thermal deformation, when T=1100, e. =0.01s-1 and T=1050 C, e. =0.01s-1, there is obvious peak stress characteristics. At this time, the dynamic recrystallization softening mechanism occupies the dominant role, while the dynamic recovery of the material is dominant under the T < 1100 C, -1 e or less 5S. (3) deformation temperature At constant time, there are significant differences in the microstructure of 17-PH stainless steel under different strain rates. With the increase of the strain rate, the working hardening is becoming more and more obvious, the grain grows along the flow direction and the dynamic softening degree decreases. When the strain rate is constant, the degree of recrystallization becomes larger and the grain distortion is changed with the increase of temperature. The volume fraction of the dynamic recrystallized grain increases correspondingly. (4) the constitutive equation of the peak stress stress of 17-4PH stainless steel is: the average error is 5.62% and within the allowable range of error. (5) the critical strain model of dynamic recrystallization is established according to the dynamic recrystallization theory. When ce3e, the material begins to occur during the thermal compression process. Dynamic recrystallization: 30.154exp (47474.95 9.04 / 8.314) X10pe eT-. (28) 0.8C PE (28) e (6) based on the dynamic material model to draw a hot working diagram of the 17-4PH stainless steel. The initial deformation of the material is easy to be unstable. When e=0.3,0.6, the characteristics of the thermal processing diagram are not significant, the power dissipation efficiency of the rheological instability zone decreases rapidly, when e=0.1, The power dissipation efficiency of the unstable region is less than 0.16, which is lower than half of the dissipative peak, and the dissipation efficiency of the unstable region is less than 0.12 and 0.15, respectively, when e=0.3,0.6 is far below the peak dissipation efficiency. (7) when e=0.6, the suitable processing parameters of 17-4PH stainless steel are T= 1062 C ~1100, e. < 0.023s-1. is not suitable for processing parameters. The interval is T=950 C ~1028 C, e. =0.27s-1~5s-1.
【學(xué)位授予單位】：江蘇大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TG142.71

【參考文獻(xiàn)】

相關(guān)期刊論文 前8條

1 李慧中;衛(wèi)曉燕;梁霄鵬;姜俊;歐陽(yáng)杰;李軼;;擠壓態(tài)AZ80鎂合金的塑性變形行為[J];粉末冶金材料科學(xué)與工程;2014年01期

2 項(xiàng)建英;宋仁伯;任培東;;316L不銹鋼動(dòng)態(tài)再結(jié)晶行為[J];北京科技大學(xué)學(xué)報(bào);2009年12期

3 張松,張春華,文R怪，

本文編號(hào)：2043669