【摘要】：本課題研究的主要是方大特鋼實(shí)際生產(chǎn)線(xiàn)上的高強(qiáng)度優(yōu)質(zhì)汽車(chē)用彈簧扁鋼51CrV4,針對(duì)51CrV4彈簧鋼的基礎(chǔ)特性展開(kāi)相關(guān)研究,為生產(chǎn)提供技術(shù)上的支持,達(dá)到整個(gè)工業(yè)生產(chǎn)線(xiàn)的集成優(yōu)化,具體研究?jī)?nèi)容以及結(jié)論如下:利用Gleeble-3800熱模擬機(jī)研究了51CrV4彈簧鋼的高溫力學(xué)性能,并采用掃描電鏡觀(guān)察了不同溫度區(qū)間下51CrV4的斷口形貌,結(jié)合J-Mat Pro軟件研究了鋼種第二相析出規(guī)律,分析了不同區(qū)域的斷裂機(jī)理。結(jié)果表明,51CrV4鋼存在高溫脆性區(qū)(1350~1284℃),主要與液膜誘發(fā)熔斷有關(guān),呈現(xiàn)出熔融斷口;低溫脆性區(qū)(904~600℃),主要與Cr7C3和Fe3C硬質(zhì)相的析出以及錳硫比的增多降低了高溫塑性,表現(xiàn)為典型的沿晶斷口。在單一的奧氏體區(qū)(1283~905℃),可獲得良好塑性,表現(xiàn)為典型的韌窩斷口。研究了51CrV4彈簧鋼過(guò)冷奧氏體連續(xù)轉(zhuǎn)變規(guī)律,采用熱膨脹法得出了其相變臨界點(diǎn),同時(shí)得出了51CrV4鋼過(guò)冷奧氏體在不同冷速下連續(xù)轉(zhuǎn)變時(shí)的膨脹曲線(xiàn)并繪制了其靜態(tài)CCT曲線(xiàn)。結(jié)合金相-顯微硬度法,研究得出了不同冷速時(shí),51CrV4鋼各個(gè)組織性能的影響。結(jié)果表明:過(guò)冷奧氏體冷速在0.5℃/s的時(shí)候,奧氏體轉(zhuǎn)變的產(chǎn)物是鐵素體和珠光體;當(dāng)冷速增加,達(dá)到1℃/s之后,貝氏體開(kāi)始生成,隨著冷速的變大,貝氏體含量也逐漸增多;馬氏體轉(zhuǎn)變冷速區(qū)間為2~30℃/s;當(dāng)冷速超過(guò)12℃/s之后,過(guò)冷奧氏體相變產(chǎn)物只有馬氏體。對(duì)51CrV4鋼使用單道次壓縮試驗(yàn),采用熱物理模擬的方法,對(duì)不同變形量、變形速率及變形溫度下的51CrV4彈簧鋼進(jìn)行真應(yīng)力-真應(yīng)變曲線(xiàn)測(cè)定同時(shí)分析不同試驗(yàn)條件下變形量、溫度、應(yīng)變速率對(duì)熱變形過(guò)程中變形應(yīng)力的影響。研究結(jié)果表明,在相同的變形溫度下,真應(yīng)力值隨著變形速率的增加而增加,應(yīng)變速率越大,真應(yīng)力值越大。在相同的變形速率下,真應(yīng)力值隨著變形溫度的增加而降低,應(yīng)變溫度越高,真應(yīng)力值越小。
[Abstract]:This research is mainly focused on the high strength and high quality spring flat steel 51CrV4 used in Fangda special steel production line, aiming at the basic characteristics of 51CrV4 spring steel to provide technical support for production. The specific research contents and conclusions are as follows: the mechanical properties of 51CrV4 spring steel at high temperature are studied by Gleeble-3800 thermal simulator, and the fracture morphology of 51CrV4 at different temperature ranges is observed by scanning electron microscope (SEM). Combined with J-Mat Pro software, the precipitation law of the second phase of steel was studied, and the fracture mechanism of different regions was analyzed. The results show that there is a high temperature brittle zone (1350 ~ 1284 鈩，

本文編號(hào)：2265177