本文選題：高強度低溫用結(jié)構(gòu)鋼 + 高溫變形行為��； 參考：《南京航空航天大學(xué)》2017年碩士論文

【摘要】：隨著鋼鐵材料在高寒地區(qū)應(yīng)用的快速發(fā)展,人們對其低溫韌性和安全性提出了更高的要求,采用控軋控冷及多元微合金化工藝開發(fā)的高強度低溫用結(jié)構(gòu)鋼具有良好強韌性、強塑性匹配。因此,低溫用結(jié)構(gòu)鋼的研發(fā)和生產(chǎn)成為世界上各大鋼鐵制造商的重要發(fā)展方向。本文采用光學(xué)顯微鏡(OM)、掃描電鏡(SEM)、透射電鏡(TEM)及附帶的能譜儀(EDS)、拉伸試驗、沖擊試驗等手段,以寶山鋼鐵股份有限公司開發(fā)的高強度低溫用熱軋態(tài)結(jié)構(gòu)鋼板為研究對象,在研究無Co鋼板的高溫變形行為、熱處理組織和力學(xué)性能的基礎(chǔ)上,研究加入微量Co(0.1wt%)對高強度低溫用熱軋態(tài)結(jié)構(gòu)鋼板的高溫變形行為、熱處理組織和力學(xué)性能的影響規(guī)律。采用Gleeble 3800熱模擬試驗機,測定了無Co高強度低溫用結(jié)構(gòu)鋼的CCT曲線,并分析了變形溫度為850~1200℃,應(yīng)變速率為5s-1條件下變形溫度對其熱壓縮變形組織與動態(tài)再結(jié)晶行為的影響。結(jié)果表明:無Co高強度低溫用結(jié)構(gòu)鋼的相變臨界點Ac1=723.9℃,Ac3=810.1℃,Ms=390℃,淬火臨界冷卻速度約為15℃/s。在850~1200℃下壓縮變形時無Co高強度低溫用結(jié)構(gòu)鋼的真應(yīng)力-真應(yīng)變曲線具有動態(tài)回復(fù)型流變曲線特征。隨變形溫度由850℃升高到1100℃,細(xì)小等軸再結(jié)晶晶粒尺寸由50μm減小至9μm,動態(tài)再結(jié)晶分?jǐn)?shù)(X)由67.4%增加至100%。研究了(800、920、950℃)正火×60min+20%冷變形+650℃×60min高溫回火復(fù)合形變熱處理工藝對無Co高強度低溫用結(jié)構(gòu)鋼組織及力學(xué)性能的影響,結(jié)果表明:正火態(tài)復(fù)合形變熱處理試樣較熱軋態(tài)冷變形回火試樣強度稍有降低而低溫韌性得到顯著改善,隨著正火溫度的升高,強度先升高后降低,低溫韌性呈持續(xù)降低的趨勢。800℃兩相區(qū)正火態(tài)復(fù)合形變熱處理試樣組織為鐵素體和回火粒狀貝氏體,具有最佳強韌性匹配,屈服強度和抗拉強度分別為637MPa、706MPa,-20℃和-50℃下的沖擊吸收能量分別達(dá)到63J和40J。以韌性斷裂方式及彎曲、扭折的二次裂紋擴展路徑為特征的800℃兩相區(qū)正火態(tài)復(fù)合形變熱處理試樣展現(xiàn)出良好的低溫韌性。研究了Co含量為0.1%的高強度低溫用結(jié)構(gòu)鋼850~1200℃溫度下壓縮變形時的高溫變形行為及復(fù)合形變熱處理(800℃兩相區(qū)淬火×60min+20%冷變形+650℃高溫回火×60min)態(tài)試樣低溫韌性的影響。結(jié)果表明:加入0.1%Co能夠增加試驗鋼在同等變形溫度下的流變應(yīng)力并延遲動態(tài)再結(jié)晶的發(fā)生,變形溫度為850℃時,真應(yīng)變?yōu)?.9的無Co和0.1%Co試樣的X值分別為67.4%和43.9%,當(dāng)變形溫度升高至1100℃時,X均增加到100%。0.1%Co添加后試驗鋼回火索氏體中滲碳體的數(shù)量增加,平均尺寸卻在減小,屈服強度由756MPa增加至787MPa,-20℃和-50℃下的低溫沖擊吸收能量由69J、41J增加到102J、65J,塑韌性呈現(xiàn)顯著提高。
[Abstract]:With the rapid development of the application of iron and steel materials in high and cold regions, the low temperature toughness and safety of steel materials have been put forward higher requirements. The high strength low temperature structural steel developed by controlled rolling and controlled cooling and multi element microalloying process has good strength and toughness. Strong plastic matching. Therefore, the research and production of low-temperature structural steel has become an important development direction of major steel manufacturers in the world. In this paper, optical microscope, scanning electron microscope (SEM), transmission electron microscope (TEM) and attached energy spectrometer (EDSU), tensile test and impact test were used to study hot rolled structural steel plate with high strength and low temperature developed by Baoshan Iron and Steel Co., Ltd. On the basis of studying the high temperature deformation behavior, heat treatment structure and mechanical properties of Co free steel plate, the effects of adding a small amount of Co 0. 1 wt) on the high strength low temperature hot rolled structural steel plate at high temperature deformation behavior, heat treatment structure and mechanical properties were studied. The CCT curves of Co free high strength low temperature structural steel were measured by Gleeble 3800 thermal simulator. The effect of deformation temperature on the hot compression deformation microstructure and dynamic recrystallization behavior was analyzed under the condition of 850,1200 鈩，

本文編號：1973231