本文選題：無碳化物貝氏體鋼 + 殘余奧氏體�。� 參考：《燕山大學(xué)》2015年博士論文

【摘要】：本文設(shè)計(jì)和制備了三種不同鋁含量(即0Al、0.6Al和1.2Al,質(zhì)量百分比)的低碳無碳化物貝氏體鋼,利用光學(xué)顯微鏡、掃描電鏡、透射電鏡、X-射線衍射、數(shù)字圖像相關(guān)法和力學(xué)性能測(cè)試等,研究了熱處理工藝參數(shù)、鋁含量和加載速率對(duì)低碳無碳化物貝氏體鋼微觀組織及其演化、以及力學(xué)性能的影響,揭示了其強(qiáng)韌化的機(jī)制;利用低周疲勞試驗(yàn),對(duì)低碳無碳化物貝氏體鋼在不同應(yīng)變幅下的低周疲勞行為進(jìn)行了研究。研究了保溫時(shí)間和等溫淬火溫度對(duì)1.2Al鋼微觀組織和力學(xué)性能的影響。結(jié)果表明,在320 oC等溫淬火溫度下,隨著等溫保持時(shí)間的延長(zhǎng),獲得的無碳化物貝氏體型鐵素體和殘余奧氏體的含量均呈現(xiàn)出先增加后保持不變的趨勢(shì),其沖擊韌性和總延伸率也先增加然后保持不變;隨著等溫保持時(shí)間的延長(zhǎng),雖然屈服強(qiáng)度基本保持不變,但是抗拉強(qiáng)度則先輕微下降然后保持不變。隨著等溫淬火溫度從350 oC降低到300 oC,等溫淬火后獲得的貝氏體型鐵素體板條的寬度、殘余奧氏體的含量和尺寸均呈現(xiàn)出減小的趨勢(shì),屈服強(qiáng)度和抗拉強(qiáng)度輕微增加,總延伸率顯著降低,而沖擊韌性則表現(xiàn)為先增加后降低的趨勢(shì)。研究了鋁含量對(duì)低碳無碳化物貝氏體鋼微觀組織和力學(xué)性能的影響。結(jié)果表明,隨著鋁含量的增加,貝氏體型鐵素體板條得到了明顯細(xì)化,其屈服強(qiáng)度和沖擊韌性得到了明顯提高。此外,隨著鋁含量的增加,殘余奧氏體的含量和尺寸均呈現(xiàn)出下降的趨勢(shì),抗拉強(qiáng)度、總延伸率隨之下降,而沖擊韌性則隨之增加。這一結(jié)果表明,鋁含量對(duì)實(shí)驗(yàn)鋼的抗拉強(qiáng)度、拉伸延性及沖擊韌性產(chǎn)生不一致性影響。研究了加載速率對(duì)1.2Al鋼兩種不同類型試樣斷裂吸收功的影響。結(jié)果表明,對(duì)于U型缺口試樣,隨著加載速率的增加,裂紋萌生功、裂紋擴(kuò)展功和總吸收功均增加;對(duì)于預(yù)制裂紋試樣,隨著加載速率的增加,盡管裂紋萌生功基本保持不變,但是裂紋擴(kuò)展功和總吸收功均逐漸增加。這主要是由于隨著加載速率的增加殘余奧氏體向馬氏體轉(zhuǎn)變的量降低的緣故。研究了兩種不同等溫溫度(300 oC和350 oC)下等溫淬火處理后1.2Al鋼的低周疲勞行為。結(jié)果表明,在給定總應(yīng)變幅下,兩種等溫淬火試樣具有相似的循環(huán)應(yīng)力響應(yīng)行為,即初始階段的循環(huán)硬化、然后循環(huán)軟化直至失效,或者在初始階段的循環(huán)硬化和循環(huán)飽和之后、循環(huán)軟化直至失效。分析認(rèn)為,初始階段的循環(huán)硬化既不是由應(yīng)變誘發(fā)的馬氏體相變引起的,也不是由增加的位錯(cuò)引起的。原始組織中存在的高密度位錯(cuò)之間的相互作用、以及可移動(dòng)位錯(cuò)的顯著降低是引起初始階段循環(huán)硬化的主要原因,而大量位錯(cuò)湮沒和位錯(cuò)重排是引起初始循環(huán)硬化之后出現(xiàn)循環(huán)軟化的主要原因。與350℃等溫淬火試樣相比,在低總應(yīng)變幅下300 oC等溫淬火試樣具有較高的疲勞壽命,而在高總應(yīng)變幅下300 oC等溫淬火試樣則顯示出較低的疲勞壽命。這主要是由于300 oC等溫淬火鋼的屈服強(qiáng)度高于350 oC等溫淬火鋼的屈服強(qiáng)度、而350 oC等溫淬火鋼具有較高拉伸延性的綜合作用所引起的。
[Abstract]:Three kinds of low carbon bainite steel with different aluminum content (0Al, 0.6Al and 1.2Al, mass percentage) were designed and prepared. The process parameters of heat treatment were studied by optical microscope, scanning electron microscope, transmission electron microscope, X- ray diffraction, digital image correlation method and mechanical properties test. The content of aluminum and loading rate of low carbon non carbonization were studied. The microstructure and evolution of bainitic steel and the influence of mechanical properties revealed the mechanism of its strengthening and toughening. The low cycle fatigue behavior of low carbon bainitic steel under different strain amplitudes was studied by low cycle fatigue test. The microstructure and mechanical properties of 1.2Al steel were studied by the heat preservation time and the isothermal quenching temperature. The results show that at 320 oC isothermal quenching temperature, with the prolongation of the isothermal retention time, the content of the bainite ferrite and retained austenite of the carbide is increased first and then remains unchanged, and the impact toughness and the total elongation at first increase then remain unchanged, with the prolongation of the isothermal retention time. However, the yield strength remained unchanged, but the tensile strength decreased slightly and remained unchanged. As the isothermal quenching temperature decreased from 350 oC to 300 oC, the width of bainite ferrite lath obtained after isothermal quenching, the content and size of retained austenite decreased, and the yield strength and tensile strength increased slightly. The total elongation rate decreased significantly, while the impact toughness was increased first and then decreased. The effect of aluminum content on the microstructure and mechanical properties of low carbon bainitic bainite steel was studied. The results showed that the bainite ferrite slab was clearly refined with the increase of aluminum content, and the yield strength and impact toughness were obtained. In addition, with the increase of aluminum content, the content and size of retained austenite showed a downward trend, the tensile strength, the total elongation decreased and the impact toughness increased. The results showed that the aluminum content was inconcomitant to tensile strength, tensile ductility and impact toughness of the experimental steel. The loading speed was studied. The effect of rate on the fracture absorption work of two different types of 1.2Al steel specimens. The results show that the crack initiation work and the total absorption work increase with the increase of the loading rate for the U notched specimen, and the crack initiation work is basically unchanged with the increase of the loading rate for the prefabricated specimen, but the crack propagation work is basically unchanged. And the total absorption work increased gradually. This was mainly due to the decrease of the amount of retained austenite to martensite with the increase of loading rate. The low cycle fatigue behavior of 1.2Al steel after isothermal quenching at two different isothermal temperatures (300 oC and 350 oC) was studied. The results showed that two isothermal quenching specimens were used under the given total strain amplitude. There is a similar cyclic stress response, that is, cyclic hardening at the initial stage, then softening until failure, or softening the cycle to failure after the initial stage of cyclic hardening and cyclic saturation. Dislocation caused by dislocation. The interaction between high density dislocation in the original tissue and the significant reduction of movable dislocation are the main causes of the initial stage of cyclic hardening. A large number of dislocation annihilation and dislocation rearrangement are the main causes of cyclic softening after initial cyclic hardening. Compared with the isothermal quenching specimens at 350 degrees C, The 300 oC isothermal quenching specimen with low total strain amplitude has a higher fatigue life, while the 300 oC isothermal quenching specimen under high total strain amplitude shows a lower fatigue life. This is mainly due to the yield strength of the 300 oC isotherm steel higher than that of 350 oC isotherm steel, while the 350 oC isotherm steel has a higher tensile elongation. Caused by the comprehensive effect of sex.
【學(xué)位授予單位】：燕山大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：TG142.1

【相似文獻(xiàn)】

相關(guān)期刊論文 前10條

1 韓光海;無碳化物貝氏體在曲軸上的應(yīng)用與展望[J];沈陽電力高等�？茖W(xué)校學(xué)報(bào);2003年03期

2 葉凌云;高鵬舉;程巨強(qiáng);劉志學(xué);;無碳化物貝氏體鋼重型釬桿的生產(chǎn)與應(yīng)用[J];鑿巖機(jī)械氣動(dòng)工具;2010年04期

3 張明如;程禮峰;;無碳化物貝氏體在車輪上應(yīng)用的展望[J];安徽冶金;2001年04期

4 洪飛;劉東雨;任啟欣;;無碳化物貝氏體/馬氏體復(fù)相鋼晶粒細(xì)化研究[J];熱處理技術(shù)與裝備;2010年01期

5 方鴻生,劉東雨,白秉哲,常開地,顧家琳,楊志剛;無碳化物貝氏體/馬氏體復(fù)相鋼的新進(jìn)展[J];金屬熱處理;2001年10期

6 程巨強(qiáng);劉志學(xué);;無碳化物貝氏體耐磨鑄鋼材料的研制與應(yīng)用[J];鑄造;2006年12期

7 李強(qiáng);張冰;;無碳化物貝氏體無縫鋼管的研究[J];天津冶金;2012年01期

8 黃巖,黑祖昆;無碳化物貝氏體鋼低溫韌性[J];大連海事大學(xué)學(xué)報(bào);2003年02期

9 程巨強(qiáng),高興明,杜鐵路;無碳化物貝氏體鑄鋼斗齒、齒座材料的性能及耐磨性[J];工程機(jī)械;2002年10期

10 劉東雨,方鴻生,白秉哲,楊志剛,楊金波;無碳化物貝氏體/馬氏體復(fù)相鋼的強(qiáng)韌性[J];機(jī)械工程學(xué)報(bào);2003年08期

相關(guān)會(huì)議論文 前2條

1 方鴻生;白秉哲;劉東雨;顧家琳;楊志剛;常開地;;無碳化物貝氏體/馬氏體復(fù)相鋼的新進(jìn)展[A];2001中國(guó)鋼鐵年會(huì)論文集（下卷）[C];2001年

2 張明如;陳聯(lián)滿;楊麗珠;顧海澄;;用染色金相鑒別無碳化物貝氏體鋼車輪的組織結(jié)構(gòu)[A];第十一屆中國(guó)體視學(xué)與圖像分析學(xué)術(shù)會(huì)議論文集[C];2006年

相關(guān)博士學(xué)位論文 前1條

1 周騫;低碳含量無碳化物貝氏體鋼的強(qiáng)韌化及低周疲勞行為研究[D];燕山大學(xué);2015年

相關(guān)碩士學(xué)位論文 前2條

1 柳堤;連續(xù)冷卻無碳化物貝氏體鋼的組織與性能研究[D];東北大學(xué);2012年

2 洪飛;無碳化物貝氏體/馬氏體復(fù)相鋼晶粒細(xì)化研究[D];華北電力大學(xué)（北京）;2010年

，

本文編號(hào)：2060363