本文選題：貝氏體鋼 + 沖擊韌性　； 參考：《西華大學(xué)》2015年碩士論文

【摘要】：轍叉是列車實(shí)現(xiàn)變軌的重要部件,隨著鐵路運(yùn)力需求的提高,對(duì)轍叉材料也提出了更高的要求,由于貝氏體鋼綜合力學(xué)性能優(yōu)異被認(rèn)為是替代傳統(tǒng)高錳鋼的最佳材料。列車在通過(guò)轍叉過(guò)程中,轍叉會(huì)受到來(lái)自車輪的周期性沖擊力,再加上環(huán)境因素影響,容易造成疲勞失效,威脅列車安全運(yùn)行。因此,提高轍叉材料綜合性能顯得尤為重要。本文選用西華大學(xué)自主研發(fā)的Si-Mn-Cr系貝氏體鋼作為實(shí)驗(yàn)材料,研究了熱處理工藝對(duì)該鋼種的沖擊韌性和滾動(dòng)接觸疲勞性能的影響,以求找到提高該鋼性能的途徑。針對(duì)試驗(yàn)用鋼沖擊韌性的研究,本文設(shè)計(jì)了兩組奧氏體化溫度分別為900℃、920℃,以及四組等溫處理溫度,依次為500℃、450℃、400℃、330℃,分別研究奧氏體化溫度和等溫溫度對(duì)沖擊韌性的影響。分析結(jié)果表明經(jīng)過(guò)熱處理后,材料沖擊韌性有很大提高,沖擊功提高近2倍。在900℃、920℃奧氏體化溫度下,試樣均在330℃等溫時(shí)沖擊韌性達(dá)到最優(yōu)。相同等溫溫度下,奧氏體化溫度為920℃時(shí),試樣沖擊功相對(duì)較低。同時(shí),經(jīng)過(guò)熱處理后,試樣硬度值有較大提高,主要集中在HRC39.0~46.9之間。本文主要研究了熱處理工藝和材料冶煉工藝對(duì)試驗(yàn)用鋼滾動(dòng)接觸疲勞性能的影響。電渣重熔工藝冶煉的試樣,經(jīng)過(guò)等溫處理,滾動(dòng)接觸疲勞壽命都有不同程度提高,且隨著等溫溫度由500℃降到330℃,其滾動(dòng)接觸疲勞壽命先增大后減小,在400℃等溫條件下,滾動(dòng)接觸疲勞壽命最高為3.91×105r;對(duì)于非真空電弧爐冶煉的試樣,隨著等溫溫度由500℃降到330℃,滾動(dòng)接觸疲勞壽命逐漸增大,當(dāng)?shù)葴販囟葹?30℃時(shí),滾動(dòng)接觸疲勞性能最高為2.43×105r。通過(guò)對(duì)組織和剝落坑形貌觀察發(fā)現(xiàn):等溫溫度由500℃降到330℃時(shí),新型轍叉用貝氏體鋼組織依次為粒狀貝氏體、板條貝氏體、針狀貝氏體;新型轍叉用貝氏體鋼疲勞失效形式主要為麻點(diǎn)剝落和淺層剝落,剝落坑呈豆?fàn)罨蚪频妊切?且同一試樣上能同時(shí)出現(xiàn)兩種剝落形式,剝落形式與材料的冶煉方式無(wú)關(guān)。
[Abstract]:Frog is an important part of the train to realize rail transformation. With the improvement of railway transportation capacity, the material of frog is also required higher. Because of the excellent comprehensive mechanical properties of bainite steel, it is considered as the best material to replace the traditional high manganese steel. In the process of crossing the frog, the frog will be subjected to the periodic impact from the wheel, and the environmental factors will influence it, which will easily cause fatigue failure and threaten the safe operation of the train. Therefore, it is very important to improve the comprehensive performance of frog material. In this paper, the influence of heat treatment on the impact toughness and rolling contact fatigue properties of Si-Mn-Cr series bainitic steel developed by Xihua University was studied in order to find a way to improve the properties of the steel. In this paper, two groups of austenitizing temperature are designed to be 900 鈩，

本文編號(hào)：1788734