本文選題：40CrNi3MoV鋼 + 50CrNi5MoV鋼�。� 參考：《昆明理工大學》2017年碩士論文

【摘要】：40CrNi3MoV鋼是一種典型的中碳CrNiMoV鋼,經(jīng)淬火和高溫回火后,具有較高的強度和優(yōu)良的韌塑性,被廣泛應用于制造高壓容器等大型鍛件。隨著壓力容器承受壓力提高和減重的要求,在保證良好的韌塑性前提下,需要將40CrNi3MoV鋼的屈服強度水平從目前的l000MPa級提高到1350MPa級。本文在40CrNi3MoV鋼的基礎上,通過提高C、Ni、Mo元素的含量,研制屈服強度為 1350MPa 級的新型 50CrNi5MoV 鋼。并通過 SEM、TEM、EBSD、XRD、Thermo-Calc計算以及相分析等方法,重點研究了回火溫度對傳統(tǒng)40CrNi3MoV鋼和新型50CrNi5MoV鋼組織與力學性能的影響。結(jié)果表明:1、在40CrNi3MoV鋼的基礎上,增加C、Ni、Mo的含量得到的50CrNi5MoV鋼經(jīng)淬火和高溫回火后的組織明顯細化,且碳化物數(shù)量增加。550℃回火后50CrNi5MoV鋼中的M2C含量是40CrNi3MoV鋼的3倍。2、與40CrNi3MoV鋼相比,50CrNi5MoV鋼中的大角度晶界所占的比例以及殘余奧氏體的含量均增加,殘余奧氏體在試驗鋼中呈粒狀或塊狀分布于基體中。3、40CrNi3MoV和50CrNi5MoV試驗鋼的硬度和強度隨回火溫度的升高而降低,塑性和沖擊吸收能量的變化趨勢則相反。將C含量從0.38%提高到0.49%,Mo含量從0.43%提高到1.06%后,由于M2C的二次硬化作用,經(jīng)500℃至550℃回火后,50CrNi5MoV鋼硬度和強度均升高。50CrNi5MoV鋼經(jīng)550℃回火后的屈服強度達到了 1350MPa級,同時具有良好的室溫塑韌性和低溫韌性;室溫AK46J,(-40℃)KV223J,KIcl04MPa·m12。4、試驗鋼經(jīng)500℃至650℃不同溫度回火后,50CrNi5MoV鋼在350℃下的抗拉強度和屈服強度分別比40CrNi3MoV鋼高210MPa和140MPa左右。5、試驗鋼經(jīng)550℃回火后,在350℃至500℃下的抗拉強度下降率相差不大。不過由于50CrNi5MoV鋼室溫強度高,其在500℃高溫下的抗拉強度仍不低于lOOOMPa,比40CrNi3MoV鋼高200MPa左右,說明50CrNi5MoV鋼更適合在高溫下服役。綜上所述,在40CrNi3MoV鋼的基礎是上,通過提高部分合金元素的含量,成功研發(fā)了具有良好韌塑性和高溫性能的1350MPa級高強度馬氏體鋼50CrNi5MoV,為高壓容器等大型鍛件減重奠定了基礎。
[Abstract]:40CrNi3MoV steel is a typical medium carbon CrNiMoV steel. After quenching and tempering at high temperature, 40CrNi3MoV steel has high strength and excellent ductility, so it is widely used in manufacturing large forgings such as high pressure vessels. With the requirement of pressure increase and weight loss in pressure vessel, the yield strength of 40CrNi3MoV steel should be raised from the current l000MPa grade to the 1350MPa grade under the premise of good ductility. On the basis of 40CrNi3MoV steel, a new type of 50CrNi5MoV steel with yield strength of 1350MPa grade was developed by increasing the content of Cni Mo element. The effect of tempering temperature on the microstructure and mechanical properties of traditional 40CrNi3MoV steel and new 50CrNi5MoV steel was studied by means of the calculation and phase analysis of SEMTEMU EBSDX XRDX Thermo-Calc. The results show that on the basis of 40CrNi3MoV steel, the microstructure of 50CrNi5MoV steel obtained by quenching and tempering at high temperature is obviously refined by increasing the content of Cni Mo. After tempering at .550 鈩，

本文編號：1935425