發(fā)布時(shí)間：2018-03-21 06:01

  本文選題：超高強(qiáng)鋼　切入點(diǎn)：馬氏體　出處：《沈陽工業(yè)大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：本文采用優(yōu)化合金的方法,自主設(shè)計(jì)了三種低合金超高強(qiáng)鋼的合金成分,分別稱為1#鋼、2#鋼和3#鋼。對三種低合金超高強(qiáng)鋼設(shè)計(jì)相應(yīng)的軋制成形以及合理的熱處理工藝,探索材料的最優(yōu)強(qiáng)韌性匹配。分別采用光鏡、掃描電鏡對試樣的微觀結(jié)構(gòu)進(jìn)行觀察和表征,采用萬能試樣拉伸機(jī)、硬度測試儀等測試材料的力學(xué)性能,采用模擬軟件模擬三種低合金超高強(qiáng)鋼的特征參數(shù)。同時(shí),試樣的耐磨性由熱處理后試樣的硬度和塑性進(jìn)行表征。主要成果如下所示:本文通過對三種低合金超高強(qiáng)鋼特征參數(shù)的模擬,得出各個(gè)鋼種的相變點(diǎn)溫度分別為:1#鋼Ac1≈770℃,Bs≈400℃,Ms≈110℃;2#鋼Ac1≈810℃,Bs≈440℃,Ms≈87℃;3#鋼Ac1≈750℃,Bs≈430℃,Ms≈141℃。通過探索1#鋼的一次等溫球化退火、二次等溫球化退火及正火+等溫球化退火三種熱處理工藝對熱軋過程中帶狀組織的影響,發(fā)現(xiàn)一次等溫球化退火與二次等溫球化退火不能完全消除帶狀組織,而經(jīng)過正火+等溫球化退火工藝能夠消除帶狀組織,且獲得了良好的淬火前組織。對比1#鋼的淬火與等溫淬火工藝發(fā)現(xiàn),經(jīng)820℃淬火后,試樣的基體組織基本為馬氏體,此時(shí)材料的屈服強(qiáng)度和抗拉強(qiáng)度分別為1200MPa和1780MPa。經(jīng)300℃等溫淬火,基體組織為下貝氏體與馬氏體混合組織,此時(shí)屈服強(qiáng)度為1220MPa、抗拉強(qiáng)度為1710MPa。相較于1#鋼淬火后的性能,等溫淬火后試樣的強(qiáng)度降低,但塑性有所提升。2#和3#鋼經(jīng)相應(yīng)的等溫淬火處理后,其抗拉強(qiáng)度分別為1280MPa和1530MPa,屈服強(qiáng)度分別為1052MPa和1227MPa,同時(shí)2#鋼經(jīng)相應(yīng)的等溫淬火處理后,試樣中的組織為下貝氏體、馬氏體、碳化物和殘余奧氏體,而3#鋼基體組織主要為下貝氏體和殘余奧氏體。通過三種高強(qiáng)鋼的組織和性能研究分析可知:1#鋼和3#鋼的綜合力學(xué)性能達(dá)到了本實(shí)驗(yàn)的目的,抗拉強(qiáng)度大于1500MPa,屈服強(qiáng)度大于1200MPa。但是,1#鋼的力學(xué)性能要更優(yōu)于3#鋼,更能滿足礦山研磨機(jī)鋼球、破碎機(jī)顎板的要求。
[Abstract]:In this paper, the alloy compositions of three kinds of low-alloy ultra-high strength steels are designed by the method of optimizing alloys. The corresponding rolling forming and reasonable heat treatment process are designed for the three kinds of low-alloy ultra-high strength steels. The microstructure of the material was observed and characterized by light microscope and scanning electron microscope, and the mechanical properties of the material were tested by universal tensile machine and hardness tester. The characteristic parameters of three kinds of low-alloy ultra-high strength steels were simulated by simulation software. The wear resistance of the specimens is characterized by the hardness and plasticity of the specimens after heat treatment. The main results are as follows: in this paper, the characteristic parameters of three kinds of low-alloy ultra-high strength steels are simulated. The temperature of phase transition point of each steel is: Ac1 = 770 鈩，

本文編號：1642566