本文選題：熱軋Mn13耐磨鋼 + 滑動磨損��； 參考：《中國礦業(yè)大學(xué)》2015年碩士論文

【摘要】：顎式破碎機顎板作為破碎機的核心部件,它受到撞擊和物料沖刷的雙重作用,工況多為中、高沖擊載荷和循環(huán)變形與疲勞作用,磨損程度較高。鑄造高錳鋼的鑄造缺陷和馬氏體耐磨鋼低韌性的缺點大大降低了顎板的工作效率。熱軋工藝可在保證高塑韌性的同時有效解決受鑄造工藝局限性帶來的組織疏松、縮孔、晶粒粗大等缺陷的影響。本文以熱軋奧氏體高錳耐磨鋼(Mn13鋼)為實驗材料,針對破碎機復(fù)雜的工況條件,以滑動磨損、磨料磨損、沖擊磨料磨損的形式開展磨損實驗綜合評價其耐磨性能,并利用掃描電鏡、X射線衍射儀、透射電鏡等,分析了磨損機理和硬化機制�；瑒幽p試驗表明,與B-Hard400鋼和B-Hard500鋼相比,除了高載荷干摩擦和低載荷煤泥粉的工況Mn13鋼的耐磨性表現(xiàn)的更為優(yōu)秀,干摩擦?xí)r磨損機理主要表現(xiàn)為犁溝和疲勞剝落磨損,以煤泥粉和石英砂為磨料時磨損機理主要表現(xiàn)為犁溝切削和鑿削切割的破壞機制,高載時還存在煤泥粉的碾壓粘著膜;磨料磨損試驗表明,Mn13鋼的耐磨性在以硬質(zhì)顆粒(煤矸石、石英砂)為磨料的情況下較好,加工硬化效果明顯,煤泥粉磨料磨損的機制表現(xiàn)為微觀切削并伴隨局部的疲勞剝落,以煤矸石為磨料的磨損機制為微觀切削,伴隨擠壓剝落和局部區(qū)域的疲勞剝落,以石英砂為磨料的磨損機制則為典型的鑿削磨損和微觀切削。在沖擊磨料磨損試驗中,1-8J沖擊功下Mn13鋼的磨損量走勢呈“M形”,在2J和5J時磨損量最大,4J和7J時磨損量最小,最佳沖擊功工況為3.5-4.5J和6-7J。在2J、4J、5J和7J的沖擊功下,隨著沖擊次數(shù)增多,磨損量逐漸增大。在中、高沖擊功條件下Mn13鋼的硬化層厚度可達(dá)3500μm以上,最高達(dá)6500μm。從磨損亞表層的金相組織中均可以觀測到形變孿晶的存在,隨著沖擊功提高在局部晶粒內(nèi)生長的孿晶密度增大。切削、塑變、鑿削和疲勞剝落是Mn13鋼沖擊磨料磨損的主要機制,隨著沖擊功的提高加工硬化程度得到提升,切削痕變少疲勞剝落坑增多。在中沖擊功的作用下,孿晶和位錯的交互作用是主要的硬化機制,少量相變ε(hcp)起輔助作用;在高沖擊功的作用下,主要硬化機制為高密度孿晶條帶互相交割使奧氏體組織細(xì)化為微晶甚至納米晶,碳化物析出、α(bcc)相變等起輔助硬化作用。
[Abstract]:Jaw crusher jaw plate, as the core component of the crusher, is affected by the double effects of impact and material scour. The working conditions are mostly medium, high impact load and cyclic deformation and fatigue, and the wear degree is high. The casting defects of the cast high manganese steel and the lack of the martensitic wear steel low toughness greatly reduce the working efficiency of the jaw plate. Hot rolling process At the same time, it can effectively solve the defects of loose tissue, shrinkage cavity and coarse grain caused by the limitation of casting process at the same time. In this paper, the hot rolled austenite high manganese wear-resistant steel (Mn13 steel) is used as the experimental material. In the case of the complicated working conditions of the crusher, the wear of sliding wear, abrasive wear and impact abrasive wear is carried out. The wear resistance was evaluated and the wear mechanism and hardening mechanism were analyzed by scanning electron microscope, X ray diffractometer and transmission electron microscope. The sliding wear test showed that compared with B-Hard400 steel and B-Hard500 steel, the wear resistance of Mn13 steel was better than that of high load dry friction and low load slime powder, and the dry friction grinding mill was used. The main damage mechanism is plough furrow and fatigue exfoliation wear. The wear mechanism of the slime powder and quartz sand is mainly manifested in the failure mechanism of furrow cutting and chisel cutting while the high load still exists the roller compacted adhesive film on the high load, and the abrasive wear test shows that the wear resistance of Mn13 steel is abrasive with hard particles (gangue and quartz sand). The mechanism of the work hardening is obvious. The mechanism of the abrasive wear of the pulverized coal powder is characterized by micro cutting and local fatigue peeling. The wear mechanism of the gangue as the abrasive wear mechanism is micro cutting, with the extrusion peeling and the fatigue exfoliation in the local area, and the wear mechanism of the quartz sand is the typical chisel wear and micro cutting. In the impact abrasive wear test, the wear of Mn13 steel under the impact of 1-8J impact is "M shape", the wear amount is the largest at 2J and 5J, the wear of 4J and 7J is the smallest. The optimum impact work condition is 3.5-4.5J and 6-7J. at 2J, 4J, 5J and the impact work, with the increase of the impact times. The thickness of the hardened layer is more than 3500 m. The deformation twin can be observed in the metallographic structure of the subsurface of the wear surface, which is up to 6500 m.. With the increase of impact work, the twin density increases in the local grain. The main mechanism of the abrasive wear of Mn13 steel is cutting, plastic deformation, chiseling and fatigue spalling. With the effect of impact work, the interaction of twin and dislocation is the main hardening mechanism, and a small amount of phase transition epsilon (HCP) plays an auxiliary role. Under the action of high impact work, the main hardening mechanism is that the high density twin strip intersections make the austenite microstructure refined. Microcrystalline or even nanocrystalline, carbide precipitates, and alpha (BCC) phase change plays an auxiliary hardening role.

【學(xué)位授予單位】：中國礦業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TG142.1

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