本文關(guān)鍵詞：Inconel625合金大規(guī)格管棒材擠壓過程的組織與性能演變　出處：《蘭州理工大學(xué)》2016年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 高溫合金 Inconel625 熱擠壓 組織 性能

【摘要】：Inconel625合金是以鉬、鈮為主要強(qiáng)化元素的固溶強(qiáng)化型鎳基變形高溫合金,具有優(yōu)良的耐腐蝕和高氧化性能,從低溫到980℃均具有良好的拉伸性能和疲勞性能,并且耐鹽霧氣氛下的應(yīng)力腐蝕。但限于鎳基合金成形溫度區(qū)間窄及變形抗力大等固有屬性,實際生產(chǎn)中大口徑管棒材的成型技術(shù)還不完善。本文通過熱擠壓的方法得到大口徑Inconel625合金管棒材,并在此基礎(chǔ)上分析不同成型參數(shù)對其成形性的影響,得到合理熱擠壓工藝參數(shù)。通過各種分析工具、力學(xué)試樣及電化學(xué)實驗研究不同擠壓參數(shù)下,材料的組織和性能的變化規(guī)律。在研究熱擠壓前后Inconel625合金顯微組織性能的變化中發(fā)現(xiàn),擠壓前后均有Nb偏析的存在。通過SEM和TEM等分析工具,發(fā)現(xiàn)熱擠壓前的加熱過程中產(chǎn)生M23C6碳化物。熱擠壓后,材料發(fā)生完全再結(jié)晶,組織均勻,但仍有部分碳化物保留在晶界;織構(gòu)密度明顯降低;力學(xué)性能整體而言有所提升;耐腐蝕性能有所改善。隨著擠壓比的增大,變形熱導(dǎo)致實際擠壓溫度升高,再結(jié)晶平均晶粒尺寸明顯增大;織構(gòu)密度減小;高溫使得晶界碳化物大量溶解,斷口二次裂紋大量減少,固溶強(qiáng)化作用增強(qiáng),強(qiáng)度升高,塑性下降;耐腐蝕性能也呈下降趨勢。同時提高擠壓比和擠壓速度,雖然變形熱會增多,但高速擠壓使得二次相溶解和再結(jié)晶晶粒長大沒有時間進(jìn)行。再結(jié)晶晶粒尺寸也呈增大趨勢,但幅度較小;相比于只增大擠壓比,晶界碳化物溶解量明顯減少,斷口二次裂紋增多;強(qiáng)度小幅增加,塑性小幅下降。耐腐蝕性處于中等水平。
[Abstract]:Inconel625 alloy is molybdenum, niobium solid solution strengthened nickel based superalloy mainly strengthening element, has excellent corrosion resistance and high oxidation resistance, from low temperature to 980 DEG C have tensile properties and good fatigue resistance, corrosion resistance and stress of salt spray atmosphere. But limited to nickel base alloy forming narrow temperature range and high resistance to deformation and other inherent properties, molding technology and actual production in large caliber pipe bar is not perfect. The large diameter Inconel625 alloy tube bar by hot extrusion molding, analysis of different parameters on the formability of the impact and on the basis of reasonable hot extrusion process through various parameters. Analysis tools, research samples and electrochemical experimental mechanics different extrusion parameters, variation of microstructure and mechanical properties of the material. The changes in microstructure and mechanical properties of Inconel625 alloy before and after hot extrusion in the study, Extrusion both before and after the Nb segregation. Through SEM and TEM analysis tools, found to produce M23C6 carbides in the heating process of hot extrusion. After hot extrusion, materials complete recrystallization microstructure, but there are still some carbide retained in the grain boundary; texture density decreased significantly; the mechanical properties of the whole improved corrosion resistance; the performance has been improved. With the increase of the extrusion ratio, thermal deformation cause actual extrusion temperature, the recrystallization of the average grain size increases; texture density decreases; the high temperature makes the grain boundary carbides dissolved, reducing the number of fracture two crack, solid solution strengthening effect is enhanced, the strength increased, the ductility decreases; the corrosion resistance also showed a trend of decline. At the same time. The increasing of extrusion ratio and extrusion speed, while the thermal deformation will increase, but the high speed extrusion makes two phase dissolution and recrystallization grains grow up in no time. The recrystallization grain size Inch also showed an increasing trend, but the amplitude was small. Compared with increasing extrusion ratio only, the amount of carbide dissolved in grain boundary decreased significantly, the cracks increased two times, the strength increased slightly, and the ductility decreased slightly. Corrosion resistance was at a medium level.

【學(xué)位授予單位】：蘭州理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：TG132.3;TG376

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