共查询到18条相似文献,搜索用时 156 毫秒
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钢包底吹氩工艺是一种经济实用且简单易行的精炼方法,通过实验室物理模拟确定出膨胀合金4J43在底吹氩工艺中氩气流量应控制在3~7 L/min之间。在该流量范围内,合金液的混匀时间随氩气流量的增加而减少。在合适的吹氩参数下进行工业生产,实验结果表明:吹氩工艺对4J43膨胀合金中氧元素及夹杂物的去除效果明显。当氩气流量为5 L/min时,与未吹氩相比合金中氧元素含量下降56.98%,非金属夹杂物总量减少46.43%,合金中大尺寸夹杂物数量明显减少,合金在室温下的各项力学性能与同组相比均得到很大提高。 相似文献
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利用Lagrange两相流模型定量研究了吹氩板坯结晶器内双循环流形成条件,并用水模型检验了数值模拟结果.在此基础上考察了吹氩量、钢流量,结晶器宽度、水口浸入深度以及下倾角度对双循环流形成的影响规律.结果表明:选择与其它工艺参数匹配的吹氩量是保证双循环流型的重要条件,且维持此流型的临界吹氩量随钢流量的增加而增加.当钢液质量流量较大(qm>2.5 t/min)时,减小结晶器宽度和增加水口浸入深度均有助于扩大临界吹氩量范围,而水口下倾角度对其影响较小;当钢液质量流量较小(qm≤2.5 t/min)时,以上工艺参数的影响均不明显. 相似文献
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以某钢厂135 t LF钢包底吹氩为原型,建立了模型和原型比为1∶3.4的钢包水力学模型,研究了透气砖布置方式和吹氩流量对钢液混匀时间的影响。试验表明,单吹工艺中,0.3 R与0.4 R下的混匀时间分别为42.7 s、43.3 s,且对壁面的冲刷作用最弱;双吹工艺中,大角度(不小于120°)工艺比小角度工艺的混匀效果更好,0.5 R~120°透气砖布置时混匀时间最短,为35.7 s。相同流量下,单吹混匀时间略低于双吹。由于双吹工艺下气体分流,对包壁的冲刷明显好于单吹工艺。综合考虑,宜采用双吹工艺模式,原型的最佳透气砖布置方案为0.5 R~120°。单吹工艺的最佳吹氩流量为500 L/min,双吹工艺的最佳吹氩流量为600 L/min。 相似文献
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《热加工工艺》2017,(15)
以某135t LF钢包底吹氩为原型,建立了模型和原型比为1∶3.4的钢包水力学模型,研究了透气砖布置方式和吹氩流量对钢液混匀时间的影响。结果表明,在单吹工艺中,0.3R与0.4R下的混匀时间最短,分别为42.7、43.3 s,且对壁面的冲刷作用最弱;在双吹工艺中,大角度(≥120°)工艺比小角度工艺的混匀效果更好,0.5R-120°透气砖布置时混匀时间最短,为35.7 s。在相同流量下,单吹混匀时间略低于双吹。双吹工艺对包壁的冲刷明显好于单吹工艺。综合考虑,宜采用双吹工艺,原型的最佳透气砖布置为0.5R-120°。单、双吹工艺的最佳吹氩流量分别为500、600 L/min。 相似文献
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板坯连铸结晶器内钢液过热消除过程的数值模拟 总被引:1,自引:0,他引:1
利用数值模拟方法研究了连铸结晶器内钢液的三维温度分布和传热,分析了水口浸入深度、水口侧孔倾角、结晶器宽度、拉速、钢液过热度、吹Ar、电磁制动及吹Ar量和电流强度等对结晶器内过热钢液的温度分布和传热的影响.结果表明,凝固坯壳前沿的最大热量传入处出现在结晶器窄面的钢液冲击点附近,钢液的大部分过热耗散发生在这一区域附近;过热钢液传递到凝固坯壳表面的热流量与拉速和过热度的增加成正比;吹Ar导致结晶器窄面冲击区域和宽面上部区域的热流密度增加;电磁制动有利于提高结晶器上部区域的温度,但对热流密度分布没有明显影响;吹Ar和电磁制动的双重作用使结晶器上部区域的宽面热流密度提高,冲击区域的热流密度分布没有明显变化. 相似文献
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《Science & Technology of Welding & Joining》2013,18(6):760-765
AbstractThe aim of this study was to investigate the influence of three shielding gases (argon and argon–hydrogen and argon–helium mixtures) and two activating fluxes (a commercial flux and a TiO2 based flux) on the geometry of welds produced by the tungsten inert gas (TIG) welding process on several casts of austenitic stainless steel AISI 316, using currents ranging from 100 to 300 A. Penetration depth increases with increasing current for all shielding gases, but weld depth to width ratio is higher for argon than for argon–hydrogen shielded welds. Both activating fluxes produce a substantial increase in penetration depth and in depth to width ratio of the welds. No correlation was found between penetration depth and oxygen content in the melted material. Some interaction exists between activating fluxes and shielding gases, which can affect the weld geometry and/or the defect formation in the welds. 相似文献
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通过对FLUENT软件进行二次开发,建立了焊接电弧和焊接熔池模型,模拟分析了不同活性组元O元素含量下定点和移动TIG焊熔池形貌变化,对比了氩弧和氦弧的电弧参量及其对熔池形貌的影响.结果表明,由活性组元O元素含量变化导致的熔池内Marangoin对流变化是熔深增加的主要因素;在氩弧下,来自于电弧的气体剪切力对熔池形貌有较大影响;与氩弧相比,氦弧明显收缩,电流密度更大,更多的热量传递到熔池,增大了电磁力引起的内对流运动,可获得更深熔深.焊缝深宽比的模拟结果与试验结果吻合较好.Abstract: Welding arc and weld pool modeh were established by FLUENT software for spot and moving TIG welding of SUS304 stainless steel to investigate the effect of the surface-activating element oxygen on the weld shape and analyze the properties of argon arc and helium arc and their effects on the weld shape. The results show that the change of the Marangoni convection induced by different oxygen contents can be considered as one of the principal factors to increase penetration. The plasma drag force from the argon arc has obvious effect on the weld shape. Compared with the argon arc, the hehum arc is more constricted, the welding current density is much greater and the much more heat flux is transferred into the weld pool, which increase the inward convection induced by the electromagnetic force, thus the deeper weld depth can be obtained.The calculated weld D/W ratio agrees with that of the experiment. 相似文献
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宣钢在生产高碳合金工具钢9SiCr过程中铸坯表面出现严重的渣沟缺陷,严重的还会导致渣沟漏钢问题。针对这些问题通过现场调研和数据分析,研究了钢种特性、钢水成分和连铸保护渣性能,得知钢中氢的质量分数高、连铸保护渣性能不匹配、连铸工艺匹配性存在问题是导致渣沟及渣沟漏钢产生的主要原因。通过将钢中氢的质量分数控制为0.000 17%~0.000 23%,将保护渣的碱度从0.83降低到0.71,并添加质量分数为0.8%的Li2O,调整连铸工艺参数将浇铸温度控制为1 480~1 495 ℃、水口插入深度为100~120 mm和结晶器锥度为1.2%~1.5%/m,最终解决了9SiCr铸坯出现渣沟及渣沟漏钢的问题。 相似文献
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During the slab continuous casting process, the flow field of molten steel in the mold plays a decisive role in the quality of the slab. In this paper, electromagnetic swirling flow in nozzle technology is proposed to control the flow field in mold.This technology can drive molten steel to rotate inside the submerged entry nozzle by electromagnetic force, thereby controlling the flow field. This research shows that it can reduce the impact of molten steel on the bottom of nozzle and partly reduce the negative pressure at the upper part of nozzle outlet which is even eliminated by optimizing the structure and angle of nozzle. The area of heat flux of the mold wall becomes larger, and the crest value of heat flux gets lower than that without swirling in nozzle and any nozzle optimization. The meniscus fluctuates smoothly, and the flow velocity at the top surface is within a reasonable range. The temperature field distribution in the mold is uniform which was beneficial to the growth of equiaxed crystal and decreased element segregation. 相似文献