共查询到20条相似文献,搜索用时 46 毫秒
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介绍了永钢采用110 t电炉→LF精炼→VD精炼→连铸工艺生产超低硫X65QS管线钢硫含量控制的生产实践。各工序硫含量得到严格控制,电炉平均脱硫率16.35%。出钢过程用铝1 kg/t脱氧,同时随钢流加入石灰6 kg/t和精炼合成渣2 kg/t。LF炉采用喂铝线、复合碳化硅和铝豆对渣面扩散脱氧,造高碱度白渣对钢水深脱氧、脱硫,LF炉平均脱硫率89.2%,精炼结束后钢水平均硫含量0.000 93%。LF精炼结束到连铸工序过程平均增硫0.000 1%,最终成品硫含量平均0.000 9%。通过控制入炉料硫含量,提高LF精炼炉深脱硫能力,防止精炼后回硫等措施,生产的超低硫X65QS大圆坯硫含量符合下游客户要求,具备批量生产成品硫含量在0.002%以下的超低硫钢的能力。 相似文献
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为了实现超低硫中厚板的稳定生产,对中厚板冶炼工艺进行了优化。转炉出钢脱氧合金化顺序调整为增碳剂—石灰、预熔渣—铝铁—硅锰合金,LF精炼进站后加入石灰造渣。工艺优化后,LF炉渣Al_2O_3含量控制在20%~27%,碱度控制在5~12。生产的Z25钢和Z35钢平均硫含量分别由0.004 5%和0.003 8%降到了0.003 6%和0.003 1%,硫含量小于0.004%的比例分别由25%和36%提升到57%和83%。采用铁水预处理,成品硫含量能稳定控制在0.002 0%以下,对有特殊需求钢种可以控制在0.001 5%以下。 相似文献
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阳红梅 《Canadian Metallurgical Quarterly》2011,2(1)
目的:探讨超声对腹水的诊断与鉴别诊断价值.方法:对162例经B超诊断的腹水患者的超声声像图表现进行分析.结果:初步了解腹水性质及来源,为临床提供诊断依据.结论:超声检查成为腹水患者无创性检查和诊断的首选方法. 相似文献
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目的:探讨B超在输尿管结石诊断中的实际价值.方法:对48例经B超检查而确诊为输尿管结石的患者资料及声像图特点进行回顾性分析.结果:结石大小介于0.2~1.8cm.左侧22例,右侧24例,双侧2例;上段结石15例,中段结石14例,下段结石19例.结论:在掌握输尿管的解剖特点的基础上,应用B超检查,能确诊输尿管结石的大小及部位,在临床工作中具有重要的应用价值,可作为诊断输尿管结石检查的首选方法. 相似文献
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CHEN Zhaoping) XU Yingtie) GU Leiming) LI Shi) GU Xuehong) ) Research Institute Baoshan Iron & Steel Co. Ltd. Shanghai China ) Cold Rolling Plant Shanghai China ) Stainless Steel Business Unit China 《Baosteel Technical Research》2010,(Z1):20
The most important characteristics of the ultra clean ferritic stainless steel is that the carbon,nitrogen and other interstitial elements are very low.The ultra clean ferritic stainless steel has been widely used for household appliances,auto exhaust system,elevator,water treatment system,building roof and other various fields,because of its low cost,pro-environment,excellent properties.They can replace some traditional austenitic stainless steel.such 304 and 316L.The addition of titanium to liquid steel has become common for stabilizing nitrogen and carbon in steel.Titanium reacts with nitrogen,carbon,and oxygen to form titanium nitride,carbide, carbonitride and oxide.These inclusions may have a deleterious effect on the properties such as toughness, ductility,weldability and corrosion.In addition,the inclusions can also agglomerate and cause surface quality problem of the slab and clogging of the submerged entry nozzle during continuous casting process. The formation rules of inclusions in ultra clean ferritic stainless steel were investigated by the thermodynamic calculation,and methods of controlling inclusions were put forward to improve the quality of product.The composition,type,amount,size and distribution of the inclusions in the slab are investigated by optical microscope and scanning electron microscope.The results can be concluded as follows.(1) In the slab,the main original inclusions,with size of larger than 2μm,are Al2O3,TiN or Ti(CN) and complex TiN or Ti(CN) inclusion with core of MgO,MgO-Al2O3 and Ti2o3,which will not affect the performance of the steel if they are in diffusing distribution.The size of these inclusions are less than 10μm except some Al2O3 inclusions in size of 10-40μm.(2) Foreign inclusions are Ti2O3-Al2O3-MgO-SiO2 in size above 50μm covered by TiN or Ti (CN).Although these inclusions are few,they do harm to the surface quality of stainless steel.It is able to reduce the risk of forming this kind of inclusion by aluminium deoxidation with increasing Al content to restrain the formation of Ti2O3.(3 ) TiN or Ti(CN) is easy to precipitate on inclusions such as MgO,MgO-Al2O3 and Ti2O3,except Al2O3.Controlling the content of[Ti]and[N]and the formation of the oxides can be used to control the precipitation of TiN or Ti(CN). 相似文献
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超高周疲劳的研究进展 总被引:1,自引:0,他引:1
论述了超高周疲劳研究的背景及意义,总结了近年来超高周疲劳的研究成果包括超高周疲劳的典型特征如S-N曲线、裂纹起源、起裂机理、影响超高周疲劳行为的因素等,介绍了超高周疲劳的常用实验手段,提出了今后超高周疲劳研究的课题。 相似文献
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《粉末冶金学》2013,56(5):378-387
AbstractSintered steel specimens with density levels of up to 7·6 g cm?3 have been prepared from Cr–Mo and Mo prealloyed powders. The fatigue response has been studied using an ultrasonic resonance testing device that enabled testing up to 109 cycles. It showed that the fatigue endurance strength can be drastically increased by raising the density and that the sintering conditions are effective, though less than the density. The existence of a true fatigue limit was disproved up to 109 cycles for all materials tested, with sintered steels thus being similar to wrought ones. Cr–Mo steels was shown to be superior to Mo alloyed grades due to the markedly finer as sintered microstructure and higher sintering activity. Fatigue crack initiation was found to originate from pores at first at multiple sites, with microstructural orientation being dominant compared to the direction of stress; with progressive loading, some cracks join to form a propagating macrocrack from which the final failure then starts. 相似文献
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YE Xiaoyu ZUO Jun ZHANG Kaihua PanGang Group Research Institute Co. Ltd. Panzhihua Chengdu Sichuan China 《Baosteel Technical Research》2010,(Z1)
Ultra fast cooling is a new technology which used to control the hot-rolling strip cooling in recent years on the international developed.If suitably cooperated with a number of other new controlled rolling technologies,can achieve fast and accurate temperature control in the hot-rolled strip production process to obtain corresponding transformation microstructure and ideal mechanical properties.This article describes the technical principle and layout of ultra fast cooling in hot-rolled as well as appli... 相似文献
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为了提高国产铁矿石利用价值,要经过反复细磨,导致铁精矿粉粒度超细,对烧结过程及产量、质量指标影响较大。为了使660 m2烧结机高比例配用微细精矿粉,降低烧结原料成本,满足4350 m3高炉的生产需要,进行了试验研究。研究结果表明:随着微细精矿配用比例的提高,烧结料层透气性恶化,烧结液相生成能力减弱,铁酸钙生成量减小。为此,在优化熔剂结构及燃料粒度的基础上,进行了预成核技术开发应用,将部分精矿粉预先制成制粒核,减少物料中黏附粉的量,以强化物料制粒效果和成矿反应,使烧结矿结构改善。 相似文献
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摘要:为了实现对超纯铁素体不锈钢VOD精炼脱碳过程的动态即时预测及控制,以酒钢宏兴不锈钢分公司100 t VOD炉冶炼超纯铁素体不锈钢的过程为研究对象,从顶吹氧气的分配行为和C Cr的竞争氧化出发,建立基于炉气分析技术的VOD动态脱碳模型,并在Matlab环境下开发相应的应用软件,得到全过程钢液成分、氧气分配比、温度等参数随时间的变化规律,对不同阶段的临界碳浓度给出估计范围。利用VOD出站成分以及精炼过程中CO/CO2的实际变化规律加以检验,与实际值吻合较好,较好地预测了实际变化趋势。 相似文献