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随着建筑钢材的用量逐渐增多,钢材的质量问题也越来越多,提高20MnSiNb性能很有必要。文章从生产工艺、铁素体晶粒度、金相组织、化学成分、重量负偏差和夹杂物等几方面分析了对20MnSiNb性能的影响,并提出了相应的改进措施,从而提高了钢的性能。     

BM510汽车大梁钢冷弯开裂原因分析

BM510汽车大梁钢板经冷弯加工时在折弯部位外侧出现裂纹;为查找开裂原因,对其进行了化学成分、力学性能、OM、SEM、EES及连铸工艺分析。结果表明：汽车大梁钢折弯开裂是由于夹杂物异常偏聚造成的;为消除夹杂物异常偏聚采取的主要措施是控制连铸过程中的拉速,避免拉速波动过大。     

硫复合系易切削钢在凝固过程中夹杂物形成的计算机模拟

开发了模拟和预测硫复合系易切削钢在凝固过程中夹杂物形成的计算机程序。用ＣＬＹＮＥ－ＫＵＲＺ模型计算溶质的微观偏析，该程序可预测钢液的瞬时成分及夹杂物的形成，夹杂物组成的实验分析表明，预测与实测结果是吻合的。     

Separation of Ni(II) and Cd(II) Ions with Supported Liquid Membranes (SLM) using D2EHPA as a Carrier

Separation of nickel(II) and cadmium(II) ions from sulphate solution with use of supported liquid membranes (SLM) has been studied. Di(2-ethylhexyl)phosphoric acid (D2EHPA) dissolved in kerosene was used as the ion carrier. Obtained data were compared with data from polymer inclusion membranes (PIM) experiments. It was shown that use of SLM membranes enables separation of Ni(II) and Cd(II) ions. Experimental results data show that faster transport and higher recovery factor values were obtained for supported liquid membranes.     

磷偏析对低碳钢孔蚀扩展的影响

    选择6种冶金因素各有特点的低碳钢,通过模拟“闭塞腐蚀电池”试验和室内挂片试验,结合金相组织、硫印、磷偏析和腐蚀形貌分析,研究磷偏析对孔蚀扩展的影响.结果表明,腐蚀形貌上呈现出凹凸状的平行腐蚀沟槽,这种平行腐蚀沟槽与磷偏析相关,而不是与沿轧制延伸的夹杂物(硫偏析)或平行的带状组织(碳偏析)相关.凹凸状的平行腐蚀沟槽形成原因是磷在溶液中离解为磷酸根离子,产生微溶的金属盐,在蚀坑的阳极活化区沉淀,从而抑制了阳极溶解.       

镀锡板表面铝类线状缺陷的分析与改进

镀锡板表面存在线状缺陷,导致镀锡板质量成本损失大幅增加。缺陷的长度、宽度、频次及发生的位置具有随机性,为了研究该类型缺陷类型及产生机理,通过JSM-6610型扫描电镜和能谱仪对缺陷部位进行分析,发现Al基夹杂是导致镀锡板表面线状缺陷的主要原因;通过增加真空合金化后循环时间、减少钢包下渣等控制措施,镀锡板表面线状缺陷发生率由0.75%降低到0.25%。     

Effect of electromagnetic stirring on metallurgical quality of GCr15 electroslag ingot

To further improve the metallurgical quality of electroslag remelting,remove the large inclusions in electroslag ingot and refine the solidification structure of electroslag ingot,an electroslag remelting furnace with electromagnetic stirring was designed,and the influence of different magnetic induction intensities on metallurgical quality of GCr15 electroslag ingot was studied.Inclusions with different sizes and types were analyzed by an ASPEX scanning electron microscope,and the morphology and composition of inclusions were further observed by a JSM-6510LV scanning electron microscope.The distribution of alloying elements on the cross section of electroslag ingot was analyzed by original position analysis(OPA).The results show that whether or not electromagnetic stirring is used,the inclusions in electroslag ingot are mainly composed of Al₂O₃,MnS,MnS-oxide and other oxides,among which Al₂O₃ is the most.Compared with an electroslag ingot without electromagnetic stirring,the number of inclusions decreases considerably,and the proportion of small inclusions increases while the proportion of large inclusions decreases when the electromagnetic stirring with remelting current of 1.1 kA and magnetic induction intensity of 62 Gs is applied.However,excessive electromagnetic force will cause the number and diameter of inclusions to increase again.Electromagnetic stirring has different effects on the segregation of different elements.Under the experimental conditions,the weak electromagnetic force with 1.1 kA and magnetic induction intensity of 108 Gs has little effect on the segregation of C,but decreases the segregation of P,and the excessive electromagnetic force aggravates the segregation of alloy elements.     

不锈钢连铸中间包内夹杂物去除行为数值模拟

针对中间包连铸过程中夹杂物的存在易导致铸坯出现质量缺陷的问题,以不锈钢连铸中间包为研究对象,通过数值模拟方法研究了控流装置、夹杂物密度以及夹杂物尺寸等参数对中间包内夹杂物去除行为的影响规律。研究结果表明,在设置堰坝和湍流控制器中间包内,密度为2 700 kg/m3,粒径为5 μm的夹杂物去除率为63.32%,而150 μm的大尺寸夹杂物去除率可达到89.04%。当夹杂物粒径为10~50 μm,密度为2 700~4 500 kg/m3时,夹杂物密度对夹杂物去除率影响较小。无控流装置中间包时,夹杂物在顶渣层呈以中心纵截面对称的分布;设置堰坝中间包时,挡渣堰坝两侧出现了70 μm以上夹杂物密集区;设置堰坝组合湍流控制器中间包时,夹杂物主要被限制在中间包第一腔室自由液面,研究结果对于进一步发挥不锈钢连铸过程中的中间包冶金功能具有指导意义。     

钢包顶渣改质对抑制旋涡卷渣的影响

钢包加盖能够显著提升钢包的保温效果,助力钢铁企业节能降耗。但钢包加盖条件下顶渣温度较高、流动性好,更易引起浇注末期旋涡卷渣,铸坯夹渣缺陷率升高。开展了顶渣改质抑制旋涡卷渣的工艺研究,以高碱度渣为研究对象,通过相图分析确定了炉渣改质增黏的基本思路,利用FactSage软件对多组改质渣系进行黏度计算。结果表明,添加石灰或轻烧白云石都有助于增大炉渣黏度,两者增黏效果相近,炉渣黏度测量试验也验证了上述结论。利用BaCO₃示踪法开展了顶渣改质的工业试验,结果表明,炉渣改质后钢中大尺寸夹杂物数量大大减少。顶渣改质新工艺在现场应用后,铸坯平均夹渣缺陷率由0.57%降低至0.42%。     

中间包电磁感应加热技术研究及应用进展

中间包是炼钢流程从间歇操作转向连续操作的重要衔接点,对于促进钢液的分流、净化、减轻铸坯宏观偏析、提高等轴晶率以及铸坯质量有着十分重要的作用。随着对连铸坯质量和钢水洁净度要求的不断提高,新型中间包冶金技术层出不穷。这其中,中间包电磁感应加热因同时具备高效稳定的中间包温度和夹杂物去除功能,有利于实现钢水低过热度恒温浇铸,逐步在连铸生产中得到应用。此技术的应用、研究现状及未来发展趋势进行了详细探讨。