EAF steelmaking process with increasing hot metal charging ratio and improving slagging regime

A new electric arc furnace (EAF) steelmaking process with increasing hot metal charging ratio and improving slagging regime simultaneously was developed and applied in a 50 t electric arc furnace for more than a year at No.1 Steelmaking Plant of Shanxi Taigang Stainless Corporation Limited. The essential fact of the new EAF steelmaking process was to charge hot metal in two portions or steps: firstly, 35wt%-40wt% hot metal was pretreated by blowing oxygen in a specially designed reactor for decar-burization...     

应用LCA分析中国典型钢铁企业的环境负荷

为得到钢材的环境负荷,基于生命周期评价方法对中国典型钢铁企业中不同流程中的各工序,系统、定量地分析评价环境负荷.采用GaBi 4.3软件提供的CML2001环境影响分类方法,将各工序的环境影响进行分类,并根据特征化因子,分析生产1 t钢材产生的环境影响.分析结果表明:长流程生产过程主要的环境影响是焦化、烧结、高炉炼铁和废钢回收环节产生的水生生态毒性、人体毒性、化石能源耗竭和矿产资源耗竭等.其中,长流程的炼钢过程对气候变化、人体毒性、水生生态毒性和固体废弃物的影响较大,分别约占该类型总环境影响值的30%,95%,50%和90%;短流程生产过程主要的环境影响为铁水和电炉炼钢过程产生的气候变化、酸化和光化学臭氧形成等.该研究结果可为钢铁企业调整两种不同流程提供一定的理论依据,有助于准确发现生产过程中各环节节能降耗、降低环境负荷的潜力所在,从而有利于钢铁企业对生产流程进行改进或优化.     

电炉炼钢厂粉尘在微波场中的升温特性

对电炉炼钢厂粉尘在微波场中的升温特性进行研究。结果表明,电炉炼钢厂粉尘对微波具有很好的吸波能力,其中不锈钢厂电弧炉粉尘在微波场中约15 min内温度就可达1000℃以上。随着微波功率的增加,粉尘表观升温速率增大。不同配碳比下粉尘的表观升温速率均较大,介于105-126℃/min之间。随着物料质量的减少,在微波场中粉尘的表观升温速率增大。粉尘颗粒粒径对表观升温速率的影响不显著。     

Mathematical model of heat transfer for bloom continuous casting

A mathematical model for heat transfer during solidification in continuous casting of automobile steel, was established on researching under the influence of the solidifying process of bloom quality of CCM in the EAF steelmaking shop, at Shijiazhuang Iron and Steel Co. Ltd. Several steel grades were chosen to research, such as, 40Cr and 42CrMo. According to the results of the high temperature mechanical property tests of blooms, the respective temperature curves for controlling the solidification of different steels were acquired, and a simulating software was developed. The model was verified using two methods, which were bloom pinshooting and surface strand temperature measuring experiments. The model provided references for research on the solidifying process and optimization of a secondary cooling system for automobile steel. Moreover, it was already applied to real production. The calculated temperature distribution and solidification trend of blooms had offered a reliable theory for optimizing the solidifying process of blooms, increasing withdrawal speed, and improving bloom quality. Meanwhile, a new secondary cooling system was designed to optimize a secondary cooling water distribution, including choice and arrangements of nozzles, calculation of cooling water quantity, and so on. 2008 University of Science and Technology Beijing. All rights reserved.     

不锈钢电弧炉粉尘的物理化学特性及形成机理探讨

本研究采用多种实验检测方法分析了不锈钢电弧炉粉尘的物理特征和化学特性。扫描电镜分析结果显示粉尘的形貌特征为聚合颗粒；X射线荧光仪（XRF）和ICP分析结果说明粉尘的化学成分随电弧炉冶炼炉料的不同而改变；X射线衍射（XRD）及波形分析确定了粉尘的物相组成，尤其明确了铬在粉尘中以CrO和FeCr2O4的形式而不是以Cr2O3的形式存在；电子探针（EPMA）分析了粉尘内主要元素的分布，有利于粉尘在冶炼过程的形成机理的探索。研究结果可为不锈钢电弧炉粉的控制、处理及综合利用提供数据。     

Activity of Reducing Steel Slag of EAF

Reducing steel slag (RSS) was mainly acquired from five electric-arc furnace (EAF) steelmaking plants (among them, the products of two plants were carbon steel and those of other plants were stainless steel) for research tests. The chemical properties, compound compositions, activities and contents of main expansive compounds were tested. The results showed that the field sampled RSS had a very high crystallinity and hydraulicity with main chemical compositions close to those of Portland cement. It can be k...     

Improvement of power input for steelmaking process in high impedance EAF

According to the electrical operation and steelmaking theory of EAF,an improved power input procedure of 70t high impedance EAF in Nanjiang Iron and Steel Corp.Ltd.was studied.The investigation method,process and result for use of power supply of high impedance EAF was proposed,and the optimized power-supply curve to EAF steelmaking practice was given,and electrical operation was improved,the electric energy consumption can be reduced by 25kW.h/t,and power supply time can also be reduced 3 min.     

残余应力对球墨铸铁容器内压极限载荷影响

为了研究残余应力对球墨铸铁容器承压性能及极限载荷的影响,提出基于数值模拟的塑性分析方法.模拟铸造工艺,获得铸件残余应力的分布规律,选取不同水平的残余应力场,依次作用于球墨铸铁有限元塑性分析模型,分析残余应力对容器极限载荷的影响.对一组型号相同但热处理工艺不同的球墨铸铁压力容器进行承压试验.比较数值模拟结果与试验结果,验证了有限元塑性分析模型的准确性.结果表明,铸造残余应力在一定程度上削弱了球墨铸铁的承压性能,降低了容器的极限载荷,但影响程度十分有限;验证了ASME Ⅷ-1规范不强制球墨铸铁容器进行去应力退火热处理的合理性.     

采用铁矿石替代废钢的炼钢工艺实践

介绍了湘潭钢铁集团公司炼钢厂80 t转炉采用铁矿石替代部分废钢作为冷料,通过调整转炉的物料配比和操作方式,以降低炼钢成本的工艺实践。实践证明,采用铁矿石替代废钢,可使矿石消耗量增加,而废钢消耗量减少,从而降低钢铁料、氧气、化渣剂等的成本支出。     

开孔双层球面网壳结构优化设计

以某火力发电厂干煤棚双层球面网壳结构为工程背景,以结构用钢指标为目标函数,利用有限元软件ANSYS对该开孔双层网壳结构进行弹性阶段的整体优化计算,优化后节省钢材约28.4%;进一步应用ANSYS参数化设计语言（APDL）进行编程,分析了网壳矢高、网壳厚度和杆件截面面积三个因素对用钢指标的影响规律：本网壳结构用钢指标对网壳厚度变化最为敏感,杆件截面面积变化的影响次之,矢高变化对结构用钢指标影响最小。计算结果将为此类网壳结构最优设计提供有益参考。     

Activity of reducing steel slag of EAF

Reducing steel slag (RSS) was mainly acquired from five electric-arc furnace (EAF) steelmaking plants (among them, the products of two plants were carbon steel and those of other plants were stainless steel) for research tests. The chemical properties, compound compositions, activities and contents of main expansive compounds were tested. The results showed that the field sampled RSS had a very high crystallinity and hydraulicity with main chemical compositions close to those of Portland cement. It can be known from the study that in case of C/S ratio higher than 2.0, the main compound compositions are C₂S, C₃S, C₂F and f-CaO. However, after the RSS was stored for six months, an obvious variation occurred with potential pre-hydration in RSS, where the SO₃ content was slightly reduced and the compressive activity index was obviously higher than that at the 28th day.     

基于JIT的炼钢-连铸生产调度模型研究

在连铸工艺、设备资源等约束条件下,为提高炼钢一连铸生产效率,避免人工调度,炼钢一连铸作业的精准调度已成为钢铁行业迫切的需求。通过对某炼钢厂现场调研,整合流程信息和时间数据,基于JIT提炼出炼钢一连铸生产调度的核心问题——炉机节奏匹配;进一步构建起基于柔性Jobshop的炼钢一连铸调度系统模型和数学模型以及基于最小松弛时间的调度规则;最后用Lekin仿真调度实例,并将仿真结果与实际生产调度数据进行了分析和比对。实验数据表明了模型的正确性。     

钢结构焊接残余应力及焊接变形控制技术

为了探究控制钢结构焊接过程变形策略,通过钢板对接方法研究了焊接残余应力及焊接变形.以两块同料、同尺寸钢板对接解析焊接工艺过程,设定常态焊接工艺参数,在焊接钢板上进行焊接横向及纵向残余应力计算,并在焊接过程构建温度场,建立有限元模型,绘制其温度曲线图,探究残余应力变化趋势及分布情况.结果表明,对接焊接钢结构焊缝附近部分残余应力较大,结构残余应力在初始加热时期会呈现较快下降趋势,后逐渐趋于平缓,钢板对接焊接变形主要原因是纵向残余应力过大,可通过平行加热处理降低纵向残余应力的影响.     

低碳钢钢锭红送裂纹形成机理

研究了低碳钢钢锭红送裂纹的形成机理,分析并计算了钢锭红送及装炉再加热全过程的温度场和应力场的变化规律,测定钢锭的组织结构和高温强度、塑性,与内应力的变化相比较,分析其开裂的可能性和开裂的时机,得出了低碳钢钢锭红送裂纹的开成机理,为主产中防止红送裂纹提供了理论依据。     

Properties of Steel Slag and Stainless Steel Slag as Cement Replacement Materials: A Comparative Study

To enhance the understanding about the utilization of steel slags as a cementitious material, we comparatively studied the chemical, mineralogical and morphological properties of two types of steel slag; basicoxygen-furnace carbon slag(BOF C) and electric-arc-furnace stainless steel slag(EAF S). Moreover, we studied the standard consistency, setting time and the effect of the slag replacement ratios on the fluidity and compressive strength of blended cement mortar. The experimental results showed that BOF C had higher alkalinity, higher pH value and more hydraulic phases than EAF S. Both types of slag showed water reduction effect due to its high fineness. Neat BOF C paste showed flash set and acceleration in the initial setting time of blended cement especially at high slag proportions. However, EAF S prolonged the setting time of blended cement even at low slag proportions. The pH values for blended cement contained 50% BOF C or EAF S were lower than those of pure cement paste. Despite of slag type, compressive strength gradually decreased with increasing slags content. The strength of BOF C mortar was higher than that of EAF S mortar with the same replacement ratio for the same age. Slag activity index demonstrated that BOF C and EAF S conformed to the Chinese National Standard(GB/T 20491-2006) requirements for steel slag as grade one and grade two, respectively.     

留渣量对“双渣+留渣”炼钢工艺的影响

通过热力学计算以及工业试验研究留渣量对"双渣+留渣"炼钢工艺的影响。理论计算结果表明,在铁水成分维持不变时,其合理的留渣量约为4.3 t,考虑在实际生产中铁水成分的波动,留渣量可取3~5 t。工业试验表明,采用新的"双渣+留渣"炼钢工艺,留渣量过低易造成第1阶段结束倒渣时渣中含Fe量过高,合理的留渣量为3~4 t,平均降低铁损为2~3 kg/t钢。理论计算结果与工艺试验结果基本一致。     

炼钢粉尘-Fenton法对亚甲基蓝降解的研究

利用炼钢粉尘富含氧化铁和少量金属铁,在酸性条件下可溶出不同价态铁离子的特点,将炼钢粉尘作为铁离子来源,直接与H2O2配制成类Fenton试剂,研究其对亚甲基蓝的降解机理. 考察pH、炼钢粉尘用量、H2O2浓度、亚甲基蓝初始浓度、反应时间和温度各因素对亚甲基蓝降解效果的影响,得出在实验室条件下降解亚甲基蓝的最佳工艺参数. 实验结果表明,炼钢粉尘与H2O2配制成的类Fenton试剂不但能对亚甲基蓝进行快速有效地降解,其降解效果还高于用Fe2+与H2O2配制的传统Fenton试剂．     

低成本高炉炼铁科学化管理与操作

低成本高炉炼铁是钢铁厂在激烈的市场竞争中取得最大经济效益的必要条件.本文主要从低燃料比指标控制、合理炉料结构、混合煤粉喷吹、高炉灰回收利用等4个方面进行＂低成本高炉炼铁＂科学化管理与操作的探索,通过挖掘高炉炼铁工序在节能降耗的潜能,最大限度降低高炉炼铁生产的成本.     

应用EAF-LF-VD工艺路线生产纯净钢的过程控制技术

概要论述了EAF-LF-VD工艺路线下,纯净钢生产的过程控制和基本技术要点。钢中[P]、[S]、[O]的控制应抓住EAF炉、LF炉温度条件、熔池条件,选择合理的脱氧制度、吹Ar模式、渣系组成,强化造渣与传质,其含量可控制在工艺设定值以内。钢中[H]、[N]的控制重点在VD炉操作和工作参数控制。钢中夹杂物的控制贯穿初炼-精炼-脱气过程,使得钢中的T[O]不断降低,经过变性、聚集、上浮、渣系吸附,净化钢水。     

电炉法生产IF钢的工艺研究

提出了用电炉法生产IF钢的合理工艺配置,阐明了通过采取相应的技术措施如选择合适的炉料配比(增加铁水、DRI或生铁的使用量)、正确的生产操作(如电炉内吹氧喷碳造泡沫渣、钢包内脱氧,注意钢水在连铸过程中的保护浇注等)并配备合适的钢水二次精炼设备如LF+VTD-OB后,可以生产部分IF钢(CQ,DQ和DDQ级)产品.