脱磷炉冶炼工艺研究与技术指标分析

阐述了脱磷炉相关工艺研究以及与常规转炉冶炼时的主要技术指标对比情况。主要工艺有少渣高效冶炼工艺、底吹系统优化,底吹深脱磷工艺、底吹可视化工艺,转炉终点静止脱碳工艺。技术指标对比分析结果显示：脱磷炉终点平均磷含量为O．014％,常规转炉终点平均磷含量为0．019％,脱磷炉脱磷效果明显;脱磷炉石灰消耗控制在41．45kg／t,常规转炉石灰消耗控制在53．27kg／t;脱磷炉终点渣中平均TFe含量为11．73％,常规转炉终点渣中平均TFe含量为14．38％,脱磷炉金属收得率高;脱磷炉平均终点钢水残锰0．102％,常规转炉平均出钢残锰0．075％,脱磷炉合金消耗少;脱磷炉平均喷溅渣量为3．93kg／t,常规转炉平均喷溅渣量为13．23kg／t,脱磷炉过程控制平稳,金属损耗少;脱磷炉冶炼钢水终点碳氧积为0．002129,常规转炉冶炼钢水终点平均碳氧积为0．002659。脱磷炉控制水平较好。     

复吹转炉两炉双联冶炼65钢工艺研究与应用

介绍了复吹转炉两炉双联法工艺在福建三钢闽光股份有限公司高碳钢生产中的应用,分别探讨了脱磷炉和脱碳炉的冶炼工艺参数和应用效果。脱磷炉顶吹供氧强度为2.0~2.7 m3/(t·min),冶炼时间7~10 min,石灰加入量平均为33.3 kg/t,平均炉渣碱度为1.51,底吹供气强度0.25m3/(t·min),温度控制在1 330~1 351℃。脱磷炉半钢平均磷质量分数为0.028 4%,平均碳质量分数为3.04%,平均脱磷率可达67.7%。脱碳炉采用少渣冶炼和高拉碳操作,供氧强度4.0m3/(t·min),底搅供气强度0.13 m3/(t·min),石灰平均加入量为13.8 kg/t,脱碳炉一倒钢水平均磷质量分数为0.013%,平均碳质量分数为0.21%,实现了低磷、高碳出钢的冶金效果。脱碳炉采用锰矿熔融还原工艺,锰矿加入量为4~6 kg/t,平均锰回收率可达46.3%,高拉碳条件下终点平均锰质量分数可达0.303%。复吹转炉两炉双联法冶炼工艺应用于高碳钢生产,实现了低磷、高碳出钢和锰矿的熔融还原,达到了预期的冶炼效果。     

攀钢半钢冶炼热补偿工艺开发及应用

针对攀钢半钢冶炼热源不足带来的问题,通过分析转炉热补偿技术优缺点,提出在提钒转炉出半钢时加入硅铁对半钢进行化学热补偿的增硅热补偿工艺,解决了增硅后预处理脱硫渣-铁难分离的问题。结果表明,半钢增硅热补偿新工艺减少半钢温降5℃,降低兑铁时碳烧损0.06%,使得半钢碳质量分数平均提高了0.16%,温度平均提高5.3℃,半钢质量更为稳定。新工艺应用后,攀钢中高碳钢转炉终点钢水碳质量分数由原来的0.05%提高到0.12%,终点钢水碳质量分数在0.07%～0.15%的比例由原来的32.2%大幅度提高到92.4%。该工艺在降低转炉冶炼成本的同时,提高了钢水质量,同时减少了烟尘排放量,具有明显的经济效益和环保效益。     

攀钢半钢冶炼热补偿工艺开发及应用

摘要：针对攀钢半钢冶炼热源不足带来的问题,通过分析转炉热补偿技术优缺点,提出在提钒转炉出半钢时加入硅铁对半钢进行化学热补偿的增硅热补偿工艺,解决了增硅后预处理脱硫渣 铁难分离的问题。结果表明,半钢增硅热补偿新工艺减少半钢温降5℃,降低兑铁时碳烧损0.06%,使得半钢碳质量分数平均提高了0.16%,温度平均提高5.3℃,半钢质量更为稳定。新工艺应用后,攀钢中高碳钢转炉终点钢水碳质量分数由原来的0.05%提高到0.12%,终点钢水碳质量分数在0.07%～0.15%的比例由原来的32.2%大幅度提高到92.4%。该工艺在降低转炉冶炼成本的同时,提高了钢水质量,同时减少了烟尘排放量,具有明显的经济效益和环保效益。     

非双联法冶炼低磷钢种工艺优化与实践

通过研究转炉留渣双渣法冶炼工艺,提高了冶炼过程深脱磷效果;通过优化氧枪参数,开发与优化自动炼钢模型,解决冶炼低磷钢种时终点补吹率高、钢水过氧化问题。实现了转炉冶炼低磷高端品种钢的稳定生产,磷含量稳定控制在0.001 2%以内,各类消耗不断降低,其中石灰消耗控制在38 kg/t左右,转炉总渣量控制在85 kg/t左右,终点磷合格率达到了98%以上。     

转炉石灰石造渣留渣操作工艺实践

对石灰石造渣技术进行了理论分析,研究了留渣操作原理和安全留渣条件,在河北钢铁集团石家庄钢铁有限责任公司转炉进行了转炉石灰石造渣留渣操作工艺的生产实践,取得了一定效果。实践结果表明,转炉石灰石造渣与留渣操作工艺结合使用,能实现提高脱磷效率、保证转炉脱磷效果、提高钢水的质量、降低生产工艺成本等良好效果;与常规不留渣操作工艺相比,采用石灰石造渣留渣操作工艺,可以降低钢铁料消耗6 kg/t、降低渣料消耗21 kg/t、提高转炉终点T一次命中率11%、降低终点磷质量分数0.003%,提高终点碳质量分数0.06%,成本可降低13.7元/t。     

150t顶底复吹转炉少渣冶炼工艺实践

石横特钢150 t转炉炼钢应用生白云石代替部分石灰和镁球进行少渣冶炼的工艺,采用优化的"溅渣+调渣"工艺改善了留渣的安全性;通过采用合理的造渣制度、吹炼制度、加入适量炉渣发泡剂、控制倒渣点,使得脱磷率约60%,排渣率约50%,有效保证了转炉的冶炼终点,各项指标得到了优化,石灰消耗从46.7 kg/t降低到30.2 kg/t;轻烧镁球消耗从13.3 kg/t降低到8.7 kg/t;氧气消耗为47.7 m~3/t;钢铁料消耗从1 075.3 kg/t降低到1 072.1 kg/t,实现安全、低成本少渣冶炼。     

转炉炼钢废钢质量控制及结构优化

控制废钢质量、优化废钢结构有利于降低炼钢生产成本,减少环境污染,对转炉炼钢生产具有重要意义。通过理论计算和熔化试验,研究了不同废钢与转炉物料消耗及渣量之间的关系。结果表明,废钢质量对转炉钢铁料消耗和炉渣量具有显著影响。当转炉废钢比为20%时,废钢中杂质质量分数增加6%,钢铁料消耗量增加约为23 kg/t,带入渣量增加约为71.4 kg;锰的质量分数增加1%,产生钢水量约减少12.4 kg。质量较好的废钢带入转炉杂质少,利于降低钢铁料消耗和炉渣量;转炉中大量使用溢渣粉等废钢会引起钢铁料消耗和炉渣量显著增加。在此基础上,利用某企业120 t转炉进行废钢结构优化试验,研究了采用不同废钢配比冶炼对钢铁料消耗、炉渣量、终点磷含量和终点碳含量的影响。发现在该企业实际生产条件下,最优废钢配比(质量分数)为重型废钢33.3%、钢筋头16.7%、普通生铁26.7%、硫钢块6.7%和溢渣物16.6%。当120 t转炉采用最优废钢配比冶炼时,平均钢铁料消耗为1 052.9 kg/t,平均炉渣量为108.7 kg/t,冶炼铁损小;且转炉终点钢水平均w([P])、w([C])分别为0.030%、0.106%,满...     

转炉高硅铁水双渣法高效生产技术实践

针对转炉传统高硅铁水双渣冶炼周期长、金属收得率低、消耗高等问题,对转炉冶炼高硅铁水进行了工艺优化.采用低成本的石灰石替代石灰造前渣,通过控制炉渣碱度、炉温快速脱Si等方式,有效避免了转炉冶炼喷溅,提高了金属收得率,降低了转炉熔剂消耗、冶炼生产周期和环保冒烟风险等.工艺优化后石灰消耗减少19.2 kg/t,冶炼周期平均缩短208 s,钢铁料消耗降低6.4 kg/t.     

120 t转炉半钢炼钢去磷保碳工艺的生产试验

针对攀钢转炉半钢冶炼中高碳钢增碳法增加成本降低钢水质量问题,采取了半钢增硅化学热补偿工艺,并根据对转炉脱磷热力学以及钢渣中磷富集规律,得出炉渣中磷的主要富集相为硅酸二钙。采用快速成渣、降低出钢温度等技术措施后,增加了炉渣中富磷相的比例,提高了脱磷效果。试验结果表明,新的热补偿工艺在提高半钢热源的同时,使得炼钢转炉成渣时间由4.1 min缩短到2.5 min,试验炉次转炉终点钢水碳含量平均为0.18%,温度平均为1653℃,炉渣TFe含量平均降低2.81个百分点,终点磷含量均控制在0.015%以内。     

Hardenability in high carbon steels

Multiplying factors (MF) for the hardenability effects of Mn, Si, Cr, Ni, Mo, Al, and B at high carbon levels were successfully derived to a pure iron or alloy free base for austenitizing conditions ranging from 1475°F (800°C) to 1700°F (927°C). Base factors were also determined for carbon in the range of 0.60 to 1.10 pct. These data supersede a similar set of MF’s determined previously by the author to a reference or base composition of 1.0 pct C and 0.25 pct of each of Mn, Si, Cr, and Ni. The new MF’s are presented in both tabular and graphical form and can be used to predict hardenability from composition for homogeneous high carbon steels as well as the so-called “case” hardenability of high carbon regions in carburizing grades. Case hardenability can be calculated for both the single quench practice wherein the steel is hardened by direct or delay quenching from carburizing, and for the double quench practice wherein the steel is reheated for hardening to some lower temperature after a prior air cooling (normalizing) or quenching from the carburizing treatment. The accuracy of hardenability prediction using these new factors has been found to be within ±10 pct of the measured hardenability atD _I’s as high as 26 in. (660 mm). This paper is based on a presentation made at a symposium on “Hardenability” held at the Cleveland Meeting of The Metallurgical Society of AIME, October 17, 1972, under the sponsorship of the IMD Heat Treatment Committee.     

Decarburization of high carbon ferromanganese melts

The effect of oxygen/argon mixing ratio in the bottom blowing gas on the decarburization behaviour of high carbon ferromanganese melt was investigated in the temperature range of 1350 – 1550°C. Thermodynamic analysis indicates that high melt temperature and low P_CO are essential for an effective decarburization. An empirical equation for the utilization ratio of oxygen for decarburization was derived as functions of the melt temperature and the oxygen/argon mixing ratio in the refining gas. The utilization ratio of oxygen for decarburization sharply increases as the melt temperature increases and the oxygen ratio in blowing gas decreases. In oxygen refining of high carbon ferromanganese melt, it is not desirable to inject oxygen through bottom tuyères in an early stage of refining. When the melt temperature is low, the oxygen predominantly oxidizes the manganese in melt in spite of high carbon contents. The injection of oxygen/argon mixture gas is found to be an effective decarburization technique when the melt temperature is higher than 1500°C.     

高碳钢高温力学性能研究

在Gleeble-2000动态热模拟试验机上采用凝固法研究了高碳钢的高温力学性能.测定了tZD(零塑性温度)、tZS(零强度温度).在4×10-4/s应变速率条件下,所测钢种在熔点到750 ℃范围存在两个脆性温度区域,即熔点到1 300 ℃的第Ⅰ脆性温度区域和750～925 ℃的第Ⅲ脆性温度区域.在第Ⅲ脆性温度区域,γ单相AIN、NbN等氮化物在γ晶界的析出和在γ α两相区先共析α相呈网膜状,在γ晶界的析出是造成钢脆化的主要原因.通过控制钢中氮、铝含量,以及采用合理的冷却方式可以提高钢种的内在质量.     

Chi-carbide in tempered high carbon martensite

Martensite in an Fe-1.22C alloy was tempered at 523, 573, and 623 K and examined by transmission electron microscopy (TEM) and Mössbauer effect spectroscopy (MES) to identify the morphology and type of carbide formed at the beginning of the third stage of tempering. Carbides formed in three morphologies: on twins within the martensite plates, in the matrix of twin-free areas of the martensite plates, and along the interfaces of the martensite plates. Chi-carbide(x), as identified by selected area diffraction (SAD), was associated with each carbide morphology in specimens tempered at 573 K. Cementite (0) together with chi-carbide was observed in specimens tempered at 623 K. Small amounts (about 2 pct) of retained austenite were observed by MES of specimens tempered at 523 K. The transformation of the 25 pct retained austenite in as-quenched specimens was related to theX-carbide formed at the martensite plate interfaces during tempering. The MES results also show the presence of κ-carbide in the specimen tempered at 523 K and yields parameters indicative of a mixture of κ and θ carbides for the specimens tempered at 573 K and 623 K. MES measurements of the magnetic transition temperatures of the carbides show diffuse transitions but suggest that κ is the dominant carbide in the tempering temperature range examined.     

Quantitative geometric characterization of high carbon martensite

Quantitative stereology was applied to study the transformation behavior and the microgeometry of athermally transformed martensite for two austenite grain sizes in Fe-1.4 wt pct C-0.02 wt pct P alloy and commercial 01 tool steel. The effects of prior austenite grain boundaries and the existing martensite plates on the nucleation of martensite were studied and each was found to play different roles during the transformation. Autocatalytic nucleation was found to be less than that for a burst transformation. Prior austenite grain boundaries were found to have a strong influence on the initial nucleation of martensite. Plate thickness was constant during the transformation except for coarsegrained 01 tool steel after ～60 pct transformation. The plate radius decreased slowly with fraction transformed and was found to be independent of the mean free path in austenite initially, but decreases with the decreasing mean free path in the later stages.     

Optimum condition for smelting high carbon ferromanganese

Abstract

In the present study, pilot plant experimental heats were designed and carried out to determine the optimum condition for smelting high carbon ferromanganese through investigating some parameters affecting the smelting process including Mn/Fe ratio of the blend, coke ratio, slag basicity and dolomite/limestone ratio of the flux. The results of pilot plant experimental heats showed that using Mn blend with high Mn/Fe ratio decreases the consumption of charging materials: Mn ores, coke and fluxing materials (limestone and dolomite). This means that lower amounts of Mn ores, coke and flux materials can be used for attaining the same output alloy weight by increasing the Mn/Fe ratio of the blend. Furthermore, the produced slag decreases as Mn/Fe ratio of the blend increases. The higher Mn/Fe ratio of the blend does not only reduce the input materials and the produced slag, but also improves the produced alloy quality by increasing the Mn percent and Mn/Fe ratio of the produced high carbon ferromanganese. For obtaining standard HCFeMn alloy containing minimum 75%Mn, it is necessary to use Mn blend with the Mn/Fe ratio of higher than 6·2. The added coke must be adjusted according to the material balance and stoichiometric to prevent the over-coke and minimise the highly endothermic ‘Boudouard reaction’ to attain the highest Mn recovery and metallic yield. Furthermore, the slag basicity should be optimised with flux addition to attain the highest Mn recovery and metallic yield. The optimum slag basicity for attaining the highest manganese recovery and metallic yield depends on the used formula. The slag basicity can be determined from the chemical composition of raw material mixture with taking into consideration that about 2% of silicon in the raw material mixture will be reduced and goes into metal phase. Much higher slag basicity is not recommended as this practice produces viscous slag accompanied with lower Mn recovery and metallic yield. The results also revealed the negative effect of increasing MgO/CaO ratio of slag on manganese recovery and metallic yield. The MgO/CaO ratio in the slag decreases by decreasing the dolomite/limestone ratio in the flux.     

The effect of chromium in high carbon bearing steels

Chromium is present in the 52100 bearing steel composition in the range 1.30 to 1.60 wt pct. Chromium has a significant influence on the spheroidization of cementite, finer carbides being formed due to chromium additions. The ferrite to austenite transformation temperatures are increased due to chromium. The microchemistry of the cementite in 52100 changes during heat treatment; the chromium content of secondary carbides is generally lower than that in the spheroidal (FeCr)₃C produced by soft annealing. The rate of carbide dissolution is controlled by the rate of chromium diffusion from the carbide-matrix interface. Also, the chromium content of the residual, spheroidal (FeCr)₃C increases during austenitization. The effect of substitution of chromium in bearing steel compositions is discussed. In view of the beneficial effect of chromium, only substitution by similar strong carbide forming elements should be considered for bearing steels.     

高碳钢的流动应力模型研究

利用THERMECMASTOR-Z热模拟实验机，用w（C）为0．8％左右的高碳钢进行热模拟实验，测定高碳钢在热加工条件下，流动应力与变形温度、变形程度、应变速率等影响因素间的关系；对实验数据进行分析，确定影响流动应力的主要因素及数学模型的结构形式，通过非线性回归分析，建立流动应力数学模型，模型预报结果与实测结果吻合。     

新型脱氧剂在高碳钢冶炼中应用

用SiCaBaMg新型复合脱氧剂对高碳钢进行工业性试验，试验结果表明，高碳钢采用SiCaBaMg合金脱氧效果较好，铸坯全氧含量低于原工艺，夹杂物尺寸、组成、分布和形态均可得到改善。