钢包增碳工艺试验

本文总结了在２０吨转炉上进行钢包加ＳｉＣ＋Ｃ系增碳剂和喂碳包芯线增碳工艺试验，叙述了明显的增碳效果。     

不同增碳剂对含钒铁水增碳的理论分析和试验

 用热力学方法计算并分析了铁水增碳过程中碳溶解反应自由能变化以及碳氧化反应自由能变化的关系,认为碳的氧化是阻碍铁液增碳的不利因素,增碳反应必须在氧气较少的气氛中进行。在此基础之上,进行增碳试验。首先利用过量石墨增碳,分别得到含钒铁水在1 450、1 500、1 550 ℃时的碳饱和溶解度,并拟合得到碳溶解度与温度的关系式,即[w(Cs)＝2.7×10－3T＋0.38。]然后将不同的增碳剂加入到由铁屑熔化而得到的含钒铁液中,并保温一定时间进行增碳试验。由试验结果可知,5种增碳剂的增碳效果优先顺序为：低氮增碳剂、石墨、无烟煤、碳粒、焦炭。由动力学计算可知,在本次试验条件下增碳反应速率常数的数量级为10－4 s－1。通过分析认为,提高温度可以促进增碳反应的进行,而增碳剂中的硫和灰分抑制增碳反应的进行。     

钢包增碳工艺的试验研究

在２０ｔ转炉上进行了向钢包加ＳｉＣ＋Ｃ系增碳剂和喂碳包芯线的工艺试验，结果表明，增碳剂加入量为１ｋｇ／ｔ时，钢水平均增碳０．０５５％，还可提高硅的收得率，经济效益十分明显；碳包芯线用于高速钢水的含碳量，碳的回收率为８２．９９％。     

不锈钢生产过程增碳原因分析与对策

不锈钢生产过程中普遍存在增碳现象,严重影响低碳不锈钢生产的稳定性。结合邢钢不锈钢生产实际,研究了增碳原因,提出稳定生产低碳不锈钢(碳含量≤0.030%)的控制措施,为不锈钢生产提供了参考。     

含钒铁水增碳与增碳剂的选择

通过分析含钒铁水增碳的热力学,证明了含钒铁水增碳的可行性。然后在1 500℃的增碳温度下,将5种增碳剂加入到含钒铁液,进行增碳试验。由试验结果可知,5种增碳剂的增碳效果优先顺序为:低氮增碳剂、石墨、无烟煤、碳粒、焦炭,增碳反应的平衡常数K的数量级为10~(-4)s~(-1)。分析认为,增碳效果的不同主要与增碳剂中硫含量和灰分含量的差别有关。综合分析表明无烟煤是含钒铁水增碳的最佳增碳剂,在实际生产中,吨铁加入13.2 kg无烟煤时,增碳量为0.5%。     

焦粉在炼钢合金化中的应用及效果分析

在钢铁行业整体萧条的大背景下,以降低成本为目的,文章提出了采用冶金焦粉替代碳粉在炼钢合金化过程中增碳的新工艺。通过生产实验,对比分析了焦粉和碳粉合金化过程碳的收得率情况以及对钢水硫含量的影响;检验了焦粉合金化增碳生产螺纹钢钢坯的内部质量和钢材的性能。对比分析表明采用焦粉合金化增碳生产螺纹钢完全能满足工艺要求,可降低63%的增碳成本,同时减少环境污染。     

电硅热三步法微碳铬铁冶炼中电极对合金增碳的探讨

在电硅热三步法微碳铬铁生产中,存在着电极对合金的增碳。集中法和堆底法由于操作制度不同,电极对合金增碳的情况和程度也有所不同。集中法电极增碳主要是在精炼期;堆底法电极对合金的增碳则贯穿在熔化期和精炼期的整个冶炼过程,故增碳更为严重。     

IF钢连铸过程增碳控制

连铸过程增碳是IF钢生产的一个关键环节。对邯钢西区炼钢厂IF钢连铸生产过程进行跟踪,分析连铸工序增碳的原因。采用无碳镁质涂料中间包、无碳长水口、无碳浸入式水口、高碱度极低碳含量覆盖剂、高粘度厚熔融层的结晶器保护渣(C≤0.5%)进行保护浇铸,使IF钢连铸过程增碳从9.1×10-6降低到3.1×10-6,降低了65.93%,解决了IF钢连铸过程增碳问题。     

煅烧无烟煤作炼钢增碳剂的研究

本文简述了无烟煤煅烧炉的构造、原理及煅烧无烟煤的生产工艺流程,并对加煅烧无烟煤钢的机械性能、夹杂、气体含量及钢的金相组织进行了分析和检验。结果表明,用煅烧无烟煤增碳,对钢的质量和性能基本无影响,可以将其作炼钢增碳剂使用,从而扩大了增碳剂的品种,解决了增碳剂原料短缺问题.     

转炉开发35ΓC钢的生产实践

介绍了八钢第一炼钢厂生产35ΓC钢的工艺,在出钢过程中利用碳锰合金球代替增碳剂增碳、脱氧,并优化了连铸工艺参数。35ΓC钢冶炼合格率达98.18%,浇铸合格率达100%。生产出了能够满足市场需求的热轧带肋钢筋。     

Steady-state electrotransport of carbon in nickel and in nickel-copper and iron-copper alloys

For comparison with previous data on iron-carbon alloys, steady-state electrotransport experiments were performed on three alloys: Nickel-0.15 wt pct carbon, nickel-20 copper-0.13 carbon, and iron-7.2 copper-0.10 carbon. The current density was 2.20 to 2.85 × 10⁷ AJm² and the temperature was 1300 K (and also 1200 K for the nickel-carbon alloy). The Z* values obtained were +5.7, +5.7, and +4.5 respectively, for the three alloys. Present theory appears to be unable to explain the relation of these data to similar data on iron-carbon alloys.     

Steady-state electrotransport of carbon in nickel and in nickel-copper and iron-copper alloys

For comparison with previous data on iron-carbon alloys, steady-state electrotransport experiments were performed on three alloys: Nickel-0.15 wt pct carbon, nickel-20 copper-0.13 carbon, and iron-7.2 copper-0.10 carbon. The current density was 2.20 to 2.85 × 10⁷ AJm² and the temperature was 1300 K (and also 1200 K for the nickel-carbon alloy). The Z* values obtained were +5.7, +5.7, and +4.5 respectively, for the three alloys. Present theory appears to be unable to explain the relation of these data to similar data on iron-carbon alloys. Formerly Postdoctoral Fellow, Department of Metallurgical and Materials Engineering, University of Florida, Gainesville, Florida     

Catalytic effect of iron on decomposition of carbon monoxide: I. carbon deposition in H2-CO Mixtures

Hematite ore reduced with hydrogen was used as a catalyst in the present investigation of the rate of decomposition of carbon monoxide in H₂-CO mixtures. It was found that the amount of carbon deposited from purified carbon monoxide was directly proportional to the amount of porous iron catalyst present in the system. However, this simple relation did not hold for H₂-CO mixtures. During carbon deposition the porous iron granules dis-integrated and were dispersed evenly in the carbon deposit. The deposit consisted of graphite, cementite and iron, with cementite/iron ratio increasing as more soot accumulated. When most of the iron was converted to cementite, carbon deposition ceased. A small amount of hydrogen enhanced markedly the rate of decomposition of carbon monoxide. Indications are that hydrogen adsorbed on iron catalyzes the decomposition of carbon monoxide, 2CO → C + CO₂, in addition to the occurrence of the second reaction H₂ + CO → C + H₂O.     

Adsorption of gold on activated carbon in bromide solutions

Adsorption of gold on activated carbon from gold bromide solutions was examined as a function of pH, particle size, amount of carbon, initial gold bromide concentration, bromine concentration, temperature, and various cations and anions. The pH did not have any effect on gold adsorption below pH = 6. Above pH = 6, pH had a dramatically negative effect. The adsorption occurred according to a first-order reaction-rate model. The reaction-rate constant was proportional to the inverse of carbon particle radius, the amount of carbon, and independent of the initial gold concentration. Temperature had very little effect on the rate of gold adsorption. Cations (Cu²⁺, Fe³⁺, Ca²⁺, Mg²⁺, and Na⁺) and anions (SO ₄ ² , Cl^-, Br^-) did not have any effect on gold adsorption. Free bromine had a very negative effect on gold uptake. Gold bromide is very stable and stays in this form on the carbon surface. Contrary to this, gold chloride is unstable, and elemental gold precipitates on the carbon surface. Loading capacity of carbon depended on the presence of free bromine. In the presence of free bromine, it was further dependent on temperature (increased with increasing temperature). AtT = 25 °C, gold loading was 27 to 64 kg Au/t carbon. In bromine-free solutions, gold loading was 174 to 315 kg Au/t carbon.     

MgO-C-S ( FeS)反应的热力学过程

采用Setsys Evolution同步热分析系统对(1)氧化镁+碳粉+单质硫,(2)氧化镁+碳粉+硫化亚铁,(3)氧化镁+碳粉+硫化亚铁+铝粉+赤铁矿(Fe₂O₃) 3种试验方案以10～25℃/min的升温速度在1 350℃氮气中试验研究了MgO-C-S(FeS)反应的热力学过程,得出差热-热重曲线。结果表明,MgO-C-FeS体系的反应温度要低于MgO-C-S体系的反应温度,在MgO-C-FeS体系中加入发热剂,会使体系的反应提前。     

化学镀碳纤维增强羟基磷灰石复合材料的性能

通过化学镀方法,在碳纤维表面分别镀上Ni和Cu+Ni镀层,以这种表面改性碳纤维与羟基磷灰石陶瓷复合,制备表面改性碳纤维增韧增强羟基磷灰石复合材料,研究各种碳纤维的含量对复合材料的抗弯强度、断裂韧度、尺寸变化率和孔隙率的影响。结果表明,表面改性碳纤维可以显著提高材料的性能,尤其是铜镍复合镀碳纤维的效果更好,其断裂韧度可达基体断裂韧度的2.5倍,抗弯强度可达基体抗弯强度的3.4倍,增韧增强后的复合材料的尺寸和孔隙率变化不大。     

Surface Carbon Chemical States of Ion Implanted AISI 440C Martensitic Stainless Steel

Carbon atoms segregate in the surface region for polished AISI 440 Cstainless steel.After ion implantation,the surface carbon atoms exist in different forms.To elucidate their existence,surface structures and carbon chemical states of unimplanted,N+implanted,Ti+implanted and N+/Ti+co-implanted samples were analyzed by X-ray diffraction(XRD),transmission electron microscopy(TEM)and X-ray photoelectron spectroscopy(XPS).The results indicated that various phases form in the surface or subsurface region after ion implantation,while the surface topography of the samples remains intact.For polished unimplanted sample,besides some Fe3 C phase and CC phase,CrxCyphase dominates its surface region.Little change of carbon chemical states occurs after N+ion implantation.For Ti+implanted sample,besides some metal oxycarbide phases,most carbon amorphous phases form in surface region.Concerning N+/Ti+co-implantation,CrxCycompound as well as Fe3 C phase dominates the surface region while no C-C phase is found.In addition,compared with single-ion implantation,N+/Ti+co-implantation would increase the ion implantation depth significantly.The formed phases of the carbon atoms play an important role in affecting the surface properties of AISI 440 Cstainless steel.     

中国钢铁生产“碳中和”解决方案探讨

根据某工程各工序碳素流计算出全流程吨热轧钢材的直接CO₂排放量为1.786 t。以此为基数,就高炉-转炉长流程工艺的几种主要减碳技术的减碳效果进行了定量评估,发现减碳效果有限,只能作为从“碳达峰”到“碳中和”的过渡方案或最终解决方案的补充。从“碳中和”要求的角度看,以全废钢或气基还原铁+废钢为原料的电炉炼钢短流程无疑是最佳解决方案。结合中国资源条件就几种典型短流程组合方案进行了适应性分析,提出了以“氢基竖炉直接还原铁+电炉炼钢方案”为主、以“高炉-转炉长流程工艺减碳技术+碳捕集与封存(CCS)方案”和“全废钢电炉炼钢方案”为补充的“碳中和”解决方案,最后给出了安全低成本获取氢基竖炉直接还原铁所需的“绿氢”方案建议。     

Anticorrosion Performance of Carbon Steel in 55% LiBr Solution Containing PMA/SbBr3 Inhibitor

The anticorrosion performance of carbon steel in 55% LiBr solution containing PMA/SbBr3 inhibitor was studied by weight-loss tests, electrochemical measurements and surface analysis. In 55%LiBr PMA/SbBr3 solution, corrosion rates of carbon steel at 145 ℃, 175 ℃, 190 ℃ and 240 ℃ are 18.32 μm·a-1, 27.68 μm·a-1, 53.58 μm·a-1 and 73.78 μm·a-1, respectively. PMA/SbBr3 inhibitor may inhibit the corrosion of carbon steel in 55% LiBr solution effectively. Especially, it shows an excellent corrosion inhibition performance at high temperature. Both anodic and cathodic reactions of carbon steel may be inhibited by PMA/SbBr3 inhibitor, so it may be classified as mixed inhibitor. In 55%LiBr PMA/SbBr3 solution, the apparent activation energy of the corrosion reaction of carbon steel is 29.61 kJ·mol-1. The corrosion inhibition mechanism of PMA/SbBr3 is suggested as follows: PMA has the effect of inhibiting hydrogen evolution and a strong oxidizing property; Sb3 also exhibits oxidizing properties, and can exist stably with PMA in LiBr solutions; the passive film comprising Fe2O3 and antimony formed on carbon steel surface may prevent Br- from diffusing into the metal surface due to the synergistic effect of PMA and Sb3 ; As a result, the anticorrosion performance of carbon steel may be improved by PMA/SbBr3 inhibitor in 55% LiBr solution.     

高频燃烧红外吸收法测定碳化硼中总碳

采用高频燃烧红外吸收法,建立了测定碳化硼中总碳量的分析方法。对称样量、助熔剂进行了试验。结果表明,当称样量为0.02 g、助熔剂为0.2 g Fe+0.02 g B₄C+0.2 g Fe+1.5 g W时,测定效果最佳。以CaCO₃为校准物质,采用本法对碳化硼样品中的碳进行测定,结果与管式炉燃烧红外吸收法的相对偏差为0.09%,小于 JIS R2015-2007标准规定的允许误差0.20%,相对标准偏差为0.37%。