氧气顶吹转炉煤气安全回收利用

本文根据国内第一个氧气顶吹转炉煤气回收工程的设计、施工、调试和投产以来十多年的经验,概述氧气顶吹转炉煤气的生产特点;贮气柜容量的设计原则;干式气柜与湿式气柜的优缺点;并分析氧气顶吹转炉煤气燃烧的特点,提出防止脱火或回火的措施以及防止爆炸和中毒的安全措施。     

顶吹转炉内二次燃烧初期的一个数学模型

本文在对顶吹转炉内气体流动，燃烧，传热研究的基础之上，合理耦合了炉内液滴北生，运动及传热的模型，给出了一个较全面的描述炉内燃烧与传热的数学模型。应用该模型研究了美国常用的１８０ｔ Ｂａｓｉｃ Ｏｘｙｇｅｎ Ｆｕｒｎａｃｅｓ炉内二次燃烧初期泡沫渣还未大量形成的燃烧及传热情况，得出了这一时期不同的二次氧枪设计与炉内二次燃烧率及热量传输效率之间的关系。     

脱碳升温率高的顶底复吹工艺

新日铁公司釜石厂发明了一种脱碳升温率(脱炭量为1%时的温升值)高的顶底复吹工艺,即:转炉装入经过预脱 Si、P 和 S 的铁水,以底吹氧气作为主要的脱碳精炼手段,顶吹氧量为底吹氧量的60%以下,利用顶吹氧气使铁水表面形成凹坑,当凹坑深度大于20mm、小于200mm 时,碳二次燃烧反     

国外氧气转炉生产提高废钢比

近几年国外不断将顶吹转炉和底吹转炉改为顶底吹转炉,并采用炉气二次燃烧技术,以及提高铁水温度,废钢预热或预先熔化,     

碱性氧气顶吹转炉倾动力矩的确定

碱性氧气顶吹转炉设计者,使用计算机程序,以快速确定倾动力矩。这种方法一般都予先假定在炉口倒渣与出钢。这种方法运用于旋转炉子;如旋转炉(Rotor)、斜吹炉(Kaldo)、垂直转动顶吹氧气转炉(Rotovert),对于碱性氧气顶吹转炉(BOF)、喷石灰纷的顶吹氧气转炉(OLP,LD～AC)*~1,仅是近拟的,因为在炉壳的侧壁上有一个出钢口,通过出钢口出钢,而炉渣完全留下来。在碱性氧气顶吹转炉(BOF)上,出钢后倒渣,而对于喷石灰纷的顶吹氧气转炉(OLP或LD-AC),则留渣供下炉使     

在真空下精炼超低碳钢的KTB工艺

日本川崎公司开发了一种KTB(川崎顶吹氧)工艺,即在循环脱气装置中真空处理的同时吹氧的工艺。氧气是通过从顶部插入脱气容器的水冷氧枪吹入。该工艺的开发可以使炼钢生产者用转炉冶炼超低碳钢时有较高的生产率,同时使初炼炉炉衬有较长的使用寿命。在真空下向钢水中吹氧,释放出的co直接在钢水上面氧化成co_2,二次燃烧释放出大量热量,大大减少了真空室中因飞溅而累积的金属。此外,明显减少了真空处理过程中钢水的辐射热损失。     

转炉顶底复合吹炼工艺的特点

顶吹氧气转炉是依靠氧枪高度、供氧流量的变更及合适的造渣制度,来获得最佳的渣与金属液的乳状化。然而控制不当,将会造成氧枪的沾钢、结瘤、炉底被击穿、喷溅等现象。此外,在吹炼末期,溶池金属含碳量降低,于是,铁、锰等氧化加剧,渣中氧化铁含量急剧上升。由于碳氧反应减弱,搅拌强度降低,溶池出现较大的化学不平衡。转炉顶底复合吹炼法,是克服以上缺陷而发展的新技术,并已成为当前炼钢工艺的主要发展趋势。转炉顶底复合吹炼,以顶部氧枪喷吹氧气为主,再从炉底吹入少量气体而得名。按其底吹气体的种类、方法及数量不同,已开发了拾余种转炉顶底复合吹炼炼钢法。本文     

近年来上海的转炉炼钢

一、概况1·1 基本情况上海的转炉炼钢,解放时只有私营日亚钢厂生产侧吹酸性转炉钢,解放后,亚细亚钢铁厂(上海机械总厂前身),上钢一厂先后亦建立侧吹酸性转炉,至1956年上钢六厂建成碱性侧吹蜗鼓型转炉,经过大量试验研究工作,形成了一套操作制度,1957年以后,酸性转炉由于原料条件限制而停产,陆续建成上钢三厂一转,二转;一厂二转,三转,上钢五厂转炉车间,限于当时没有供氧条件,均采用侧吹碱性蜗鼓型转炉,使上海的转炉成为主要的产钢方法。1966年上钢一厂三转炉首先改建为30T×3的氧气顶吹转炉车间随后各厂转炉均改氧气顶吹,目前上海有四个氧气顶吹转炉车间,共12座转炉270公称吨位(宝钢除外)。见表1。1·2 上海转炉钢的产量质量品种上海的转炉钢产量一直占全国首位,到1983年,上海累计生产了转炉钢5000万吨。近几年在各转炉车间轮流大修改造的情况     

全废钢装料的氧气转炉

苏联开发出了用100％废钢装料的氧气转炉炼钢法。采用较便宜的燃料如烟煤和天然气来熔化废钢和把钢水加热到所要求的温度。生产的钢质量符合要求。采用了顶底复合吹转炉,配有底喷咀和侧喷咀喷吹碳氢燃料,和顶吹氧枪。氧气和天然气是通过装有必要的供气控制装置和控     

炼钢方法外文字缩写词浅释

外文钢铁杂志常常出现不少的缩写词,一时费解,即使科技缩写词典也无从查出,为了便于顺利阅读,就常见的一些缩写词浅释如下。1.顶吹氧气转炉LD 法。1952年先后在奥地利 Linz 和Donavi 为两钢厂的顶吹氧气转炉正式投入工业生产,从此就用这两钢厂地名的字头缩写成为 LD 法。在美国把 LD 法叫作 BOF法(Basic oxygen Funnad)或 BOP 法(Basicoxygen Process)).Kaldo 法,50年代中期瑞典 Bo,Kalling教授研究成功的一种炼钢方法,在瑞典Domnarvet 钢厂建成了30t 和150t 的顶吹氧气转炉,以人名和地名命名为 Kaldo 法。Kaldo 转炉操作时呈倾斜转动,顶吹氧气在     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.