U75V高速轨钢脱碳的影响因素分析

在不同炉内气氛、加热温度、停留时间以及是否采用保护涂料等条件下,对U75V高速轨钢脱碳的影响因素进行分析。结果表明,正常轧制时,应尽量避免预热段为氧化性气氛,在预热段空气消耗系数为1.2、均热段空气消耗系数为0.8时,钢坯的脱碳层深度最浅;采用保护涂料方式可使钢坯氧化烧损量减少20%～30%,脱碳层深度减少29.7%。     

全氧侧吹转炉间歇时间炉内气氛的测定

空气转炉和氧气顶吹转炉的炉龄与间歇时间的长短有密切关系;间歇时间越长,炉龄越低。很多人都认为,其重要原因之一是间歇期间炉内氧化气氛对焦油白云石炉衬进行脱碳;间歇时间越长,脱碳越严重。 我国目前的全氧侧吹转炉,空炉期间仍然供给一定数量的油和氧,以保护氧枪。大家认为,如能适当控制间歇期间的油、氧供应,保持炉内为还原性气氛,则可以避免或减轻炉内脱碳,甚至可将炉衬内表面的氧化铁还原,有利于提高炉龄。因此,我们决定对间歇期间炉内的气氛进行测定,以便查明为保持间歇期间炉内还原性气氛的合理供氧供油参数,达到既     

氨基保护气氛中轴承钢球的热处理

在氮基保护气氛中，应用氧探头自动控制炉内气氛的碳势，对ＧＣｒ１５钢球进行加热光亮淬火，研究了气氛碳热的变化对加热时钢球表层质量的影响通过金相分析，获得了优质钢球最佳控制参数，从而提高了轴承钢球表面的力学性能。     

脱碳退火工艺对含铌Hi-B钢组织与织构的影响

借助红外碳硫分析及EBSD技术,研究了含铌Hi-B钢在不同脱碳退火工艺处理后的碳含量及织构变化。结果表明,当炉内气氛和露点温度一定时,含铌Hi-B钢中碳含量随着脱碳温度的升高而下降,随着保温时间的延长先下降,180s以后基本稳定;经850℃×180s工艺退火后钢样的脱碳效果最佳,钢中碳含量为0.0037%。退火试样中均主要含有{411}148、{111}112和{111}110织构组分,少量的Goss晶粒零散地分布在{111}112或{411}148晶粒之间。此外,有利于Goss晶粒异常长大的Σ9及Σ13b晶界的数量,随着脱碳保温时间的延长大致呈增加的趋势,随着脱碳温度的升高先增加后减少,即在840℃退火后出现极大值。     

硅钢脱碳工艺研究

通过对硅钢退火原理的分析，研究了影响硅钢退火的因素，指出调整炉内气氛，改进脱碳工艺，可以达到提高产品质量的目的。     

重轨钢脱碳的研究

以U71Mn钢为例，通过观察在加热和轧制过程中的钢坯脱碳层的变化，研究加热时间、保护涂料和轧制形变率对重轨钢坯脱碳和氧化的影响。通过对实验数据进行回归分析，给出坯料加热脱碳及轧制脱碳的预报模型。     

微波加热内配碳酸钙高碳锰铁粉固相脱碳试验研究

以碳酸钙为脱碳剂,采用微波加热进行高碳锰铁粉固相脱碳,可避免高温下金属锰的蒸发,实现高碳锰铁粉快速固相脱碳。试验结果表明,内配碳酸钙高碳锰铁粉在微波加热场中进行固相脱碳,脱碳物料的碳含量随脱碳温度的升高、保温时间的延长、配碳比的增加而降低。高碳锰铁粉在微波加热场中固相脱碳物料的XRD物相分析结果表明,脱碳物料的氧化程度随脱碳温度升高而加剧。综合考虑,适宜的脱碳条件为:脱碳温度1 000℃,脱碳时间为60min。内配碳酸钙高碳锰铁粉在微波加热场中和常规加热场中分别加热到900,1 000,1 100,1 200℃并保温脱碳60min,微波加热场中脱碳率分别为76.69%,82.90%,84.11%,85.75%,远高于常规加热场的脱碳率(34.14%,48.28%,49.66%,63.03%),微波加热能增强碳的扩散能力,显著提高了脱碳效率。     

感应加热自保护膏剂渗铬新工艺的研究

感应加热自保护膏剂渗铬新工艺和现行的常规渗铬工艺相比渗铬速度提高30倍以上,渗剂和电能均可节约20～50％,工件变形大大减少,渗剂具有良好的自保护能力,不需要装箱密封或保护气氛,可以在空气介质中进行加热,工件表面不氧化脱碳,表面光洁度不降低。用于处理旋压加工定向套时,45~#钢高频感应渗铬比原用Cr_(12)钢淬火的使用寿命提高5倍以上;45~#钢制蜂窝煤冲针经感应加热渗铬处理后其使用寿命比45~#钢常规热处理提高3～5倍。     

U71Mn钢在空气中高温脱碳实验研究

为了研究U71Mn重轨钢在空气中的高温脱碳规律,对U71Mn重轨钢进行了空气中950℃、1050℃、1150℃和1250℃等四个不同温度条件下的恒温30min、60min、90min、120min的加热,通过金相法检测了上述条件下的脱碳层深度,在考虑碳扩散和氧化后,进行了脱碳动力学计算。结果表明,U71Mn钢在950℃-1250℃温度加热时,随着温度的升高和时间的延长,脱碳层深度逐渐增加,碳原子的扩散长度与加热时间的平方根成线性关系,扩散激活能为133.08KJ/mol。     

高棒车间加热制度的优化

本文主要通过分析钢坯在炉内氧化铁皮的形成机理,分析找出影响钢坯产生氧化烧损的主要因素,提出利用控制加热炉炉内气氛、降低加热炉的最高炉温和降低钢坯的加热时间等方法来减少钢坯在炉内的氧化烧损.结合高棒车间投产初期加热炉炉温控制所存在的问题,优化得到高棒车问的加热制度,并严格控制加热炉各段的空气过量系数,确实有效的降低高棒车间加热炉的氧化烧损.同时制定HRB500E加钒钢种的加热制度.     

取向硅钢脱碳过程的数值模拟分析

通过对硅钢钢带表面的脱碳反应动力学和碳在钢带内部扩散机理的研究,建立取向硅钢脱碳过程的数学模型,模拟分析脱碳气氛、退火温度、钢带的初始碳含量和厚度等因素对脱碳过程的影响,并与试验结果进行对比分析。结果表明,所建模型是可靠的;气氛中的水氢比过高会引起钢带表面过氧化而阻碍脱碳;钢带初始碳含量只在脱碳初期对脱碳过程有所影响;钢带中心部位的碳向外表面的扩散是影响脱碳过程的重要环节;提高退火温度并适当降低露点有利于加快取向硅钢钢带脱碳过程的进行。     

Surface decarburization characteristics and relation between decarburized types and heating temperature of spring steel 60Si2MnA

The characteristics of complete and partial decarburizations in spring steel 60Si2MnA were systematically investigated, including the microstructure, the hardness gradient, and the formation mechanism. The relation between decarburized types and heating temperature of the steel was comprehensively discussed. It is found that heating temperature has an important influence on the decarburized types. With the rise of heating temperature, the decarburized types change from no decarburization to complete decarburization, complete and partial decarburizations, partial decarburization, and no decarburization.     

Coordinated control of carbon and oxygen for ultra-low-carbon interstitial-free steel in a smelting process

Low residual-free-oxygen before final de-oxidation was beneficial to improving the cleanness of ultra-low-carbon steel. For ul-tra-low-carbon steel production, the coordinated control of carbon and oxygen is a precondition for achieving low residual oxygen during the Ruhrstahl Heraeus (RH) decarburization process. In this work, we studied the coordinated control of carbon and oxygen for ultra-low-carbon steel during the basic oxygen furnace (BOF) endpoint and RH process using data statistics, multiple linear regressions, and thermodynamics computations. The results showed that the aluminum yield decreased linearly with increasing residual oxygen in liquid steel. When the mass ratio of free oxygen and carbon ([O]/[C]) in liquid steel before RH decarburization was maintained between 1.5 and 2.0 and the carbon range was from 0.030wt%to 0.040wt%, the residual oxygen after RH natural decarburization was low and easily controlled. To satisfy the re-quirement for RH decarburization, the carbon and free oxygen at the BOF endpoint should be controlled to be between 297 × 10?6 and 400 × 10?6 and between 574 × 10?6 and 775 × 10?6, respectively, with a temperature of 1695 to 1715°C and a furnace campaign of 1000 to 5000 heats.     

Cleanliness of Ti-bearing Al-killed ultra-low-carbon steel during different heating processes

During the production of Ti-bearing Al-killed ultra-low-carbon (ULC) steel, two different heating processes were used when the converter tapping temperature or the molten steel temperature in the Ruhrstahl-Heraeus (RH) process was low:heating by Al addition during the RH decarburization process and final deoxidation at the end of the RH decarburization process (process-I), and increasing the oxygen content at the end of RH decarburization, heating and final deoxidation by one-time Al addition (process-Ⅱ). Temperature increases of 10℃ by different processes were studied; the results showed that the two heating processes could achieve the same heating effect. The T.[O] content in the slab and the refining process was better controlled by process-I than by process-Ⅱ. Statistical analysis of inclusions showed that the numbers of inclusions in the slab obtained by process-I were substantially less than those in the slab obtained by process-Ⅱ. For process-I, the Al₂O₃ inclusions produced by Al added to induce heating were substantially removed at the end of decarburization. The amounts of inclusions were substantially greater for process-Ⅱ than for process-I at different refining stages because of the higher dissolved oxygen concentration in process-Ⅱ. Industrial test results showed that process-I was more beneficial for improving the cleanliness of molten steel.     

钢坯高压水除鳞后的表面氧化铁皮形貌及内部组织演变

在不同温度和时间条件下对钢坯进行加热,出炉后利用高压水去除钢坯表面氧化铁皮,然后利用光学显微镜和扫描电镜观察钢坯表面形貌及内部组织,利用XRD分析除鳞后钢坯表面氧化物相组成。结果表明,除鳞后的钢坯表面残留一层氧化铁皮,该层氧化物相组成取决于加热温度和保温时间。低温短时加热时,残留氧化铁皮相组成中含有单质Fe;提高加热温度和延长保温时间使钢基体表面被完全氧化成Fe3O4和Fe2O3。钢坯在炉中长时间高温加热使残留氧化铁皮晶粒粗大,钢坯基体内部出现过热、晶界氧化以及脱碳等问题,加热温度越高、加热时间越长,氧化烧损越严重。     

热处理参数对异步轧制硅钢极薄带三次再结晶的影响

采用常规和异步轧制分别将0 3mm厚的成品取向硅钢板冷轧到0 10mm以下,然后在不同气氛的热处理炉中进行三次再结晶高温退火,研究同步、异步轧制条件下,热处理工艺参数(退火温度、保温时间、退火气氛、升温速度)对取向硅钢极薄带的磁性能和三次再结晶行为的影响·结果表明,相同的工艺参数下,真空退火的硅钢极薄带的磁性能优于氢气处理的;退火温度越高,保温时间越长,升温速度越快,磁性能越好,三次再结晶发展得越完善·     

Forming condition and control strategy of ferrite decarburization in 60Si2MnA spring steel wires for automotive suspensions

The ferrite decarburization behavior of 60Si2MnA spring steel wires for automotive suspensions, including the forming condition and the influence of heating time and cooling rate after hot rolling, was investigated comprehensively. Also, a control strategy during the reheating process and cooling process after rolling was put forward to protect against ferrite decarburization. The results show that ferrite decarburization, which has the strong temperature dependence due to phase transformation, is produced between 675 and 875℃. The maximum depth is found at 750℃. Heating time and cooling rate after rolling have an important influence on decarburization. Reasonable preheating temperature in the billet reheating process and austenitizing temperature in the heat-treatment process are suggested to protect against ferrite decarburization.     

加热炉燃气火焰模式分类分析

将燃气火焰的大小、形状、颜色等进行分类是评价钢铁厂加热炉燃气气氛的一种直接途径,也是解决对燃气气氛自动控制设备研制的关键问题。在基于模式识别理论和方法的基础上对加热炉燃气火焰分类进行了分析,并提出了实现模式分类的具体方法。火焰模式分类的设计思想可以为钢铁厂进行加热炉炉膛燃气气氛自动控制设备的技术改造解决其关键性的问题,也可以适合于其它类似工业行业的有关设备的火焰模式分类。