原始成分组成对Ti(C,N)基金属陶瓷烧结性能的影响

采用真空烧结工艺制备了Ti(C,N)基金属陶瓷,研究了原始成分组成对材料烧结特性和力学性能的影响规律。结果表明:保持Mo/(Mo+Ni)为定值,随着硬质相成分的增加,烧结体抗弯强度降低,硬度增加;硬质相成分TiN含量超过一定阈值时,烧结体疏松导致硬度和抗弯强度同时大幅下降;TiN含量保持定值,硬质相成分含量增加,烧结体硬度增加,抗弯强度下降;粘结相成分用Co部分替代Ni,随Co含量的增加,烧结体硬度略有升高的基础上抗弯强度升高。     

Mathematical Simulation of Flow Field for Molten Steel in an 80–ton Single Snorkel Vacuum Refining Furnace

The three–dimensional flow field of molten steel in an 80–ton single snorkel vacuum refining furnace has been mathematically simulated to attain the optimal configuration and operation parameters, such as the bottom blowing Ar flow rate, the eccentric position of bottom blowing Ar port at ladle bottom, the single snorkel inner diameter, and the single snorkel immersion depth into molten steel. The mathematical simulation results show that a stable flow field of molten steel can be achieved in 70–second; meanwhile, the maximal circulation intensity of molten steel in the 80–ton single snorkel vacuum refining furnace can be found on a cross–section with y as 0 mm based on the middle of ladle bottom as circular point of the Cartesian space coordinate under the condition of injecting Ar gas on x coordinate considering the asymmetry of flow field for molten steel in the single snorkel vacuum refining furnace. The recommended parameters of the 80–ton single snorkel vacuum refining furnace with ideal circulation intensity as 970.1 kg/s are the bottom blowing Ar flow rate as 450–500 Nl/min, the eccentric position of bottom blowing Ar port as 250 mm, the single snorkel inner diameter as 1000 mm, and the single snorkel immersion depth as 500 mm.     

Study of Argon/Molten Steel Two-Phase Flow in Refining of High Clean Steel Using Two-Fluid Model

RH vacuum degasser is a very important secondary refining device in the production of high quality steels. The flow field of molten steel in RH system plays a significant role in determining productivity of the equipment. The homogeneous model and VOF method were often used to predict the flow field in RH system, but these kinds of models simplified the interaction between gas bubbles and molten steel. In the present work, a numerical model of a whole RH system, including vacuum degasser, immersed legs and ladle,was built based on gas-liquid two-fluid model, and it could be used to analyze the interaction between argon bubbles and molten steel, to understand the effect of the bubble size to the flow field.     

3种类型石油酸的腐蚀性以及相互影响

以相对分子质量相近的正辛酸、环己基乙酸和苯甲酸为模型石油酸,采用SEM、X射线能谱和拉曼光谱等手段,分析了相同酸值(2.3 mgKOH/g)下各种石油酸模拟油全浸静态腐蚀实验后的试片和模拟油的形貌和组成,探究了不同类型石油酸的腐蚀特性和相互影响.结果表明:在190℃静态腐蚀实验中,腐蚀速率由大到小的顺序依次为环烷酸、芳...     

浅析高温吸料天车温度及粒度控制系统

真空物料输送系统是高温吸料天车的重要组成部分。本文通过论述分析真空物料输送系统中温度及粒度控制系统的设备组成、工作原理及控制过程,可以使含粉尘的气流温度和回收后可继续利用的焦炭粒度得到有限控制。     

60t VD炉脱氢工艺优化实践

影响60tVD炉脱氢效果的主要因素有真空度、熔渣、吹氩流量和压力、原始[H]含量等,通过优化脱氢工艺,抽真空时,蒸汽压力稳定在0.80～0.85MPa,真空度67Pa以下,真空保持时间一般钢种8～10min、氢敏感性钢种10～12min、特殊要求钢种15min,吹氩压力≥0.20MPa,吹氩流量≥150L/min,钢中氢含量控制在了2.5×10-6以下,使单工位VD炉满足了快节奏生产的需求。     

新型真空热还原法制镁工艺分析

通过对真空条件下A l-S i-Fe合金还原白云石煅白的热力学分析及实验研究,得到真空条件下还原反应的吉布斯自由能及反应临界温度,确定工艺可行性;所进行还原实验的结果表明:在还原温度1 443 K、还原时间2 h、真空度4 Pa、制团压力50 MPa条件下,可获得86.4%的镁收率,相比同等条件下硅热法镁还原率仅为73.9%。     

湘钢120 tVD真空设备技术特点及故障分析

VD炉是我国近年来推广的冶炼工艺的重要设备,该设备工艺复杂,运行于高温、高压状态下,对设备本身质量和施工安装质量要求严格.据此,详细分析了该设备的技术特性和存在的故障,提出了相应的措施,使该设备完全适应了湘钢转炉-连铸工艺流程的生产周期,达到了顺产和提高产品质量、调整产品结构、降低消耗的目的.同时具有见效快、投资少的特点,经济效益非常显著.     

4Cr5MoSiV1 钢热挤模真空渗氮工艺试验研究

分析了4Cr5MoSiV1钢热挤模经低真空氮化的渗层组织及其显微硬度分布、工艺运行特点及其生产应用情况,以期推动真空渗氮工艺在我国铝挤压模具的推广应用,提高铝型材热挤压模使用寿命,并实现绿色热处理的目标。     

真空玻璃支撑压痕控制准则

为避免过大的支撑物支撑应力导致真空玻璃基片赫兹裂纹的产生,首先建立了力学模型,分析了支撑物接触部位玻璃的应力分布特征.应用Griffith断裂理论和均强度理论,分别得到了玻璃基片在不产生压痕下支撑物的最大临界支撑力计算公式.通过与试验结果进行比较,发现两种理论计算结果均与试验结果相吻合,,但断裂力学理论得到的支撑物临界支撑力比试验结果偏小,而均强度准则结果偏大.对真空玻璃结构设计,在已知的真空玻璃材料参数下,根据上述理论,计算出玻璃基片不产生压痕下支撑物的最大临界支撑力,从而确定支撑物最佳排列间距,使真空玻璃达到"热学与力学"最佳配制.