树脂自硬砂铸造“气渣坑”、“气渣隔”缺陷

“气渣坑”和“气渣隔”都是树脂自硬砂铸造特有的铸造缺陷。这些缺陷出现在铸件表面 ,严重影响铸件表面质量 ,深度超过加工余量范围时将导致铸件报废。通过几年的生产实践 ,初步探索到这类缺陷的形成原因和预防对策     

树脂自硬砂铸造“气渣坑”“气渣隔”缺陷

“气渣坑”和“气渣隔”都是树脂自硬砂铸造特有的铸造缺陷，“气渣坑”过去我们曾称之为渣斑。这些缺陷出现在铸件表面，严重影响铸件表面质量，深度超过加工余量范围时将导致铸件报废。通过几年的生产实践，初步探索到这类缺陷的形成原因和预防对策。1缺陷特征“气渣坑”和“气渣隔”缺陷常常出现在厚大截面，浇注高度较小的，浇注位置向上的大平面，有时侧面也有出现，大平面向下浇注时铸件的上部也有出现。轻微的“气渣坑”面积1～6cm’，深度0·1～1．omm。铸件落砂后涂料层随同砂块剥落的即明显看出；涂料层末剥落的，凡鼓出部分，去…     

基于渣-气耦合运动模型的铝合金铸件渣气孔形成研究

针对铝合金铸件中常见的渣气孔缺陷,综合考虑铸造过程中渣粒的聚合运动与氢气的析出吸附之间的动态耦合特征,构建了渣气耦合运动数学模型。研究了铝合金充型及凝固过程中氢气析出、吸附长大、碰撞聚合及随流运动过程,并对圆柱形试样中渣气孔的分布及形貌进行了试验与模拟研究。结果表明,渣气耦合现象促进了渣粒与氢气的上浮,降低了铸件内部渣、气缺陷出现几率。所建立的渣气耦合运动模型提升了对渣气孔缺陷预测的准确性。     

树脂自硬砂铸造“气渣坑”“气渣隔”缺陷

叙述了铸造用树脂自硬砂铸造过程中产生的缺陷及解决办法。     

钛型渣系气保护药芯焊丝焊接参数相互关系

采用高速摄影、平板实焊等试验方法,研究了钛型渣系气保护药芯焊丝焊接参数的技术特征、电弧形态、熔滴过渡形态以及焊接工艺参数间的匹配关系.结果表明,钛型渣系气保护药芯焊丝熔滴过渡的基本形态是非轴向排斥过渡,焊丝的电弧形态属于活动、连续型,焊丝熔滴过渡受主导力控制.该工艺方法的关键参数是焊接电流和电弧电压,它们之间存在最佳数...     

气-渣平衡法研究高炉渣钾容量

为了降低碱金属对高炉的危害,提高炉渣的排碱能力,用一定组成K（g）-CO-CO2-Ar混合气体提供一定的氧分压和钾分压,采用气―渣平衡法测定高炉渣钾容量。通过高炉渣钾容量的预备试验,本文详细介绍了气―渣平衡法研究高炉渣钾容量的试验过程,为进一步提高炉渣排碱能力提供理论依据。     

CW250气缸体夹渣缺陷分析

CW250气缸体单台重量4.8 t,是大型灰铸铁铸件,由重庆潍柴转移至潍柴重机滨海铸造厂生产。由于两地气候差异及生产工艺的变化,导致气缸体质量出现波动。其中,夹渣缺陷尤为突出。本文针对夹渣缺陷进行了原因分析并提出了解决措施。经过生产验证,彻底解决了CW250气缸体的夹渣问题。     

钛型渣系气保护药芯焊丝研究进展

从药芯焊丝的电弧形态和熔滴过渡形态以及影响因素、焊丝的发展和改进等方面,综述了钛型渣系气保护药芯焊丝研究的某些进展.结果表明,药芯焊丝熔滴过渡的基本形态是非轴向排斥过渡,焊丝的电弧形态属于活动、连续型,焊丝熔滴过渡受主导力控制.影响气保护药芯焊丝熔滴过渡的主要因素有:药芯组成物、焊丝截面形状、焊丝直径和钢带厚度、焊接工艺参数等.提出了通过熔滴过渡指数控制焊接飞溅和通过电弧中熔滴吸收氢的总质量控制焊缝中气孔(压坑)的新思路.焊丝内在质量关键技术是熔敷金属韧性稳定性的控制,必须重视焊丝生产线装备的技术先进性因素.     

底吹钢包内气／钢液／渣三相流模型及渣层行为的研究

建立了底吹钢包内气/钢液/渣三相流动数学模型,利用多相流动体积法(VOF)模拟了渣层运动行为.模型结果再现了底吹钢包内气/钢液/渣三相流动现象.当Ar气被吹进钢包时,在钢液内产生气泡,上升的气泡间歇地冲击并突破渣层,产生渣眼;同时,渣层发生波动,波动频率随着Ar气流量的增加而增加.参数研究显示:220t钢包底吹流量由100增加到300 L/min,渣眼直径由0.43增加到0.81m.计算的无量纲渣眼面积与文献中渣眼的实验结果很接近.Ar气喷吹期间,渣层发生重大的变形,近渣眼处的渣层变薄,近钢包壁处的渣层变厚.渣眼周围钢液流速很大,并导致部分渣滴卷入钢液中.     

钛型渣系气保护药芯焊丝研究进展北大核心

从药芯焊丝的电弧形态和熔滴过渡形态以及影响因素、焊丝的发展和改进等方面,综述了钛型渣系气保护药芯焊丝研究的某些进展。结果表明,药芯焊丝熔滴过渡的基本形态是非轴向排斥过渡,焊丝的电弧形态属于活动、连续型,焊丝熔滴过渡受主导力控制。影响气保护药芯焊丝熔滴过渡的主要因素有:药芯组成物、焊丝截面形状、焊丝直径和钢带厚度、焊接工艺参数等。提出了通过熔滴过渡指数控制焊接飞溅和通过电弧中熔滴吸收氢的总质量控制焊缝中气孔(压坑)的新思路。焊丝内在质量关键技术是熔敷金属韧性稳定性的控制,必须重视焊丝生产线装备的技术先进性因素。     

Black Dross: Processing Salt Removal from Black Dross by Thermal Treatment

The salt removal from black dross by thermal treatment has experimentally been studied under different conditions in both a stationary resistance furnace and in a laboratory scale rotary furnace. The experiments were designed based on partial pressure calculations using the Thermo-Calc software (Thermo-Calc Software, Stockholm, Sweden). The salt removal efficiency was evaluated by scanning electron microscope (SEM) energy-dispersive x-ray spectroscopy and x-ray diffraction analyses, and the optimum conditions for treatment established, i.e., temperature, gas flow rate, holding time, rotation rate, and sample size. The overall degree of chloride removal was established to increase as a function of time and temperature, as well as by reduced pressure. Under atmospheric pressure, the highest degree of chloride removal from a 20 g sample was obtained after 10 h at 1523 K resulting in a 98% removal and a final chloride content of 0.3 wt.% in the residue. Under reduced pressure, the chloride concentrate was lowered to 0.2 wt.% after thermal treatment of a 20 g sample at 1473 K for 8 h. In the case of 200 g samples treated in a rotary furnace, the chloride concentrate was 2.5 wt.% after 14 h at 1523 K, representing a removal of 87%. Below 0.3 wt.% chloride content, the material is deemed a nonhazardous waste.     

Sodium Treatment of Copper Dross

A new patented process for recovering lead from rough copper dross by sodium treatment was implemented at Asarcoys Glover Smelter in 1979. The basic metallurgical principles of the process are explained, and current plant operating procedures and results are described. The advantages of the sodium process, as compared to traditional dross treating in a reverberatory, and its possible application to treating complex lead blast furnace drosses are discussed.     

铝灰管理的艺术

人们一般认为铝灰的产生应当保持最少的数量，同时又十分看重铝灰中铝含量最大化的重要性。一些人错误地认为，低的铝含量是一件好事情。其实铝一直留在炉子中，由于冷却和铝热反应不充分，铝实际上已经损失了。     

铝灰处理工艺研究

铝熔炼过程中产生的铝灰含铝量大约在45%-50%,有很高的利用价值。通过实验证明了通过铝灰热处理、球磨、中频炉熔炼等工艺,可回收铝灰中大部分金属铝,并将低含铝量的铝灰做成电解铝用阳极钢爪保护环,使铝灰循环利用,充分开发了铝灰的价值,减少了铝灰对环境的污染,并收到了较好的经济效益。     

再生铝铝渣成分组成研究

对不同粒度的再生铝铝渣进行研究,分析了其化学组成,研究了提高铝渣颗粒之间聚集效果的的途径。对更高效地除渣具有一定的实用意义。     

采用铝灰和粉煤灰合成Sialon粉

以铝灰、粉煤灰和碳黑为主要原料,采用碳热铝热复合还原氮化工艺制备了Sialon粉体.研究了原料组成(Si/Al比分别为1.5、1和0.27)、碳黑含量(分别为10%、17%、22%和27%)以及合成反应温度(分别为1400, 1450, 1500 ℃)对生成物相的影响.结果表明,合成温度为1450 ℃,可以得到较纯的物相;随着还原剂碳黑含量的增加,使还原氮化反应进行的更为充分;在原料中Si/Al比为1时,加入17%的碳黑可以得到主要物相为Si_3Al_3O_3N_55(β-Sialon,z=3)和SiAl_4O_2N_4(15R)的产物;在原料中Si/Al比为1.5时,即加入80%的粉煤灰,在1450 ℃可以制备较纯的Si_3Al_3O_3N_5粉.     

Dross treatment in a rotary arc furnace with graphite electrodes

Aluminum baths are always covered with a layer of dross resulting from the aluminum surface oxidation. This dross represents 1–10% of the melt and may contain up to 75wt.% aluminum. Since aluminum production is highly energy intensive, dross recycling is very attractive from both energy and economic standpoints. The conventional recycling process using salt rotary furnaces is thermally inefficient and environmentally unacceptable because of the production of salt slags. Hydro-Quebec has developed a new technology using a rotary arc furnace with graphite electrodes. This process provides aluminum recovery rates of 80–90%, using a highly energy efficient, environmentally sound production method.     

阿尔德克热铝炉渣压渣机的综合评述

介绍了美国阿尔德克（AltekInternaiona）的专利产品,热铝炉渣压渣机的设备组成,工艺及技术特点,处理效果及典型的经济分析。     

Processing of Aluminum Dross: The Birth of a Closed Industrial Process

This is the history of a modern aluminum dross recycling company, from its beginnings in the last years of the twentieth century to the present day. The vision of the founders was to build a local recycling plant and take full responsibility for sensitive environmental issues by recycling aluminum dross locally rather than shipping it abroad. The paper tells the history of the company from the environmental perspective, and gives an overview of some of the challenges and the decisions that followed from this vision, for instance the selection of technology. The company developed a closed industrial process for the recycling of aluminum dross, and the paper discusses some of their laboratory experiments and industrial trials. An important milestone has now been reached as the process in its present form is recognized by the environmental authorities in the country. Furthermore, it seems realistic that in the near future the final product from this process will be comparable to the product delivered in the processing of salt cake in specialized chemical plants, but at a fraction of the cost.