Properties of Cross-Rolled Low Alloy White Cast Iron Grinding Ball

Lowalloy white cast iron has high hardness andwear-resistance ;however ,the material has lowduc-tility ,because the carbideinthe structureis distrib-uted in the formof continuous network, which li m-its its application. Therefore , the method to i m-prove the toughness of this material has attractedthe interests of the researchers worldwide . The ex-peri mental results showed that when white cast ironis hot deformed, the network structure of carbidebreaks and becomes independent blocks , which…     

消失模铸造(高锰球墨铸铁)磨球及缺陷分析与对策

为了保质保量地生产出选矿用铁球,我们采用消失模的方法铸造磨球,生产出尺寸精度高、表面质量好的高锰贝氏体球墨铸铁为材质的铁球.     

Abrasive Wear Behavior and Mechanism of High Chromium Cast Iron

The abrasive wear behavior of high chromium cast iron(containing 12.9mass%chromium)austenitized at1 050 ℃for 2hand austempered in salt bath at 320℃for 4hwas evaluated.Abrasive wear was performed using alumina abrasive under four different loads,namely 50,100,150,and 200 N,for 36 000 cycles.The worn surfaces and wear debris were analyzed by scanning electron microscopy,laser confocal microscopy and X-ray diffraction.Microhardness profiles were also obtained in order to analyze the strain-hardening effects beneath the contact surfaces.Results indicate that the retained austenite in high chromium cast iron has experienced induced martensitic transformation after tests,for small amounts of retained austenite could be detected by X-ray diffraction.In addition,there is a close relationship between wear mechanism and test load.Under the condition of lower test load,the wear mechanism is an uninterrupted and repeated process,during which matrix is cut at first and then fine carbides flake off.As to higher test load,scratching and spalling induced by cleavage fracture of blocky carbide are the wear mechanism.     

介质直径及其加载量对立磨机磨矿效果影响的初探

本文通过建立实验室模型,对影响立磨机磨矿效率的介质直径及加载量大小进行了分析研究。小直径介质有利于磨机内能量密度的提高和磨削面积的增加,而适当增大介质直径则可提升有效磨矿容积和延迟磨矿时间。介质参数的最终选取还要根据其它因素综合考虑。     

磨矿方式对赤铁矿球团预热焙烧性能的影响

模拟链篦机—回转窑工艺,研究磨矿方式对赤铁矿粉生球的预热焙烧性能。结果表明,未经磨矿处理的赤铁矿球团预热焙烧性能较差,为满足后续工序要求,生球预热温度需达到1 075℃,焙烧温度为1 280℃。高压辊磨处理对赤铁矿球团工艺条件改善效果较好,润磨次之,湿式球磨效果较弱。经高压辊磨处理后,球团制备过程中可以降低预热温度70℃,焙烧温度60℃,缩短焙烧时间2 min。赤铁矿磨矿处理能够改善球团焙烧过程中Fe2O3晶粒的发育、迁移和连接,提升球团抗压强度。矿粉比表面积和粒度组成的优化是影响球团微观结构和宏观强度的主要原因。     

高铬铸铁磨碗块的热处理工艺设计

文章探讨了热处理工艺对高铬铸铁磨碗块硬度和冲击性能的影响,并且对不同淬火和回火后的磨碗块组织进行了分析。结果表明,采用设计的热处理工艺,生产出的高铬磨其较高的硬度和冲击性能碗块很好的满足了使用要求。     

Abrasive Wear Behavior of High Chromium Cast Iron and Hadfield Steel-- A Comparison

 Abstract： Wear properties of two different crushers used for grinding raw materials of cement industry are compared using pin-on-disk wear test. The wear test was carried out with different loads on a pin. Abrasive wear behavior of two alloys was evaluated by comparing mass loss, wear resistance, microhardness and friction coefficient. The microstructure of the specimens was detected using optical microscope. The results showed that abrasive wear of high chromium cast iron is lower than that of Hadfield steel. Due to the presence of M7C3 carbides on the high chromium cast iron matrix, impact crushers exhibited higher friction coefficient.     

顽石作磨矿介质下含金铜硫矿的磨矿规律研究

以半自磨机排出的顽石作为磨矿介质,考察了顽石自磨磨损规律及其自磨产品粒度分布和顽石磨矿时顽石磨损规律及其磨矿产品粒度分布。结果表明：在不同的自磨磨矿时间、充填率和磨矿浓度下,顽石自磨损后产生的磨矿细度均在-0.125 mm以下;顽石作为磨矿介质时,在充填率为50%,浓度为60%,磨矿时间为19 min,入磨矿样为500 g的磨矿条件下,能获得-45 μm含量为60%的磨矿产品,其中新生-45 μm含量为18%左右;与钢球磨矿时矿物表面被大量的铁絮状物覆盖而遭到严重腐蚀相比,顽石磨矿时颗粒表面有少量絮状物,没有腐蚀带,矿物的轮廓平整、干净。顽石是一种细磨过程较为理想的磨矿介质。     

屈氏体高铬铸铁球的生产工艺对磨球质量的影响

详细介绍了生产屈氏体高铬球的化学成分的控制范围、铸造工艺、熔炼工艺、浇注及开箱时间、时效处理工艺等。使用厂家生产实践表明，采用文中所述生产工艺生产的屈氏体高铬铸铁球，能明显降低球耗。     

钒钛球铁齿轮的基础性能

作者对等温淬火的钒钛球铁齿轮进行了7种基础性能试验。结果表明:这种齿轮的接触疲劳极限σ_Hum值、抗磨损能力、结构阻尼比和降低噪声等方面具有优良的性能,而弯曲疲劳强度较低。用这种钒钛球铁制造QJ系列减速器齿轮,其承载能力可提高50%。     

Structures and Properties of Iron Matrix Composites with Tungsten Carbide Particle by EPC-V Process

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球磨助剂对凹印金粉性能的影响

讨论了不同助剂、助剂加入时间和助剂加入量等对凹印金粉性能的影响规律，结果表明，采用复合试剂２＃可得到综合性能较好的凹印金粉。此外，助剂加入时间和助剂加入量应分别控制在２ｈ和２％～６％。     

落球冲击下高铬铸铁磨球中残余奥氏体的形变与相变

用透射电镜和微区Ｘ射线衍射分析了落球冲击后高铬铸铁磨球皮下不同深度残余奥氏体形变和相变情况。发现不同深度发生形变和相变的程度是不同的，在磨球表面最大，随着深度增加形变和相变的程度减小。产生可观塑性变形的深度在５ｍｍ以内，而发生相变的深度可达１０ｍｍ。不同深度相变的机理不同。共晶碳化物在落球冲击下也能发生一定的塑性变形。最后分别讨论了显微组织变形和相变对磨球抗剥落破碎性能的影响。     

岩矿抗破坏特性在磨矿中的应用

分析了国内一些重要选矿厂粗磨机的钢球尺寸,认为其多数偏大对磨矿作业带来诸多不利,通过岩矿的抗压强度和自然矿块破断力力学试验研究,找到了降低粗磨机钢球尺寸的理论依据,在实验室磨矿对比试验和有关选厂粗磨机工业试验中取得了明显的效果。     

铸铁段用于氧硫铅锌混合矿磨矿工艺的试验研究

从磨矿工艺入手,针对矿石的特殊力学性质采用特殊的磨矿新工艺,具体就是采用介质尺寸精确及选择破碎作用强的选择性磨矿新工艺,降低过磨过粉碎,降低磨矿产品中-500目粒级的含量,使磨矿产品尽量满足选矿的条件,有利于矿石分选。结合会泽采选厂工业试验情况进行实例分析,从而验证上述结论的合理性。     

细长轴闭式砂带磨机的设计、安装及调试

为了扩展普通卧式车床的实际加工范围,使得普通卧式车床能够完成细长轴类零件的半精加工、精加工。本文根据车间已有模型提出了此类加工的砂带磨机的设计方案,并对其零部件进行了整体的安装调试,最终投入车间内使用,解决了细长轴类零件的精加工问题。     

浅析磨机临界转速的确定

通过对球磨机内研磨介质运动状态的分析,可以明确的了解抛落式运动状态的研磨介质的运动状态,从而清楚的计算出研磨介质的工作参数。对磨机的磨矿性能控制十分有利。     

莱芜铁矿磨矿系统工艺流程改造

莱芜铁矿选矿厂原两段磨矿流程负荷不平衡，第二段磨机长期处在低负荷状态下运行，通过流程考查确定，将第二段磨机由格子型改为溢流型，两段磨机由２∶２配置改为２∶１配置，使第二段磨机利用系数由０．４７ｔ／ｍ３ｈ，提高到０．９９ｔ／ｍ３ｈ，钢球消耗降低０．３６ｋｇ／ｔ原矿，电耗降低２．１８ｋＷｈ／ｔ原矿。     

Wear Behavior and Mechanism of Spheroidal Graphite Cast Iron

Wear behavior and mechanism of spheroidal graphite cast iron were studied on a pin-on-disk elevated temperature wear tester. The phase and morphology of worn surfaces were examined by X-ray diffraction and scanning electron microscopy. Results show that with an increase of load, wear rate of spheroidal graphite cast iron gradually increases under low loads, rapidly increases or potentially increases under high loads; wear rate increases with increasing ambient temperature. At 25–200 °C, adhesive wear prevails; oxidative wear and adhesive wear coexist at 100 °C. As load surpasses 150 N at 100 °C, extrusive wear appears. The elevated-temperature wear of spheroidal graphite cast iron is a physical and chemical process including the following reactions: xFe + y/2O₂?Fe_xO_y, 2C + O₂?2CO and Fe_xOy + yCO?xFe+yCO₂. Hence, at 400 °C, the amount of graphite and tribo-oxides are substantially reduced because of reductive function of graphite. It can be suggested that wear-reduced effect of graphite and tribo-oxides is impaired.