高温熔融-电感耦合等离子体原子发射光谱法测定含铁尘泥中5种有害元素

准确、快速地测定含铁尘泥中有害元素,对含铁尘泥节能降废项目研究及综合利用有着重要的指导意义。实验针对含铁尘泥试样因含碳量高,导致常规酸溶解方法如果不增加除碳步骤则很难完全分解试样的问题,采用高温熔融法将试样制成熔融液后倾倒于稀酸中溶解的方法,解决了碳含量高难溶解的问题。采用四硼酸锂-碳酸锂混合熔剂在高温下将试样熔融,熔融液高温倾倒于稀酸中制成澄清溶液,由于骤冷,试样炸裂成微小玻璃珠,无迸溅,操作简单,使得后续溶解过程快速完成,从而建立了电感耦合等离子体原子发射光谱(ICP-AES)测定P、Pb、K、Na、Zn共5种有害元素的方法。按照实验方法测定含铁尘泥中P、Pb、K、Na、Zn,测定值的相对标准偏差(RSD,n=9)在1.4%～5.7%之间,加标回收率在96%～110%之间。研究结果表明方法能够满足含铁尘泥样品中5种元素的定量分析要求。     

应变速率对中碳低温贝氏体钢强塑性的影响

摘要：为探索低温贝氏体钢的断裂行为,研究应变速率对低温贝氏体钢TRIP效应的影响,采用不同应变速率的拉伸试验对低温贝氏体钢的强塑性进行研究。利用扫描电镜（SEM）、透射电镜（TEM）及X射线衍射（XRD）等试验方法对低温贝氏体钢的微观组织、断口形貌及裂纹走向进行表征。结果表明,随着应变速率的提高,试验钢的屈服强度由771MPa上升至806MPa,抗拉强度由1554MPa上升至1606MPa,断后伸长率由13.5%下降至9.0%。主要原因是高应变速率拉伸引发的绝热温升抑制了残余奥氏体的马氏体相变,对试验钢塑性造成负面影响。     

金刚石的高温化学稳定性研究

金刚石的高温化学稳定性直接影响着陶瓷结合剂的耐火度和陶瓷结合剂金刚石制品的使用寿命。通过研究不同品级的金刚石在不同烧成条件下金刚石晶体的烧失量变化，结果表明：①相同条件下，金刚石品级越高，烧失量越小；裸烧时温度越高，烧失量越大，当温度达到1073K时发生明显的化学反应，达到1173K时，热腐蚀较大。②当通入氩气作保护气时，到1173K才开始发生明显的化学反应。③而埋砂烧成（陶瓷结合剂金刚石试块中）的金刚石与裸烧后金刚石的晶体腐蚀情况相比，埋砂烧成的金刚石晶体耐热腐蚀性好，当温度高于1073K时，埋砂条件下金刚石的抗冲击强度比在同等温度、同等烧成气氛下裸烧金刚石要高出大约30～40％，因此在试验温度范围内陶瓷结合剂不会加速金刚石晶体的氧化腐蚀。     

HH902钢铁常温发黑剂配套工艺研究

本文着重介绍了HH902钢铁常温发黑剂的特点及配套工艺,介绍了清洁生产、节能的、具有可操作性、适用性的几种工艺流程及应用效果.     

铜元素和退火温度对TRIP冷轧钢板组织和力学性能的影响

将含铜和不含铜的两种TRIP钢板(0．2％C、1．5％Si、1．5％Mn)冷轧至1mm厚，然后分别在750℃、760℃、770℃、780℃下退火5min，最后在450℃等温3min，获得了不同含量和不同稳定性的残留奥氏体。金相和力学性能试验结果表明，铜元素能提高残留奥氏体量和钢板的力学性能；退火温度影响残留奥氏体量和力学性能，当退火温度选择在Ac1 10％时可获得最佳的力学性能。     

电子束焊接工艺参数与温度场的关系

采用有限元方法,定量分析了电子束焊接工艺参数与铍环内表面温度的关系。结果表明,加热深度或电子束斑点半径增加,内表面温度增加,焊接速度增加,内表面温度降低。     

Aging and mechanical properties of NR/BR blends

The mechanical properties and post-thermal aging properties of natural rubber (NR) and polybutadiene rubber (BR) blends at different blending ratios are investigated herein. The experimental results show that both tensile and tear strengths of NR/BR blends increase with increasing NR content. BR has a higher compression stiffness than NR. The deformation of BR is less than that of NR under the same load conditions. With regard to aging properties, both tensile stress and strain of NR/BR blends decrease after prolonged aging. In addition, the stress loss of BR is lower than that of NR, meaning that the aging resistance property of BR is superior to that of NR. Furthermore, accumulated thermal history has shifted the glass transition temperature (T _g) of NR/BR blends toward lower temperatures while the loss tangent (tan δ) value increases with prolonged thermal aging.     

Roll force,torque, lever arm coefficient,and strain distribution in edge rolling

Due to the growing importance of width control in strip and plate mills, edge rolling is currently an im-portant process in hot rolling mills. Research in edge rolling has been carried out, and in the present ar-ticle, models for roll force, torque, and lever arm coefficient are derived using the upper bound method. A simple, kinematically admissible deformation zone and velocity field, independent of friction in the roll gap, is proposed, and the energy dissipation rate is derived. The formula for energy dissipation rate has, in practice, no limitation because all edge rolling geometries are safely in the area where the formula is valid. Roll force and torque are derived by means of two independent integrals. Thus, the lever arm coef-ficient is evaluated from the expressions for roll force and torque using conventional rolling theory. Roll-ing trials report good agreement with theory. Measured roll forces are similar to calculated forces. Furthermore, the shape of the dogbone that arises during edge rolling is in fairly good agreement with the calculated dogbone shape. Deviations are due to the deviation from ideally plastic material in the ex-periments. Also, the strain distribution over the dogbone is similar to the proposed deformation zone. Thus, a new formula has been developed to a stage that it can be implemented in width control systems for edge rolling stands in hot strip and plate mills.     

Effects of sintering pressure and temperature on microstructure and tribological characteristic of Cu-based aircraft brake material

A novel Cu-based P/M aircraft brake material was prepared and the effects of sintering pressure and temperature on microstructure and tribological characteristic were investigated. For the constant sintering temperature, when the sintering pressure increases from 0.5 MPa to 1.5 MPa, the porosity, wear loss and friction coefficient decrease remarkably. When the sintering pressure increases from 1.5 MPa to 2.5 MPa, the porosity further decreases but in a little degree and wear behaviors are improved slightly. However, once the sintering pressure is larger than 2.5 MPa, it has no obvious effect on microstructure and tribological characteristic. For the constant sintering pressure, when the sintering temperature increases from 900 ℃ to 930 ℃, the sintered density remarkably-increases, and wear behaviors are obviously improved. For further increasing sintering temperature to l 000 ℃, the density keeps on increasing, but wear behaviors change slightly.     

550 MPa级中厚板矫直过程中表面凹坑缺陷的成因与对策

针对550 MPa级高强中厚板在矫直过程中极易出现氧化铁皮压入凹坑缺陷的问题，根据现场矫直工艺，研究了在不同温度下进行热变形时试样表面和横截面的形貌，钢基体与氧化铁皮界面处平直度的变化规律。结果表明，热变形温度为450 ℃时，表面氧化铁皮开始出现裂纹，且随着变形温度的降低，裂纹的数量逐渐增加；此外，氧化铁皮与钢基体之间的界面长度随变形温度的降低而呈直线增加，表明氧化铁皮与钢基体界面平直度随着热变形温度的降低越发粗糙、易脱落而形成凹坑缺陷。为此，应适当提高终轧温度以确保矫直时钢板表面温度大于450 ℃，同时提高钢板的运行速率，防止氧化铁皮在低温变形发生破碎和脱落的同时降低氧化铁皮厚度，从而减小因氧化铁皮脱落而造成凹坑缺陷的发生几率。