Analysis of Corrosion Mechanisms of Low-cement or No-cement Al_(2)O_(3)-MgO Gunning Mix with Special Calcined Alumina in Rotary Slag Test

Al_(2)O_(3)-MgO and Al_(2)O_(3)-spinel low cement castables(LCC-AM and LCC-AS)have been extensively used in steel ladles as working linings.Nevertheless,the use of alumina-magnesia gunning mixes has been mainly kept for maintaining these castable linings,because of high rebound loss,poor green strength,high porosity and short life-span.Thanks to a high BET alumina(MC-G),it is now possible to develop a series of high-performance no-cement or low-cement Al_(2)O_(3)-MgO gunning mixes(NCG-AM or LCG-AM).The paper focuses on the BOF slag resistance of NCG-AM,LCG-AM,LCC-AM and LCC-AS.The corrosion mechanisms of rotary slag samples were studied by scanning electron microscopy(SEM/EDS).The results reveal different microstructures around MgO particles,depending on the four used compositions.Continuous and thicker spinel phases were formed in NCG-AM,which was proved to have the best corrosion resistance after the dynamic slag test.MC-G can provide a high diffusion flux of Al^(3+)in terms of kinetics and hence inhibits Kirkendall porosity around MgO particles.In addition,a continuous spinel phase acts like a pinning nail to reinforce the matrix and thus decreases erosion by slag.In contrast to NCG-AM,the porous spinel phase was found around unreacted MgO particles and some particles were carried away near the interface of LCC-AM and slag.The NCG-AM containing MC-G had been tested in two steel plants,and it extended the service life of the ladles up to 50%.In addition,this study suggests the potential application of NCG-AM as steel ladle linings.

Numerical Simulation and Measurement of Dynamics of Testing Gun Mount

In order to decrease the impact on shooting accuracy caused by human factors in the machine gun type approval testing,a new type testing gun mount system was developed to replace gunner to conduct the automatic shooting.The finite element model was first established and then the natural characteristics of the system were obtained by calculation.On basis of calculation results,the modal testing system was set up and the experimental points,including the exciting points and the measure points were determined.Finally,modal experiment of the system was carried out and the experimental modal parameters were obtained.The simulation and experiment results indicate that the dynamic characteristics of the system have a rational matching with the shooting frequency and the finite element model were well demonstrated.The study provides a new way for shooting accuracy test in type approval testing of firearms and possesses reference value for dynamic modification and optimization design.

Comparative analysis of the effects of gunpowder and plasma ignition in closed vessel tests

This paper presents the results of a comparative investigation into the effects of the ignition method on the ballistic properties of a single-base gun propellant,as determined via closed vessel tests.Conventional gunpowder ignition and plasma jet ignition methods were used,and differences in the ignition time were analysed.The influence of the ignition method on the dynamic vivacity is discussed.It is shown that this influence is significant in the first phase of the combustion process,and with respect to the low values of the loading density.In the second phase of the combustion process,and for large values of the loading density,the dynamic vivacity plots for the two ignition methods converge.Regarding the burning law,close values of the exponent were obtained for the two ignition methods.The dynamic vivacity plots determined for plasma ignition reveal stronger dependence on the loading density than those determined for gunpowder ignition.The conclusion is that plasma ignition is not a solution to the problems inherent to the process of determining the ballistic properties of propellants,which results in deviation of the burning process from the geometric burning law.

Design,fabrication,and testing of an X-band 9-MeV standing-wave electron linear accelerator

In this study,an X-band standing-wave biperiodic linear accelerator was developed for medical radiotherapy that can accel-erate electrons to 9 MeV using a 2.4-MW klystron.The structure works atπ/2 mode and adopts magnetic coupling between cavities,generating the appropriate adjacent mode separation of 10 MHz.The accelerator is less than 600-mm long and constitutes four bunching cells and 29 normal cells.Geometry optimizations,full-scale radiofrequency(RF)simulations,and beam dynamics calculations were performed.The accelerator was fabricated and examined using a low-power RF test.The cold test results showed a good agreement with the simulation and actual measurement results.In the high-power RF test,the output beam current,energy spectrum,capture ratio,and spot size at the accelerator exit were measured.With the input power of 2.4 MW,the pulse current was 100 mA,and the output spot root-mean-square radius was approximately 0.5 mm.The output kinetic energy was 9.04 MeV with the spectral FWHM of 3.5%,demonstrating the good performance of this accelerator.

Quantitative Testing of Defect for Gun Barrels

The magnetic flux leakage (MFL) method is commonly used in the nondestructive evaluation (NDE) of gun barrels. The key point of MFL testing is to estimate the crack geometry parameters based on the measured signal. The analysis of magnetic leakage fields can be obtained by solving Maxwell’s equations using finite element method (FEM). The radial component of magnetic flux density is measured in MFL testing. The peak-peak value, the separation distance between positive and negative peaks of signal and the lift-off value of Hall-sensor are used as the main features of every sample. This paper establishes the multi-regression equations related to the width (the depth) of crack and the main characteristic values. The regression model is tested by use of the magnetic leakage data. The experimental results indicate that the regression equations can accurately predict the 2-D defect geometry parameters and the MFL quantitative testing can be achieved.

2/1樟单基发射药的真空与非真空环境安定性试验可替代性研究

基于深空探测用单基发射药在外太空中要经受长时间真空、温度交变等复杂的太空环境,而现有标准的安定性评估方法对其不适用的情况,设计了2/1樟单基发射药在75℃高温真空和非真空条件下的对比试验,测试双环境应力下药剂的安定剂含量、热分解性能及药剂成分等安定性敏感参量。结果表明:在试验周期10d内,药剂在75℃真空和非真空的试验环境下,其二苯胺含量、分解温度和氮含量等参数无显著性差异。本研究可为单基发射药在复杂多变环境下的安定性评估提供参考。

降低射孔爆轰伤害的超深探井测试管柱安全控制措施

国内超深探井试油采用射孔-测试联作工艺,超深井小井眼射孔易出现封隔器下部管柱及封隔器中心管弯曲和断裂等井下复杂情况。根据气体克拉柏龙方程和爆轰气体能量公式,导出射孔爆轰井底和封隔器处最大峰值压力计算公式;根据管柱力学屈曲理论和材料力学弯曲理论,导出射孔段管柱的弯曲应力计算公式;结合峰值压力下的活塞效应,导出射孔冲击载荷作用下管柱的应力计算公式,判断管柱的强度安全。根据射孔段管柱力学分析成果,采用改变管柱组合、调整工具下入顺序、加入双向减震器、分段延时射孔等技术,建立了超深探井测试管柱安全控制措施。以LX1井为例,实测了管柱震动加速度,上、下高速压力计实测上、下峰值分别为100、150 m/s 2和60、80 m/s 2,相差40%~50%,说明双向减震器可以起到减震降损的作用。经多口超深井探井现场应用,验证了安全控制措施的可靠性。

渤海C井深层超高温射孔断爆案例分析

随着渤海油田勘探向深层发展,探井测试作业中采用超高温射孔的频次逐渐增多。由于作业经验相对较少,采用超高温射孔测试联作工艺的渤海C井在作业过程中出现断爆事故。为了深入探究原因,建立了断爆原因分析决策树,从火工品质量、射孔器材、射孔枪装配质量控制以及射孔枪下入操作规范性四个方面进行了系统而详细的分析研究。最终,确定射孔枪弹架结构缺陷为主要原因,同时也不能排除射孔枪人员装配质量控制可能存在的次要因素。基于此,制定了一系列关于超高温射孔作业的质量控制措施,包括射孔枪装配、射孔枪送入操作规范以及作业管理等,对今后超高温射孔作业具有非常重要的指导意义。

Influence of Gas Composition on the Resisting Ability of Gunning Material for Blast Furnace to Carbon Monoxide Corrosion

This paper describes the resisting ability of gunning material for blast furnace to carbon monoxide corrosion under the mixed gas condition through inletting hydrogen into pure CO . A standard for testing ike resisting ability of refractory to CO corrosion with mixed gas instead of pure CO has also been discussed. The results show : the addition of hydrogen accelerates the CO corrosion on gunning material ; the same results has been reached with the CO , 200 hours and CO 95 % + H2 5 % , 24 hours. It is reasonable to use CO 95% + H25% , 24 hours instead of pure CO, 200 hours to lest the resisting ability of refractory to carbon monoxide corrosion.

Test Apparatus for Performance Evaluation of Compressed Air End-Use Applications

Compressed air is an integral utility part of industrial utility systems. Any improvement in compressed air system will lead to reduction in utility cost. The effectiveness of utilization side of compressed air is usually dependent upon operator’s discretion. There are no performance testing methods available for testing existing end use equipments. A test apparatus for estimation of compressed air flow based on measurement of pressure reduction in a fixed volume cylinder in a given time is developed. The test apparatus is easy to build and simple to operate in an industrial environment. This can be used for measuring performance of any pneumatic end-use equipment and for benchmarking the performance. The test apparatus was used in a foundry for quantifying the performance of the old and new blow guns.

枪口焰烟光学特性测试研究

针对狙击作战中对狙击手的探测、定位及告警的需求,开展了枪口焰烟光学特性测试研究。根据枪口焰烟文献资料与光学测量设备的性能参数,设计了枪口焰烟光学特性外场测试详细方案。对某5.8 mm与7.62 mm口径弹道步枪的枪口焰烟光学特性进行了外场测试。测试结果表明,枪口焰烟辐射主要集中在2μm~5μm,持续时间约为6 ms,辐射能量最大值出现在2 ms附近,5.8 mm弹道步枪枪口焰烟在中波和长波的辐射强度均高于7.62 mm。枪口焰烟光学特性的测试结果为枪口焰烟的探测及武器发射药的改进提供了重要依据。

基于AMSAA模型的复杂舰炮武器系统可靠性增长方法

可靠性增长主要用于产品以完成初样机研制,在产品未定型之前,利用有限的时间完成故障纠正,对产品设计和制造工艺进行更改。针对复杂舰炮武器系统具有机、电、液高度耦合的工作方式,以及其系统失效时间分布复杂、难以用单一分布描述的特点,在完成系统故障模式、影响分析(FMEA)和故障树分析(FTA)的基础上,定义系统的两类故障(A类故障及B类故障),提出了基于AMSAA模型的复杂舰炮武器系统可靠性增长方法,通过趋势检验、参数估计、拟合度检验的过程,将有限的试验信息纳入AMSAA的可靠性增长和预测模型,并在系统完成定型时给出其可靠性增长水平,用于判断其可靠性指标是否满足用户提出的研制要求。

块煤智能干选技术在新疆某选煤厂的应用研究

为解决新疆某选煤厂200 mm以上块煤人工手选工艺中存在的分选效率低、劳动强度大、工人工作环境差等问题,对块煤智能干选工艺的不同智能煤矸识别方法、智能分离方式、智能算法等进行了特点对比和试验研究。采用智能干选工艺代替现有人工手选工艺。智能干选工艺突破了传统智能干选上限,使物料的识别和执行粒度上限由300 mm提高到600 mm及以上,大大提高了分选效率,降低了工人劳动强度,改善了工作环境。阐述了新疆某选煤厂采用智能干选工艺代替现有手选工艺的具体改造方案。改造后方案和原有手选系统相比,多回收块精煤3.36万吨/年,节约了人工成本,提高了选煤厂智能化水平,创造了可观的社会和经济效益。智能干选工艺的成功应用,为选煤行业超大块煤干法分选、代替手选、动筛和浅槽排矸、块煤智能干选直接出产品等工艺需求提供了参考。

基于无坐力炮复合身管上瞄准镜座的系统可靠性研究

针对无坐力炮复合身管和瞄准镜座的绑缚连接与单一金属无坐力炮身管瞄准镜座的机械连接比较而言,前者在连接瞄准镜后进行射击时,容易出现绑丝松脱、崩丝等造成瞄准镜座松动的问题,影响装备连接可靠性和射击瞄准精确度。为了验证无坐力炮复合身管上瞄准镜座在寿命周期内的可靠性问题,采用实炮射击试验,得到镜座绑缚处身管的轴向、环向最大变形率分别为0.082%、0.08%,X、Y和Z方向的振动加速度峰值分别为213 g、258g和230g,以实炮射击试验结果为依据,分析并确定冲击试验的X方向标准峰值加速度和标准脉冲宽度分别为225 g和2 ms,冲击试验结果表明:瞄准镜座的结构、强度、尺寸、与无坐力炮的绑缚连接满足可靠性要求;无坐力炮内膛尺寸偏差值在0.01~0.03 mm,其变化量值属于可控范围,对射击效果影响较小;无坐力炮配装瞄准镜后的系统零位走动量小于0.2 mil,对于400 m立靶密集度试验而言,弹丸着靶的距离偏差值约为8 cm,满足射击精度要求。该瞄准镜座可用作无坐力炮复合身管与瞄准镜的连接机构。

外能源转管航炮的精度修正方法

转管航炮采用多管串行发射技术。当炮管转动到射击位时,由航炮机械结构带动炮弹在射击炮管中完成进膛、击发、抽壳的射击动作循环。转管航炮大幅度提高了火炮的射速、寿命和立靶密集度,但转管航炮与直管航炮相比,射击时炮弹和炮管均作高速旋转运动,高速旋转运动产生的陀螺效应会影响炮弹外弹道的动态特性,除此以外,转管航炮射击精度还与射击点的高度、速度、风速、炮管转动速度、飞机结构刚度和航炮后坐力相关,理论公式难以描述该精度规律,因此需采取理论分析与校靶试验结合的方式对航炮瞄准点进行修正,提高飞行员使用航炮的命中率。

枪面侧倾对外弹道的影响及修正方法

当射手存在无意识的侧倾射击习惯,或由于执行任务时的地形环境限制,需要操作枪面侧倾进行射击时,以瞄准线为基准,枪面的侧倾导致枪口的空间位置变化,从而弹道垂直面和水平面变化引起弹着点的偏移。为确定枪面侧倾射击时瞄准镜的装定方法,以某型7.62 mm高精度狙击步枪为研究对象,利用三维设计软件的空间建模功能,建立射击诸元坐标系,采用几何方法分析了枪面侧倾对外弹道的影响和弹着点偏差分布规律,推导出了枪面侧倾射击时的弹着点偏差计算公式,研究了弹道修正方法,提出了计算弹道修正量的方程组,指出了射手操枪射击时的注意事项和训练要点。在100 m射距处,设计并进行了枪面侧倾射击时的弹着点偏差和弹道修正试验,对实验结果进行了分析,以期为某型7.62 mm高精度狙击步枪在实战应用中进行枪面侧倾射击提供弹道装定参考,同时提供了一种测试弹丸偏流值的新方法。

火炮身管寿命预测问题的研究

该文根据火炮膛内烧蚀机理，提出了预测身管寿命的过程和方法。首先按核心流为两相流、边界层为湍流的模式建立了预测壁温的膛内流动数学模型，对一定火炮进行了数值模拟。其次按膛壁烧蚀量与壁温成指数关系的经验公式计算烧蚀量。最后按烧蚀量计算弹丸初速下降量，再由初速下降百分量来预估身管寿命。

水下枪械活动件运动分析

该文根据水下枪械的特点 ,组建了水下枪械活动件运动测量系统 ,在此基础上做了大量的实验。对影响活动件运动的因素进行了分析 ,包括工作介质的变化、导气孔的变化等。得到了对水下突击步枪自动机设计有一定的指导意义的理论 ,为水下枪械的开发和研制打下了坚实的基础。

大口径机枪枪管寿命趋势分析

为研究某单管高射机枪枪管寿命趋势,进行了枪管综合寿命试验和数据采集,获得了一套完整的性能衰减数据.对采集的数据进行整理,结合历年来生产验收的试验数据,分析了初速下降率、散布精度、枪管烧蚀和膛口尺寸随射弹数的变化规律及产生的原因,获得了关于该大口径机枪枪管寿命变化趋势及其影响枪管寿命因素的新认识,为该大口径机枪的验收、使用与维护规范的修改及改型设计提供了试验依据.