Microstructure of shot-blasting casting roll and effect on strip solidification during strip-casting process

In the strip-casting process,the surface topography of the casting roll has a significant influence on the solidification microstructure and surface quality of the as-cast strip. Shot-blasting treatment is an important way to achieve a suitable surface topography on the casting roll. In this study,a casting roll of beryllium copper alloy was shot blasted using steel pellets in the laboratory,resulting in a randomly distributed discontinuous peak and dent surface topography,in which cold deformation-slip bands and fine-deformation twins were formed. The thickness of the deformed copper alloy was about 100 μm during the shot-blasting process,and the copper hardness value increased significantly within 40 μm of the surface,with a maximum increase of more than 20% compared to the mean substrate hardness value. Within 60-100 μm of the surface,the hardness at the peak position was still higher than the copper substrate mean value,but the hardness at the dents was not,which was mainly due to the copper alloy slip and twinning deformation mechanisms. The surface hardness was similar to that of the substrate after the shot-blasted sample had been subjected to thermal shock. The molten steel first chilled and nucleated at the surface peaks of the casting roll;furthermore,fine dendrites grew and crossed over the middle of the dents. Therefore,the peak intervals of the shot-blasted surface are an important factor in solidification quality control.

Research on the inwall shot blasting of the S30432 high-pressure boiler tube

Inwall shot blasting is a method of improving the surface hardness and high temperature oxidation resistance of the S30432 high-pressure boiler tube.The differences on residual stress,sub-grain size,micro-hardness and structure between the S30432 inwall shot-blasting tube produced by Baosteel with six technological process parameters and the imported super 304H were studied systematically by contrast test research.It has been demonstrated that the S30432 obtains a higher residual stress,a deeper distributed layer and a better sub-grain size of the inwall field shot-blasting layer;the martensite content of the shot-blasting surface was low;and micro-hardness and structure refinement were better.After 2000 h’ oxidation test under the 650℃/26MPa steam condition,steam oxidation resistance of the Baosteel steel tube shot-blasting surface was higher,the oxide layer was thinner,and was well combined with bulk material.

Effect of Shot Blasting on Oxidation Behavior ofTP304H Steel at 610℃-770℃ in Water Vapor

Shot blasting on a tube steel of TP304H can greatly improve the oxidation resistance at *50°C—770°C in water vapor, by the presence of an appropriate blasting intensity. SEM and EPMA analysis indicated that the structure of the oxide scale turned from multi-layer to monolayer after blasting and Cr2O3 in predominant. The untreated sample characterized in multi-layer oxide was composed of Fe in the outer layer and Fe and Cr underneath. For blasted one, the increase of diffusion rate of Cr and the decrease of effective diffusion energy of scale led to a uniform Cr-rich oxide layer, which was dense and protective and the oxidation resistance was increased.

Synergic Effect of Shot Blasting and Deposit RE on Corrosion Behavior of TP304H steel in SO_2-O_2 at 923K

The corrosion behavior of TP304H steel with combined treatment of shot blasting and electrophoresis deposited RE coating in l%SO2+14%O2+85%Ar mixture gaseous has been studied at 923K for 150 hours. The results show that both RE coating and shot blasting can improve the corrosion resistance of TP304H steel, and combined treatment has the best effect. Combined treatment reduces 50% mass gain, enhances the continuous and compactness of scale and changes the scale phase forms from FeaOs/Fe^S/Ni^/S to Cr2O3/FeCr2S4/Ni3_xS2. The synergistic effects of combined treatment on corrosion resistance and the effect of shot blasting on corrosion kinetics are discussed. Shot blasting increases the outward diffusion and surface concentration of Cr, Ce coating promotes the selective oxidation of Cr.

Numerical Simulation of Derusting Treatment of Steel Parts By Shot Blast

In this paper,we investigated the shot blast treatment for derusting application through finite element(FE)simulations with a large number of random shots.The element deletion technique based on dynamic failure criteria was used to model the removal of rust.The cohesive surface model with damage evolution was used to characterize the decohesion of the rust/substrate interface.The effects of various processing and material parameters on the derusting effectiveness were examined.The results show that the rate of derusting mainly depends on the shot size,velocity and impinging angle,with little relevance to the rust thickness.The spalling of the rust fragments resulted from the decohesion of the rust/substrate interface were observed,especially during the later stage of the treatment.Furthermore,the residual stress and the surface roughness was also investigated and the beneficial effects of shot blast treatment in terms of these aspects were highlighted.

Friction Behavior of Laser Beam Texture Sheets and Shot Blast Sheets

The friction behaviors of steel sheets at the corners of die and punch, under different conditions of surface textures (laser beam texture, shot blast texture), steel sheet rolling directions and lubricants, are studied by both SEM micro surface observations and friction coefficients measurement. The results show the friction coefficient at the corner of die is smaller than that at the corner of punch during stamping. The friction coefficient along rolling direction is lower than that along transverse direction, especially at the corner of punch. Differential initial surface texture has different sensitivity of friction coefficient to the lubricants. The sheet surface with laser beam texture (LBT) has shown a stronger adaptation to various lubricants than that with shot blast texture (SBT). After stamping, the surface with laser beam texture is still clear, the shot blast texture is indistinct.

SHOT PRO和BOOM BOX系统控制时序分析

本文主要对SHOTPRO和BOOMBOX两种遥爆系统的工作方式和控制时序进行分析。从遥爆系统的功能、起爆延迟时间(钟TB)的概念及其调整的意义着手,说明了这两种遥爆系统的普通工作方式和主-从(重复器)工作方式,并对它们的时序进行了详细的分析。

Shot Pro爆炸机启爆脉冲识别及其精度调整

本文在对ShotPro爆炸机启爆时钟脉冲序列的意义和作用进行分析和讨论的基础上 。

Shot ProⅡ遥爆系统微处理器功能及故障检修

Shot ProⅡ遥爆系统采用单片机结构微处理器控制,其工作状态与微处理器密不可分。本文主要阐述了ShotProⅡ遥爆系统所用的微处理器芯片H8S/2357的性能、各管脚在遥爆系统中的功能及控制作用,并从微处理器的角度出发对部分故障实例进行了分析。

Boom Box与Shot Pro系列遥爆系统的比较

本文根据Boom Box和Shot Pro系列(Shot Pro和Shot ProⅡ)遥爆系统的相同点和不同点,对这两个遥爆系统的电路原理、主/从工作方式、重复器工作方式、与记录系统的联机以及接口电路中隔离信号等方面进行了详细地对比。

基于有限元仿真的钛合金喷丸技术应用综述

喷丸强化工艺作为一种常用的表面强化技术,在钛合金相关零部件的表面强化中起到重要作用,有限元技术在探究喷丸强化工艺机理和强化效果中应用广泛。目前,多数喷丸仿真研究都是以钢和铝合金为材料,以钛合金为材料的喷丸仿真研究相对较少。本文总结了国内外学者关于钛合金传统喷丸仿真技术、钛合金新型喷丸仿真技术以及钛合金传统喷丸技术与新型喷丸仿真技术的联系,并对钛合金喷丸仿真方面的发展趋势进行展望。

抛丸和抛浆对金属基体表面完整性的影响对比

以Q235热轧带钢为研究对象,利用ANSYS/AUTODYN模块模拟了抛丸和抛浆对基体表面的冲击过程,并结合抛丸和抛浆冲击试验研究了带钢表面粗糙度和残余应力。结果表明,抛丸冲击后基体表面冲击深度和冲击直径分别比抛浆高20%~49%和9%~22%;抛丸冲击基体表面瞬时温度为247~413℃,抛浆冲击基体表面瞬时温度为60~97℃,说明浆体中的流体可以带走大量冲击热能。抛丸冲击后基体表面粗糙度和表面残余应力比抛浆冲击分别高22%~37%和3.7%~13.8%,抛浆冲击后基体表面完整性优于抛丸冲击。

抛丸机叶片瞬时碰撞动力学行为及应用研究

船舶用钢的除锈处理是影响日常维护的关键工艺,而抛丸机叶片磨损断裂是影响除锈设备使用寿命的重要因素。本文叙述了抛丸机叶片磨损断裂形成机制、弹丸碰撞非线性动力行为及撞击侵蚀过程、叶片磨损特性等方面的研究进展,讨论了叶片旋转软化效应下的振动响应与结构特性,分析了叶片材料的晶体取向、元素含量与磨损的关系,根据磨损机理(如摩擦、微切削、疲劳裂纹等)研究了相对应的冲撞侵蚀量化模型,总结了仿真与试验等手段在不同弹丸参数对叶片侵蚀研究中的应用,对抛丸机叶片瞬时碰撞分析技术进行了展望。

Enhanced mechanical performance of gradient-structured CoCrFeMnNi high-entropy alloys induced by industrial shot-blasting

In this study,CoCrFeMnNi high-entropy alloys(HEAs)with a surface gradient nanostructure were produced using industrial shot blasting,which improved their mechanical properties compared to the untreated alloy.The severely plastically deformed(SPD)surface layer had a multi-scale hierarchical structure with a high density of stacking faults,deformation nanotwins,and amorphous domains.The depth of the SPD layer steadily increased as the shot-blasting time increased.The differences in the microhardness and tensile strength before and after shotblasting demonstrated the significant effect of the SPD layer on the mechanical performance.The microhardness of the homogenized HEA was~5 GPa.In comparison,the maximum microhardness of the specimens after 20 min of shot blasting was~8.0 GPa at the surface.The yield strength also improved by 178%,and a large ductility of~36%was retained.Additional nanograin boundary,stacking fault,and twin strengthening within the gradientnanostructured surface layer caused the strength to increase.During tensile deformation,strain concentration began at the surface of the specimen and gradually spread to the interior.Thus,the gradient-nanostructured surface layer with improved strain hardening can prevent early necking and ensure steady plastic deformation so that high toughness is achieved.

车轮辐板抛丸强化试验数据分析与研究

根据轧制车轮辐板抛丸强化得到的试验数据,经PA2软件处理后绘制出阿尔门饱和曲线,结合抛丸强化工艺参数及抛丸强化机理,对车轮辐板抛丸强化试验数据及阿尔门饱和曲线进行研究分析。结果表明:弧高值的大小取决于弹丸对试片的冲击功,满足弧高值要求的情况下,冲击功越小,饱和时间越短。当冲击功低于一定值后,冲击功越小,饱和时间反而越长。在满足弧高值要求的情况下,提高工件喷丸强化生产效率的唯一方法是提高单位时间内的喷丸量,即增大抛丸器功率。

基于互联网的抛喷丸成套装备远程运维服务云平台设计

针对目前抛喷丸装备种类繁多、分布广,面临运维成本高、不及时、效率低等问题,系统阐述了抛喷丸装备数据采集到互联网平台并实现远程运维服务的方法,通过采用云组态技术、物联网技术、数据库技术和HTML5技术等开发了物联和运维于一体的远程运维云平台,实现售后服务过程中“人、机、料”要素的有效融合,具有操作简便、界面友好、灵活、实用、安全等特点。

喷丸和离子注入对镁合金摩擦腐蚀性能的影响

针对镁合金摩擦耐蚀性能差的问题,对镁合金AZ31进行喷丸和离子注入工艺处理,研究不同强化工艺对镁合金摩擦和耐蚀性能的影响,使用X射线衍射仪、显微硬度计、摩擦磨损试验机、电化学工作站等对强化处理后的镁合金试样进行了测试与表征。结果表明:喷丸和离子注入强化后镁合金AZ31,相较于抛光处理以及喷丸处理的镁合金的显微硬度更高,这是由于N离子注入后有新相Mg_(3)N_(2)出现。摩擦磨损实验表明,离子注入和喷丸复合处理的镁合金摩擦系数更低,且磨损量相较于抛光处理试样降低近一倍。电化学结果显示复合处理的镁合金试样,自腐蚀电位提高至-1.13,自腐蚀电流密度大幅减小,这是由于合金表面形成的Mg_(3)N_(2)新相以及过饱和氮的扩散保护作用,说明表明离子注入和喷丸的复合工艺是进一步提高镁合金摩擦耐蚀性能的有效手段。

抛丸工艺对60Si2Mn热轧弹簧钢表面残余应力的影响

采用不同抛丸时间、抛丸电流的抛丸工艺对高速铁路扣件用弹条原材料(60Si2Mn热轧弹簧钢)进行抛丸,弹丸为粒径0.6~0.7 mm的S230铸钢丸,并通过X射线应力测定仪测量60Si2Mn热轧弹簧钢表面残余应力。结果表明:经不同抛丸工艺处理后,热轧弹簧钢表面残余应力均为压应力;在抛丸电流相同抛丸时间减小、抛丸时间相同抛丸电流减小两种情况下,残余应力场特征参数(最大残余应力、最大残余应力对应的深度和残余应力影响深度)和半高宽(层深相同时)均减小,抛丸效果变差;抛丸覆盖率100%、抛丸时间16 s、抛丸电流50 A时,残余应力场特征参数和半高宽最大,抛丸效果最好。

一种钢管外壁抛丸清理设备的研发与应用

介绍了钢管外壁抛丸清理设备的原理、组成以及技术参数,并对其组成部件的功能与特点进行分析,着重指出了辊道输送系统的创新性。该设备已得到广泛应用并获得一致好评。

特种气体瓶内壁高洁净研磨技术开发及应用

采用电化学机械研磨技术及钢瓶自转和公转的研磨方式,然后通过内部抛丸除锈、高压水清洗、内壁研磨、第三次清洗、去离子化处理和高度真空及置换等主要关键工序,研制出容积为30~50L、达到气瓶内壁Ra≤0.3μm的Rmax1S标准的充装7N高纯电子气体的高洁净研磨气瓶,并且处理后的水份含量小于0.5PPM,油分含量小于25mg/m^(2),钢瓶内壁研磨均匀,研磨周期短。