核电机组重要物项在贮运过程中的气相防锈包装技术研究

通过1500h交变湿热试验、1000h中性盐雾试验及3000h老化试验对核电机组重要设备部件的三种气相防锈包装方法的防锈效果进行研究。结果表明,采用高阻隔材料与气相防锈包装材料的双层密封包装方式,包装内部采用干燥剂控制湿度、气相防锈无纺布加强防锈能力的防锈包装方法具有优异的防锈性能,并且防锈材料容易去除、不残留,该种防锈包装方法适用于核电机组重要设备部件在长周期贮存及运输过程中的防锈保护。     

船舶奥氏体不锈钢管TIG自动焊腐蚀行为研究

为了研究船舶管道系统焊接件的腐蚀行为,通过全位置TIG自动焊技术对316L奥氏体不锈钢接头进行焊接,采用接头拉伸、弯曲、宏观金相测试以及通过加速腐蚀试验后腐蚀深度、表面形貌、微区电化学测试,就焊接工艺对试样的力学性能和腐蚀行为的影响进行研究。经焊接试验与检测发现,通过改变分区焊接参数设计,可有效保证焊接接头的焊接质量,焊接接头的力学性能合格。对此焊接工艺下焊接后不锈钢管道的腐蚀行为研究结果表明：焊接材料在模拟盐雾湿热/SO₂大气环境中进行腐蚀试验后以点蚀为主,腐蚀产物为团状物,且随着腐蚀过程继续进行,腐蚀产物不断生长,相互连接成片,形成完整锈层,对基材起到保护作用,延缓腐蚀向基材深入;腐蚀优先在热影响区进行,并且随腐蚀周期延长,试样母材区的耐蚀性始终高于热影响区。     

气相防锈热收缩包装技术应用于核电设备防锈

目的 介绍气相防锈热收缩包装技术,并应用该技术解决大型核电金属设备在三年期封存过程中的锈蚀问题。方法 以气相防锈热收缩薄膜为核心的组合封存技术对大型核电设备进行三年期的封存防锈,并对气相防锈热收缩包装技术在现场应用的效果进行评价。结果 通过现场应用效果验证,采用气相防锈热收缩包装技术进行三年期组合封存的核电设备未发生锈蚀,核电金属设备表面与三年前无明显差别,光洁如新,防锈效果优异。结论 气相防锈热收缩包装技术是实现大型核电金属设备在库房内三年期封存防锈的一种有效方法,操作工艺简单、防锈材料易去除。     

木盒和涂料微气氛腐蚀的解决方法

我厂量具产品,在正常情况下,能保证2～5年不锈。但装在木盒中的量具产品某些部位,不时出现锈蚀。例如经汽油清洗、涂BM—16防锈油、再包11~#气相防锈纸的块规,插入木盒隔板内的下半截部位;防锈方法与块规相同,但未包防锈纸的薄壳千分尺测杆外露部位;经汽油清洗,再装入聚乙烯塑料袋的V型架各个面等,其出现锈蚀的时间则不尽相同。从锈蚀部位和形貌看来,我们认为木盒内定有某种气相腐蚀因素存在。于是,我们对木盒材质和涂料进行分析和试验。     

复合薄膜对P_(11)气相防锈粉散失量影响的试验

1 试验目的气相缓蚀剂是一类在常温下具有挥发性的防锈剂。气相缓蚀剂的防护寿命与所使用的包装材料的气密性有直接关系。为了减少气相缓蚀剂向包装体外部空间散失,必须选择适当的密封包装材料。在气相防锈包装中,聚乙烯薄膜是使用较多的一种密封包装材料。近年来,随着铝塑复合技术的发展,铝塑复合薄膜也逐渐在包装领域中得到应用。本试     

碳钢用绿色复配气相缓蚀剂的制备

目的 制备一种绿色高效复配气相缓蚀剂,用于金属的防锈包装.方法 选用苯甲酸钠(C7H5CO2Na)、葡萄糖酸钠(C6H11O7Na)、植酸(C6H18O24P6)和柠檬酸钠(C6H5Na3O7)为复配药品,以A3钢和45#钢为实验对象.通过密闭挥发减量实验、气相快速甄别实验电化学实验和湿热实验筛选出缓蚀率最高的复配气相缓蚀剂配方.将确定的最高缓蚀率气相缓蚀剂制成气相防锈纸,与防锈原纸、市售气相防锈纸进行防锈效果对照,对照实验采用扫描电子显微镜(SEM)、能谱仪(EDS)和接触角仪测试.结果 筛选出四元复配组11 g/L苯甲酸钠+11 g/L葡萄糖酸钠+15 g/L植酸+5 g/L柠檬酸钠的缓蚀率最高,对A3钢的缓蚀率达到了94.36％,对45#钢的缓蚀率达到了94.47％.经该防锈纸防护的A3钢和45#钢表面光滑,无锈蚀出现,氧元素含量低,且接触角大于90°,呈现明显疏水性.结论 经过4种缓蚀剂药品的复配筛选,最终确定出了缓蚀率最高的气相缓蚀剂配方为11 g/L苯甲酸钠+11 g/L葡萄糖酸钠+15 g/L植酸+5 g/L柠檬酸钠,且制成的复配气相防锈纸防锈效果优于空白组的防锈原纸以及市售气相防锈纸.     

浓硫酸中304不锈钢焊接接头腐蚀行为的电化学研究

为了给应用于浓硫酸工业生产的304不锈钢管道的防护提供指导,采用电化学阻抗谱法与动电位扫描法研究了304不锈钢焊接接头各个区域在质量分数为98%的浓硫酸中不同温度下的腐蚀行为。结果表明:304不锈钢焊接接头在浓硫酸中的腐蚀形式以点蚀为主。在相同条件的浓硫酸介质中,焊接接头各区域耐蚀性优劣依次为:基材、焊缝、热影响区,焊接过程对不锈钢的腐蚀起到促进作用。随着硫酸介质温度的逐渐升高,基材的钝化膜比较稳定,而焊缝与热影响区的钝化膜会发生破裂;并且各区域的自腐蚀电流与腐蚀速率会逐渐增大,耐腐蚀性逐渐下降。     

防锈防护组合技术在装备器材防锈封存中的应用

目的介绍防锈防护组合技术。方法通过典型装备器材防锈封存应用说明组合技术的特点、内容和效果,并进一步提出装备器材防锈防护技术包装的发展趋势。结果防锈-缓冲-阻隔包装技术已经在装备器材封存中广泛应用,现已形成标准化;以气相防锈棒为核心的组合封存技术已在火炮封存中成功应用,并得到权威部门鉴定和认可;气相防锈、干燥和除氧组合技术用于枪械封存包装,封存期可达10年以上。结论通过对装备器材防锈防护技术包装发展趋势进行分析和展望,提出装备快速反应、包装轻量化、材料多功能化、效果可视化和封存技术组合化是未来的发展方向。     

浅谈气相防锈包装技术

气相防锈包装是利用气相缓蚀剂常温下缓慢气化,并以分子或离子形式吸附于金属表面,从而阻隔金属与外界水分、氧气等腐蚀介质的接触,达到防锈的目的。中国每年因腐蚀造成的损失高达2800亿元。因此,如何有效防止金属腐蚀,已成为各种金属相关产品在运输过程中非常关键的因素。气相防锈包装作为一种新兴技术,以其简便实用、安全有效、防锈时期长、应用范围广而受到青睐。特别是气相防锈包装适合于表面不平、结构复杂且多空隙的金属制品更引起越来越多企业的关注。     

预处理对AZ31镁合金表面Ni-B化学镀层形貌及性能的影响

镁合金Ni-B化学镀层具有高耐蚀性、高硬度、高耐磨性等特点,具有广泛的应用价值,过去对其研究不够.采用化学镀在AZ31变形镁合金表面制备了Ni-B镀层,研究了酸洗、活化、浸锌等基材预处理工艺对Ni-B化学镀层形貌及性能的影响.结果表明:CrO_3+KF酸洗对基材的腐蚀较轻,而采用CrO_3+HNO_3酸洗时基材腐蚀严重;HF和NH_4NF_2+H_3PO_42种活化作用的机理在于形成MgF_2的中间转换层,保护基材不被镀液腐蚀,HF活化后在基材表面形成了较大面积的MgF_2,活化能力更强,对基材的保护能力更好;浸锌工艺对镀层的性能有较大影响,二次浸锌后锌颗粒和锌层厚度都小于一次浸锌,Ni-B镀层更平整致密,硬度和结合力优于一次浸锌,显微硬度为458 HK,明显高于镁合金基材的硬度(77 HK),同时镀层的耐蚀性也有较大的提高.     

MODIFICATION OF THE COMPOSITION OF LASER WELDS IN ELECTROGALVANIZED STEEL AND THE EFFECT ON CORROSION PROPERTIES

Compositional modification of the weld metal during laser welding of electrogalvanized steel sheet was achieved by the injection of metal powder or by a technique in which zinc that had been volatilized as a result of the welding operation was redeposited on the weld bead. Corrosion testing by means of the linear polarization technique showed that the coating corrosion rate in the case of laser welds containing redeposited zinc was substantially lower for an initial period than for normal laser welds. Only a small decrease in corrosion rate was achieved by the injection of tool steel powder during laser welding while an increase in coating corrosion rate was produced by the injection of nickel powder or stainless steel powder     

Microstructure,hardness and petroleum corrosion evaluation of 316L/AWS E309MoL-16 weld metal

The current work presents some observations about the effect of welding heat input on the microstructure, hardness and corrosion resistance of AWS E309MoL-16 weld metal, diluted with AISI 316L austenitic stainless steel plates. Such welds are widely used during overlay of equipment in the petroleum and gas industries. Results show that the welds contained δ-ferrite varying between vermicular to lathy morphology, typically encountered in welds which solidify in ferrite–austenite mode (FA). Conversely, contents and morphology of δ-ferrite in the weld metals were altered, showing an increase of welding heat input. The corrosion rate of the weld metal indicated that when higher levels of welding heat input are used the corrosion rate is reduced. This may be attributed to metallurgical changes, especially variations in the proportion of δ-ferrite, caused by changes in cooling rate.     

镀锌板焊接件磷化工艺研究

针对目前焊接件焊缝区磷化效果不理想的情况,对镀锌板焊接件进行了3种不同工艺的磷化。通过扫描电镜观察磷化表面的形貌,采用硫酸铜滴定试验评价磷化膜的耐蚀性。研究表明:镀锌板焊接件用同一种磷化工艺很难达到预期效果;而先对焊缝用硝酸锌调节的磷化液喷淋磷化2 min,然后在Zn O调节酸度的磷化液中浸泡磷化2 min,焊缝和母材都可得到均匀、细小、致密的磷化膜,耐蚀性均较好。     

含Zn-Al磷酸盐防腐蚀涂层的制备与腐蚀机理研究

为制备出具有更高耐蚀性、尤其是耐海洋气候腐蚀的Zn-Al基金属陶瓷涂层,以磷酸二氢铝作为粘结剂,氧化镁、氧化锌作为固化剂,锌、铝粉作为填料,聚四氟乙烯作为助剂,制备了一种含Zn-Al磷酸盐防腐蚀涂料,通过空气喷涂后热固化的方式在300M高强钢表面制备出含Zn-Al磷酸盐防腐蚀涂层,并对涂层进行了中性盐雾试验以及电化学试验,采用扫描电镜和能谱分析形貌及成分。结果表明:涂层中性盐雾腐蚀寿命达到1 000 h;涂层的自腐蚀电位低于基体,能为基体提供阴极保护;含Zn-Al磷酸盐防腐蚀涂层的腐蚀过程分为4个阶段,涂层的主要防护机制为金属粉的牺牲阳极作用和腐蚀产物的屏蔽效应。     

Welding of aluminium by the MIG process with indirect electric arc (MIG-IEA)

A novel modification of the metal inert gas (MIG) welding method, which was developed to weld metal matrix composites, was applied to join plates of aluminium 12.5 mm thick. The plates were prepared with square edges and with a small single-V preparation with an angle of 45° in the upper part. The electric arc was indirectly applied on the single-V butt weld over strips of Al-2024 placed on top of the joint. Thermal analysis showed that the efficiency of the MIG process with indirect electric arc (IEA) is increased due to the reduction of heat losses and fully penetrated welds with a high depth-to-width ratio can be produced as compared to plain MIG welding in which partial penetration and lack of lateral fusion were observed. Microstructural examination of the welds revealed distinct characteristics such as partially melted grains trapped within the weld next to the fusion line for IEA welds and the typical epitaxial and columnar growth from the base metal partially melted grains for plain welds, i.e. direct application of the electric arc (DEA).     

Effects of temper condition and corrosion on the fatigue performance of a laser-welded Al–Cu–Mg–Ag (2139) alloy

The effects of temper condition and corrosion on the fatigue behavior of a laser beam welded Al–Cu–Mg–Ag alloy (2139) have been investigated. Natural aging (T3 temper) and artificial aging (T8 temper) have been applied prior to welding. Corrosion testing has been performed by exposing the welded specimens to a salt spray medium for 720 h. Aging influences the corrosion behavior of laser welds. In the T3 temper, corrosion attack is in the form of pitting in the weld area, while in the T8 temper corrosion is in the form of pitting and intergranular corrosion in the base metal. In the latter case corrosion is attributed to the presence of grain boundary precipitates. Corrosion degrades the fatigue behavior of 2139 welds. The degradation is equal for both the T3 and T8 tempers and for the corrosion exposure selected in this study corresponds to a 52% reduction in fatigue limit. In both cases fatigue crack initiation is associated with corrosion pits, which act as stress raisers. In the T3 temper, the fatigue crack initiation site is at the weld metal/heat affected zone interface, while for the T8 temper the initiation site is at the base metal. Fatigue crack initiation in uncorroded 2139 welds occurs at the weld toe at the root side, the weld reinforcement playing a principal role as stress concentration site. The fatigue crack propagates through the partially melted zone and the weld metal in all cases. The findings in this paper present useful information for the selection of appropriate heat treatment conditions, to facilitate control of the corrosion behavior in aluminium welds, which is of great significance for their fatigue performance.     

Weldability and properties of martensitic/austenitic stainless steel joints

Abstract

A series of studies has been carried out to examine the weldability and properties of dissimilar steel joints using martensitic and austenitic stainless steels F6NM (OCr13Ni4Mo) and AISI 347, respectively. This type of joint requires good mechanical properties, corrosion resistance, and a stable magnetic permeability in addition to a good weldability. Weldability tests include weld thermal simulation of the martensitic steel to investigate the influence of weld thermal cycles and post-weld heat treatment (PWHT) on the microstructure and mechanical properties of the heat affected zone (HAZ); implant testing to examine the tendency for cold cracking of martensitic steel; and rigid restraint testing to determine hot crack susceptibility of the multipass dissimilar steel joints. The simulation results indicated that the toughness of the martensitic steel HAZ did not change significantly after the weld thermal cycles. The implant test results indicated that welds produced using nickel based filler show no tendency for cold cracking, whereas welds produced using martensitic or ferritic filler show such a tendency. Based on the weldability tests, a welding procedure (tungsten inert gas welding for root passes with HNiCrMo-2B wire followed by manual metal arc welding using ENiCrFe-3B coated electrode) was developed and a PWHT at 600°C for 2 h was recommended. Joints produced using the developed welding procedure are not susceptible to hot and cold cracking. After PWHT the joints exhibit both satisfactory mechanical properties and stress corrosion cracking resistance.

MST/1955     

锂电池PACK包Al-Zn-Mg-Cu铝合金CMT 焊接组织与性能研究

以锂电池包箱体常用的7003铝合金为研究对象,采用冷金属过渡焊接工艺(CMT)对7003铝合金进行焊接后,经过固溶(485 ℃,3 h)、人工时效(160 ℃,2 h)和自然时效(72 h)热处理后,进行组织和性能研究。通过慢应变速率拉伸试验、常温拉伸试验、显微维氏硬度测试、扫描电子显微镜分析等方法,对该铝合金接头的母材和焊缝的抗腐蚀性能、力学性能以及微观组织形貌进行研究。结果表明:当慢应变速率为1×10-6 s-1时,基材和焊接试样的应力腐蚀敏感性指数(ISSRT)分别为2.73%和9.74%;对焊接试样的接头进行晶间腐蚀和剥落腐蚀测试并评级,晶间腐蚀为4级,剥落腐蚀为PA级;焊接接头的电导率、抗拉强度、延伸率分别为22.0%(IACS)、330.7 MPa、10.0%。     

Fracture toughness (J1C) of electron beam welded AA2219 alloy

AA2219 (Al–6%Cu) was butt welded in T87 temper (solution heat-treated, cold worked and precipitation hardened) and T6 temper (solution heat-treated and precipitation hardened) using electron beam welding (EBW). Variables studied were base metal temper condition and mode of EBW. Mechanical properties of the weld joint and fracture toughness at fusion zone (FZ) and heat-affected zone (HAZ) were evaluated and compared with those of the base metal. Results showed that EB welds have higher joint efficiency and fracture toughness than that of gas tungsten arc welding (GTAW). Fracture toughness of T6 base metal was found to be higher than its T87 counterpart. When welded, FZ and HAZ in T87 showed higher fracture toughness than that of T6; HAZ was the toughest. Pulsed current (PC) EB weld showed marginal reduction in toughness compared to constant current (CC) weld. Toughness variation is analyzed with the help of tensile test, Charpy impact test and scanning electron microscopy (SEM) and transmission electron microscopy (TEM).     

Assessment of Weld Embrittlement in A516 Steel Due to Multiple Repair Welds

A 3-million gallon petroleum storage tank was fabricated in the Midwest using A516 steel. The initial fabrication schedule had become compressed; welders worked hurriedly and did not produce good welds. Numerous welds had to be repaired via grinding and rewelding. The quality of the steel near the welds were questioned regarding their ductility; it was thought that the material had become embrittled and would fail prematurely in a catastrophic manner and be more susceptible to poor performance during the winters (−25 °F) because of welds being repaired up to six (6) times. The contracting company requested that the repair welds be evaluated and compared to the base metal and the original welds. The repair welds could not be removed from the structure. Therefore, the welding vendor was requested to provide mock-up welds and mock-up repair welds that simulated the welding process used during fabrication. The welding vendor provided base metal, mock-up of in-service weld, and mock-up of in-service repair weld for metallographic evaluation and mechanical testing. The vendor also provided hardness data for in-service weld and in-service repair weld along with hardness data for mock-up of in-service weld and mock-up of in-service repair weld. The mock-up welds adequately represent the production welds (original welds and repaired welds). All the test results indicate that the repaired welds are of similar quality as the original weld.