φ5.35mm-2100MPa桥梁用锌铝钢丝的工艺与组织性能

 为了制备更高强度级别的桥梁缆索用热镀锌铝钢丝，通过对高碳钢盘条的成分设计、低损伤拉拔技术以及热浸镀锌铝等工艺过程的优化，成功试制出?5.35 mm-2 100 MPa级桥梁缆索用热镀锌铝钢丝。设计的SWRS92Si盘条主要成分为（质量分数）：C 0.90%～0.95%，Si 0.8%～1.1%，Cr 0.20%～0.30%。试制结果表明，?13 mm-SWRS92Si盘条经铅浴处理后，珠光体层片平均尺寸从120下降至90 nm，盘条强度上升约260 MPa。经冷拉拔与热镀锌铝后，层片宽度约40 nm的珠光体层片未明显球化，可制备出2 100 MPa级直径5.35 mm的桥梁缆索用热镀锌铝钢丝。钢丝的平均抗拉强度为2 128 MPa，平均断后伸长率为5.4%，扭转圈数平均值为22圈，断口均为平断口，镀层较均匀致密；其他性能指标均优于交通部标准JT/T 1104—2016《桥梁用热镀锌铝合金钢丝》中的要求。     

镀层重量对钢丝绳疲劳的影响研究

从生产实际出发,研究分析了镀层重量对钢丝绳疲劳的影响。实验表明:在实际生产过程中镀层重量对钢丝绳的疲劳有一定的影响,镀层重量太高或者太低都不利于钢丝绳疲劳的提高。镀层重量太高,热镀锌生产时钢丝表面存在较多的η纯锌相,在进行绳疲劳测试时纯锌层容易被磨损,产生表面损伤,导致钢丝绳疲劳寿命相对较低;而镀层重量太低,热镀锌生产时钢丝表面完全形成铁锌合金层,并且这种铁锌合金以脆性的Γ相为主,镀层表面易产生裂纹,在进行绳疲劳检测时更易使钢丝表面产生脱落,形成凹坑,导致绳疲劳寿命的降低;合适的镀层重量,使得在热镀锌生产时,钢丝表面的η纯锌较少,基本形成铁锌合金,并且在形成的铁锌合金中存在塑性的δ相,在进行绳疲劳检测时既不易被磨损又不易脱落,相对来说就有效地提高了绳的疲劳次数。     

镀锌铝合金钢丝镀层中主要元素分析

为了准确控制镀锌铝合金层中主要添加元素的含量,本文设计采用电感耦合等离子发射光谱法检测镀锌铝合金钢丝镀层中的铝、铁含量,分别测定了2个规格共6根桥梁缆索用热镀锌钢丝的镀层中的铝、铁含量(铝含量4.71~7.05%,铁含量0.01~0.02%)。该方法线性好,分别为铝0.999957、铁0.999855;检出限低,分别为铝20g·L^-1、铁11g·L^-1;相对标准偏差分别为铝1.0~1.4%之间,铁2.1~4.8%之间,由此得出该检测有效可行的结论。     

《锌-5%铝-混合稀土合金镀层钢丝、钢绞线》国家标准将要出台

2004年12月1-3日在天津市召开了《锌-5％铝-混合稀土合金镀层钢丝、钢绞线》国家标准讨论会。与会专家们结合实际，对天津市环钟钢丝有限公司起草的《锌-5％铅-混合稀土合金镀层钢丝、钢绞线》国家标准进行了认真地讨论，达成了共识，通过了该国家标准的讨论稿。     

无结晶形成Zn-Al-RE机械镀合金镀层研究

采用机械镀方法在钢铁制品表面上形成锌基铝-稀土合金镀层,试图以无结晶方式形成镀层主体.试验发现,镀层主体的构成是金属粉颗粒混杂的镶嵌体,具有相应的金属特性和对铁基的电化学保护性,镀层形成过程中镀层主体的形成可以不发生结晶现象.复合稀土金属添加剂能细化金属粉藻团,提高金属粉和基体材料表面的活性和润湿性,加快了吸附过程,从而使金属粉的利用率得到提高,镀层的外观、致密性、结合强度、耐腐蚀性能等得到改善.在复合稀土金属添加剂加入量为1%～3%时,机械镀Zn-Al-RE合金镀层的致密度、电化学特性和耐腐蚀性能优于机械镀锌层,并在加入量1%处各项性能指标出现最佳值.     

拉丝断面压缩率对10B30钢球化退火组织及力学性能的影响

研究了拉丝断面压缩率(5%～35%)对Φ9.67～11.69 mm 10B30钢丝(/%:0.28～0.34C, 0.0005～0.0030B)球化退火组织及力学性能的影响。结果表明：随着球化退火前拉丝断面压缩率的增加,球化退火组织级别提高,抗拉强度降低,断面收缩率提高,这是因为拉丝促进了球化退火过程中的自发球化和碳化物的ostwald熟化;当拉丝断面压缩率达到25%以上,球化组织和相应的抗拉强度和断面收缩率趋于稳定;实际生产中,退火前拉丝断面压缩率不应低于25%。     

锌铝镁镀层钢板的镀层质量以及镀层中铝镁铁的测定

在锌铝镁镀层钢板生产中,单位面积上镀层质量和镀层中合金元素组成是产品质量的重要评价标准。试验对锌镁铝镀层的单位面积上镀层质量、镀层元素分布以及合金元素含量分别进行了探讨。利用重量法测定单位面积上镀层质量,腐蚀溶液由4.5g/L六次甲基四胺-盐酸(1+1)溶液组成。利用扫描电镜(SEM)观察镀层表面的形貌,并通过能谱仪(EDS)进行了微区元素成分分析,发现了不同物相在镀层中的分布特征及各元素在不同相中的分布规律。利用电感耦合等离子体原子发射光谱法(ICP-AES)同时测定了镀层中铝、镁、铁含量。按照实验方法采用ICP-AES测定热浸镀锌铝镁镀层钢板的镀层中铝、镁和铁,结果的相对标准偏差(RSD,n=6)分别为0.80%、0.76%和1.4%,加标回收率为97%~102%。     

锌铝镁镀层钢板的镀层质量以及镀层中铝镁铁的测定

在锌铝镁镀层钢板生产中,单位面积上镀层质量和镀层中合金元素组成是产品质量的重要评价标准。试验对锌镁铝镀层的单位面积上镀层质量、镀层元素分布以及合金元素含量分别进行了探讨。利用重量法测定单位面积上镀层质量,腐蚀溶液由4.5g/L六次甲基四胺-盐酸(1+1)溶液组成。利用扫描电镜(SEM)观察镀层表面的形貌,并通过能谱仪(EDS)进行了微区元素成分分析,发现了不同物相在镀层中的分布特征及各元素在不同相中的分布规律。利用电感耦合等离子体原子发射光谱法(ICP-AES)同时测定了镀层中铝、镁、铁含量。按照实验方法采用ICP-AES测定热浸镀锌铝镁镀层钢板的镀层中铝、镁和铁,结果的相对标准偏差(RSD,n=6)分别为0.80%、0.76%和1.4%,加标回收率为97%~102%。     

铅浴淬火工艺对70钢丝组织和性能的影响

研究了900℃均热+500℃铅浴54 s空冷处理对70钢(0.67%～0.75%C)Φ5.5 mm热轧钢丝经38.9%压缩率拉拔的冷拔钢丝组织和性能的影响。结果表明,500℃铅浴等温处理,该钢过冷奥氏体转变的孕育和转变时间最短,该钢丝抗拉强度提高了21.4%,伸长率提高9.5%,为随后通过细拉工艺进一步提高钢丝的综合力学性能建立了基础。     

锌-5％铝稀土合金问世

一种新型的镀层材料——锌-5％铝混合稀土合金在广东韶关冶炼厂研制成功,并通过了冶金部鉴定。我国目前钢板、钢管、钢丝普遍使用的镀层材料是纯锌、热镀锌等,但这些镀层材料耐腐蚀性能不够理想、耗量大、成本高、寿命短。八十年代初国外出现了锌-5％铝混合稀土合金镀层。这种合金镀层兼有普通锌     

Effect of Copper Coating and Reinforcement Orientation on Mechanical Properties of LM6 Aluminium Alloy Composites Reinforced with Steel Mesh by Squeeze Casting

Uncoated and copper coated steel wire mesh reinforcing LM6 aluminium alloy composites have been produced using squeeze casting process by varying reinforcement orientation viz., 0°, 45° and 90° respectively. Microstructure of the castings has been examined and mechanical properties such as hardness, tensile strength and ductility have been investigated. Fracture surface of tensile specimens has been analysed using field emission scanning electron microscope. Microstructure of samples reveals that copper coating on steel wires improves the interface bonding between matrix and reinforcement. Average hardness values of 259 and 90 Hv have been observed in steel wire and matrix respectively. Tensile strength of composites increases with increasing angle of reinforcement orientation from 0° to 90°. Tensile strength increases up to 11% by reinforcing copper coated steel wire mesh at 90° orientation as compared to LM6 aluminium alloy. Fracture surface of composites shows pullout of steel wires in uncoated steel wire mesh composites and broken wires in copper coated steel wire mesh composites respectively. Dimples have been observed on the fracture surface of LM6 aluminium alloy. In general, copper coated steel wire mesh composites offer better hardness and tensile strength compared to uncoated steel wire mesh composites and LM6 aluminium alloy. This may be attributed to the copper coating on steel wires which results better interface bonding between matrix and reinforcement.     

镀铝锌彩涂板爆孔缺陷分析

对镀铝锌彩涂板生产中产生爆孔缺陷的原因进行了分析,认为爆孔缺陷主要由镀铝锌合金镀层的化学特性差异、热物性差异和镀铝锌合金层缺陷等因素造成。通过改善镀铝锌板合金镀层的表面质量、提高轧辊光整粗糙度、减少镀铝锌板表面疏松孔洞缺陷、改进彩涂固化工艺温度曲线,消除了镀铝锌彩涂板爆孔缺陷,满足了彩板用户的质量要求。     

涂镀板涂层表面质量表征与分析

为了定量化地快速准确评定涂镀板涂层质量,针对涂镀板涂层质量评定过程中出现的检测时间长、测试过程复杂等难题,利用辉光光谱法对4种涂镀板样品的质量分数-深度谱图分析,可以得出涂镀板涂层厚度及质量、结构总体判定、表面缺陷等信息,分析涂镀板涂层中元素的组成,有效观察缺陷样品中有害元素氧在基板表面的富集,通过改变工艺条件,提高软熔处理温度,改善涂镀板缺陷问题。利用电化学方法,应用极化曲线和电化学阻抗技术,对涂镀板在不同温度下腐蚀性能进行分析研究,结果表明,在0~40℃范围内,镀锌板的腐蚀速率变化不大;当温度升高到60℃时,腐蚀速率快速增大;利用扫描电镜能谱法对正常和缺陷涂镀板表面微观形貌分析对比,发现缺陷涂镀板镀层结构较为稀疏,镀层不连续且存在颗粒状分布,此结构不能有效保护基体组织。实验方法可以找出缺陷问题原因,保证了涂层质量的评定结果。     

汽车用预涂镀钢板的工艺和产品研发

汽车用预涂镀钢板随着模块化汽车设计的实现得到越来越多的关注。介绍了钢铁企业未来汽车用表面产品的结构、技术特征和发展目标,以及在此领域内的研发进展,对锌镁合金镀层的结构、性能及未来应用目标进行了讨论,分析总结了不同带钢真空镀膜体系的应用方式及不同工艺镀层的差异,锌镁合金镀层可以作为新一代的具有良好综合性能的金属镀层基板,以此为基础,可以采用SiOC系列镀层作为后续镀层,进而完成汽车用预完成钢板。该工艺将有可能在模块化汽车零部件和个性化和高端产品领域率先实现工业化。新型表面技术及个性化表面产品将成为未来开发钢铁新产品的基础和高端钢铁产品的核心。     

铸造紫铜及铜合金的湿砂型模表面涂料的研究

采用“罗90—1”表面处理涂料的结果表明:操作方便,导热性好,高温不氧化,透气性强,结合不易剥落,表面光洁,保温及润滑性好,能保证金属液应有的流动速度,不需专用工具清砂。基本上解决了原紫铜及铜合金铸件表面或表层质量差的问题,从而使铜铸件表面或表层质量在原75％的基础上再提高20％。     

Coating of 6028 Aluminum Alloy Using Aluminum Piston Alloy and Al-Si Alloy-Based Nanocomposites Produced by the Addition of Al-Ti5-B1 to the Matrix Melt

The Al-12 pctSi alloy and aluminum-based composites reinforced with TiB₂ and Al₃Ti intermetallics exhibit good wear resistance, strength-to-weight ratio, and strength-to-cost ratio when compared to equivalent other commercial Al alloys, which make them good candidates as coating materials. In this study, structural AA 6028 alloy is used as the base material. Four different coating materials were used. The first one is Al-Si alloy that has Si content near eutectic composition. The second, third, and fourth ones are Al-6 pctSi-based reinforced with TiB₂ and Al₃Ti nano-particles produced by addition of Al-Ti5-B1 master alloy with different weight percentages (1, 2, and 3 pct). The coating treatment was carried out with the aid of GTAW process. The microstructures of the base and coated materials were investigated using optical microscope and scanning electron microscope equipped with EDX analyzer. Microhardness of the base material and the coated layer were evaluated using a microhardness tester. GTAW process results in almost sound coated layer on 6028 aluminum alloy with the used four coating materials. The coating materials of Al-12 pct Si alloy resulted in very fine dendritic Al-Si eutectic structure. The interface between the coated layer and the base metal was very clean. The coated layer was almost free from porosities or other defects. The coating materials of Al-6 pct Si-based mixed with Al-Ti5-B1 master alloy with different percentages (1, 2, and 3 pct), results in coated layer consisted of matrix of fine dendrite eutectic morphology structure inside α-Al grains. Many fine in situ TiAl₃ and TiB₂ intermetallics were precipitated almost at the grain boundary of α-Al grains. The amounts of these precipitates are increased by increasing the addition of Al-Ti5-B1 master alloy. The surface hardness of the 6028 aluminum alloy base metal was improved with the entire four used surface coating materials. The improvement reached to about 85 pct by the first type of coating material (Al-12 pctSi alloy), while it reached to 77, 83, and 89 pct by the coating materials of Al-6 pct Si-based mixed with Al-Ti5-B1 master alloy with different percentages 1, 2, and 3 pct, respectively.     

Improving the performance of lightning-protection cables for overhead power lines

The influence of various factors on the performance of cables used for lightning protection of power lines is investigated. The guaranteed working life of the cables is considerably increased by applying a zinc coating of elevated density and by plastic compression of linear-contact cables.     

Evaluation of the behavior of shrouded plasma spray coatings in the platen superheater of coal-fired boilers

Nickel- and cobalt-based coatings were formulated by a shrouded plasma spray process on boiler tube steels, namely, ASTM-SA210-grade A1 (GrA1), ASTM-SA213-T-11 (T11), and ASTM-SA213-T-22 (T22). The Ni-22Cr-10Al-1Y alloy powder was sprayed as a bond in each case before the final coating. The degradation behavior of the bared and coated steels was studied in the platen superheater of the coal-fired boiler. The samples were inserted through the soot blower dummy points with the help of stainless steel wires. The coatings were found to be effective in increasing resistance to degradation in the given boiler environment. The maximum protection was observed in the case of Stellite-6 (St-6) coating.     

二氧化钛粉体的硅包膜研究

为提高二氧化钛的产品性能,以硅酸钠作为包膜剂,利用化学液相沉积法对二氧化钛初品进行了致密的二氧化硅包膜。使用X射线衍射分析法分析了样品的物相结构,并研究了包膜过程中钛浆料浓度、pH值、浆料温度和硅的含量,对其白度、光泽度和吸油量的影响。得到包覆硅氧化物的优化工艺条件为：TiO2浆料的浓度为166.67g/L,pH值为10,温度为70℃,硅的比例占钛的1%。经过硅包膜的样品的白度、吸油量和耐候性等性能得到了明显改善。     

彩涂板涂层附着力时效性能的研究

通过研究找到快速预测彩涂板涂层附着力时效性能的试验方法,对实验进行系统分析,表明涂料树脂结构、基板粗糙度、基板种类和彩涂预处理工艺等均对彩涂板涂层附着力时效性能有较大影响,提出了改善彩涂板涂层附着力时效性能的途径.