论文总字数：23157字

摘 要

铝包钢丝由铝和钢丝复合而成，具有较高的抗拉强度和良好的耐蚀性，可被广泛的应用在桥梁缆索、线路铺设、工业起重等领域。在实际应用中发现铝包钢丝存在着塑性较差的现象，严重的影响了铝包钢丝的整体性能，提高铝包钢丝塑性的研究无疑是重中之重。论文通过对铝包钢丝的组织和性能进行对比和分析，探索出了提高铝包钢丝塑性的工艺。

研究结果表明：珠光体钢丝拉拔，珠光体片层取向沿着拉拔方向的渗碳体片层被拉长，偏离拉拔方向的渗碳体片层发生了弯曲，有的甚至发生了断裂。光面钢丝和铝包钢丝金相组织状态都呈纤维状，无明显区别。冷拔状态下，光面钢丝比铝包钢丝具有更高的延伸率，即光面钢丝的塑性更好。铝包钢钢丝低温退火后，钢丝强度下降，延伸率显著提高。退火8小时，钢丝抗拉强度由1453MPa降低至1408MPa，延伸率由1.5%升至3.7%。而与抗拉强度相反，钢丝硬度由380HV左右，升高至500HV。从原始钢丝到退火3h、退火8h的钢丝的组织对比发现，原始钢丝中存在大量位错，随着退火时间的延长，铁素体中的位错减少，退火3h时尚还存在位错缠结，退火8h时铁素体中位错基本回复消除。退火3h时，渗碳体仍保持片层，已出现晶化的特征，而铁素体片发生了部分回复；退火时间延长至8h时，整个渗碳体片层出现破裂，晶化特征十分明显，铁素体回复尺寸变大，明显可看到等轴状铁素体晶粒。铝包钢丝的强度由位错机制占据主导作用，随着退火时间的延长，位错密度的下降，导致抗拉强度下降。铝包钢钢丝延伸率的提高来源于钢丝中铁素体发生了明显的回复，位错密度降低。

关键词：拉拔，变形，组织

Abstract

Aluminum-clad steel wire is composed of aluminum and steel wire, has high tensile strength and good corrosion resistance, and can be widely used in bridge cables, line laying, industrial lifting and other fields. In actual application, it is found that there is a poor plasticity in the aluminum-clad steel wire, which seriously affects the overall performance of the aluminum-clad steel wire, and the research on the plasticity of the aluminum-clad steel wire is undoubtedly the most important issue. The paper compares and analyzes the microstructure and properties of aluminum-clad steel wire, and explores the process of improving the plasticity of aluminum-clad steel wire.

The results show that the pearlite steel wire drawing and the pearlite sheet orientation are elongated along the drawing direction of the cementite sheet. The cementite sheets that deviate from the drawing direction are bent and some of them even break. . Both the smooth steel wire and the aluminum-clad steel wire have a fibrous state with no obvious difference. In the cold-drawing state, the smooth steel wire has a higher elongation than the aluminum-clad steel wire, that is, the plasticity of the smooth steel wire is better. After the low-temperature annealing of Baosteel steel wire, the strength of the steel wire decreased, and the elongation increased significantly. After annealing for 8 hours, the tensile strength of the steel wire decreased from 1453 MPa to 1408 MPa, and the elongation increased from 1.5% to 3.7%. In contrast to the tensile strength, the wire hardness increases from about 380 HV to 500 HV. From the original steel wire to annealed 3H, the microstructure of steel wires annealed for 8 hours shows that there are a large number of dislocations in the original steel wire. As the annealing time prolongs, the dislocations in the ferrite decrease, and the annealing 3H fashion still has dislocation tangles. After annealing at 8H, the dislocations in the ferrite were basically recovered and the 3H was eliminated. As a result, the cementite still maintained the lamellae, and the crystallization occurred. However, the ferrite was partially recovered. When the annealing time is prolonged to 8H, the entire cementite sheet is cracked, the crystallization characteristics are very obvious, and the ferrite recovery size becomes large, and the equiaxed ferrite grains can be clearly seen. The strength of the aluminum-clad steel wire is dominated by the dislocation mechanism. As the annealing time increases, the dislocation density decreases and the tensile strength decreases. The increase of the elongation rate of the aluminum-clad steel wire stems from the obvious recovery of ferrite in the steel wire and the decrease of the dislocation density.

Key words: drawing, deformation, tissue

目 录

摘 要 I

Abstract II

第一章 绪 论 1

1.1引言 1

1.2铝包钢丝概述 1

1.2.1铝包钢丝简介 1

1.2.2铝包钢丝特点 1

1.2.2铝包钢丝的应用 2

1.3铝包钢丝的生产工艺流程 3

1.3.1钢丝的预处理 3

1.3.2钢丝热处理 4

1.3.3包覆拉丝 4

1.4退火工艺 5

1.4.1退火概述及特点 5

1.4.2退火工艺的分类 5

1.5选题目的及主要研究内容 5

1.5.1研究目的 5

1.5.2主要研究内容 6

第二章 实验设备与试验方法 7

2.1原材料 7

2.2低温退火处理 7

2.3实验方法 8

2.3.1金相显微组织观察 8

2.3.2扫描电镜显微组织观察 8

2.3.3透射电镜显微组织观察 8

2.3.4拉伸测试 9

2.3.5硬度测试 10

第三章 铝包钢丝和光面钢丝的显微组织和拉伸性能分析 11

3.1光面钢丝与铝包钢丝金相组织分析 11

3.2钢芯金相组织SEM分析 12

3.3光面钢丝与铝包钢丝拉伸性能对比 13

3.4本章小结 14

第四章 低温退火处理对铝包钢丝显微组织和性能的影响 15

4.1铝包钢丝低温退火拉伸性能分析 15

4.2铝包钢丝拉伸性能分析 16

4.3铝包钢丝硬度分析 17

4.3.1钢芯硬度分析 17

4.3.1铝层硬度分析 17

4.4铝包钢丝金相组织分析 19

4.5铝包钢丝钢芯SEM分析 20

4.6铝包钢丝钢芯TEM分析 21

4.6.1原始铝包钢丝钢芯TEM分析 21

4.6.2低温退火3h铝包钢丝钢芯TEM分析 22

4.6.3低温退火8h铝包钢丝钢芯TEM分析 23

4.7本章小结 24

第五章 总结及展望 25

5.1总结 25

5.2展望 25

参考文献 26

致 谢 27

第一章 绪 论

1.1引言

在人类社会发展过程中，钢铁的使用历史悠久，因为其良好的加工性能以及在不同的加工状态下表现出的多样的机械性能，不论是人类生活中还是工业领域都能看到钢铁的身影，并发挥着巨大的作用，是引起时代变革和人类进步的一种最基础的材料。

钢丝是钢铁材料的一种常用品种，是以热轧金属盘条为原材料，通过去皮、烘干、热处理、酸洗、拉拔、表面处理等一系列加工工序而制成的^[1]。传统的钢丝产品大多应用在人类生活和一些要求较低的工业作业中，比如做成各种孔型的金属筛网和工业起重的钢丝绳等。随着我国工业的进步以及各种基建工程的大幅度开展，传统钢丝已经不能满足越来越高的要求，研究更高强度、综合性能优良的新型钢丝迫在眉睫。

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