热处理对高强度冷拉钢丝塑性影响的研究.pdf

第35卷第3期
上海金属
Vol 35. No.3
16
2013年5月
SHANGHAI METALS
May,2013
热处理对高强度冷拉钢丝塑性影晌的研究
姚赞张忠铧
(宝山钢铁股份有限公司研究院,上海201900)
摘要】桥梁缆索钢丝通过高碳索氏体盘条冷拉拔生产,但镀锌和稳定化处理常导致钢
丝扭转值显著降低,无法满足缆索指标要求。主要糢拟镀锌和稳定化热处理过程对冷拉钢丝塑
性的影响并开展研究,结果显示,在420~500℃温度范围内进行27s短时间热处理对钢丝塑性
影响不明显,随460℃保温时间的延长钢丝扭转值先缓慢上升,后迅速降低,由27s时的35次
下降到72s的13次,钢丝塑性显著降低。保温初期扭转值缓慢上升主要与钢丝拉拔应力释放
有关,进一步延长保温时间钢丝硬度不断提高,塑性降低,导致钢丝扭转值显著降低,继续増加
保温时间将导致钢丝纤维状组织的渗碳体片层发生球化,硬度下降。
【关键词)热处理高强度冷拉拔镀锌钢丝塑性
EFFECT OF HEAT TREATMENT ON DUCTILMY OF
HIIGH STRENGTH COLD DRAWING STEEL WIRE
a0∠am
Zhang Zhonghua
(Research Institute, Baoshan Iron & Steel Co, Ltd, Shanghai 201900, China)
Abstract] The galvanizing process and stabilizing treatment always induced the wire ductility
decreased. The torsional properties of steel wires could not reach the cable requirement. Effect of heat
treatment on plasticity of high strength cold drawing steel wire was studied. It was found that twist
number of the wire sample did not be changed significantly after 27 s heat treatment within the
temperature range 420-500 C. As the holding time inereased at 460 C, the twist number of wires
increased firstly and then dropped quickly from 35 turns by 27 s to 13 turns by 72 s. At early stage of
heat treating the ductility improvement could be the stress releasing. Further increased holding time
would induce hardness increased and ductility decreased. Too long time treatment would lead to
cementite spheroization in the cold drawing steel wire
( Key words Heat Treatment, High Strength, Cold Drawing, Galvanized Steel Wire, Ductility
斜拉索桥和悬索桥是目前大跨径桥梁建设及提高强度,经大减面率冷拉拔加工后强度进
的两种主要形式4,其中斜拉索桥主跨跨度已一步提高。冷拉拔硬化钢丝经热镀锌处理覆盖
超过千米,我国苏通大桥跨度达到1088n为世锌层,提高耐空气腐蚀能力。为降低钢丝长期
界最长,悬索桥最大跨度达到1991m,由日本承载下的松弛率,还需进行200~400℃稳定化
明石海湾大桥创造。大跨径桥梁的建设推动桥热处理5。镀锌和稳定化过程中热影响常导
梁缆索镀锌钢丝向高强度方向不断发展,由致冷拉钢丝塑性急剧降低,钢丝扭转检测值下
1670MPa增加到1770MPa,再向1860MPa方降幅度达到80%,无法满足缆索性能指标要求。
向迈进。桥梁缆索钢丝主要依靠索氏体盘条生本文主要对热处理温度和时间对冷拉钢丝塑性
产,通过轧后快速冷却细化碳钢盘条层片结构的影响开展实验研究。
作者简介:姚赞,男,博士,主要从事金属材料研究,电话:26649455, Emaill: yaoyan@ baosteel.,com