CN107142425A - 780MPa级双相高强镀锌带钢及其制备方法 - Google Patents
780MPa级双相高强镀锌带钢及其制备方法 Download PDFInfo
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Abstract
本发明公开了一种780MPa级双相高强镀锌带钢及其制备方法,其包括加热、热轧、冷轧、连续镀锌、光整和钝化工序;所述镀锌带钢基板成分的质量百分含量为:C≤0.20%,Si≤0.50%,Mn 1.70~2.50%,Cr 0.40~0.70%,P≤0.012%,S≤0.002%,Als≤0.070%,其余为Fe和不可清除的杂质。本镀锌带钢采用添加Mn和Cr元素来提高钢的淬透性,增加快冷过程中马氏体的生成比例;其成品具有良好的成型性能、机械性能和抗腐蚀性能,抗拉强度在780MPa以上,且生产简单,成本较低。本方法采用新的成分设计,通过控制各工序的工艺参数进行制备,大大降低了生产成本,提高了合格率;具有生产简单,实施难度小,成本低,生产稳定,具有烘烤硬化效应和屈强比低等特点。
Description
技术领域
本发明涉及一种镀锌带钢,尤其是一种780MPa级双相高强镀锌带钢及其制备方法。
背景技术
随着汽车工业发展、汽车产量与保有量的增加,必然面临油耗、安全和环保三方面的问题。汽车轻量化越来越得到业界的重视,高强钢在汽车用钢中的比例越来越高;同时带钢的耐蚀性决定汽车的使用寿命,目前国内热镀锌带钢的产量逐年增加。
DP系列高强钢镀锌汽车板产品的显微组织由铁素体和马氏体组成,马氏体组织以岛状弥散分布在铁素体的基体上。铁素体较软,使钢材具备较好的成形性;马氏体较硬,使钢材具备较高的强度。随着马氏体所占比例的升高其强度越高。根据用途,可生产不同强度级别和不同屈强比(YS/TS) 的双相钢。双相钢易切割成形,可用传统的焊接方法焊接。其具备无屈服延伸、无室温时效、低屈强比、高加工硬化指数和烘烤硬化值的特点。
高强镀锌带钢的生产过程中,工艺参数的控制决定着带钢的板型、表面质量和力学性能。同时由于Mn和Si元素的添加量较多,在退火过程中,Mn和Si元素向表面富集,生成氧化物,再后续还原过程中不能被还原,造成带钢表面与纯锌的粘附性降低,甚至会造成锌层的漏镀。常规780MPa级双相高强镀锌带钢需要添加Ti、Nb和Mo等合金元素,造成其生产成本较高。
发明内容
本发明要解决的技术问题是提供一种低成本的780MPa级双相高强镀锌带钢;本发明还提供了一种工艺简单的780MPa级双相高强镀锌带钢的制备方法。
为解决上述技术问题,本发明基板成分的质量百分含量为:C≤0.20%,Si≤0.50%,Mn 1.70~2.50%,Cr 0.40~0.70%,P≤0.012%,S≤0.002%,Als≤0.070%,其余为Fe和不可清除的杂质。
本发明方法包括加热、热轧、冷轧、连续镀锌、光整和钝化工序;所述镀锌带钢基板成分的质量百分含量如上所述。
本发明方法所述热轧工序:精轧终轧温度为875~905℃,卷取温度为660~700℃。
本发明方法所述冷轧工序:冷轧压下率≥75%。
本发明方法所述连续镀锌工序:均热温度为770~830℃;先缓冷至690~730℃,再快冷至420~450℃;镀锌温度458~462℃。所述连续镀锌工序中,均热时间为100~200s,缓冷冷却速率10~20℃/s,快冷冷却速率35~65℃/s,镀锌时间5~15s。所述连续镀锌工序包括预热段、加热段1和加热段2;所述预热段露点为-5℃~+15℃,加热段1露点为-5℃~+10℃,加热段2露点为-5℃~-30℃。
本发明方法所述光整工序:光整延伸率为0.2%~1.2%。
本发明方法所述钝化工序:钝化温度80~120℃。
本发明方法所述加热工序:加热温度为1250~1320℃,总加热时间为90~180min。
采用上述技术方案所产生的有益效果在于:本发明采用添加Mn和Cr元素来提高钢的淬透性,增加快冷过程中马氏体的生成比例;并在带钢表面镀上一层纯锌层,有效的阻碍了基体的腐蚀,其成品具有良好的成型性能、机械性能和抗腐蚀性能,抗拉强度在780MPa以上,且生产简单,成本较低,具有很好的应用前景。
本发明方法采用添加Mn和Cr元素来提高钢的淬透性,增加快冷过程中马氏体的生成比例;但是Si和Mn元素向表面富集,容易产生漏镀,本方法通过调整炉区的露点值,避免漏镀的产生,并在带钢表面镀上一层纯锌层,有效的阻碍了基体的腐蚀,其成品具有良好的成型性能、机械性能和抗腐蚀性能,抗拉强度在780MPa以上,且生产简单,成本较低。本方法采用新的成分设计,通过控制各工序的工艺参数进行制备,大大降低了生产成本,提高了合格率;具有生产简单,实施难度小,成本低,生产稳定,具有烘烤硬化效应和屈强比低等特点。
具体实施方式
下面结合具体实施例对本发明作进一步详细的说明。
实施例1~10:本780MPa级双相高强镀锌带钢采用下述方法制备而成。
(1)各实施例采用表1所述化学成份的连铸坯进行生产。
表1:实施例1-10连铸坯的化学成分(wt.%)
表1中,余量为Fe和不可清除的杂质。
(2)上述连铸坯经加热、热轧、冷轧、连续镀锌、光整和钝化工序制备得到所述的双相高强镀锌带钢。加热工序采用步进式加热炉加热,连铸坯的加热温度为1250~1320℃,总加热时间为90~180min。热轧工序的精轧终轧温度为875~905℃,卷取温度为660~700℃。冷轧工序的冷轧压下率为75%及以上。连续镀锌工序的均热温度为770~830℃,缓冷结束温度690~730℃,快冷结束温度420~450℃,镀锌温度(锌液温度)458~462℃;所述连续镀锌工序包括预热段、加热段1和加热段2;所述预热段露点为-5℃~+15℃(目标值+5℃),加热段1露点为-5℃~+10℃(目标值+3℃),加热段2露点为-5℃~-30℃(目标值-20℃);均热时间为100~200s,缓冷冷却速率10~20℃/s,快冷冷却速率35~65℃/s,镀锌时间5~15s。光整工序的光整延伸率为0.2~1.2%。钝化工序的钝化温度为80~120℃。各实施例中加热、热轧、冷轧、光整和钝化工序的工艺参数见表2,连续镀锌的工艺参数见表3。
表2:各实施例加热、热轧、冷轧和光整工序的工艺参数
表3:各实施例连续镀锌的工艺参数
(3)各实施例所得镀锌带钢进行性能检测,取横向试样,试样标距为80mm,平行段的宽度为25mm,检测得到的力学性能见表4。
表4:实施例1-10所得产品的力学性能
Claims (10)
1.一种780MPa级双相高强镀锌带钢,其特征在于,其基板成分的质量百分含量为:C≤0.20%,Si≤0.50%,Mn 1.70~2.50%,Cr 0.40~0.70%,P≤0.012%,S≤0.002%,Als≤0.070%,其余为Fe和不可清除的杂质。
2.一种780MPa级双相高强镀锌带钢的制备方法,其特征在于:其包括加热、热轧、冷轧、连续镀锌、光整和钝化工序;所述镀锌带钢基板成分的质量百分含量为:C≤0.20%,Si≤0.50%,Mn 1.70~2.50%,Cr 0.40~0.70%,P≤0.012%,S≤0.002%,Als≤0.070%,其余为Fe和不可清除的杂质。
3.根据权利要求2所述的780MPa级双相高强镀锌带钢的制备方法,其特征在于,所述热轧工序:精轧终轧温度为875~905℃,卷取温度为660~700℃。
4.根据权利要求2所述的780MPa级双相高强镀锌带钢的制备方法,其特征在于,所述冷轧工序:冷轧压下率≥75%。
5.根据权利要求2所述的780MPa级双相高强镀锌带钢的制备方法,其特征在于,所述连续镀锌工序:均热温度为770~830℃;先缓冷至690~730℃,再快冷至420~450℃;镀锌温度458~462℃。
6.根据权利要求5所述的780MPa级双相高强镀锌带钢的制备方法,其特征在于,所述连续镀锌工序中,均热时间为100~200s,缓冷冷却速率10~20℃/s,快冷冷却速率35~65℃/s,镀锌时间5~15s。
7.根据权利要求5所述的780MPa级双相高强镀锌带钢的制备方法,其特征在于:所述连续镀锌工序包括预热段、加热段1和加热段2;所述预热段露点为-5℃~+15℃,加热段1露点为-5℃~+10℃,加热段2露点为-5℃~-30℃。
8.根据权利要求2所述的780MPa级双相高强镀锌带钢的制备方法,其特征在于,所述光整工序:光整延伸率为0.2%~1.2%。
9.根据权利要求2所述的780MPa级双相高强镀锌带钢的制备方法,其特征在于,所述钝化工序:钝化温度为80~120℃。
10.根据权利要求2-9任意一项所述的780MPa级双相高强镀锌带钢的制备方法,其特征在于,所述加热工序:加热温度为1250~1320℃,总加热时间为90~180min。
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CN113958777A (zh) * | 2021-09-10 | 2022-01-21 | 浙江荣凯科技发展股份有限公司 | 一种化工用高强度连续管及其制备方法 |
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CN104328348A (zh) * | 2014-10-13 | 2015-02-04 | 河北钢铁股份有限公司邯郸分公司 | 800MPa级冷轧双相钢及其生产方法 |
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CN109439873A (zh) * | 2018-11-28 | 2019-03-08 | 北京首钢冷轧薄板有限公司 | 一种1000MPa级马氏体汽车用钢的工艺控制方法 |
CN113958777A (zh) * | 2021-09-10 | 2022-01-21 | 浙江荣凯科技发展股份有限公司 | 一种化工用高强度连续管及其制备方法 |
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