高温退火对低密度中锰钢中带状δ铁素体的影响  

Effect of high temperature annealing on bandedδferrite in low-density medium manganese steels

作　　者：蒋家乐 余灿生 李云杰[1] 常智渊 康健[1] 袁国[1] JIANG Jiale;YU Cansheng;LI Yunjie;CHANG Zhiyuan;KANG Jian;YUAN Guo(State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,China;State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization,Pangang Group Research Institute Co.,Ltd.,Panzhihua 617000,China)

机构地区：[1]东北大学轧制技术及连轧自动化国家重点实验室,辽宁沈阳110819 [2]攀钢集团研究院有限公司钒钛资源综合利用国家重点实验室,四川攀枝花617000

出　　处：《轧钢》2024年第5期151-158,共8页Steel Rolling

基　　金：辽宁省科学技术计划项目(2022-MS-109);钒钛资源综合利用国家重点实验室开放基金课题项目(2021P4FZG07A)。

摘　　要：低密度钢中一般含有较高含量的Al元素,可以降低材料密度,达到更好的轻量化效果,但容易产生高温δ铁素体相,在热轧过程中形成粗大带状组织,难以通过热处理消除,最终造成钢材严重各向异性。针对上述问题,设计了一种化学成分为0.36%C-4.5%Al-7.6%Mn-0.31%V-0.31%Si-0.07%Ti的低密度中锰钢,研究了不同轧制方式(热轧和温轧)以及退火工艺参数(1000、1100、1200℃保温30 min)对高温δ铁素体演变行为的影响。结果表明:随着退火温度的升高,实验钢中带状高温δ铁素体逐渐变为短棒状,奥氏体含量占比不断下降,且高温δ铁素体尺寸不断变宽,热轧试样中高温δ铁素体的宽度由3μm增加到11μm,而温轧试样中高温δ铁素体的宽度由0.5μm增加到9μm;随着退火温度的升高,带状高温δ铁素体中的大角度晶界增多,整个粗大带状δ铁素体晶粒被分割;在1200℃退火时,热轧试样中高温δ铁素体典型晶界取向差为3.92°、13.4°和35.6°,而温轧试样中高温δ铁素体典型晶界取向差为42.2°、54.2°和58.5°。与热轧试样相比,温轧试样的短棒状高温δ铁素体更多且尺寸相对更细,温轧试样在1200℃保温30 min,带状高温δ铁素体基本全部转变为短棒状,表明温轧工艺更有利于消除带状组织。此外,直接冷却试样容易发生脆断,低温回火能提高低密度中锰钢的力学性能,可使其强塑积从0.95 GPa·%大幅提升至29.36 GPa·%。Low density steel generally contains higher content of Al elements,which can reduce material density and achieve better lightweight effects,but it is easy to generate high temperatureδferrite phase.This phase forms a coarse banded structure during the hot rolling process,which is difficult to eliminate through heat treatment,ultimately resulting in severe anisotropy of the steel.In response to the above issues,a low-density medium manganese steel with a chemical composition of 0.36%C-4.5%Al-7.6%Mn-0.31%V-0.31%Si-0.07%Ti was designed.Different rolling methods(hot rolling and warm rolling)and annealing process parameters(30 minutes insulation at 1000℃,1100℃,and 1200℃)were studied to reveal their influence on the evolution behavior of high temperatureδferrite.The results indicate that with the increase of high temperature annealing temperature,the banded high temperatureδferrite in the experimental steel gradually becomes short rod-shaped,the proportion of austenite content continuously decreases,and the size of high temperatureδferrite continues to widen.The width of high temperatureδferrite in the hot-rolled sample increases from 3μm to 11μm,while its width in the warm-rolled sample increases form 0.5μm to 9μm.As the annealing temperature increases,the large angle grain boundaries in banded high temperatureδferrite increases and the entire coarse bandedδferrite grain is segmented.When annealing at 1200℃,the typical grain boundary orientation differences of high temperatureδferrite obtained from the hot-rolled sample are 3.92°,13.4°,and 35.6°,while the grain boundary orientation differences obtained from the warm-rolled sample are 42.2°,54.2°,and 58.5°.Compared with the hot-rolled samples,the short rod-shaped high temperatureδferrite can be obtained in the warm-rolled samples with a higher volume faction and finer size.The banded high temperatureδferrites are basically all transformed into short rod-like shape in the warm-rolled sample annealed at 1200℃for 30 min,which indicates that t

关 键 词：高温退火 轧制工艺 低密度中锰钢 带状高温δ铁素体 拉伸性能 

分 类 号：TG142.1[一般工业技术—材料科学与工程] TG156.2[金属学及工艺—金属材料]