回火温度对600MPa级低碳贝氏体钢组织和力学性能的影响.pdf

第31卷第8期北京科技大学学报Vol.31No.8
2009年8月JournalofUniversityofScienceandTechnologyBeijingAug.2009

回火温度对600MPa级低碳贝氏体钢组织和力学性
能的影响

陈林恒1)康永林1)黎先浩1)温德智2)刘国民2)

1)北京科技大学材料科学与工程学院,北京1000832)湖南涟源钢铁集团有限公司,娄底417009

摘要利用扫描电镜(SEM)、透射电镜(TEM)等实验方法,研究了不同回火温度对屈服强度600MPa级Fe-Mn-Nb-B系
低碳贝氏体高强钢组织和性能的影响.结果表明:回火温度对屈服强度和抗拉强度均有较大影响.各回火温度下的低碳贝氏
体钢性能与回火前相比,屈服强度均有不同程度的升高,而抗拉强度则均有不同程度的下降;600℃回火时屈服强度比回火前
高出105MPa.随着回火温度的升高,屈服强度先上升后又略有下降并在600℃时达到最大值,抗拉强度下降明显,伸长率略
有升高,屈强比升高.分析认为:回火前后力学性能的变化主要与回火后有更多弥散的尺寸在20nm以下的新的细小粒子析
出以及马氏体占绝大多数的大块M/A岛的分解和发生位错多边形的回复有关.
关键词低碳贝氏体钢;回火温度;析出;M/A岛
分类号TG142.2;TG156.5

Effectoftemperingtemperatureonthemicrostructureandmechanicalproperties
of600MPagradelowcarbonbainiticsteel

CHENLin2heng1),KANGYong2lin1),LIXian2hao1),WENDe2zhi2),LIUGuo2min2)

1)SchoolofMaterialsScienceandEngineering,UniversityofScienceandTechnologyBeijing,Beijing100083,China
2)HunanLianyuanIronandSteelCo.Ltd.,Loudi417009,China

ABSTRACTTheeffectsoftemperingtemperatureonthemicrostructureandmechanicalpropertiesof600MPagradelowcarbon
bainiticsteelbelongedtoFe2Mn2Nb2Bserieswereinvestigatedbyutilizingscanningelectronmicroscopy(SEM)andtransmissionelec2
tronmicroscopy(TEM).Theresultsshowthattemperingtemperaturehasconsiderableinfluenceonboththeyieldstrengthandthe
tensilestrength.Theyieldstrengthincreaseswithincreasingtemperingtemperaturewhilethetensilestrengthhasanadverselaw.In
comparisonwiththeas2receivedsteel,theyieldstrengthofthesteeltemperedat600℃increases105MPa.Withtheincreaseintem2
peringtemperature,theyieldstrengthincreasefirstandhasaslightdeclineafteritreachesthehighestpointat600℃,thetensile
strengthdecreasessignificantly,theelongationincreasesslightlyandtheyieldratioincreasesalso.Throughanalysisitisconcluded
thatthemajorchangeofmechanicalpropertiesaftertemperinghasaconnectionwithdispersiveprecipitateswiththesizeoflessthan
20nm,thedecompositionoflargeM/Aislandsinwhichmartensitehasalargeproportionandthereversionofdislocationsandpoly2
gonferrite.
KEYWORDSlowcarbonbainiticsteel;temperingtemperature;precipitati