SHEN Xianpu ZHANG Jie WU Baorong Central Iron and Steel Research Institute.Ministry of Metallurgical Industry.Beijing
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ChinaLEI Tingquan Harbin Institute of Technology
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Harbin.China Dept.No.13
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Central Iron and Steel Research Institute
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Ministry of Metallurgical Industry
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Beijing
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China
金属学报(英文版)
A theorectical expression for the driving force and M_(?) point of martensitic transformation has been proposed.The M_(?) values using this expression are in good agreement with that obtained experimentally.It was found that the values of M_(?) and M_(?) are not only related to the carbon content in martensite,but also to the volume fraction of ferrite.
关键词:
dual-phase steel
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null
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null
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null
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null
ZHENG Yesha WANG Zhongguang AI Suhua State Key Laboratory of Fatigue and Fracture for Materials
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Institute of Metal Research
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Academia Sinica
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Shenyang
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110015
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China
金属学报(英文版)
SEM microfractography of near-threshold fatigue crack propagation were carried out in the dual-phase steels of 3 martensite morphologies and 6 volume fractions of martensite (V_m). All of them are featured by cyclic cleavage characteristics in near-threshold region,i.e.,main- ly controlled by mode Ⅱ stress.In the higher ΔK regions,the fracture surfaces are character- ized by mixed modes including cyclic cleavage facets,two types of secondary cracks and striations,etc..The roughness-induced crack closure of fracture surface is attributed primarily to extreme high fatigue crack growth threshold values.
关键词:
dual-phase steel
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null
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null
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null
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null
DENG Rongying
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YE Zhijun Institute of Mechanics
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Academia Sinica
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Beijing
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China LIU Shuhua
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ZOU Dingqiang China Academy of Railway Sciences
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Beijing
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China Institute of Mechanics
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Academia Sinica
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Beijing 100080
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China
金属学报(英文版)
The effect of ferrite content in ferrite-martensite dual-phase steel on the initiation and prop- agation of fatigue crack and the plastic deformation at crack tip has been studied.In the range of ferrite content from 24.2 to 41.5%,the optimum seems to be 33.8%,of which the crack ini- tiation will be prolonged,the threshold value increased,the propagation rate decreased and the closure stress intensity factor increased.As the propagation force is described by effective stress intensity factor,three steels with various ferrite contents will show the same propagation behaviour on da/dN vs △ K_(eff)curve.It is shown that the closure effect increases with the decrease in △K at the fatigue crack tip.When △K equals to △K_(th),the closure effect reaches a maximum value of0.7 in a dual-phase steel with 33.8%ferrite.
关键词:
dual-phase steel
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null
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null
龚宇
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M.Hua
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J.Uusitalo
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A.J.DeArdo
钢铁钒钛
doi:10.7513/j.issn.1004-7638.2016.04.026
双相钢具有高强度的同时表现出良好的成形性能,因而被广泛应用.这类钢具有高的n值、均匀伸长率和总伸长率,不过,限制高强度双相钢应用的因素之一是在冲裁边部拉延过程中出现失效.为了开发具有良好冲裁边部塑性的高强双相钢,必须精心控制组织中硬相和软相的比例和硬度.冲裁边部拉延时出现的失效机制与微观组织密切相关(不同相的比例、硬度、尺寸和分布),发现在铁素体-马氏体界面出现裂纹萌生.研究了退火前的条件(热轧和冷轧条件)、不同的连续镀锌线工艺过程以及合金化元素对双相钢冲裁边部成形性能的影响,发现所有这三个参数都对扩孔试验中测定的冲裁边部塑性产生强烈影响.
关键词:
双相钢
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成形性能
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热轧工艺
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冷轧工艺
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扩孔率
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钒
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残余奥氏体
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回火马氏体
WANG Huaming Institute of Metal Research
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Academia Sinica
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Shenyang
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ChinaZHANG Qing Central Iron and Steel Research Institute
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Ministry of Metallurgical Industry
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Beijing
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ChinaSHAO Hesheng Beijing Graduate School
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China University of Mining and Technology
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Beijing
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China Institute of Metal Research
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Academia Sinica
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Shenyang 110015
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China
金属学报(英文版)
The role of austenite in impact-abrasion process was studied on the basis of the impact-abrasion test results of a newly developed austenite-bainitic ferrite dual-phase abrasion-resistant steel with high strength,high toughness and high strain-hardening ability. It is found that the morphology,distribution and mechanical stability,rather than the volume fraction,of austenite govern the impact abrasion behaviour.Only the appropriate amount of fine and evenly dispersed austenite with adequate mechanical stability in high strength matrices,contribute effectively to the irnpact-abrasion resistance of the materials.While large quantity of coarse austenite with poor mechanical stability,especially when it acted as a continuous matrix of the material,is extremely detrimental to impact-abrasion resistance.
关键词:
austenite
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null
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null
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null
SUN Zhengming
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WANG Zhongguang
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AI Suhua Institute of Metal Research
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Academia Sinica
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Shenyang
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China. To whom correspondence should be addressed.
材料科学技术（英）
Low cycle fatigue tests under plastic strain control were carried out with a dual-phase steel containing 23 Vol.-% martensite. Specimens hardened rapidly at first few cycles followed by a slight softening to saturation stages when cycled at higher strain amplitudes, whereas at lower strain amplitudes the specimens presented continually hardening for a long time until saturation. TEM examination of the saturation dislocation structures show that clusters, parallel walls and cells were found at low, medium and high strain amplitude, respectively. It also has been found that the martensite/ferrite interfaces did not affect the dislocation structures signi- ficantly when a specimen was fatigued at lower strain amplitude. However, the dislocation struc- ture adjacent to the two-phase boundary is dif- ferent to some extent from that in the remote regions in the ferrite when a higher strain amplitude is applied.
关键词:
cyclic deformation
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null
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null
李桂艳
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刘凤莲
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时晓光
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赵宝纯
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杨静
机械工程材料
利用Gleeble-3800型热模拟试验机测定了DP600双相钢压缩变形后动态连续冷却转变（CCT）曲线，并模拟其热轧生产工艺过程以研究轧制工艺参数对显微组织的影响，进而优化轧制工艺参数结果表明：CCT曲线上存在独立的铁素体区和贝氏体区，在两区中间存在较宽的奥氏体稳定区；轧制工艺参数对显微组织有明显的影响，试验钢850℃终轧后以1℃·s^-1的冷却速率从750℃冷至710℃后再快冷至600℃卷取所得到钢板的显微组织最优。
关键词:
双相钢
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动态CCT曲线
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优化
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工艺参数
水恒勇
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金光灿
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陈淑英
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岳旭东
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赵爱民
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唐荻
机械工程材料
通过模拟双相钢的热镀锌退火处理,研究了钢的组织和织构演变。结果表明：冷轧后试验钢加热到630℃时,在变形铁素体晶界附近出现少量再结晶晶核,当加热温度升高至690℃时,变形组织已基本消失,再结晶过程基本完成;在再结晶过程中析出的细小弥散TiC、NbC相对{111}织构的形核具有促进作用,阻碍了不利织构的形核,从而使得γ织构密度增强,α取向线上的{001}〈110〉至{112}〈110〉范围内的织构密度减弱,甚至消失;在再结晶晶核长大阶段,TiC、NbC相对{111}织构的长大具有阻碍作用,使得{001}〈110〉织构密度升高。
关键词:
双相钢
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再结晶
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织构
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退火
