J.B. Liu
,
L.J. Hu
,
Y.T. Wang
,
Z.Q. Liu
,
K. Miao
,
Z.L. Tian
金属学报(英文版)
The transformation behavior and microstructure development in the heat affected zone
(HAZ) of 800MPa grade ultra fine structured steel was investigated. It was found that
the HAZ has intermediate temperature transformation characteristics in a wide range
of cooling rates, with the bainite sheaves consisting of bainite ferrite plates without
carbide precipitation and retained austenite in the fast cooling regime. At relatively
high cooling rates, which corresponded to low heat inputs, the hardness of the simulated
HAZ was above that of the base metal. When the cooling rate was below 9±C/s, the
welding HAZ would have an obvious softening. The analysis of transformation rates
in continuous cooling processes was completed by numerical differential method. The
result indicated that the microstructure transformation rate of the HAZ in 800MPa
grade ultra fine structured steel changed sharply to slow speeds when the cooling time
t8=5 is longer than 7s.
关键词:
ultra fine structured steel
,
null
,
null
,
null
,
null
Y.T.Chen
,
X.Chen
,
Q.F.Ding
,
J.Zeng
金属学报(英文版)
The microstructure and the characteristics of the inclusions embedded in ferrite matrix in simulated coarse-grain heat affected zone (CGHAZ) of a Ti-Zr-treated high strength low alloy (HSLA) steel have been investigated. The microstructure of the simulated CGHAZ dominantly Consisted of intragranular acicular ferrite (IAF) combining with a small amount of polygonal ferrite (PF), widmanstiitten ferrite (WF), bainite ferrite (BF), pearlite and martensite-austenite (M-A) islands. The PF, WF and BF were generally observed at the prior austenite grain boundaries and the interlocking acicular ferrite was usually found intragranularly. It was found that the inclusions were composed of Ti2O3 ZrO2, Al2O3 locating at the center of the particles and MnS lying on the surface layer of the inclusions. The intragranular complex inclusions prorooted the acicular ferrite formation and the refinement of microstructure whilst those at prior austenite grain boundaries caused PF formation on the inclusions. The simulated CGHAZ consisting of such complicated microstructure exhibited desired mechanical properties.
关键词:
microalloyed HSLA steel
,
null
,
null
ZOU Zengda WANG Yong REN Dengyi Shandong Polytechnic University
,
Jinan
,
China
金属学报(英文版)
The structural change in heat affected zone(HAZ)and its influence on properties of welded white cast iron have been investigated by means of thermal cycle simulation technique.The structure of the white cast iron at peak temperature 800℃ was examined as cementite in pearlitic matrix,of which the hardness and impact toughness are the lowest,while the struc- ture after cyclic heating at high peak temperature is mainly cementite together with twin martensite,of which the hardness and impact toughness are rather higher.The phase bounda- ries in the structure of low hardness are smooth and regular as well as with fine precipitates. Both the cleavage and interphase fracture were revealed in the structure of low hardness,while the transgranular fracture was found in those areas of higher hardness.
关键词:
white cast iron
,
null
,
null
C. D. Lundin and C. Zhou (The University of Tennessee Knoxville
,
TN 37996
,
USA)
金属学报(英文版)
Accurate thermal simulation is the key in the simulation approach to defining the unique microstructure and properties of the HAZ regions. Simulation enables an expansion of the volume of material char- acteristic of each H4Z region to a sufficient size for property determination.The combined influence of heat input,preheat temperature, plate thickness, and widing process on HAZ microstructure and properties relics on the accurate simulation of thermal cycles corresponding to different peak temperatures using an HAZ simulator like the Gleeble.Several computer programs have been developed to predict thermal excursions in various HAZ regions during welding. Some were developed based simply on the thermal propertics of a material;whereas, others were generated on the basis of actual experimental data.A suitable HAZ thermal simulation program must be ons that can authntically duplicate an ac- tual thermal cycle experienced during welding within reasonable limies. Therefore, the similarities and differences among the HAZ thermal cycles predicted by various methodologies should be fully under- stood. A total of sts thermal cycle prediction methodologies were compared in this evaluation. It was de- termined that some HAZ simulation programs have sever limitations due to the idealized assumptions considered in their development.According to the experieare at The University of Tennessee and the comparison results in this study, the HAZ thermal simulation programs; " HAZ Calculator" and F(s, d); are recommended for accurate HAZ thermal cycle duplication.
关键词:
welding
,
null
,
null
赵文贵
,
杨汉
,
王炜
,
曲锦波
机械工程材料
采用热模拟技术，对X100管线钢在不同焊接热输入和二次热循环峰值温度下热影响区的组织与冲击韧性进行了研究。结果表明：单道次焊接热输入为15kJ·cm-1时，热影响区组织以板条贝氏体为主，具有优异的冲击韧性；而热输入为kJ·cm-1。时，以粒状贝氏体组织为主，其韧性明显恶化；双道次焊接热输入为15kJ·cm-1、二次热循环峰值温度为600℃时，热影响区具有良好的冲击韧性，但随二次热循环峰值温度升高，热影响区组织均为粗大的粒状贝氏体，其冲击韧性显著降低；焊接热输入为25kJ·cm-1时，热影响区组织均以粒状贝氏体为主，其冲击韧性均非常差。
关键词:
X100管线钢
,
焊接热输入
,
热影响区
,
组织
,
冲击性能
张英乔
,
薛飞飞
,
丁玲芳
,
张汉谦
材料热处理学报
采用气电立焊及热模拟试验研究了原油储罐用高强钢大热输入焊后热影响区、尤其是粗晶热影响区的组织与性能.结果表明,TMCP高强钢大热输入焊后粗晶区组织粗大,以板条贝氏体为主,距熔合线0.5 mm处冲击吸收功最低(77 J),冲击值完全高于标准要求(47 J).Nb0.026％ TMCP钢热影响区中导致冲击韧性严重下降的脆性M-A组元含量极少,这与钢中固溶的Nb含量较少有关,固溶Nb能降低γ-α转变温度,促使粒状贝氏体形成;Nb0.014％ RQ+T钢降低了Nb含量,同时添加少量Ti,形成Ti、Nb复合添加,热影响区M-A组元含量很少,冲击韧性接近TMCP钢.
关键词:
低合金高强钢
,
热影响区
,
大热输入
,
Nb
杨国祥
,
孔建稳
,
郭迎春
,
刀萍
,
吴永瑾
,
管伟明
贵金属
doi:10.3969/j.issn.1004-0676.2010.01.004
在开发了1种微合金配方的基础上,重点研究了真空熔炼连铸工艺,研制出1种适用于半导体分立器件和集成电路封装的高强度低弧键合金丝.结果表明:1)微合金元素得到有效添加,且分布均匀.2)铸锭组织为粗大柱状晶沿轴向分布.3)机械性能均匀稳定,Φ19 μm:断裂负荷≥5 cN,延伸率2%～6%;Φ15 μm:断裂负荷≥3 cN,延伸率2%～6%.4)与国内外相同规格键合金丝相比,具有更高的强度和更大的熔断电流.
关键词:
金属材料
,
键合金丝
,
连铸
,
熔断电流
,
热影响区
李光
,
李雪萍
,
徐学利
,
张骁勇
,
高惠临
,
刘彦明
机械工程材料
doi:10.11973/jxgccl201512019
采用部分再结晶区加速冷却的方法获得了 X100抗大变形管线钢,利用焊接热模拟技术制备了不同热影响区试样并研究了其冲击功和显微组织.结果表明：X100抗大变形管线钢具有较强的极限应变能力,其组织为粒状贝氏体和多边形铁素体；模拟热影响区试样的冲击功随热循环峰值温度的升高而下降,当峰值温度为1300℃时,冲击功为247．9 J,比母材的降低了17．3％,冲击断裂方式也从韧性断裂转为解理断裂；热循环峰值温度升高使热影响区组织发生再结晶,并且晶粒粗化,降低了其韧性.
关键词:
抗大变形管线钢
,
焊接热模拟
,
热影响区
,
冲击功
张熹
,
陈延清
,
章军
,
郭占山
,
张楠
,
雍岐龙
钢铁
通过对不同成分焊接试板进行力学性能测试、金相组织分析及热影响区第二相粒子透射电镜观察,研究了Ni,Ti两个关键合金元素对09MnNiDR钢热影响区韧性的影响规律,从而达到改善热影响区低温韧性的目的.结果表明:通过增加Ni含量改善热影响区韧性的效果不明显且成本较高,而通过将Ti质量分数由0.016％增加到0.021％～0.026％,可在不增加Ni含量的前提下使热影响区冲击韧性显著改善;Ti元素改善09MnNiDR钢热影响区韧性的机制是随着Ti含量增加高熔点第二相粒子的数量增加、尺寸细化、热稳定性提高,从而达到提高第二相粒子抑制热影响区晶粒长大,减小热影响区宽度的作用,进而改善热影响区韧性.
关键词:
合金元素
,
09MnNiDR
,
热影响区
,
韧性
张毅斌
材料开发与应用
通过Gleeble热模拟试验,研究了一种低碳铜沉淀纳米相强化铁素体钢焊接热影响区组织及性能,测试了试验钢粗晶区焊接CCT曲线.结果表明,试验钢焊接粗晶区组织主要为贝氏体,其它区域均为铁素体;铜沉淀纳米强化相随热循环不同而发生不同演变,从而引起热影响区性能变化.试验钢粗晶区冲击功及硬度与基体相当,细晶区、临界区及亚临界区冲击功均高于基体,有一定软化现象.在试验t8/5范围内,试验钢粗晶区对焊接热输入较为敏感,随t8/5的增加,组织粗化,并产生较多的粒状贝氏体组织,冲击功降低明显.
关键词:
铜沉淀
,
热影响区
,
冲击功
,
显微硬度
