材料期刊网

Effects of B and Ti on the Toughness of HSLA Steel Weld Metals

SI Zhongyao WANG Zhaoqing LIU Peng YU Dehua LIU Lei ** Institute of Metal Research , Academia Sinica , Shenyang , 110015 , China*** Capital Iron and Steel Company , Beijing , 100053 , China+ To whom correspondence should be addressed

材料科学技术（英）

Effects of microalloying Ti and B on the microstructures and low temperature toughness of manual metal arc (MMA) deposits were investi- gated.Weld metals containing 200-300 ppm Ti and 29-60 ppm B deposited by manual coated elec- trodes provided an optimum low temperature toughness.The addition of B in weld metals low- ered the γ→α transformation temperature which promoted the acicular ferrite (AF) transformation. Solid solutioned B suppressed grain boundary ferrite as well as side plate ferrite formation and benefited the acicular ferrite formation.Titanium protected B from oxidizing as well as nitriding and formed Ti-Mn silicate inclusions.Ultra-high volt- age electron microscope analyses showed that TiO structure in the Ti-Mn silicate inclusions was the favorable nucleation site for acicular ferrite forma- tion.

关键词: toughness , null , null , null , null

Influence of vanadium on mechanical properties and microstructure of simulated heat affected zone of Nb-V Treated HSLA steels

Y.T. Chen

金属学报(英文版)

The simulated heat affected zone (HAZ) of the high strength low alloy (HSLA) steels containing 0, 0.047, 0.097 and 0.151% vanadium, respectively, were studied with Gleeble-2000 thermomechanical simulator to determine the influence of vanadium addition on the mechanical properties of the HAZ. The HAZ simulation involved reheating the samples to 1350oC, and then cooling to ambient temperature at a cooling rate of 50 oC/s ranging from 800 to 500oC (Dt8/5=60 s). The mechanical properties including tensile strength and -20 oC impact toughness were conducted. The microstructures of the base steel and the simulated HAZs were investigated using optical microscope, scanning electron microscope(SEM) and transmission electron microscope(TEM). Based on the systematic examination, the present work confirmed that about 0.05% vanadium addition to low carbon low alloy steels resulted in expected balance of strength and toughness of the HAZ. And more than 0.10% levels addition led to detrimental toughness of the HAZ. SEM study showed that the simulated 0.097% and 0.151%V HAZs consisted of more coarse ferrite plates with greater and more M-A constituents along austenite grain and ferrite plate boundaries. The impact fracture surfaces of the simulated 0.097% and 0.151%V HAZs showed typically brittle mode with predominant cleavages. The size of the facet in the fracture surface increased with increasing vanadium level from 0.097% to 0.151%. As a result, the simulated 0.151%V HAZ has the lowest impact toughness of the four specimens.

关键词: Vanadium , null , null

MODELING OF ISOTHERMAL PRECIPrrATION KINETICS IN HSLA STEELS AND ITS APPLICATION

X.M.Zhao , D.Wu , L.Z.Zhang , Z.Y.Liu

金属学报(英文版)

Microalloying elements in high-strength low-alloy steels, such as Nb, Ti and V, precipitate during hot-rolling processes. On the basis of classical theory of nucleation and growth, quantitative modeling of isothermal precipitation was developed, which was tested by the stress relaxation method, the calculated precipitation-time-temperature curve is in good agreements with the measured results, then the model was applied to predict the precipitation behavior during continuous cooling.

关键词: isothermal precipitation , null , null

Controlled Rolling and Controlled Cooling Technology of Ultra-High Strength Steel with 700 Mpa Grade

钢铁研究学报(英文版)

关键词:

亚温淬火下组织形态对高强低合金钢冲击韧性的影响

康健 , 袁国 , 王国栋

材料热处理学报

以一种高强度低合金钢为研究对象,分析了淬火-亚温淬火-回火(RQ-IQ-T)工艺与控轧控冷-亚温淬火-回火(TMCP-IQ-T)工艺对组织演变及力学性能的影响,并对不同显微组织特征实验钢的冲击断裂行为进行讨论.结果表明:RQ-IQ-T工艺获得的显微组织由条状铁素体与回火马氏体构成,试样-40℃冲击功达到205 J;而TMCP-IQ-T工艺获得的显微组织则由块状铁素体与回火马氏体组成,试样具有较高的强度,但冲击功相对较低,仅为149 J.冲击裂纹在条状铁素体中扩展包括沿长轴方向和剪切条状铁素体两种方式;在块状铁素体中主要以穿晶方式进行扩展.经RQ-IQ-T工艺获得的条状铁素体与回火马氏体双相组织对裂纹扩展具有较大的阻碍作用,有利于冲击韧性的提高.

关键词: 亚温淬火 , 高强度低合金钢 , 显微组织 , 冲击韧性 , 裂纹扩展

Ac1附近临界区处理对785 MPa级船体钢屈强比的影响

杨景红 , 薛钢 , 蒋颖 , 王任甫

材料热处理学报

通过对一种785 MPa级低合金高强度船体钢Ac1附近临界区热处理试样的性能测试,研究了Ac1附近临界区处理对其性能及屈强比的影响,采用光学和透射电镜观察了试验钢的微观组织,分析了试验钢性能与微观组织结构的相关性.结果表明:Ac1附近临界区热处理改变了试验钢的微观组织结构,热处理后钢板组织为回火马氏体基体上分布细小马氏体/M-A组元、碳化物、少量残留奥氏体、细小弥散的纳米铜析出相;多元复相组织中的转变马氏体及残留奥氏体降低了试验钢的屈服点,提高了钢板的加工硬化率和均匀伸长率,降低了试验钢的屈强比;同时,细化的组织结构保证了材料的塑韧性.

关键词: 热处理 , 低合金高强度钢 , 屈强比 , 加工硬化

Ni-Cr-Mo-B低合金钢模拟焊接热影响区的组织和性能

王小勇 , 潘涛 , 苏航 , 李向阳

材料热处理学报

用Gleeble-3800热模拟机对Ni-Cr-Mo-B低合金高强度钢进行不同焊接热输入条件的下热模拟试验,研究了模拟焊接热影响区的组织和性能,探讨了不同热输入条件（对应不同的t8/5）对钢中微观组织及形态的影响以及组织与低温韧性的关系。结果表明：随着热输入能量的增加,此类钢焊接热影响区的低温韧性呈现先增后降的规律。当以中等焊接热输入施焊,在热影响区形成贝氏体/马氏体复相组织,先形成的贝氏体对原始奥氏体晶粒的分割作用,使后生成的板条马氏体具有更细的板条束,从而获得最佳的低温韧性。而低热输入时形成全马氏体组织,高热输入时获得一定量的粒状贝氏体,两种组织的低温韧性均低于贝氏体/马氏体的复相组织。

关键词: 低合金高强度钢 , 焊接热影响区 , 冲击韧性 , 复相组织 , 粒状贝氏体

Effect of Heat Input on Microstructure and Toughness of Coarse Grain Heat Affected Zone in Nb Microalloyed HSLA Steels

钢铁研究学报(英文版)

关键词:

Q345B结构钢的热压缩变形行为及流变应力模型

董方 , 宿成 , 张寄东

钢铁

利用Gleeble-1500D热模拟试验机对钒、钛、铌微合金化Q345B低合金高强度结构钢（HSLA）进行了高温单道次压缩试验。测量了不同变形温度和变形速率下该钢的变形行为,分析了各变形参数对该钢动态再结晶和变形抗力的影响,得出动态再结晶激活能为451.47 kJ/mol。并且建立了高温变形抗力的分段函数流变模型,该模型计算结果与试验值吻合较好。

关键词: HSLA钢 , 动态再结晶 , 流变应力 , 应变 , 流变模型

1200 MPa级HSLA钢的SH－CCT曲线及其热影响区组织与性能

徐彬 , 马成勇 , 李莉 , 齐彦昌 , 彭云

材料科学与工艺 doi:10.11951/j.issn.1005-0299.20160305

为在工程应用中对焊接工艺的合理选取与制定提供理论和试验依据，采用焊接热模拟技术研究了800～500℃冷却时间（ t8／5）对1200 MPa级低合金高强钢焊接热影响区粗晶区（ CGHAZ）显微组织和性能的影响．结果表明：t8／5为6～20 s时，该钢热影响区的粗晶区组织为板条马氏体，硬度为477～456 HV5；随着冷却时间的延长，组织中开始出现板条贝氏体，在t8／5为60 s时硬度下降到380 HV5；当t8／5为60～600 s时，粗晶区组织为板条贝氏体和粒状贝氏体，硬度为380～300 HV5；t8／5＞600 s时粗晶区组织主要为粒状贝氏体，硬度为300～315 HV5．试验钢碳当量为0．626％，冷裂纹敏感系数为0．335％，说明其淬硬倾向较大，焊接热影响区容易产生裂纹．

关键词: 焊接热模拟 , 低合金高强钢 , 焊接热影响区 , 显微组织 , 硬度