轧后冷却制度对X100管线钢组织与性能的影响

 采用热模拟试验机研究了X100管线钢的连续冷却相变规律和控轧控冷工艺中不同冷却制度下微观组织特征及显微硬度的变化规律。结果表明,随着冷却速度的升高和终冷温度的降低,试验钢微观组织逐渐细化,其中粒状贝氏体含量不断减少而板条贝氏体含量逐渐增加,显微硬度也随之增加;M/A岛含量随着冷却速度的增加而减小,随着终冷温度的降低呈现先降低后增加的“V”型趋势,且在340℃获得最低值。     

采用控轧控冷工艺试制X100管线钢的研究

在实验室采用控轧控冷工艺轧制X100管线钢,并利用金相显微镜、扫描电镜、透射电镜等研究了其力学性能、显微组织、EBSD及析出物,实验结果表明,采用控轧控冷两阶段轧制工艺,在终轧温度为806 ℃,终冷温度在415 ℃,冷却速度为18.6 ℃/s时,实验钢综合性能较终冷温度为491 ℃时良好。经EBSD分析该实验钢大角度晶界百分比含量达78.8%,透射电镜下观察该实验钢析出物随尺寸增大形状规则化,且随尺寸增大,Nb/Ti降低。     

Process Control for Structure of Martensite/Austenite Islands of 15.3 mm X100 Pipeline Steel in BX Steel

This paper mainly studies the influence of deformation amount and cooling rate,which existed in X100 pipeline steel rolled at 2300mm rolling mill in BX STEEL,on morphology,size relations and distribution of M/A islands of steel plate structure.Experimental results show that structures of M/A islands are homogenized and refined under the conditions of appropriately increasing the deformation amount in non-recrystallization region on basis of rational deformation amount in recrystallization region and cooling rate after deformation,respectively.Finally,according to the actual situation of 2300mm hot rolling mill,this paper gives rational deformation amount and cooling rate used to obtain ideal structure of M/A islands.     

TM8带钢控轧控冷工艺实践

介绍了天铁集团炼钢厂带钢车间用控轧控冷工艺生产TM8带钢的情况,对影响产品性能的因素进行了分析。通过控轧控冷工艺提高了带钢综合性能,节约了生产成本。     

合金成分和奥氏体变形对粒状贝氏体和粒状组织转变的影响

在Gleeble热模拟试验机上研究了低碳Mn-B系贝氏体钢的组织转变,分析了合金成分和奥氏体变形对粒状贝氏体及粒状组织转变的影响。结果表明,在相同冷却条件下,添加铬、铌元素后更利于粒状贝氏体组织的转变;在奥氏体未再结晶区,变形对粒状贝氏体及粒状组织的转变有明显的影响,随奥氏体变形温度的降低以及变形程度的增加,组织由粒状贝氏体向粒状组织变化。     

Microstructures and Mechanical Properties of X100 Pipeline Steel Strip简

Dynamic CCT （continuous cooling transformation） curves and effects of microstructures and M/A islands of X100 hot rolled strip on mechanical properties were studied by means of a thermal simulator, a scanning electron mi- croscope （SEM）, a transmission electron microscope （TEM）, a digital micro-hardness tester and Image-Pro Plus analysis software. The results show that high contents of C and Mo can make transformation lines of acicular ferrite and bain- ite shift rightward. High Mo tested strip has higher strength and micro-hardness and lower toughness than the other one because lath bainite appears instead of quasi-polygonal ferrite. Tested strip with granular bainite, lath bainite and M/A islands has better mechanical properties and in the microstructures lath bainite content is around 36.50% and M/A islands are fine and disperse in the matrix.     

Effect of Alloying Element on Process Control of High Strength Hot-Rolled Dual Phase Steel

Microstructure evolution of C-Si-Mn-Nb,C-Si-Mn-Cr-Nb and C-Si-Mn-Cr-Mo-Nb tested steels during step-cooling process were studied.Effects of alloying element and process data on microstructure and mechanical properties of high strength Nb bearing DP steel were analyzed,to illustrate the relationship between alloy composition design and process control stability during DP microstructure and property control.It is shown that,700MPa ferrite and martensite DP steel is obtained respectively by three kinds of composition tested steel under different step-cooling process.C-Si-Mn-Nb steel with simple alloying design of low cost is provided with low hardenability,and has strong process sensibility during microstructure evolution.DP microstructure of ferrite and martensite of C-Si-Mn-Nb steel just can be obtained by coiling at low temperature of 250℃.The process control stability of C-Si-Mn-Cr-Nb steel is stronger than that of C-Si-Mn-Nb steel,to obtain DP microstructure by coiling at low temperature.C-Si-Mn-Cr-Mo-Nb steel with complex alloying design of high cost is provided with excellent process control stability.Alloy element Mo can promote stabilizing of metastable austenite to obtain F+M DP microstructure by coiling at medium temperature of 600℃.     

Alloying Design for High Wear-Resistant Cast Hot-Forging Die Steels

The alloying design of cast hot-forging die steels was analyzed. The relationship of the life of cast hot-forging dies with the failure patterns was studied. The thermal wear resistance was believed to be the key property for the alloying design of cast hot-forging die steels. The alloying design parameters were selected and optimized for the cast hot-forging die steel with high wear resistance. The wear resistance of the optimized cast die steel was evaluated in comparison with commercial H13 steels and 3Cr2WSV steel. In the new cast hot-forging die steel, VC is predominant carbide with Cr and Mo as the main solution elements in α-Fe. It is found that the cast die steel has significantly lower wear rate than normal H13 steel and 3Cr2W8V steel, almost the same as that of high purity H13 steel. The high wear resistance of the new cast hot-forging die steel can be attributed to its reasonable alloying design and nonsensibility to the detrimental function of S and P.     

热轧条件下Nb-Mo及Nb微合金化X100管线钢的组织特征及力学行为

采用实验室热轧、显微分析及力学性能检测手段,对Nb-Mo及Nb微合金化X100管线钢在不同工艺条件下的组织特征及力学行为的变化规律进行了研究.分析结果表明:工艺参数对Nb-Mo复合成分试验钢影响较大,控轧控冷工艺条件下Nb-Mo及Nb微合金化X100管线钢力学性能均能达到API 5L中X100管线钢要求,但Nb-Mo复合成分力学性能富余量较大,性能较优.随冷却速度的增加及终冷温度的降低,试验钢强度增加,韧性及塑性恶化.板条马氏体与贝氏体复相组织较板条马氏体可大大提高试验钢的塑性及低温冲击韧性.     

热轧工型钢控冷工艺及温度场研究

首先采用有限元分析软件Workbench对不同控冷工艺下热轧工型钢进行了温度场模拟,从中找到了较优的控冷工艺:初始温度900℃,空冷5s后水冷5s[水流密度不同,其中R角强冷为5.5L/(m2·s),腿部3.5L/(m2·s),其余的为4.5L/(m2·s)],最后空冷回火5s;然后,利用温度测量仪对温度场进行了验证,经过验证理论值和模拟值基本相符。此方案下的组织和性能得到了极大的改善,为进一步优化控冷工艺提供了理论基础。     

TMCP工艺生产X100管线钢的微观组织及强化机理

利用扫描电镜（SEM）、透射电镜（TEM）对TMCP工艺生产的X100管线钢的显微组织进行了观察与分析,并在此基础上对X100管线钢的强化机理进行了研究。结果表明：TMCP工艺生产X100管线钢是可行的;X100管线钢的显微组织以粒状贝氏体为主,同时弥散分布着大量细小的M／A岛和少量的板条贝氏体;X100管线钢的强化机...     

终轧和终冷温度对X65/X70中厚板管线钢屈强比的影响

通过对不同终轧、终冷温度条件下X65/X70中厚板管线钢的板屈强比值和微观组织的变化研究发现,当终轧温度低于Ar3温度时,钢板进入两相区轧制,钢板组织呈带状分布,钢板屈服强度的提高幅度大于抗拉强度的提高,屈强比呈上升趋势.水冷中钢板头部温度过冷对屈强比控制也非常不利.通过对X65/X70管线钢进行控轧控冷工艺优化,屈强比值得到显著降低,大幅提高了管线钢板合格率和成材率.     

Influence of Mn Content and Hot Deformation on Transformation Behavior of C-Mn Steels

The hot deformation behaviors and the microstructural evolution of plain C-Mn steels with similar contents of C and Si but different contents of Mn have been investigated by compressive processing using Gleeble-1500 mechanical simulator.Influence of Mn and hot deformation on continuous cooling transformation of steels has been studied.The experimental results showed that deformation in austenite region accelerated transformation process,and the extent is dependent on the hot deformation and cooling conditions.The hot deformation would promote transformation process,but the increase of transformation temperature is dependent on Mn contents.The results have also shown that the effect of deformation on ferrite transformation becomes more obvious with the increase of Mn content at relatively low cooling rate.     

转炉合金优化控制系统的开发与应用

针对鞍钢股份有限公司第一炼钢厂转炉冶炼合金化操作的特点和要求,设计并开发了转炉合金优化控制系统,能够自动按照生产计划中某一熔炼号对应的钢种生成相应的备选合金方案,并根据成本、加入量、杂质元素含量等工艺要求筛选方案。结合企业信息系统,实现了系统运行的自动化。     

弛豫—析出—控制相变技术中冷却速度对组织的影响

利用热模拟实验,对在非再结晶温度变形后弛豫一段时间,再以不同冷速冷却的低碳贝氏体钢的相变组织进行了研究,并与同等条件不弛豫的试样组织进行了对比.给出了弛豫和冷速对中温转变组织类型及组织细化程度的影响.实验结果表明,弛豫及冷却速度对变形奥氏体的相变组织是有影响的.低冷速下主要得到边界及取向不清晰的粒状贝氏体,这时弛豫时间对细化程度影响不明显,在10℃/S以上冷速下得到的是以板条贝氏体为主的组织,与未弛豫试样比较,其组织更细,板条形状更清晰,弛豫试样组织中残余奥氏体或M/A岛的形状更细长,弛豫有利于在同等冷却条件下得到板条组织,并且在高冷速下,弛豫试样中M/A量较未弛豫试样中的要少.     

微合金化控冷工艺开发HRB500E高强度抗震钢筋

针对红河钢铁有限公司炼钢、轧钢工艺装备,采用微合金化控轧控冷工艺生产HRB500E高强度抗震钢筋,并利用金相显微镜、拉力试验机对钢筋的力学性能、金相显微组织、夹杂物进行检验。结果表明:钢筋强韧性适中,具有较好的抗震性能和低应变时效性;控制钢中Mn含量小于1.55%,Nb含量小于0.025%,控冷终止温度大于680℃,钢筋心部组织为铁素体+珠光体+5%贝氏体,综合性能较佳。     

铝热还原钛氧化物直接合金化机理研究

用热力学计算及动力学变化机制分析的方法,对氧化钛在钢液中的还原行为进行了研究。在炼钢条件下,铝完全可以还原钛矿中的TiO2,粒径为10μm的TiO2颗粒全部转变成Al2O3的时间小于1.27s,铝粉和氧化钛粉混合物加入钢液,瞬间钛就会被铝还原,被还原出的金属钛可对钢液进行合金化,而且对整个冶炼体系不会造成不良后果。     

过程控制剂对Fe-C-Ti粉末机械合金化的影响

研究了过程控制剂对Fe-C-Ti合金粉末的出粉率、粉末形态及机械合金化过程的影响。结果指出,添加过程控制剂可明显提高出粉率,且合金粉末大小均匀,但降低了碳和钛向铁中的固溶速率,使机械合金化过程滞后。     

耐火钢的性能及工艺研究

测定了耐火钢的CCT曲线,研究了耐火钢的性能,包括室温和高温拉伸性能、系列温度下的冲击性能、应变时效性能等;探讨了终轧温度、冷却速度、回火对耐火钢性能的影响.结果表明:试验钢的综合性能完全满足了设计指标的要求,生产工艺的研究工作为耐火钢的工业生产提供了有益的参考.