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通过金相、扫描、透射电镜研究不同锻造工艺下V-Ti、Nb-V-Ti两种微合金化非调质钢的微观组织结构及力学性能。结果显示:添加Nb能够显著提高非调质钢的奥氏体粗化温度,有效阻止奥氏体晶粒的快速长大,细化非调质钢晶粒,降低珠光体层片间距,使渗碳体呈粒状或球状分布;另外,添加的Nb促进V-Ti非调质钢中细小含铌碳化物的弥散析出,细化基体组织,同时提高非调质钢的强度。因此,Nb-V-Ti复合微合金化非调质钢经过未再结晶区变形后可获得均匀细小的铁素体-珠光体双相组织,且在相对较低的温度进行形变处理能够有效改善Nb-V-Ti微合金非调质钢的强韧性。 相似文献
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微合金非调质钢的强韧化及优化设计 总被引:3,自引:2,他引:1
徽合金非调质钢是应用微合金化理论和强韧化理论发展起来的一类钢种。本文简述微合金非调质钢的发展概况,分析了微合金强韧化的机制,探讨了微合金非调质钢成分、工艺、组织和性能间关系的数学模型以及钢种设计和工艺的优化问题 相似文献
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微合金非调质钢技术浅析 总被引:1,自引:0,他引:1
微合金非调质钢因其成本较低、性能优良、环境污染小等优点,得以开发和应用,已成功应用于汽车工业、重型机械、建筑、石油化工、桥梁等领域。对微合金非调质钢中合金元素的作用及微合金非调质钢强韧化的方法等进行了分析,对微合金非调质钢的分类作了介绍,并阐述了铁素体-珠光体型、贝氏体型、马氏体型微合金非调质钢的特点及其生产技术。 相似文献
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使用Gleeble-1500热/力模拟机,对四种V-N微合金非调质钢和一种非V-N微合金化对比钢进行了静态再结晶实验研究.研究结果表明:当钢中C质量分数为0.33%时,V-N微合金钢的静态再结晶要比未V-N微合金化的对比钢有明显滞后,尤以820~880℃温度范围内最为明显,因此钢中V析出物对道次间再结晶过程影响很大.进一步研究表明,V-N微合金非调质钢道次间静态再结晶量受C含量的影响并不呈简单线性关系:在760~880℃温度范围内,道次间静态再结晶量在钢中C质量分数为0.33%时均为极大值,而940℃下所有五种实验钢均完成了静态再结晶;钢中V析出物对道次间静态再结晶的影响机制相当复杂,与其析出时机关系很大.在此C含量下且V和Ti量均近似相同的V-N微合金实验钢中,发现当N质量分数从140×10-6增加到210×10-6时,该温度范围内道次间静态再结晶量下降14%~19%,N含量增加有明显抑制道次间静态再结晶的作用. 相似文献
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含铌非调质钢的组织与性能 总被引:2,自引:0,他引:2
简单介绍了含铌非调质钢35MnVNb的金相组织与力学性能。35MnVNb钢通过适当控制热变形工艺,可以得到均匀的铁素体和珠光体组织,用QA-b图像分析仪测定了珠光体体积百分数,结果为Φ16~Φ45mm轧材的铁素体晶粒和珠光体团的平均尺寸为11.5~19.5μm,相当于9.7级和8.2级晶粒度;Φ80mm锻材的晶粒度平均尺寸为35.2μm,也达到7级。含铌非调质钢奥氏体连续冷却转变曲线说明,要得到铁素体和珠光体组织,最大冷却速度为3.6℃/s,高于此冷速,将产生贝氏体组织,对钢的韧性有严重的影响。 相似文献
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变形工艺对V、Ti微合金钢连续冷却相变的影响 总被引:1,自引:0,他引:1
采用Gleeble-1500热模拟实验机,结合显微硬度测试,建立了含V、Ti微合金钢的未变形和50%形变奥氏体的CCT曲线.利用光学显微镜、透射电镜分析研究了冷却速度、变形条件及微合金元素对显微组织的影响.结果表明,变形使铁素体 珠光体相变区左移,获得铁素体 珠光体组织的临界冷速增大.变形也使贝氏体相变温度有所提高,同时在较高的冷速下,变形可使显微组织变得更加细小.V、Ti的复合添加,提高了过冷奥氏体的稳定性,使相变温度降低,有利于得到细小的组织. 相似文献
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Effect of Prestrain on Microstructures and Properties of Si-Al-Mn TRIP Steel Sheet with Niobium 总被引:1,自引:0,他引:1
TANG Zheng-you 《钢铁研究学报(英文版)》2010,17(4):59-65
Paint baking treatment was carried out in a silicon oil bath at 170℃ for 20min for Si-Al-Mn TRIP Steel sheet with different prestrains,and effect of prestrain on microstructures and properties was studied before and after baking.The results show that with the increasing of prestrain amount during prestraining and baking,the volume fraction of retained austenite decreases,and the volume fraction of martensite and bainite increases as well as yield strength increases;as prestrain ranges from 0 to 4%,the baking-hardening(BH)value increases;while the prestrain ranges from 4% to 16%,the BH value decreases;when the prestrain amount is 4%,the highest BH value is about 70MPa for Si-Al-Mn TRIP steel sheet with niobium,which displays excellent baking-hardening behavior. 相似文献
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Effect of Manganese and Niobium and Rolling Conditions on the Properties of Low-Alloy Steel 总被引:1,自引:0,他引:1
A series of studies was conducted to determine the optimum manganese and niobium contents in steels alloyed with the system C–Mn–Nb. Researchers also wanted to find the starting and finishing temperatures for rolling on a 2800 mill that would be best in order to obtain the necessary mechanical properties when the metal is deformed in the austenite range with small reductions.The studies established the following:– a greater improvement in strength properties is obtained from an increase in the mass content of manganese if the carbon content is reduced (0.09–0.10%) rather than increased (0.12–0.13%);– other conditions being equal, an increase in the niobium content of the steel from 0.02–0.03% to 0.04–0.06% leads to a substantial increase in strength and toughness properties and a decrease in ductility;– it was established that in terms of its effect on the yield point, microalloying steel with 0.01% niobium is equivalent to alloying with 0.30–0.40% manganese;– the percentage of the tough B component in the fracture of IPG specimens of low-alloy steel with a niobium content of 0.02–0.03 mass % can be increased from 30 to 100% by decreasing the temperature of the slab after the second pass through the two-high stand from 1020 to 980°C. For steels with a higher niobium content (0.05–0.06%), the temperature of the metal when it enters the roughing stand can be increased to 1010–1040°C without adversely affecting the standard characteristic B (%);– a decrease in the finishing temperature is accompanied by an increase in the strength and toughness properties of the metal and a decrease in ductility. Reducing the finishing temperature to below 760°C makes it possible to increase strength properties but does not change impact toughness. 相似文献
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The precipitation of niobium carbo‐nitrides in the austenite phase, interphase and ferrite phase of microalloyed steel was assessed by a critical literature review and a round table discussion. This work analyses the contribution of niobium carbide precipitates formed in ferrite in the precipitation hardening of commercially hot rolled strip. Thermodynamics and kinetics of niobium carbo‐nitride precipitation as well as the effect of deformation and temperature on the precipitation kinetics are discussed in various examples to determine the amount of niobium in solid solution that will be available for precipitation hardening after thermomechanical rolling in the austenite phase and successive phase transformation. 相似文献
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Effect of Baking Process on Microstructures and Mechanical Properties of Low Silicon TRIP Steel Sheet with Niobium 总被引:1,自引:0,他引:1
After 2% predeformation,the baking treatment with different schedule was carried out for low silicon TRIP steel sheet with niobium.The effects of baking temperature and time on microstructures and mechanical properties were investigated.The results showed that with increasing the baking temperature and time,the volume fraction of retained austenite decreases,and the volume fraction of tempered martensite increases;as baking temperature ranges from 80 ℃ to 170 ℃,the bake-hardening(BH)value increases obviously,while from 170 ℃ to 230 ℃,the variation of BH value is very slight;as baking time ranges from 2 min to 20 min,the BH value increases significantly,while the BH value decreases when baking time exceeds 20 min.So that when the baking temperature is 170 ℃ and the baking time is 20 min,the low silicon TRIP steel sheet exhibits good bake-hardening behavior,and the highest BH value is above 70 MPa. 相似文献
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EfectofRareEarthsonPrecipitationKineticsofNiobiumCarbideinMicroaloyedStelYeWen(叶文),LiuYonghua(刘勇华),LinQin(林勤),ChenNing(陈宁)(De... 相似文献
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采用高频真空感应炉在1 550℃的Ar气氛中冶炼不同钛含量的钛、铌微合金化钢并对其进行热处理。分析了钛加入量对钢的成分、组织结构、钢中典型夹杂物及宏观力学性能的影响。研究结果表明:采用Al脱氧后的钛、铌微合金化钢氧含量降低到0.002 0%左右,合金元素的利用率超过80%。钢中的夹杂物主要有球形或近似球形的Al2O3、SiO2、TiOx及其复合夹杂。(Ti,Nb)(C,N)、NbC、TiC夹杂以氧化物夹杂为核心析出。随着钛合金加入量的增加,钢样中的部分夹杂物形貌由球形发展成长方形。经共聚焦激光扫描高温显微镜热处理过的钢样中析出较多细小的(Ti,Nb)(C,N)夹杂物。随着钛含量的增加,热处理后的钢中小于1μm夹杂物数量急剧增加,尺寸大于1μm的夹杂物的数量呈现减少的趋势。高温在线金相组织分析表明:钢中钛加入量增加,高温奥氏体晶粒变小,钢的组织细化,从而钢的宏观硬度增高。 相似文献