微量铌对低碳钢退火再结晶组织和性能的影响

通过对硬度异常钢板的生产工艺进行分析发现,钢板中铌含量过高是造成同一生产工艺下钢板硬度异常的主要原因。利用冷轧退火模拟试验装置,模拟了3种不同铌含量低碳钢板在不同温度条件下的退火过程,通过对比分析样板显微组织和力学性能,研究微量铌对低碳钢退火再结晶组织和性能的影响。结果表明,当钢中含有微量铌元素时,低碳钢的再结晶完成温度显著提升。含铌0.0012%和0.0023%的低碳钢要满足T5料的性能要求,退火温度应提高至650℃。     

钛、铌添加量对超深冲IF钢板力学性能的影响

在实验室中研究了钛、铌合金元素含量变化对ＩＦ钢力学性能的影响,得到了最佳的合金成分控制范围。文中还研究了钛、铌合金含量对ＩＦ钢再结晶温度和热轧后组织的影响。     

钛对高强度Nb+Ti-IF冷轧罩式炉退火钢板性能的影响

研究了钛（铌固定）对高强度Ｎｂ＋Ｔｉ－ＩＦ冷轧罩式炉退火钢板性能的影响。结果表明，当Ｔｉ／Ｎ≈１（原子比）时伸长率和ｒｍ值最高，随着钛含量的进一步增加，钢中过剩的钛将和磷形成ＦｅＴｉＰ析出相，延迟了再结晶，使伸长率和ｒｍ值降低。     

铌钛复合微合金化对含磷冷轧结构钢板组织性能的影响

以低碳含磷钢为研究对象,通过分析不同卷取温度（600、650、700℃）时热轧态和冷轧退火态的显微组织、力学性能及退火再结晶动力学行为,对比研究了微铌（0．02％）处理和铌钛复合微合金化（0．02％Nb＋0．012％Ti）对钢的组织和性能的影响。研究结果表明,与微铌处理钢相比,铌钛复合微合金化钢在600℃卷取时析出物数量更多,在更高温度卷取时熟化速度更快,650℃卷取时即熟化到一定程度。低温（600℃）卷取时,铌钛复合微合金化钢的退火再结晶更难,800℃×30s连续退火可以保证完全再结晶。将温度继续升高至800℃以上,会导致强度下降,在一定程度上影响板卷之间的性能稳定性。     

含铌微合金带钢精轧过程中的再结晶行为

介绍了含铌微合金带钢在精轧过程中的再结晶行为。在不同条件下，含铌钢将发生静态再结晶、动态再结晶和亚动态再结晶，而且沉淀的析出对再结晶有不同程度的影响。     

含铈IF钢中含钛夹杂物的析出行为

通过热力学计算研究了IF钢中含钛夹杂物的形成过程以及铈对钢液中Al2O3夹杂物的变质机理,并采用扫描电镜、能谱仪观察和分析了IF钢和含铈IF钢中的含钛夹杂物。热力学计算和扫描电镜观察结果表明:TiN不能在熔炼温度下形成;在IF钢液凝固的过程中TiN以异质形核的形式生成并长大,生成TiN-Al2O3夹杂物;在含铈IF钢中TiN-Al2O3夹杂物被稀土铈变质为TiN-CeAlO3夹杂物,稀土铈减小了含铈IF钢中含钛复合夹杂物的尺寸。     

稀土铈对钢中含钛夹杂物析出行为的研究

应用热力学计算软件Factsage7.0在800～1 600℃温度范围内计算了含钛夹杂物、稀土对含钛夹杂物的析出情况,并采用扫描电镜及其能谱观察和分析了不添加稀土、添加稀土的钢中含钛夹杂物尺寸、形貌变化。热力学计算与扫描电镜结果表明:添加稀土元素Ce后可以减少钢中有害元素O、S含量,钢中Ti_4C_2S_2、Ti_3O_5析出量减少,有效Ti含量增加,细小弥散的Ti(C,N)析出量增多,稀土Ce能够有效的变质钢中大尺寸,具有坚硬性棱角的TiC-AlO_3复合夹杂,将其转变为尺寸相对较小,形状为椭圆形TiC-CeAlO_3夹杂,在一定程度上减少了因其形状对钢产生的有害作用,通过对夹杂物分析比较可得,钢中添加适量稀土可以提高钢的性能。     

铌和稀土对厚规格轮辐钢板组织和性能的影响

 通过对汽车轮辐用钢板的铌和稀土微合金化试验和生产实践,分析了铌、稀土元素对汽车车轮用钢组织和性能的影响。结果表明：铌微合金化可以细化晶粒;钢中加入稀土,可改变夹杂物形状和尺寸,铌、稀土可以提高钢材的综合性能,尤其是提高了钢板的耐疲劳性能。     

Nb-Ti微合金钢中的奥氏体晶粒长大行为研究

Nb、Ti是管线钢中常用的合金元素。主要通过热处理和喷碳处理等手段研究了合金元素Nb、Ti的含量及加热制度对再加热奥氏体晶粒长大的影响。试验结果表明:试验钢在再加热过程中,奥氏体晶粒尺寸随加热温度升高而增大;在常规含铌钢中,为获得较小的加热态奥氏体晶粒,钛的质量分数应控制在一定范围内(0.010%~0.015%),钛含量过高或过低都对晶粒细化有不利影响。此外,在钛含量相同的情况下,高铌钢奥氏体晶粒长大明显,高铌钢的最佳钛含量范围也与常规含铌钢的最佳钛含量不同。     

稀土及铌微合金化Fe-3%Si无取向硅钢热变形行为的研究

针对稀土及铌微合金化Fe-3%Si无取向硅钢,在实验室利用Gleeble-1500D热模拟机进行了变形温度为900℃~1100℃、变形速率为0.001 s-1~5 s-1、变形量为60%的单道次热变形实验。分析了不同热变形条件下实验钢的应力-应变曲线以及变形组织,并计算了实验钢的热变形激活能Qd的值。实验结果表明,稀土及铌微合金化Fe-3%Si无取向硅钢在热变形过程中有部分再结晶晶粒出现在原始晶界以及晶界三角地带,但不同变形条件下的应力-应变曲线仍均为动态回复型;热变形激活能Qd分别为449.00 k J/mol、431.59 k J/mol,稀土及铌微合金化可以显著提高Fe-3%Si无取向硅钢热变形激活能,抑制动态再结晶的发生。     

Study of Rare Earths in Pipeline Steel

ＳｔｕｄｙｏｆＲａｒｅＥａｒｔｈｓｉｎＰｉｐｅｌｉｎｅＳｔｅｌＬｉｕＹｏｎｇｈｕａ（刘勇华），ＹｅＷｅｎ（叶文），ＬｉｎＱｉｎ（林勤）ＣｈｅｎＮｉｎｇ（陈宁）（ＤｅｐａｒｔｍｅｎｔｏｆＰｈｙｓｉｃａｌＣｈｅｍｉｓｔｒｙ，ＵｎｉｖｅｒｓｉｔｙｏｆＳｃｉ...     

Effect of Nb on Microstructure Evolution in Cold Rolled Dual-Phase Steels:Interaction of Recovery,Recrystallization and Phase Transformations

The effects of Nb addition,individually and in combination with Ti,were evaluated over a range of coiling temperatures.Coiling temperature influences the ratio of soluble and precipitated Nb in the hot rolled steel containing 0.08 % C and 2.2 % Mn.Nb bearing precipitates can co-precipitate on TiN and impact the microstructure and mechanical properties of the steel after annealing treatment.Microstructure characterization revealed that recovery and recrystallization processes preceded austenite formation.The effects of Nb on austenite formation in cold rolled steels during heating and isothermal holding and on austenite decomposition during subsequent cooling were investigated using dilatometry.The addition of Nb retarded ferrite recrystallization starting temperature,but had no significant effect on the starting temperature of austenite formation during heating.The Nb addition also accelerated austenite formation once the transformation started,and was beneficial for the formation of a finer and homogeneous microstructure.     

B443超低碳氮铁素体不锈钢的研究

为开发价格昂贵的SUS304奥氏体不锈钢的替代产品,试验研究了不同含量C N和Nb,Ti稳定化对B443系列铁素体不锈钢再结晶组织、力学性能、点蚀电位的影响.试验结果表明,Nb,Ti双稳定化提高了B443铁素体不锈钢的再结晶温度和点蚀电位.在试验室研究基础上,宝钢不锈钢分公司试制了B443NT超低碳氮铁素体不锈钢.该产品不仅具有与SUS304相当的耐腐蚀性能,而且具有优良的深拉伸性能和满意的焊接性能,可用于运输、建筑、厨具等众多行业.     

Structure and Texture Formation During Single and Double Cold Rolling and Annealing Processes for Nb+Ti Added Interstitial-Free Steels

 The structure and texture formation for single cold rolling (SCR) with annealing and double cold rolling (DCR) with annealing were investigated based on optical microscope and X-ray diffraction (XRD) with a Nb+Ti bearing interstitial free (IF) steel. The results indicated that DCR recrystallization grain was smaller than that of SCR sample and double cold rolling process resulted in better mechanical properties than those resulted from single cold rolling process with the same total reduction conducted. The plastic strain ratio increases from 2. 23 for single cold rolling process to 3. 2 for double rolling process. The fish-bone structure was observed in all SCR and DCR samples. DCR annealed sample is made up of equiaxed grains of almost uniform size, whereas SCR annealed sample shows a duplex grain structure, consisting of both large and small-sized grains. (Ti+Nb)C and Fe(Ti+Nb)P type precipitates were very rarely observed in SCR annealed and DCR annealed steels. The intensity of {111}∥ND for the DCR annealing was higher than that for SCR annealing.     

Microstructure and Properties of Ti and Ti+Nb Ultra-Low Carbon Bake Hardening Steels

 Hot rolling, cold rolling and continuous annealing processes of Ti bearing and Ti+Nb stabilized ultra low carbon bake hardening(ULC-BH) steels were experimentally studied. The microstructure and texture evolution, as well as the morphology, size and distribution of the second phase precipitates during the hot rolling, cold rolling and continuous annealing were also analyzed. The results showed that the size of NbC precipitates in Ti+Nb stabilized ULC-BH steel was smaller than that of TiC precipitates in Ti bearing ULC-BH steel, this caused the average grain size of Ti+Nb stabilized ULC-BH steel to be finer than that of Ti bearing ULC-BH steel, for the yield strength, the former was higher than the latter, but for the r value which reflecting the deep drawing performance, the former was lower than the latter.     

铌与钛对铁素体不锈钢析出和成形性的影响

研究了铌、钛对铁素体不锈钢析出相、织构和成形性的影响。结果显示:添加铌、钛后的析出相主要是TiN和(Nb,Ti)C,其析出尺寸分别为4μm和200 nm;同时,铌、钛的添加抑制了冷轧薄板α纤维织构的生长,促进了γ纤维织构强度的增加。添加稳定化元素铌、钛后,冷轧薄板的平均r值由1.05增加到1.46,起皱高度也由29.1μm下降到18.9μm,薄板成形性能的改善同再结晶织构的变化密切相关。     

00Cr12Ti铁素体不锈钢的再结晶退火与成形性研究

 研究了1.0 mm厚 00Cr12Ti冷轧板在再结晶退火工艺条件下力学性能的变化规律。研究结果表明,随着退火温度的升高,维氏硬度、屈服强度、抗拉强度和屈强比均呈快速下降趋势,在超过800 ℃之后变化不大。再结晶退火后,00Cr12Ti钢拥有较多的{111}取向的晶粒,塑性应变比值r0、r45、r90和r-在退火温度超过780 ℃以后都有较大升高,并且r90>r0>r45。在700～800 ℃之间,平面各向异性Δr值变化不大,随后Δr值随温度上升急剧升高,因而成形时易产生严重的制耳现象。通过杯突试验发现,杯突值IE与r-值的变化相一致,表明00Cr12Ti冷轧板在高温再结晶退火后,可获得良好的成形性能。     

Ti-Nb对高强IF钢板连续退火再结晶的影响

试验研究得出，加入过量的Ｎｂ（０．２％）导致Ｔｉ＋Ｎｂ处理的高强ＩＦ钢板的连续退火再结晶延滞，在合适的Ｔｉ含量下，钢中Ｎｂ处于固溶状态时，有利于再结晶进行。     

Microstructure and Properties of Ti and Ti+Nb Ultra-Low-Carbon Bake Hardened Steels

Hot rolling, cold rolling and continuous annealing processes of Ti bearing and Ti+ Nb stabilized ultra-low-carbon bake hardened steels were experimentally studied. The microstrueture and texture evolution, as well as the morphology, size and distribution of second phase precipitates during hot roiling, cold rolling and continuous annea-ling were also analyzed. The results showed that the size of NbC precipitates in Ti+ Nb stabilized ultra-low-carbon bake hardened steel was smaller than that of TiC precipitates in Ti bearing ultra-low-carbon bake hardened steel, which made the average grain size of Ti+ Nb stabilized ultra-low-carbon bake hardened steel finer than that of Ti bearing ultra-low-carbon bake hardened steel; for the yield strength, the former was higher than the latter; but for the γ value which reflects the deep-drawing performance, the former was lower than the latter.