Nb-Ti微合金钢力学性能的预报模型

根据Nb Ti高强度低合金钢 (0 0 8%～ 0 11%C ,0 0 1%～ 0 0 4 %Nb ,0 0 1%～ 0 2 3%Ti)板材实际生产数据 ,采用多元逐步线性回归 ,得出钢板屈服强度σs(MPa)和抗拉强度σb(MPa)的数学模型 :σs=2 94 0 1Wc+74 7 89WNb+10 2 1 0 9WTi- 0 17Tc+5 95 99;σb=135 6 73WNb+136 1 39WTi- 0 0 1b - 1 6 9h +44 2 4 3(Wc,WNb,WTi为成分质量分数 / % ;Tc 为卷取温度 ;b为成品板宽 ;h为成品板厚 )。同时建立了BP神经网络预报模型 ,两种模型均具有较好的预报精度 ,神经网络预测值与实测值之间的相对误差小于± 10 %。     

卷取温度对Ti-Nb微合金钢微观组织和力学性能的影响

利用试验轧机和热处理炉进行了低碳Ti-Nb微合金钢的模拟轧制和卷取试验,研究卷取温度对微观组织和力学性能的影响。结果表明,随着卷取温度的降低,钢的相变过程逐步由扩散型相变过渡到切变型相变,微观组织由等轴铁素体依次转变为多边形铁素体、粒状贝氏体、板条贝氏体;由于析出强化和相变强化的综合作用,卷取态试验钢强度先降低后升高,延伸率持续降低;卷取过程微合金碳氮化物的析出强化导致卷取态试验钢强度高于空冷态试验钢,且随着卷取温度的降低,卷取态试验钢较空冷态试验钢强度的增量逐步降低;Ti-Nb微合金钢的卷取温度设定在560～630℃时,钢屈服强度744～754 MPa,延伸率19%～20.9%,可获得良好的综合性能。     

热轧温度对含钛微合金钢组织性能的影响研究

通过试验以及力学性能检验,研究了温度参数对含Ti微合金钢组织性能的影响。结果表明:生产Ti微合金化钢应采用较高的加热温度,同时严格控制粗轧温度、终轧温度和卷取温度,充分发挥细晶强化和析出强化作用,使钢板的强韧性匹配良好。     

轧制工艺对Ti微合金钢力学性能的影响

安钢1780热连轧生产线生产的汽车用钢和高强度钢板主要以Ti微合金化为主,Ti微合金元素含量在0.02%~0.10%范围内。而轧制工艺对Ti微合金钢的性能起着决定性的作用。通过对某Ti微合金钢进行不同终轧温度和卷取温度的工艺试验,对比了不同工艺条件下的性能指标。结果表明终轧温度在890℃、卷取温度在600℃时,Ti微合金钢达到强度最高值。     

加工工艺对含钒微合金钢力学性能的影响

讨论了在控制轧制和加速冷却条件下,含钒微合金较洁净钢的工艺参数对力学性能的影响,给出了所用成分钢要得到较佳力学性能所需的一种控制轧制和加速冷却工艺制度。对含钒微合金较净钢而言,加速冷却对屈服强度的贡献是冷却速度提高１０℃／ｓ,屈服强度约增加１０ＭＰａ。     

热轧温度对易拉罐用3004H19的力学性能和金相组织的影响

本文采用力学性能测试、金相、ＴＥＭ和ＳＥＭ观察分析技术,研究了热粗轧温度和热精轧温度对３００４Ｈ１９易闰罐用特薄铝板的内部组织和力学性能的影响,并进行了分析讨论。实验结果表明：第一,当热粗轧温度≥７３３Ｋ,热精轧温度≥ ６３３Ｋ时,３００４Ｈ１９薄板中具有较好的综合性能;第二,随着热精轧开轧温度的升高,热精轧终了坯料组织纤维状减弱,回复与再晶组织增强。且当热精轧温度达到６３４Ｋ时,位错胞增大,有回     

加热工艺对Nb-Ti微合金钢奥氏体晶粒长大的影响

 为了解加热制度对Nb Ti微合金钢的奥氏体晶粒长大和析出行为的影响,采用OM、TEM和EDS分析技术,研究了Nb Ti微合金钢在不同加热温度和保温时间的奥氏体晶粒长大行为,以及微合金元素碳氮化物析出行为。结果表明,随加热温度升高,奥氏体晶粒尺寸逐渐长大,当加热温度超过1 200 ℃时奥氏体晶粒尺寸快速长大。随保温时间延长,奥氏体晶粒尺寸逐渐长大,当保温时间超过2.0 h时奥氏体晶粒尺寸快速长大。EDS分析显示Nb Ti钢中的析出物为(Nb,Ti)(C,N)复合相,随着加热温度升高和保温时间延长,析出相体积分数减少,尺寸增大,从而减弱对奥氏体晶粒的细化作用;Nb Ti微合金试验钢合适的加热温度范围为1 150～1 200 ℃,保温时间低于2.0 h。     

Effect of Finishing Rolling Temperature on Microstructure and Mechanical Properties of Microalloyed TRIP Steels

Different samples of TRIP (transformation induced plasticity) steel obtained by two different hot-rolling schedules are investigated by using a SEM (scanning electron microscope). The microstructure is characterized by using an OM (optical microscope) for phase distribution and by EBSD (electron backscatter diffraction) for texture and phase mapping. ODF (orientation distribution function) graphs are used to investigate the effect of recrystallization behavior of the hot-deformed austenite on phase transformation during the controlled cooling process. The mechanical behavior is interpreted in terms of the strength of both hard and soft phases, in combination with the quantity, location and transformation kinetics of the mechanically induced martensite (TRIP effect). The results show that more austenite grains exist in the steels obtained at finishing rolling temperature (FRT) of 750 °C, which inherited the deformation structure after the hot-rolling process. The instantaneous n value (n_i) of those steels is kept high during a large range of strain before failure, while the tensile strength and total elongation of the steels with respect to the different finishing rolling temperatures do not show any significant differences.     

高氮钒微合金钢中终轧温度和锰的综合作用

通过对高锰高终轧温度钢和低锰低终轧温度钢的力学性能测试、并观察其组织及其碳氮化物的析出,研究了Mn和终轧温度在高氮钒微合金钢中的综合作用.结果表明： 高锰含量可以弥补高的终轧温度对组织的不利影响,而高的终轧温度可以弥补高的锰含量对析出的不利作用;提高锰含量同时提高终轧温度比降低锰含量同时降低终轧温度有利于组织细化和析出.     

时效温度对贝氏体型冷作强化非调质钢力学性能的影响

 研究了时效温度对一种低碳Mn-B-Ti系贝氏体型冷作强化非调质钢力学性能的影响。结果表明：试验料的强度随时效温度的升高先是增加,并在250℃时存在一个峰值,随后强度又随时效温度的升高而降低,当温度升高到400℃以上时强度明显降低;试验料的塑性和屈强比则随时效温度的升高逐渐增加,其中后者增加的幅度更显著。与未充氢试样相比,试验料拉拔并充氢后的延迟断裂性能显著降低。随着时效温度的升高,充氢试样中的氢含量降低,缺口抗拉强度RBN和延迟断裂强度比R缓慢增加,当时效温度大于200℃时,RBN和R则明显增加。因此,在满足保载永久伸长变形量及强度和塑性要求的前提下,应选择合适的时效温度,以保证材料的延迟断裂性能。     

控轧控冷工艺对低碳铌微合金钢组织和性能的影响

用Gleeble-1500热模拟实验机测定了低碳铌微合金钢变形后的连续冷却转变曲线(CCT曲线),并在实验室对该实验钢采用不同的工艺进行了控制轧制和控制冷却的实验.研究了工艺参数对实验钢力学性能和微观组织的影响,分析了低碳铌微合金钢的强韧化机制.热模拟实验结果表明,实验钢在较宽的冷却速度范围(0.5～30 ℃/s)内可以获得贝氏体组织.控轧控冷的实验结果表明,实验钢的组织主要为铁素体和贝氏体.随着终轧温度的降低,组织得到细化,强度提高,但屈强比也随之增加;降低卷取温度使组织中的贝氏体含量略有增加,强度有所提高.初步探讨了贝氏体对实验钢性能的影响,为制定合适的生产工艺制度提供了依据.     

Effect of Thermomechanical Processing on Mechanical Properties of Hot Rolled Multiphase Steel

The effect of thermomechanical processing（TMP）on the mechanical properties of hot rolled multiphase steel was investigated.TMP was conducted using a laboratory hot rolling mill,in which three different kinds of finish rolling deformation degrees and temperatures were applied.The results indicate that polygonal ferrite,granular bainite,and a considerable amount of stabilized retained austenite can be obtained by TMP.The stability of the retained austenite increases with decreasing finish rolling temperature and increasing finish rolling deformation degrees.Ultimate tensile strength（σb）,total elongation（δ）,and the product of ultimate tensile strength by total elongation（σb·δ）for 50% reduction at finish rolling temperature of 700 ℃ reach maximum values [791 MPa,36% and 28 476（MPa·%）,respectively].     

轧制工艺对Ti微合金化马氏体钢力学性能的影响

 通过采用扫描电镜、透射电镜、X射线衍射以及相分析等手段来观察组织的微观结构和对析出相的验证,研究轧制温度对轧态Ti微合金化马氏体钢强度的影响。研究结果表明,通过降低轧制温度可以明显提高含Ti马氏体钢的屈服强度,这主要是因为当轧制温度从1100℃降低到950℃过程中,形变诱导析出大量的TiC析出相,随着轧制温度的降低,析出相数量明显增加,并且平均尺寸也逐渐变小。马氏体中大量存在的1～20nm范围的析出相可以起到明显的析出强化作用。     

Microstructural Evolution and Mechanical Properties of Nb-Ti Microalloyed Pipeline Steel

 The correlation between microstructures and mechanical properties of a Nb-Ti microalloyed pipeline steel was investigated. The results revealed that with decreasing the finish rolling temperature and the cooling stop temperature, the matrix microstructure was changed from quasi-polygonal ferrite to acicular ferrite, as a result of improvement of both strength and low temperature toughness. By means of electron backscattered diffraction observation, an effective acicular ferrite packet contained several low angle boundaries or subboundaries plates which made important contributions to improvement of strength. It was found that many fine quasi-polygonal ferrite grains with high angle boundaries as the toughening structure were introduced into the acicular ferrite matrix to refine effective grain size and improve the toughness.     

Effect of Controlled Cooling After Hot Rolling on Mechanical Properties of Hot Rolled TRIP Steel

A three-step cooling pattern on the runout table（ROT）was conducted for the hot rolled TRIP steel.Microstructural evolution during thermomechanical controlled processing（TMCP）was investigated.Processing condition of controlled cooling on a ROT in the laboratory rolling mill was discussed.The results indicated that the microstructure containing polygonal ferrite,granular bainite and a significant amount of the stable retained austenite can be obtained through three-step cooling on the ROT after hot rolling.TMCP led to ferrite grain refinement.Controlled cooling after hot rolling resulted in the stability of the remaining austenite and a satisfactory TRIP effect.Excellent mechanical properties were obtained through TMCP for the hot rolled TRIP steel.     

热机械控制工艺对热轧TRIP钢力学性能的影响

通过实验室热轧机研究了热机械控制工艺(TMCP)对热轧TRIP钢力学性能的影响.结果表明:在热轧变形过程中应变诱导铁素体相变,低温大变形量造成铁素体晶粒细化.随终轧温度的降低和终轧变形量的增加,残余奥氏体的稳定性增加,相变诱发塑性(TRIP)效果更好.在700 ℃终轧且终轧变形量为50%时,抗拉强度、屈服强度和总伸长率分别达到791 MPa,538 MPa和36%的最大值.     

异步轧制TWIP钢的力学性能和微观组织

 利用金相显微镜、X射线衍射仪和透射电子显微镜对异步轧制及热处理TWIP钢的力学性能与微观组织进行了研究。结果表明,TWIP钢经500℃异步轧制后强度显著提高,而塑性降低,这是位错与孪晶共同作用的结果。轧制后的热处理降低了位错密度以及变形孪晶数量,导致强度降低,伸长率升高。经600℃和700℃退火后,TWIP钢表现出良好的强度和塑性综合性能。因此,异步轧制后热处理是获得具有优良综合力学性能TWIP钢的可行途径。