Mo微合金化对82B钢高温力学性能及显微组织的影响

研究了添加Mo（质量分数）为0.02%、0.04%、0.07%、0.11%的82B钢对不同温度下高温拉伸后的组织和性能的影响及Mo对82B高碳钢的强韧化机理。结果表明：（1）200～300℃高温拉伸时,4组试验钢力学性能较好,300℃达到峰值,Mo为0.11%试验组最优,抗拉强度由1 139 MPa增至1 192 MPa,屈服强度为736 MPa,略有降低,伸长率与断面收缩率均有显著提高,分别为22%和72.9%。相较于Mo为0.02%试验钢,虽屈服强度下降约5%,但抗拉强度升高5%,伸长率、断面收缩率大幅增加,且塑性随Mo含量同步提高,随着温度继续升高,由于材料开始软化,各项力学性能均呈下降趋势。（2）Mo为0.02%和0.04%时,显微组织除渗碳体随拉伸温度的提高逐渐增多外,索氏体与珠光体未出现明显变化,与室温相同,当Mo增至0.07%和0.11%时,索氏体、珠光体团逐渐细化且分布均匀。同时,4组试验钢在300℃高温拉伸时出现蓝脆现象,通过断口观察发现,有Al、Si等元素的夹杂物存在,且失效方式为韧性断裂,断口主要可分为剪切唇区和纤维区,剪切唇区的面积随着温度的升高逐渐缩小。     

Cr-V-Al微合金化SWRH82B钢生产工艺研究

SWRH82B是日系牌号的高强度预应力钢绞线用钢,而目前天津荣程联合钢铁集团有限公司实施的JIS G3506日系标准,已无法满足SWRH82BΦ13mm盘条抗拉强度≥1180MPa的市场要求,因此需要在此标准的基础上实施微合金化,以提高盘条抗拉强度.本文对SWRH82B硬线钢的微合金强化工艺进行了研究,并介绍了SWRH...     

微合金化粒状贝氏体钢的显微组织和力学性能

本文研究了微合金化12SiMoVNb 钢经不同工艺处理后得到的粒状贝氏体显微组织与力学性能的关系。结果表明,显微组织参数的变化对准静态力学性能σ_(0.2),σ_b,δ,ψ影响不大,而对动态力学性能α_k 影响较为显著。微合金化的粒状贝氏体组织有高的缺口敏感性。在冷却过程中形成细小碳化物沉淀降低基体塑性变形能力,是致脆因素之一。加快冷却速度,形成较细小的,富奥氏体的(M-A)小岛将改善冲击韧性。     

Nb-V微合金化0.15 ~ 0.35Mo含量和轧制温度对建筑用耐火钢性能的影响

试验钢采用50 kg中频感应炉熔炼,并轧成13mm钢板。试验了R1-0.15MoNb,R2-0.15MoV,R3-0.35MoNbV,R4-0.35MoNbVB和R5-0.35MoNbVTiB耐火钢的轧制温度（1 010～1 050℃）对该钢性能的影响。结果表明,R3钢（/%:0.04C,1.12Mn,0.32Si,0.018P,0.023S,0.35Cr,0.35Mo,0.025Nb,0.15N）在1030℃轧制后具有最佳的综合性能,即抗拉强度598 MPa、屈服强度514 MPa、延伸率28%、屈强比0.86、600℃回火前后HV硬度值分别为215和204、0℃冲击功124J;600℃的屈服强度355 MPa,屈强比为0.69,满足耐火钢国家标准要求。     

铜含量对高碳TWIP钢组织和力学性能的影响

 采用真空熔炼法制备了Fe-20Mn-XCu-1.3C系高强度高塑性合金钢。通过单向拉伸试验和OM观察,研究了铜含量的变化对该合金微观组织和力学性能的影响。结果表明：Fe-20Mn-XCu-1.3C系合金拉伸变形前后均为单相奥氏体组织。随着铜含量的增加,合金的屈服强度和伸长率提高,而抗拉强度降低,Fe-20Mn-3.0Cu-1.3C合金的抗拉强度为1256MPa,伸长率为77.6%,强塑积达到97465.6MPa·%,具有优异的综合力学性能。铜含量的增加提高合金的层错能,推迟了变形过程中孪晶的形成并降低了孪晶的形成速率,使位错滑移更容易发生。Fe-20Mn-XCu-1.2C系合金具有较高的加工硬化速率水平,其加工硬化速率随着铜含量的增加而降低。     

变形温度及冷却速度对微合金化82B盘条组织和性能的影响

利用热模拟仪、金相显微镜、万能试验机等手段对微合金化82B盘条的变形温度及冷却速度进行了研究分析,试验结果表明:较快的冷速会促进钒合金化试样中含钒第二相的析出,提高材料强度的同时降低其塑性,该合金化方式需控制钒含量;钒氮合金化是一种适合82B盘条的强化方式,但材料的钒和氮含量比例关系,以及与冷速的交互作用可显著影响材料...     

82B钢的微合金化-相变控制与生产实践

为了优化82B钢的成分和热轧冷却工艺,以提高82B盘条的强度,测定了80钢和82B钢的等温转变温度对相变时间、珠光体片层间距的影响以及Cr元素对82B相变温度的影响,分析了Cr合金化和相变控制对82B盘条的微观组织和抗拉强度的影响。对于82B,当温度在595～615℃相变速度最快,其转变时间为10～15s,在590～625℃可得到理想的0.10～0.20μm的珠光体片层间距;通过添加0.18%～0.24%Cr和控制热轧冷却速度,可以控制82B钢的相变温度区间和相变速度,得到均匀细片状的珠光体组织;将Φ12.5mm 82B盘条的主要成分调整为0.78%～0.84%C、0.15%～0.35%Si、0.78%～0.88%Mn和0.18%～0.24%Cr;在热轧控冷过程中,弱化水冷,强化风冷,控制82B盘条的吐丝温度为840～880℃,目标值860℃,增大82B盘条在风冷线上的冷速,提高了盘条的强度。     

合金化元素对热轧多相钢显微组织和力学性能的影响

回顾了良好成型性的高强度微合金钢的成分设计和形变热处理。通过添加Ti或Ti＋B复合添加使奥氏体晶粒优化，加之在轧材输出及卷取过程中进行恰当控轧和控冷可以获得拉伸强度超过1200MPa的马氏体钢。业已发现添加Si会降低材料对卷取温度变化的敏感性，从而也减少了力学性能值的离散。研究还发现，由于这些钢的强度较高。因此可以以较薄和较轻的型材用于汽车的安全关键部件，由于无需附加的热处理工序，因此马氏体钢种可降低生产成本。还对微合金化元素Nb及Ti对双相钢和TRIP钢性能的影响进行了探讨。     

Ti-Nb微合金化对低碳高强度钢组织和性能的影响

0.153Ti-0.038Nb和0.080Ti-0.062Nb两种Ti-Nb微合金化低碳钢(/%:0.061～0.075C、0.22Si、1.76～1.77Mn、0.002～0.003S、0.006P、0.003Als、0.003 8～0.004 2N、0.004 0～0.004 5O)由50 kg真空感应炉冶炼,轧成10 mm板,终轧温度880℃,水冷至630℃。试验结果表明,两种Ti-Nb微合金化钢的析出物均为(Nb,Ti)(C,N)复合析出物;当Ti含量由0.080%增加至0.153%,同时Nb含量由0.062%降至0.038%时,钢屈服和抗拉强度分别从558 MPa和653 MPa提高至633 MPa和756 MPa,屈强比、伸长率和断面收缩率变化较小。表明,添加Ti代替部分Nb进行复合微合金化可提高钢材强度,降低生产成本。     

微合金元素Ti-Nb对低碳贝氏体钢组织和力学性能的影响

试验的700 MPa级低碳贝氏体钢由30 kg真空感应炉熔炼铸成断面100 mm×50 mm扁锭-轧成12mm板。通过CCT曲线和3～30℃/s冷却速度下组织的分析,研究0.01Ti-0.03Nb和0.06Ti-0.05Nb两种微合金化对(%)0.059～0.066C、1.41～1.67Mn、0.30～0.36Si、0.37～0.48Cu、0.21～0.24Ni、0.18～0.22Mo、0.000 8～0.002 2Bs、0.002 6N低碳贝氏体组织和力学性能的影响。结果表明,0.06Ti-0.05Nb钢的强度高于0.01Ti-0.03Nb钢,但前者Ti含量高,-40℃冲击功较后者低。700 MPa级低碳贝氏体钢合适的微合金化Ti-Nb成分为0.04%～0.05%Nb-0.015%～0.025%Ti。     

Effect of Microalloying Additions on the Microstructure and Mechanical Properties of Low Carbon Steel

Low carbon steels are characterized by good weldability,formability and fracture toughness properties.However,the low strength levels of these steel grades limit their wide applications.On the other hand,increasing the strength by increasing the carbon content and alloying elements deteriorates the other properties.In this study,the microalloying technique was used to examine the possibility of attaining low carbon steels with good combination of strength,ductility and impact properties.A low carbon steel microalloyed with single addition of vanadium and another one microalloyed with combined addition of vanadium and titanium were used in this investigation and their properties were compared with non-microalloyed low carbon steel having the same base composition.Furthermore,other two nonmicroalloyed and V-microalloyed steels with higher carbon,silicon and manganese contents were also investigated to reveal the effect of base composition.Tensile,hardness,room and zero temperature Charpy V-notch impact tests were conducted to evaluate the variations in the mechanical properties of low carbon hot forged steel containing vanadium and combinations of vanadium and titanium.In addition,the microstructures of the different investigated steels were observed using both optical microscope and scanning electron microscope.Furthermore,the hardness of the ferrite phase was also determined using micro-hardness technique.The results showed improvement of the mechanical properties of the investigated steels by both single V-and combined V + Ti-microadditions.Tensile,hardness and impact tests results indicated that good combinations of strength,ductility and impact properties can be achieved by V-microalloying addition.Steel with combination of V and Ti microaddition has much higher hardness,yield strength,ultimate tensile strength and impact energy at both room and zero temperatures compared with non-microalloyed and single Vmicroalloyed steels.Higher C,Si and Mn contents result in increasing the strength accompanied with decrea     

轧制工艺参数对0.06C-0.31Mo微合金化高强度钢组织和性能的影响

用Gleeble热模拟试验机研究了0.06C-0.31Mo V-Nb-Ti-B微合金化钢再结晶区压下率(35.0%~ 52.0%)、非再结晶区压下率(60.2%～70.3%)、冷却速度(20~38 ℃/s)等轧制参数对钢的组织和机械性能的影响。试验结果表明,随着轧后冷却速度加大,上贝氏体的体积比增加导致钢强度的提高;贝氏体基体中针状铁素体 含量越多,上平台能(USE)越大,韧-脆转变温度越低,因此,贝氏体基体中针状铁素体能改善管线钢的机械性能。     

冷轧变形量对Nb-Ti微合金化IF钢组织和性能的影响

试验研究了Nb-Ti微合金化无间隙原子(IF)钢(/%:0.006C、O.005Si、0.15Mn、0.008P、0.006S、0.039A1、0.01Nb、0.048 Ti、0.003 4N)在实验4辊冷轧机由3.98 mm热轧机冷轧至0.4mm(变形量40%～90%)过程组织和力学性能的变化。结果表明,随着冷轧变形量的增加,Nb-Ti微合金化IF钢组织中晶粒逐渐变为细小且纤维化,第二相粒子趋于沿轧制方向排列;钢的硬度、屈服强度、抗拉强度均增加,伸长率下降。变形量在75%和77%时出现低的屈强比,并可获得好的综合力学性能。     

Effect of Nb-V Microalloying on Microstructures and Mechanical Properties of Medium Carbon Non-Quenched and Tempered Steel

Based on optical microscope(OM),transmission electron microscope(TEM) and mechanical performance measurement,the microstructures and mechanical properties of Nb-V micro-alloying non-quenched and tempered steels have been studied.The results showed that the microstructure consists of ferrite and pearlite,in which there exists a lot of intragranular ferrite.Niobium carbide is the main form of carbonitrides,Nb-enriched carbonitrides refine grains,V-enriched carbonitrides have precipitation strengthening effect,which promotes the toughness of the studied steel.The mechanical properties for steels 1,2 and 3 have met the standards required by high load automobile crankshaft,in which the comprehensive property for No.2 is the best.     

Effect of M-EMS Parameters on Quality of 82B High Carbon Steel

In this paper,the rule of M-EMS onΦ250mm 82B high carbon steel during the casting process was investigated by numerical simulation and experiments.The influence of M-EMS current and frequency on distribution of flow field was researched.The simulation results show that:At the same current,velocity increases with the frequency increase.With the increase of frequency,the velocity first decreases and then increases as the frequency increase along the casting direction.At the same frequency,velocity increases with the current increase.The turbulence zone also become more strenuous,especially in free surface,the suitable turbulence is benefit to uniform steel temperature.Experiment results show that the quality defects of 82B high carbon steel can be significantly improved with M-EMS.The zone of central pipe decreases.With the increase of current,equiaxed zone ratio increases.Considered the results of numerical simulation and experiments,the optimized EMS parameters ofΦ250mm high carbon steel are the stirring current of 480A and the stirring frequency of3Hz,which can improve strand quality greatly.     

轧制-直接淬火参数对Ti-B微合金化低碳Si-Mn钢组织和性能的影响

用0.06%(Ti+B)微合金化(%)0.17C-0.92Si-1.63Mn钢135mm连铸坯在实验室φ500mm中厚板轧机轧成24 mm板材,试验了终轧、开始和终止水冷温度对实验钢组织和力学性能的影响。结果表明,终轧920℃开冷900℃终冷180℃,冷却速度30℃/s和终轧880℃,开冷860℃终冷280℃,冷却速度22℃/s,钢的组织和性能与传统的880℃1h淬火+220℃ 6 h回火的组织和性能相当。     

Nb-RE微合金化对复杂刀具用TGM2高速钢组织和性能的影响

Nb-RE微合金化TGM2高速钢(%:0.88～0.89C、4.14～4.16Cr、4.73～4.76Mo、6.09～6.12W、1.85～1.86V、0.05～0.10Nb、0.05～0.06RE)由25 t EAF-30 t LF(VD,加Nb-RE)-1 t ESR工艺冶炼.试验结果表明,经Nb-RE微合金化后,TGM2高速钢Φ96 mm材淬火晶粒尺寸明显细化,晶粒度由原来未微合金化钢的9.5级提高至10～10.5级;淬、回火后硬度HRC为65.2～65.8,600℃4 h红硬性HRC为62.1～62.3,Nb-RE TGM2钢制成刀具的切削寿命较原TGM2钢提高20%.     

Nb、Ti碳化物的溶解与析出对低C微合金钢组织和性能的影响

采用理论计算方法分析了Nb、Ti碳化物在低C微合金钢(%:0.09C、1.42Mn、0.035Nb、0.012Ti)奥氏体中的溶解与析出,测试了不同加热温度下奥氏体晶粒尺寸以及固溶-时效后实验钢的硬度。结果表明,Nb、Ti碳化物在1060℃全部溶解,800℃时效时,奥氏体中的Nb、Ti基本以NbC、TiC形式析出。700℃时效时,Nb、Ti碳化物在铁素体内析出,随温度降低,碳化物析出减慢。600℃时效,钢的硬度达到最大值。