罩式炉退火工艺对IF钢性能的影响

以CSP工艺IF钢为研究对象,利用硬度测量、显微组织观察和力学性能检测等方法研究了退火工艺对IF钢再结晶和组织性能的影响。结果表明:CSP工艺IF钢的再结晶温度为670~680℃;高的加热温度和较长的保温时间有利于改善IF钢深冲性能。     

退火温度对双辊薄带连铸高强度无取向硅钢组织和性能的影响

摘要：研究了退火温度对双辊薄带连铸Si质量分数为3.2%的高强度无取向硅钢组织、织构和性能的影响。结果表明,700℃保温时试验钢开始发生再结晶;800℃保温时,试验钢已完全再结晶,平均晶粒尺寸为26.4μm;900和1000℃保温时,试验钢中的晶粒开始逐渐长大,平均晶粒尺寸分别长大到33.8和40.9μm,且900℃退火时晶粒组织最均匀。随着退火温度的升高,试验钢中有利织构组分λ织构逐渐增强,Goss织构则在900℃退火时强度最强。因此,试验钢在900℃退火时有利于兼顾磁性能和力学性能。     

卷取温度和冷轧压下率对高强度IF钢力学性能的影响

以不同卷取温度(分别为670℃和710℃)工业生产的高强度IF钢热轧板为研究材料,进行了不同冷轧压下率(分别为55%、65%、75%和85%)的实验室冷轧试验,结合连续热镀锌线的工艺特点进行了盐浴退火试验,采用金相和力学性能测试方法,研究了热轧卷取温度和冷轧压下率对高强度IF钢力学性能的影响。结果表明,较低温度卷取时,热轧卷晶粒尺寸较细,冷轧退火态晶粒尺寸相对较粗,rm值相对较低。冷轧退火态仍具有较细小的晶粒,但屈服强度明显降低,这与间隙碳原子在退火过程通过NbC粗化被大量清除有关。卷取温度对试验钢冷轧退火态的强度、断后伸长率和nm值几乎没有影响。随着冷轧压下率从55%增加到75%时,退火后铁素体晶粒尺寸变化不明显,当冷轧压下率进一步增加到85%时,铁素体晶粒尺寸有所减小。冷轧压下率对强度和断后伸长率影响较小,对nm值没有影响,而rm值随着冷轧压下率的提高而提高。     

Nb-Ti高强IF钢板最优再结晶退火温度确定

以工业生产的Nb-Ti高强IF钢为试验材料,在实验室研究了退火温度对试验钢的显微组织、力学性能和织构的影响.结果表明:在试验条件下,退火温度750℃时,试验钢为未完全再结晶组织,退火温度升高至780 ～870℃时,试验钢均为完全再结晶组织；随着退火温度的升高,试验钢的ReL、R(ns)逐渐降低,A50、Ae逐渐增加.退...     

CSP工艺冷轧薄板盐浴退火再结晶实验

 研究了以CSP工艺热轧板卷为原料的冷轧薄板在盐浴退火过程中的再结晶行为,通过显微组织、显微硬度及电子背散射衍射技术观察、分析揭示了再结晶的规律,结果表明,CSP工艺冷轧薄板经盐浴退火后的再结晶组织为等轴状晶粒;在相同温度下盐浴退火,冷轧压下率较大时,完成再结晶所需的保温时间较短,再结晶晶粒细小。     

IF钢罩式退火过程中再结晶组织与织构的演变

研究了IF钢(/%:0.005C、0.02Si、0.16Mn、0.011P、0.004S、0.042Als、0.061Ti、0.003 1 N)0.8 mm冷轧板在500～800℃退火时的再结晶组织及织构,采用X射线衍射技术结合微观组织观察分析了IF钢罩式退火过程中{111}再结晶织构形成机制和显微组织演变规律。结果表明,随退火温度的升高,再结晶数量逐渐增多,640℃为实验钢实际再结晶温度,同时{111}再结晶织构强度亦逐渐增大,{111}取向的晶粒主要在再结晶过程中形成,并在{111}取向晶粒长大过程中,γ纤维织构之间也发生相互转化,主要由{111}〈112〉织构转变为{111}〈110〉织构。     

卷取温度对微合金化含磷钢薄钢板组织和性能的影响

以低碳微合金化含磷钢为研究对象,通过分析热轧态和冷轧退火态的显微组织和力学性能以及退火再结晶动力学行为,研究了卷取温度(600、650、700℃)对微合金化含磷钢组织和性能的影响.研究结果表明,热轧卷取温度对微合金化含磷钢的显微组织和力学性能有显著的影响,随着热轧卷取温度从700℃降低到600℃,试验钢退火再结晶受到明显延迟,再结晶激活能明显提高;卷取温度对热轧态和退火态铁素体晶粒尺寸影响较小,但热轧态强度随着卷取温度降低而提高;随着卷取温度的降低,冷轧退火态的强度提高,且力学性能对退火温度的敏感性增加.     

卷取温度对高强IF钢再结晶及织构的影响

为了研究卷取温度对高强IF钢250P1罩式退火再结晶规律的影响,采用氮气炉加热模拟罩式退火工艺,研究了高温及低温卷取工艺下含磷高强IF钢250P1冷轧板再结晶规律;采用X射线衍射仪对700 ℃模拟退火板及罩式退火成品板进行了织构分析,并对成品板金相组织进行了观察。结果表明,低温卷取冷轧板再结晶温度约为675 ℃,高温卷取冷轧板再结晶温度约为700 ℃;低温卷取退火板具有较高强度的{111}有利织构、较高的{111}/{100}比值以及r值,成品板的饼形晶粒更大。     

铌微合金化对高Al冷轧TRIP钢组织与力学性能的影响

采用二段式盐浴热处理、金相显微镜(OM)、扫描电镜(SEM)、X射线衍射(XRD)和拉伸实验等方法,研究了添加0.025%微合金元素Nb对高Al(1.5%Al)冷轧相变诱导塑性钢(TRIP)组织与性能的影响规律.结果表明:Nb微合金化使高Al冷轧TRIP钢在连续退火后组织得到细化,残余奥氏体含量及其碳含量比无Nb钢均有所升高.含Nb钢在370℃和400℃等温后抗拉强度均大于650MPa,且总伸长率达到35%,具有优异的综合力学性能.Nb微合金化,将本实验所研究的高Al冷轧TRIP钢的最优贝氏体区等温温度由400℃左右扩大到370~400℃,提高了生产的工艺稳定性.     

IF钢罩式退火再结晶晶粒分布函数

研究了两种加热速率（200℃/min和50℃/h)下60％,70％和80％冷形变量的IF钢罩式退火再结晶晶粒分布规律;当冷变形量大于或等于70％时,IF钢再结晶晶粒分布符合对数正态分布,在此基础上采用非线性回归求出再结晶晶粒尺寸分布函数（SDF）;研究结果表明,形变量对再结晶晶粒的影响比加热速率显著。     

Determination of Optimal Recrystallization Annealing Temperature of Nb-Ti Microalloyed High Strength IF Steel

The Nb-Ti microalloyed high strength IF steel sheet was used to study the effect of annealing temperature on the microstructures,mechanical properties and textures.The experimental results show that experimental steel is incomplete recrystallization at 750℃ annealing,but complete recrystallization from 780℃ to 870℃ under experimental conditions.When the annealing temperature was increased,the yield strength and tensile strength would gradually reduce,the plastic strain ratio and yield point elongation would gradually increase.The yield strength,tensile strength,elongation,the plastic strain ratio and the strain hardening exponent were approximate 300MPa,410MPa,36.5%,1.7 and 0.22 respectively under annealing temperature 810℃ to 840℃.When the annealing temperature was increased,the α-textures and γ-textures were gradually weakened,and the α-textures have a trend to {111} texture.Therefore,the suggestion of the optimal recrystallization annealing temperature is about 810℃ to 840℃ in industrial production.     

退火工艺对汽车用高强度IF440热镀锌钢板性能和织构的影响

通过在CAG-2000模拟机上对汽车用高强度IF440热镀锌钢板进行退火,采用OM研究退火后的显微组织;用拉伸试验研究其力学性能;采用EBSD分析其退火织构的演变规律.结果表明,在790～850℃范围内钢板都充分再结晶;伸长率和n值随退火温度的升高先升高后降低,γ值则随保温时间的延长呈先升高后降低的趋势;并且升高退火温...     

退火温度和时间对含磷高强IF钢组织性能的影响

以超低碳含磷高强IF钢为研究对象,在实验室条件下进行了冷轧及模拟退火试验。结果表明,随退火温度的升高及退火时间的延长,试验钢再结晶越完全,晶粒形状更趋近等轴晶;试验钢退火后具有较强的{111}110和{111}112织构;采用700~720℃退火4 h可使试验钢各项力学性能指标满足标准要求。     

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。     

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On industrial scale, high strength P- containing IF (Interstitial Free) steels were produced with both batch annealing and continuous annealing processes and their microstructures and properties were studied. Forming abilities of the two steels were compared with commercial Al- killed steel DC01 and extreme deep drawing IF steel DC04 produced with batch annealing. The results show that the microstructures of high strength IF steels are composed of equi- axial ferrite and their mechanical properties meet the requirement of relevant standard. The batch annealed high strength P- containing steels show poorer formability than continuous annealed ones. The test results of texture and orientation distribution function (ODF) demonstrate that density of ??- fiber increases in order of batch annealed high strength P- containing IF steel, commercial DC01, continuous annealed high strength P- containing IF steel and normal IF steel DC04.     

退火工艺对铁素体不锈钢SUS410L热轧钢板组织和性能的影响

研究了不同退火温度和保温时间对SUS410L热轧态钢板再结晶行为和力学性能的影响。试验结果表明,当保温温度为700℃时,保温480 min后SUS410L热轧钢板仍未完成再结晶。当保温温度为750℃和800℃时分别于120 min和30 min基本完成再结晶,晶粒在之后的保温时间里逐步长大。为避免退火过程中出现马氏体而降低材料的延伸率,退火温度≤800℃。材料的力学性能与热处理后的再结晶程度密切相关。当保温温度为750℃且保温时间为480 min时可获得最佳的综合机械性能:延伸率38%,HRB硬度值67,屈服强度236 MPa,抗拉强度441 MPa。     

退火工艺对Cu-Ni深冲DP钢组织与性能的影响

 为了探讨Cu-Ni合金化深冲双相钢组织性能演变规律,在实验室采用DIL805A/D淬火热膨胀仪与盐浴炉对其连续冷却转变行为及连续退火工艺进行了研究。结果表明,试验钢的Ac1、Ac3分别为821与969 ℃。贝氏体转变冷却速率为0.5~60 ℃/s,铁素体转变冷却速率为0.5~5 ℃/s,冷却速率为3 ℃/s时未发生珠光体转变。在820~880 ℃退火温度范围内试验钢的组织为铁素体与岛状马氏体;随着退火温度的升高,强度与伸长率先减小后增大,而r值呈现先增大后减小的趋势。在880 ℃退火时综合力学性能最佳,屈服强度达401.2 MPa、抗拉强度达451.4 MPa、伸长率为18.6%、r值为1.21。     

Investigation on Precipitation Hardening High Strength IF Steel Sheet for Automotive Application

High strength IF steel sheets with sufficient formability had been extensively used in automotive industry.In this paper,a new type of high strength cold-rolled IF steel with higher carbon and niobium contents was studied.Thermal plastic and continuous annealing were performed on thermo-mechanical simulator.The transformation points were tested by thermal expansion apparatus.Optical microscopy and transmission election microscope (TEM) were used to analyze the microstructure and the secondary precipitates of the steel.The results showed,the ductibility temperature range was from 950℃ to 1250℃ and the transformation points were 887℃ and 913℃ respectively.The grain size of this steel was smaller than that of conventional high strength IF steel.At the mean time,there were many fine Nb(C,N) precipitates distributed in the intra-granular regions and the PFZ (precipitate free zone) were formed in the neighborhood of grain boundaries.Due to the unique micro-structural feature,the yield strength and the yield ratio of the steel were decreased while the tensile strength was increased.With the increasing of the annealing temperature,the strength decreased,the total elongation A50,r-value at 15% strain and n-value were all increased.In order to obtain the favorable mechanical properties,the skin-pass rolling rate should be chosen at 0.6-0.8%.     

Effects of Finish Rolling Temperature on Microstructure and Mechanical Properties of Ferritic-Rolled P-Added High Strength Interstitial-Free Steel Sheets

  The steels were rolled at 3 different finishing temperatures. The mechanical properties were tested by tensile tests. The results show that as finish rolling temperature decreases from 620 to 560 ℃ in ferrite region, the deep drawability of ferritic rolled P added high strength IF steels is improved, and r value rises from 114 to 137. Finish rolling temperature (FT) has less influence on other mechanical properties, such as yield strength, tensile strength and elongation. Microstructures of hot rolled and annealed steel sheets and precipitates of annealed steel sheets were also analyzed.