冷轧工艺对IF钢r值和n值的影响

研究了经铁素体区热轧后的IF钢板坯在随后的一次冷轧和两次冷轧工艺中所表现出的深冲性能规律。试验结果表明：经两次冷轧及两次退火后，IF钢的深冲性能获得了明显的良性遗传，在应变硬化指数n有所提高的情况下，塑性应变比r超出一次冷轧工艺相应值的30％左右。同时发现，两次冷轧工艺中总变形率在前后两次轧制中的分配方式是影响IF钢最终性能指标的关键。     

超深冲冷轧薄钢板（IF钢）的研制

一种能满足汽车制造厂生产难冲件要求的新型超深冲冷轧薄板,即钛、铌复合添加的无间隙原子钢(IF钢)BWJ18于1990年底在宝钢试制成功。实验室试验研究对成分、轧制工艺和退火工艺参数的选择提供了可靠的依据。 BWJ18超深冲冷轧薄板,其工艺流程为转炉冶炼→RH真空脱气→连铸→热轧→酸洗→冷轧→连续退火→平整。 BWJ18超深冲冷轧薄板的成品综合性能良好,其塑性应变比r值,加工硬化指数n值、延伸率δ都较高,无时效,无屈服平台。 BWJ18超深冲冷轧薄板在汽车制造厂的实冲试验,表明宝钢生产的IF钢能满足汽车厂生产难冲件的要求。     

IF钢平面各向异性与制耳效应的研究

分析了提高IF钢的冷轧压下率、调整Ti和Nb含量等方式对IF钢平面各向异性性能及后续深冲过程制耳的影响。结果表明,冷轧压下率从70%提高至82%,IF钢的各向异性性能得到改善;在冷轧压下率为82%时,加入适量Nb元素代替部分Ti,Δr和r值下降的同时制耳指数增加;制耳是塑性应变比和平面各向异性度综合作用的结果。     

冷轧压下量对铁素体区热轧Ti—IF钢冷轧板深冲性能的影响

研究了于铁素体区润滑热轧的Ti-IF钢在随后的冷轧及退火工艺中深冲性能的变化。结果表明，在冷轧压下量为75%时IF钢所获得的r值最高，织构分析表明，于铁素体区润滑热轧的IF钢具有较强的[111]//ND再结晶织物组分；冷轧时采用75%的压下量和随后的退火工艺可获得最强的[111]//ND再结晶织构，冷轧压下量进一步增加时。[111]//ND再结晶织构将会削弱。这种织构变化与冷轧时ND纤维晶粒内部的剪切带变化有关。     

高强深冲冷轧170P1板的试验研究

以高强IF钢(170P1)为研究对象,采用2种不同热轧工艺(常规热轧工艺、铁素体区热轧工艺)及随后相同的冷轧工艺、罩式炉退火及平整工艺进行了工业试制,试制结果表明:采用铁素体区热轧工艺,热轧板预退火及冷轧后,利用罩式炉退火就可保证高强IF钢的r值达2.1,采用这一工艺生产的高强IF钢板在汽车厂生产翼子板等难冲件时合格率可达100%.     

冷轧压下率对铁素体区热轧Ti-IF钢冷轧板深冲性能的影响

研究了于铁素体区润滑热轧的Ti-IF钢在随后的冷轧及退火工艺中深冲性能的变化.结果表明,在冷轧压下率为75 %时IF钢所获得的r值最高.织构分析表明,于铁素体区润滑热轧的IF钢具有较强的{111}∥ND再结晶织构组分;冷轧时采用75 %的压下率和随后的退火工艺可获得最强的{111}∥ND再结晶织构;冷轧压下率进一步增加时,{111}∥ND再结晶织构将会削弱.这种织构变化与冷轧时ND纤维晶粒内部的剪切带变化有关.     

铁素体轧制生产超深冲冷轧板

通过铁素体轧制生产超深冲冷轧Ti-IF钢的工业试验,研究了化学成分、工艺制度对热轧IF钢金相组织、织构和第二相粒子析出的影响,分析了热轧IF钢再结晶状态与产品性能的关系,阐述了提高冷轧Ti-IF钢深冲性能的生产控制要素.试验结果表明:在采用适宜的成分、低的加热温度、高的卷取温度和铁素体区强润滑轧制时,热轧板具有粗大的二相粒子和强的{111}织构;与常规轧制相比,冷轧板的r值在横向和45.方向平均提高1.3和1.0,试验冷轧板的最高r值达到了3.23.     

退火工艺对冷轧高强IF钢组织及织构的影响

为了观察高强IF钢退火处理后的显微组织和再结晶织构的变化规律,采用两种不同退火工艺对高强IF钢进行热处理。结果表明,IF钢在两种退火方式下均形成了γ-{111}纤维织构,快速升温(350℃/min)退火时,再结晶新核呈等轴状,由变形带内的亚晶合并形成,与冷轧变形基体保持相同取向。慢速升温(2℃/min)退火时,新核在晶界弓出形成,且沿轧制方向呈饼形分布,与基体没有明显取向关系。慢速升温退火样品的γ-{111}取向密度强于快速升温的。对进一步改善薄板钢深冲性能具有指导作用。     

IF钢铁素体区热轧工艺参数对深冲性能的影响

 采用润滑轧制,在不同压下率、终轧温度及退火制度下,研究了IF钢铁素体区热轧时,不同工艺参数对IF钢深冲性能的影响。结果表明：在实验范围内,随压下率增加,r值提高;终轧温度下降,r值略微增加;高温退火可使变形铁素体充分再结晶,从而提高r值。ODF织构分析结果与检测结果是一致的。     

深冲用超低碳冷轧带钢DC04生产实践

介绍了安钢冷轧在1 550 mm酸连轧、1 550 mm连续退火生产线上对深冲级IF钢的生产工艺,包括酸连轧、退火、平整工艺设计和采用的工艺措施。通过合理制定轧机压下率和退火温度工艺开发的DC04钢种,组织性能优良,对于批量生产深冲性能带钢具有重要的意义。     

Effect of Annealing Time on Microstructure and Mechanical Properties of Cold-Rolled Niobium and Titanium Bearing Micro-alloyed Steel Strips

Effects of annealing time on microstructure of cold-rolled niobium-titanium bearing micro-alloyed steel strips were investigated by optical microscopy, scanning electron microscopy, electron back-scatter diffraction (EBSD) and transmission electron microscopy. The complete recrystallization annealing temperature of 670 °C and complete annealing time of 9 min were determined using Vickers-hardness testing and EBSD analysis. The ferrite microstructure with spheric cementite particles and nano-scale precipitates of Nb(C, N) in matrix was obtained. The kinetics of the ferrite grain growth is lowered due to ferrite grain boundaries pinned by the cementite particles, so the ferrite grain size of 5. 5 μm remains unchanged among the annealing time ranging from 9 to 30 min. In addition, the strength of tested steel also keeps unchanged with the increase of annealing time. The higher yield strength of approximately 420 MPa can be obtained by grain refinement and precipitation hardening and the higher elongation of approximately 40% and work-hardening exponent of approximately 0. 2 can be gained due to grain refinement and presence of cementite particles, indicating that the balance of strength, ductility and forming property is realized.     

受热不均匀对低碳钢SAE1010板材组织及成形性能的影响

为了研究退火过程受热不均匀对板材组织及成形性能的影响规律,对热轧态SAE1010低碳钢板进行冷轧及连续退火,分析热轧态、冷硬态及退火态钢板边部和芯部的显微组织,分别对退火态钢板边部和芯部试样进行拉伸和折弯试验。结果表明,热轧态试样少量岛状珠光体分布在铁素体晶界处,边部组织晶粒尺寸小于芯部,珠光体中部分片层渗碳体退化为球状。冷硬态板材组织沿轧制方向呈现明显的晶粒破碎特征,退火态边部组织存在较多的大晶粒和粒状渗碳体团,芯部组织较为均匀细小。退火态板材芯部材料伸长率高于边部而强度低于边部,经180°折弯后芯部钢板无开裂而边部出现裂纹。退火温度均匀性对于SAE1010低碳钢板组织和性能具有重要的影响。     

700MPa冷轧低合金超高强钢的典型连续退火工艺

为了开发新一代冷轧低合金超高强钢,利用连续退火实验机对Ti-0．12％、Nb-0．076％的冷轧低合金超高强钢进行连续退火实验,设计了760~830℃四种不同退火温度,研究了退火温度对实验钢的相组成、晶粒尺寸和力学性能的影响．在800℃退火、400oC过时效的条件下,可得到铁素体和少量贝氏体的组织,铁素体晶粒尺寸约为1．4μm,屈服强度可达700MPa．同时利用扫描电镜和透射电镜观察到钢中存在大量纳米尺寸的亚晶结构、少量位错以及纳米级的Ti、Nb的析出物．这些微结构单元对强度有较大的提升作用．      

无取向电工钢连续退火模拟在生产中的应用

应用MULTIPAS连续退火机试验机,对冷轧无取向电工钢进行连续退火工艺模拟,通过对试验工艺的不断完善,实现了对无取向电工钢连续退火温度曲线、张力的模拟,通过有效的板形控制措施,试验样板板形完全满足单片磁性能检测和力学性能检测需要,从而使该模拟方法模拟的试验结果超出纯理论研究的范畴,能够有效应用到生产实践中。     

DC01EK冷轧搪瓷用钢开发及其抗鳞爆性能

在保证成形性能和抗鳞爆性能的前提下,以传统冷轧板DC01的成分为基础,适当的提高碳、锰和硫的含量,通过热轧、冷轧和退火工艺控制,获得了一种低成本高贮氢性能的搪瓷用钢。钢板的屈服强度不大于270 MPa,抗拉强度不大于400 MPa,伸长率不小于30%。钢板中的Fe3C和MnS均为有效的贮氢陷阱。随着退火温度的升高,Fe...     

快速加热条件下BH钢再结晶规律

 通过Gleeble-3500热模拟试验机以及运用金相、显微硬度、EBSD技术等研究方法,研究了不同加热速率对BH钢再结晶退火组织和织构演变的影响。结果表明：再结晶温度随加热速率的提高而升高。加热速率的提高,缩短了BH钢完成再结晶所需时间。快速加热条件下,BH钢再结晶晶粒得到细化,再结晶织构组分强度降低。EBSD分析发现：提高加热速率,再结晶完成后,再结晶织构仍以有利于深冲性能的管状γ织构为主。再结晶结束后,升高温度和增加保温时间有助于{111}织构的发展。在780℃保温一定时间的条件下,低加热速率形成以{111}〈112〉组分为主的再结晶织构,而快加热速率下{111}〈110〉织构组分得到一定的发展,γ织构强度分布更加均匀,有利于BH钢的成型性能。     

冷轧低碳冲压门板用钢的生产开发

以冷轧低碳钢为原料,通过对化学成分、退火工艺等方面改进,试制生产冷轧低碳冲压门板用钢。试制结果表明试制生产的低碳冲压门板用钢力学性能稳定,钢卷表面质量优良,很好地满足了用户使用要求。     

Surface rust of cold-rolled bell-type annealing strip steel

This paper offers systematic analysis and in-depth research on the surface rust problem of cold-rolled bell-type annealing strip products.The defect characteristics,occurrence rules,generation mechanism,and influencing factors of surface rust are presented.This research employed a cold-rolled bell-type furnace annealing unit in a coastal steel factory as an example and conducted production process tests,on-site production tests,scanning electron microscopy,energy spectrum analysis,MINITAB statistical analysis,etc.Moreover,six significant influencing factors and their rules were studied:the cooling time of the final cooling table,the storage time of the intermediate storage,the temperature setting of the intermediate storage,the temperature of leveling liquid,the purging pressure of leveling machine,and the dust in the environment.     

冷轧微碳深冲钢板的非{111}织构及其形成原因和对策

结合实际生产和实验室实验,介绍了试制的冷轧微碳深冲钢板中出现的远离常规的非{111}织构的情况。分析了这种非{111}织构的特征及其对钢板塑性应变比的影响,并研究了非{111}织构的工序演变过程及冷轧织构的形成特点,在此基础上进一步分析了非{111}织构的热轧原因,并研究了冷轧压下率和罩式退火升温速度对非{111}织构的影响。最后,依据非{111}织构的形成特点和{111}织构的产生条件提出了控制冷轧微碳深冲钢板织构的对策。     

Effects of heat treatment and alloying elements on the microstructures and mechanical properties of 0.15 wt pct C transformation-induced plasticity-aided cold-rolled steel sheets

The main emphasis of this study has been placed on understanding the effects of manganese and silicon additions and of heat-treatment (intercritical annealing and isothermal treatment) conditions on the microstructures and mechanical properties of 0.15 wt pct C transformation-induced plasticity (TRIP)-aided cold-rolled steel sheets. The steel sheets were intercritically annealed and isothermally treated at the bainitic region. Microstructural observation and tensile tests were conducted, and volume fractions of retained austenite were measured. Steels having a high manganese content had higher retained austenite fractions than the steels having a low manganese content, but showed characteristics of a dual-phase steel such as continuous yielding behavior, high tensile strength over 1000 MPa, and a low elongation of about 20 pct. The retained austenite fractions and mechanical properties varied with the heat-treatment conditions. In particular, the retained austenite fractions increased with decreasing intercritical annealing and isothermal treatment temperatures, thereby resulting in the improvement of the elongation and strength-ductility balance without a serious decrease in the yield or tensile strength. These findings suggested that the intercritical annealing and isothermal treatment conditions should be established in consideration of the stability of austenite and the solubility of alloying elements in the austenite formed during the intercritical annealing.