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The influence of continuous casting of steel on the high-temperature plasticity of microalloyed steel is investigated. The Gleeble-3800 system is used for the physical modeling of the steel’s hot plasticity. The temperature ranges of plasticity are determined in different conditions of slab cooling in the continuouscasting machine. In all the simulations, a trough is seen on the temperature dependence of the steel’s plasticity. With enlargement of the grain boundaries (decrease in grain size), the high-temperature plasticity increases. 相似文献
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汽车用超高强度双相钢CR550/980DP冷轧边裂问题,严重影响热轧/冷轧工序界面生产顺行,易造成冷轧机架间及连退炉内断带事故,成为超高强度双相钢生产的难题。基于高温热塑性曲线和热轧动态CCT曲线,采用对显微组织、力学性能、裂纹扩展分析等手段明确冷轧边裂产生原因。试验结果分别指出,精轧阶段带钢横向温度分布不均匀、边部温降大,导致在第Ⅲ脆性区轧制;同时,受Nb作用再结晶温度提高,边部低温区为未再结晶区轧制;当应变量超过塑性极限、轧制力超过边部热强度时,形成热轧卷边裂。边部形成细小弥散的铁素体(F)和马氏体(M)两相组织,不协调应变将导致F/M相界面产生应力集中而形成裂纹;裂纹以微孔聚集方式进行扩展,形成热轧卷无边裂-冷轧边裂现象。通过投用边部加热器和优化初轧定宽量、精轧入口温度、精轧机架间冷却水、终轧温度、卷取温度等措施,实现热轧卷边部质量改善、解决边裂问题。 相似文献
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汽车用超高强度双相钢CR550/980DP冷轧边裂问题,严重影响热轧/冷轧工序界面生产顺行,易造成冷轧机架间及连退炉内断带事故,成为超高强度双相钢生产的难题。基于高温热塑性曲线和热轧动态CCT曲线,采用对显微组织、力学性能、裂纹扩展分析等手段明确冷轧边裂产生原因。试验结果分别指出,精轧阶段带钢横向温度分布不均匀、边部温降大,导致在第Ⅲ脆性区轧制;同时,受Nb作用再结晶温度提高,边部低温区为未再结晶区轧制;当应变量超过塑性极限、轧制力超过边部热强度时,形成热轧卷边裂。边部形成细小弥散的铁素体(F)和马氏体(M)两相组织,不协调应变将导致F/M相界面产生应力集中而形成裂纹;裂纹以微孔聚集方式进行扩展,形成热轧卷无边裂-冷轧边裂现象。通过投用边部加热器和优化初轧定宽量、精轧入口温度、精轧机架间冷却水、终轧温度、卷取温度等措施,实现热轧卷边部质量改善、解决边裂问题。 相似文献
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《钢铁冶炼》2013,40(6):452-457
AbstractAn experimental HSLA steel was produced by the electric arc furnace, vacuum degassing, ladle treatment and continuous casting route. The experimental steel was then rolled in a laboratory using a hot rolling schedule to simulate an industrial controlled hot rolling procedure for the production of plates as closely as possible to investigate the effect of a thermomechanical processing schedule plus the use of water quench, accelerated cooling followed by forced nitrogen gas or air as cooling media, on the mechanical properties of plates. The results showed that the controlled thermomechanical hot rolling schedule of slabs followed by the cooling of plates in either forced nitrogen gas or by accelerated cooling exhibited target properties equivalent to a steel grade API X-80. 相似文献
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在过去的10年里,CSP工艺生产的产品范围不断扩展。现在它已能生产高强度结构钢、弹簧钢、工具钢、可热处理钢、耐磨钢、硅钢和不锈钢。CSP工艺浇涛区域特有的冶金条件及其直接装炉、轧制、冷却的工艺方法导致热轧带钢晶粒细、强度高、塑性好。CSP生产流程中尚可汇集形变热处理工艺,因此CSP工艺技术将技术将拓展出更广阔的产品范围。 相似文献
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用Gleeble-1500热/力模拟机研究了成分(%)为:0.20C-1.08Si-1.43Mn TRIP(相变诱导塑性)钢连续冷却时的组织,并测得动态CCT(连续冷却转变)曲线,得出冷却速度达10℃/s时出现粒状贝氏体,冷却速度15℃/s时得到板条贝氏体。在实验室模拟C-Si-Mn TRIP钢薄板坯连铸连轧工艺试验:用10 kg真空感应炉冶炼,成分(%)为:0.20C-1.54Si-1.55Mn的TRIP钢,钢锭尺寸为(mm):60×100×130,经7道次轧制成厚度6.40 mm板,终轧温度810℃,轧后空冷至700℃,再水冷至400℃模拟卷取。试验结果表明,该钢组织含有5.13%残余奥氏体,37.20%贝氏体,机械性能σb715 MPa,σs520 MPa,屈强比0.73,δ20%。 相似文献
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论述了X56钢级热连轧卷板试制的结果,该钢采用Nb-V-Ti微合金化。加控轧控冷的生产工艺。通过调整冶炼工艺提高了钢擀的纯净度,降低了钢中的硫含量;采用钙处理改变了硫化物的形态;模铸转连铸后,减轻了成分偏析,提高了钢的韧性。 相似文献
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高锰TWIP钢的塑性机制与其堆垛层错能有关。采用试验法和热力学计算法确定TWIP钢层错能的研究结果存在差异,TWIP效应与层错能的对应关系也未达成一致。高锰TWIP钢凝固温区宽,凝固时容易形成疏松、偏析等铸态缺陷。铸态TWIP钢高温时的断面收缩率均低于40%,可能导致连铸弯矫时开裂。水平连铸和双辊薄带连铸在TWIP钢生产上具有突出优势。TWIP钢的热轧温度区间窄,与其固相线温度低和高温塑性差有关。冷轧后连续退火温度和退火时间也尚在摸索之中。Fe-Mn-Si-Al系TWIP钢的强化机制以孪晶形成动态细化晶粒为主,而Fe-Mn-C-(-Al)系TWIP钢中动态应变时效可能是主导作用。TWIP钢的延迟断裂敏感性可通过Al合金化来改善,其主要机制是在试样表层下形成的α-Al2O3层阻止氢的渗入。 相似文献
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近10年中国轧钢的技术进步 总被引:1,自引:0,他引:1
简要总结介绍了近10年中国轧钢技术进步的情况,其中包括:1)近10年中国钢材产量和品种结构的发展;2)热轧宽带钢、宽厚板、大型冷连轧、三辊连轧管机组生产线的技术集成与开发,以及薄板坯连铸连轧生产线等轧钢装备现代化的发展;3)半无头轧制、薄规格轧制、100 m长尺钢轨轧制,新一代控制冷却技术等轧钢工艺技术的进步;4)轧制过程组织性能控制研究与应用,高性能高强度中厚板、冷轧带钢、长材及管材等生产技术与品种开发。最后,对今后轧钢生产技术的发展作了展望。 相似文献
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采用微合金化技术及ASP连铸连轧工艺和控轧控冷工艺,济钢自主研发了S450热轧管线钢带产品。该产品钢质纯净,焊接性能优良,具有很高的强度、良好的韧性和耐腐蚀性,各项技术指标均符合标准的要求。 相似文献
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In the concept of direct charging linking continuous casting with rolling of thin slabs, some differences in the design of process parameters are necessary. By example of a commercial low carbon NbTi-microalloyed steel, laboratory tests have been carried out by using a thin-slab continuous casting simulator on-line with the hot deformation simulator Wumsi. The influence of the temperature of intermediate holding (between casting and rolling), total strain εΣ, finishing temperature and cooling rate after finishing on the microstructure and mechanical properties was investigated on rolling schedules with or without roughing prior to finishing. Conventional cold charging (with reheating of thicker slabs) was simulated as a comparison to this. Whereas the static properties (tensile test) were less influenced by εΣ and by the design of rolling schedule (with or without roughing), the properties measured by the low temperature impact test (at -30°C) were more sensitive. By the optimizing process parameters of direct charging (finishing at temperatures of lower austenite, employing accelerated cooling after rolling) mechanical properties superior to those of cold charging (despite of largely reduced εΣ) are attainable. 相似文献
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建立温度计算模型针对22 mm和28 mm规格20MnSi棒材热连轧及控制冷却过程温度场进行了计算机模拟分析,获得了棒材精轧及轧后分级控冷过程的温度变化规律。对轧制圆钢和螺纹钢筋不同条件下成品道次温度变化特点进行了研究。研究结果是,轧制22 mm和28 mm规格20MnSi螺纹钢筋时的终轧温度比轧制相同规格圆钢时显著升高。轧制螺纹钢筋时精轧末道次轧材表层形成螺纹出现较大的局部应变量和应变速率,由此产生大量变形热是终轧钢筋表层急速升温的根本原因。与轧制圆钢相比,为完成同等控冷效果及有效控制轧后组织性能,20MnSi螺纹钢筋精轧后第1水冷段的换热系数明显较高,因此需要相应采用较大的冷却水量。 相似文献
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In the twin-roll strip casting process,hot cast strips can be broken or torn if the casting speed does not match the rolling speed.Usually,a certain length of hot steel strip is hung freely between the caster and rolling mill to deal with the effect of this speed difference.In this paper,the freely hanging hot steel strip is referred to as the free loop of hot steel strip.Accurately measuring and controlling the height of this free loop is the key factor in maintaining a stable casting operation.Several methods for measuring the loop height of a steel strip are discussed and a method for accurately measuring and controlling the free loop height of hot steel strip is presented.Based on the results of the casting loop quantity change curve,this control method is confirmed to be effective and able to meet the requirements of continuous casting strip production. 相似文献