Q345BH型钢高应变低周疲劳性能研究

根据建筑用钢在地震时的受力状态,阐述了钢材的高应变低周疲劳性能在抗震设计中的重要性,讨论了静载荷强度、塑性与低周疲劳性能间的关系,并对材料在高应变和地震载荷谱下的疲劳性能进行了研究,试验结果表明莱钢生产的Q345BH型钢在地震谱载荷下具有较好的抗震性能。     

Q345B H型钢高应变低周疲劳断口分析

介绍了典型的拉-压疲劳失效的形成机理、宏观形貌以及微观形貌,并对Q345B H型钢高应变低周疲劳断口进行了分析,为今后进行相关疲劳研究奠定基础。     

HRB500E钢筋高应变低周疲劳性能研究

针对钢筋在地震载荷下的失效模式,在恒应变条件下对HRB500E钢筋的高应变低周疲劳性能进行系统测试。利用威布尔双参数方法对疲劳寿命进行了统计分析,得出了不同置信度下的疲劳寿命和95%置信度下的循环韧度。并对疲劳机理和进一步提高高强钢筋高应变低周疲劳性能的途径进行了讨论。     

高强度热轧H型钢的开发

分析了高强度（Q345）热轧H型钢的特殊性能要求，论述了新产品化学成分优化设计思路，介绍了新产品生产的工艺流程，采用了各种先进技术提高产品的实物质量，探讨了解决高强度与良好塑韧性相矛盾的对策、铌微合金化的机理、新产品焊接性、异形连铸坯与H型钢质量的关系等问题。     

含铌Q275D热轧H型钢的研制

为保证莱钢Q275D热轧H型钢极限规格的-20℃冲击功值满足GB/T 700-2006要求,采用Nb微合金化结合再结晶控轧工艺试制了极限规格H400mm×200mm×8mm×13mm的Q275D热轧H型钢。结果表明:试制产品的上屈服强度为360~368 MPa,抗拉强度为480~500 MPa,伸长率为32.5%~33.0%,平均冲击功为154~233J,各项性能指标满足标准要求。     

H型钢及其微合金化的进展

简述了国内外Ｈ型钢的发展情况，以及国际上Ｈ型钢微合金化，控轧控冷技术的最新进展，概述了马钢在钢材微合金化技术方面的发展情况，提出了马钢Ｈ型钢在微合金化方面的发展建议。     

欧标耐低温热轧H型钢质量改善研究

山钢股份莱芜分公司采用V-N微合金工艺开发了欧标耐低温热轧H型钢,但产品冲击性能不合、翼缘内侧裂纹。为此,对原工艺进行优化,采用V-Ti微合金化工艺替代V-N微合金化工艺后,利用Ti的细化晶粒作用,冲击性能明显提升,最高达到115 J。产品单批次生产过程中在腹板出现裂纹,经分析产生的原因是钢中N含量较高,与V、Ti等合金元素形成氮化物在晶界析出导致了异型坯裂纹的发生,采用V-Fe合金代替部分V-N合金后,消除了腹板裂纹的产生。     

工程结构钢在地震载荷下的高应变低周疲劳性能

本文从工程结构钢在地震时受力状况出发,阐述了钢材的高应变低周疲劳性能在抗震设计中的重要性。讨论了静强度、塑性与低周疲劳抗力间的关系和微合金化、焊接、应变时效等因素对低周疲劳性能的影响以及在地震载荷谱下钢材的随机疲劳抗力。对含V抗震钢筋钢22MnSiV在地震载荷下的高应变低周疲劳性能与常用几种工程结构钢作了对比试验。     

极低屈服点钢低周疲劳特性

对100 MPa级的极低屈服点钢BLY100进行了包括模拟地震载荷的系列高应变低周疲劳试验。试验结果表明,BLY100钢板具有良好的低周疲劳性能,完全满足抗震设计用钢的需要。     

热轧薄壁高强度H型钢的数值模拟

应用所建立的有限元模型在Deform平台下结合550MPa轻型薄壁H型钢的成分设计,系统模拟研究了550MPa轻型薄壁H型钢的控制轧制工艺,模拟了关键道次的轧制过程,得到了轧件在轧制过程中的轧制力等参数,为薄壁H型钢的实际生产提供了理论依据,为该H型钢开发建立了理论和实验基础。     

低成本超高强度热轧锚杆钢筋的开发

利用新建100万t棒材车间具备完善的控制空冷的条件优势,通过制定合理的工艺方案和可控轧控冷参数,采用微合金化+控轧控冷工艺路线,成功开发出低成本、超高强度的热轧锚杆钢筋。经检测,该产品屈服强度达到690 MPa,抗拉强度达到860 MPa,冲击功达到36 J,具有良好的综合性能。     

Effects of Strain Rate on Low Cycle Fatigue Behaviors of High-Strength Structural Steel

 The low cycle fatigue (LCF) behavior of a high-strength structural steel was investigated in the strain rate range of 4×10-5-0. 12 s-1 (0. 001-3 Hz) under constant total strain (±1%) control. The cyclic stress response at all strain rates exhibited behavior of rapid softening in the early stage of fatigue life and subsequent saturation up to failure. It was found that the stress amplitude, the plastic strain amplitude, the plastic strain energy density and the fatigue life depend mainly on the strain rate. The strain rate of 0. 012 s-1 was found as a transition point where the LCF of the steel showed different behavior from low strain rate to high strain rate. The relationship between the time to failure and strain rate was expressed well by a power law relation. The fracture surfaces of the fatigue samples were characterized by using a scanning electron microscope (SEM) and the fracture mechanisms were discussed in terms of time-dependent deformation of the steel.     

含铌微合金化热轧多相钢的控轧控冷工艺

通过热轧试验研究了两阶段轧制+层流冷却、空冷、超快冷的TMCP工艺对高硅铌钢、高硅Nb-Ti钢、低硅Nb-Ti钢显微组织和力学性能的影响。结果表明,控轧控冷后的试验钢含有铁素体、贝氏体、马氏体以及少量残余奥氏体的混合组织。在控轧控冷工艺参数相近的情况下,高硅铌钢、高硅Nb-Ti钢、低硅Nb-Ti钢的抗拉强度依次减小,其伸长率和强塑积依次增大。低硅Nb-Ti钢的伸长率和强塑积分别达到了41%、25 256 MPa.%的最大值。     

静电搪瓷用高强度热轧薄钢板的性能

 简述了工业生产高强度热轧薄钢板的成分和生产工艺，其室温组织由极细的铁素体晶粒和极少量的珠光体组成。模拟高温搪烧时，随着温度的提高和保温时间的延长，屈服强度和抗拉强度下降，伸长率提高。经857 ℃保温10 min后，钢板的屈服强度满足了不小于310 MPa的要求。预变形时的变形量对模拟高温搪烧后钢板的力学性能也会产生影响。所研究的钢板在制作热水器内胆时能满足耐压不小于12 MPa和2万次的压力循环试验要求。     

鞍钢热轧镀锌板HD340LAD+Z开发

阐述了鞍钢开发的热轧镀锌板HD340LAD+Z其基板成分、组织及工艺设计,归纳出该热轧镀锌板开发过程中的控制要点,对钢板的金相组织、显微组织及表面形貌进行了检测。结果表明,热轧镀锌板HD340LAD+Z力学性能、表面质量等指标完全满足标准及用户要求。     

轴承钢热轧钢带的开发

介绍了南钢利用自炼的优良坯料资源进行轴承钢带钢的开发,以替代棒材轴承钢,简化了下游的制造工艺,降低了加工成本。通过对加热工艺、轧制工艺、冷却工艺的摸索,使产品的碳化物控制水平达到并超过了棒材的水平,实现对棒材成功替代。     

Energy-Based Prediction of Low Cycle Fatigue Life of High-Strength Structural Steel

 Energy-based models for predicting the low-cycle fatigue life of high-strength structural steels are presented. The models are based on energy dissipation during average of cycles, cycles to crack propagation and total cycles to failure. Plastic strain energy per cycle was determined and found as an important characteristic for initiation and propagation of fatigue cracks for high-strength structural steels. Fatigue strain-life curves were generated using plastic energy dissipation per cycle (loop area) and compared with the Coffin-Manson relation. Low cycle fatigue life was found similar from both methods. The material showed Masing-type behavior. The cyclic hysterisis energy per cycle was calculated from cyclic stress-strain parameters. The fracture surfaces of the fatigue samples were characterized by scanning electron microscope and the fracture mechanisms were discussed.     

Development of Ti-Microalloyed 600 MPa Hot Rolled High Strength Steel

A high strength steel with yield strength on the order of 600 MPa was developed successfully with only addition of titanium alloying element based on a low-carbon steel.The results showed that the hot deformation accelerated ferrite and pearlite transformation and retarded bainite transformation under continuous cooling condition.The microstructure of this steel was mainly composed of fine grained ferrite and carbides distributing along the ferrite grain boundaries.The yield and tensile strengths of steels ...