共查询到19条相似文献,搜索用时 171 毫秒
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冷轧带肋钢筋的应变时效导致钢筋强度升高,伸长率下降,影响砼构件的质量,介绍了采用低温回火处理和机械消除应力方法,对消除应变时效有较好的效果。 相似文献
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冷轧带肋钢筋是国外70年代初开发的一种新型建筑铜材,采用冷轧减径—冷轧刻痕工艺,可将低碳线材的抗拉强度由380 MPa提高到≥550MPa,伸长率仍不低于8%。因其强度高,塑性良好,与混凝土的握裹力强等优点,得到了迅速发展。仅西德在年产300×10~4t线材中就有100×10~4t以上用于生产冷轧带肋钢筋。广泛用于混凝土公路、机场跑道、隧道等钢筋焊接网。 相似文献
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由钢铁研究总院与北京市玉立科技实业公司等4单位协作完成的冷轧带肋钢筋生产技术推广及直进式无扭冷轧带肋钢筋生产装备与工艺研究,于1993年9月4日由冶金工业部在北京组织鉴定。经专家评议,认为:冶金部钢铁研究总院在推广和发展我国冷轧带肋钢筋生产技术与装备方面取得明显效果。设备研制,由“滑轮式”发展到“直 相似文献
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通过电化学加速锈蚀、钢筋和UHTCC直接拉拔试验对不同锈蚀率(0,1%,2%,3%和5%)下钢筋与UHTCC的粘结性能进行了研究,并与同条件下的混凝土试件进行对比。通过直接拉拔实验得到不同锈蚀率时平均粘结应力与滑移量的关系,采用粘结滑移的连续模型进行拟合,模型值与实验值吻合较好。与混凝土试件锈蚀率超过2%后最大平均粘结应力迅速下降现象不同,UHTCC能充分发挥其对钢筋的约束作用,在锈蚀率小于3%范围内,最大平均粘结应力随锈蚀率增大线性增加,锈蚀率超过3%直到5%基本维持不变,保持较好的粘结性能。 相似文献
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The feasibility of using 2304 duplex stainless steel rebar in seawater concrete was determined by studying the passivation and corrosion behavior of steel in solutions simulated curing and service stage of concrete, respectively. The results demonstrate that 2304 duplex stainless steel rebar could be used with seawater concrete because of a stable passive film formed on the steel surface during the curing stage of concrete even in the presence of 2 M chloride ions. However, due to the synergistic effect of concrete carbonation, the rebar suffered a corrosive attack by chloride due to the lack of OH? inhibition. 相似文献
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The Influence of Corrosion and Cross-Section Diameter on the Mechanical Properties of B500c Steel 总被引:1,自引:0,他引:1
Ch. Alk. Apostolopoulos 《Journal of Materials Engineering and Performance》2009,18(2):190-195
Corrosion is a negative contributor on the structural integrity of concrete structures and leads to degradation of the mechanical
properties of steel rebar. Exposure to chloride, seawater, salt and saltwater and deicing chemical environments influences
the concrete-steel bond and weakens it. A considerable strength factor of the two-phase steel B500c (martensitic, ferritic-perlitic) is considered to be the outer martensitic cortex thickness, which varies according to the
area of the rebar cross section. In order to evaluate the influence of corrosion and the size of the area on the mechanical
properties of B500c steel, an experimental investigation was conducted on B500c ribbed steel rebar of 8, 12, 16, and 18 mm diameter, and which were artificially corroded for 10, 20, 30, 45, 60, 90, and
120 days. The laboratory tests suggest that corrosion duration and rebar cross-sectional area size had a significant impact
on the strength and ductility degradation of the specimens. The tensile mechanical properties before and after corrosion indicated
progressive variation and drastic drop in their values. The extended salt spray exposure enhanced the damage and created pits
and notches, resulting in stress concentration points and progressive reduction of ductility and available energy. Anti-seismic
design and codes that ignore the influence of the size of the cross-section area and the level of corrosion and mechanical
behavior of reinforcing steel could lead to unpredictable performance during severe ground motion. 相似文献
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采用圆孔扩张理论对混凝土钢筋锈胀过程进行分析,推导了不同钢筋锈胀量对应的塑性区边界混凝土应力及塑性区半径计算公式,在此基础上建立了混凝土锈胀开裂寿命准则及寿命预测模型。锈胀开裂寿命模型分析表明,预测寿命值与钢筋相对保护层厚度m和混凝土等级有直接关系。随着相对厚度m增加,锈胀开裂预测寿命值增加,并且前期增加较快,后期增加较缓慢。混凝土强度等级对预测寿命值影响显著,随混凝土强度增大,混凝土锈胀开裂寿命增大。工程应用表明,该模型预测寿命可为工程的中度维护提供参考。 相似文献
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热轧带肋钢筋是我国产量最大的钢材产品,而提高钢筋产品质量并降低生产成本一直是技术创新的动力。为了使高强度钢筋轧制工艺和装备适应我国热轧带肋钢筋新标准的要求,对其控轧控冷工艺进行了探讨,对现有棒材轧机进行改造的工艺进行了详细分析,比较了切分轧制和高速轧制两种工艺的优缺点,提出了工艺布置新思路,为新钢筋生产线工艺设计,老线改造设计,或者钢铁企业工程技术人员开发品种提供了独特的途径。 相似文献
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研究了HRB335、HRB400 钢筋筋时效后的拉伸性能变化,找出了热轧带肋钢筋力学性能指标值的波动特点,并提出了减小工厂检验与用户检验力学性能指标值的差异的方法。 相似文献