精轧螺纹钢筋非金属夹杂物的控制

为提高精轧螺纹钢筋内部质量,对工艺优化前生产的精轧螺纹钢筋中非金属夹杂物进行了统计分析。结果显示,在实际生产及使用过程中发生断裂的精轧螺纹钢筋,其夹杂物等级均≥2.0级,超出生产控制要求。分析认为,炼钢过程中大尺寸夹杂物未能得到充分控制,钢中硅铝酸盐及D类球状氧化物夹杂超标是精轧螺纹钢筋夹杂物超标的主要原因。通过对炼钢工艺过程进行优化,精轧螺纹钢筋中夹杂物数量及种类大幅度改善,满足了精轧螺纹钢筋中夹杂物的控制要求。     

PSB830精轧螺纹钢筋生产工艺实践

介绍了PSB830精轧螺纹钢筋力学性能要求和生产工艺,分析了生产过程中易出现的问题,采取措施进行优化,生产出满足GB/T20065-2016标准要求的PSB830精轧螺纹钢筋。     

韶钢热轧带肋钢筋控轧控冷工艺生产实践

介绍热轧带肋钢筋控轧控冷工艺技术在韶钢的应用,通过控轧控冷工艺技术,实现较低合金成份的钢坯生产出各种性能指标稳定的螺纹钢筋,大幅度降低韶钢螺纹钢筋的生产成本.     

靠高科技竞争取胜 轧二钢筋进三峡

天津市轧二制钢有限公司靠高科技竞争取胜,研制出高强度精轧螺纹钢筋被长江三峡工程开发总公司选中,首批200余吨于已运抵三峡永久性船闸工地。 1997年,该公司生产的高强度精轧螺纹钢筋被亚洲第一重载大桥——三峡覃家砣大桥采用,质量     

Φ40mm螺纹钢筋的开发

在φ３００横列式小型轧机上生产φ４０螺纹钢筋属小轧机轧大材，文章通过分析现有工艺装备，优化工艺方案，改善成品咬入，使φ４０螺纹钢筋的生产取得了成功，不仅配齐了该公司螺纹钢筋的产品规格，而且为大规模螺纹钢筋在横列式小型轧机上的生产开辟了一条途径。     

天铁轧二自主研发的高强度精轧螺纹钢筋市场占有率达80％

今年5月,天铁轧二研发生产的高强度精轧螺纹钢筋,在京津城际高速铁路工程招标中,以其产品质量精良独家中标。天津市天铁轧二制钢有限公司与中铁十七局京津城际轨道交通工程联合制板场在北京房山签订了总量为4000t的德国标准左旋高强度精轧螺纹钢筋的供货合同,并于6月开始供货。据了解,目前,国内高强度精轧螺纹钢筋市场年需求量为26000t至27000t,天铁轧二去年为用户提供该产品21000t,占80%;今年前五个月已为用户提供该产品9000t。面对国内市场的竞争,天铁轧二坚持以市场变化为导向,坚持差异化销售,在“夹缝”中找市场。他们通过市场调研了解…     

河北钢铁集团宣钢又添新品种

日前,河北钢铁集团宣钢炼钢厂成功开发生产了精轧螺纹钢筋原料坯,标志着宣钢产品品种家庭又添新成员。     

细晶粒螺纹钢筋生产的研究与应用

四川德胜集团钒钛有限公司在现有轧钢生产线上进行了细晶粒螺纹钢筋生产的研究与应用,使螺纹钢筋组织性能满足了GB 1499.2-2007中"其金相组织主要是铁素体加珠光体,不得有影响使用性能的其他组织"的规定,其螺纹钢筋产品基圆上没有闭合的回火马氏体组织。生产工艺更加灵活,通控轧控冷工艺实现了微合金化生产细晶粒螺纹钢筋,大大降低了生产成本。     

Φ25mm预应力混凝土用螺纹钢筋生产实践

为解决Φ25 mm预应力混凝土用螺纹钢筋在试制过程出现的横肋错牙和力学性能不符合标准等问题,通过分析,鞍钢股份有限公司大型厂提出了修改轧辊数控车削程序、优化调整办法及改进控轧控冷工艺等措施,实现了预应力混凝土用螺纹钢筋的顺利生产,使螺纹钢筋外形尺寸和力学性能均符合标准要求。     

?14mm螺纹钢筋五切分工艺改造实践

针对?14 mm螺纹钢筋四切分工艺生产机时产量偏低、能耗偏高的弱点,萍安钢铁公司通过对其精轧孔型系统进行技术改造并成功升级为五切分工艺,使得?14 mm螺纹钢筋的机时产量增加,生产成本下降,经济效益提升。     

低成本V N微合金化高强度钢筋的研究与生产

介绍了低成本V N微合金化高强度钢筋的研究开发及生产情况。在含钒钢筋中增氮,促进了V（CN）的析出,显著提高了V的沉淀强化效果。批量工业性生产试制结果表明：采用V N微合金化技术,HRB400钢筋中的V含量降低至003%~004%,和V钢筋相比,V质量分数降低了50%左右,大大降低了合金成本。适当的轧后加速冷却工艺使V(CN)析出粒子的粒度分布更加优化,可使钢中V含量进一步降低。     

N含量对Nb微合金化HRB400E钢筋组织与性能的影响

摘要：为了更好地发挥N元素在Nb微合金化钢筋中的作用,降低生产成本以及为钢筋成分设计提供理论依据。利用金相显微镜、扫描电镜、透射电镜、力学试验机对不同N含量的Nb微合金化高强抗震钢筋进行显微组织表征及力学性能测试,探究N含量对Nb微合金化钢筋的组织与力学性能的影响。研究表明,轧制过程中的奥氏体组织,随着N含量的增加,平均奥氏体晶粒有所减小;最终组织为铁素体和珠光体,随着N含量的增加,铁素体平均晶粒尺寸而减小,片层状珠光体的连续性增加,片层间距减小;析出相Nb(C,N)随着N含量的增大,沉淀析出的第二项颗粒体积分数增大,颗粒尺寸随之减小;在力学性能方面,屈服强度逐渐增加,抗拉强度先增加后减少。     

Effect of N content on microstructure and properties of Nb microalloyed HRB400E rebar

The purpose of this study is to better play the role of N in Nb microalloyed rebars, in order to reduce production costs and provide a theoretical basis for the design of rebars. Using metallographic microscope, scanning electron microscope, transmission electron microscope, and mechanical testing machine to carry out microstructure characterization and mechanical performance test of different N content of Nb microalloyed high strength seismic rebars, and explore the effect of N content on the structure and mechanics of Nb microalloyed high strength anti seismic rebars. The results show that the austenite structure during the rolling process decreases with the increase of N content; the final structure is ferrite and pearlite. As the N content increases, the average ferrite grain size and the interlamellar spacing decreases, but the continuity of lamellar pearlite increases. In Nb microalloyed high strength anti seismic rebars, the precipitated phase is Nb(C,N). With the increase of N content, the number of precipitated phase and the second particle volume fraction of precipitation increases, but the particle size decreases accordingly. In terms of mechanical properties, the yield strength gradually increases, and the tensile strength shows a phenomenon of increasing first and then decreasing.     

Research, Development, and Production of V-N Microalloyed High Strength Rebars for Building in China

The research,production,and application of V-N microalloyed high strength rebars in China were reviewed.Enhanced nitrogen in vanadium-containing rebars promotes the precipitation of fine V（C,N）particles,and markedly improves the precipitation strengthening effectiveness of vanadium.Therefore,vanadium added to V-N microalloyed rebars can be reduced by 40% compared to the same strength level of vanadium-containing rebars.     

高强度建筑钢筋质量分析及标准修改建议

 深入调查了中国HRB400/400E和HRB500/500E高强度热轧钢筋的质量现状。从不同地区的钢筋生产厂和使用场所取样分析了高强度热轧钢筋成分、宏观金相、微观组织和截面硬度。按照钢筋化学成分范围,目前中国高强度热轧钢筋可归为4类,即含钒钢筋、低钒钢筋（<0.02%钒）、20MnSi钢筋和C-Mn钢筋。宏观金相和微观组织观察结果表明,只有含钒钢筋能完全满足热轧钢筋的组织要求,其他3类钢筋截面基圆外围均出现非铁素体－珠光体组织的表面硬化层。基于高强度热轧钢筋的质量分析结果,提出了热轧带肋钢筋国家标准GB1499.2—2007的修订建议。     

微合金化控冷工艺开发HRB500E高强度抗震钢筋

针对红河钢铁有限公司炼钢、轧钢工艺装备,采用微合金化控轧控冷工艺生产HRB500E高强度抗震钢筋,并利用金相显微镜、拉力试验机对钢筋的力学性能、金相显微组织、夹杂物进行检验。结果表明:钢筋强韧性适中,具有较好的抗震性能和低应变时效性;控制钢中Mn含量小于1.55%,Nb含量小于0.025%,控冷终止温度大于680℃,钢筋心部组织为铁素体+珠光体+5%贝氏体,综合性能较佳。     

Ф50mm大规格HRB400E、HRB500E抗震钢筋的研究与生产

介绍了莱钢生产4）50Inrn大规格HP．B400E、HKB500E抗震钢筋的研究与生产过程,通过钢筋的窄成分范围设计,钒微合金化等工艺来稳定钢材的化学成分,并通过设计合适的轧制工艺,达到满足钢筋性能要求。试制结果表明,莱钢由50mm大规格抗震钢筋具有较好的综合性能,实物质量达到了GB1499．2—2007标准要求。     

Bond Strength of Fiber Reinforced Polymer Rebars in Normal Strength Concrete

The bond behavior of reinforcing bars in concrete is a critical issue in the design of reinforced concrete structures. This study focuses on the bond strength of fiber reinforced polymer (FRP) rebars in normal strength concrete. Four different types of rebars were tested using the pullout method: aramid FRP (AFRP); carbon FRP (CFRP); glass FRP (GFRP), and steel. This involved a total of 151 specimens containing 6, 8, 10, 16, and 19?mm rebars embedded in a 203?mm concrete cube. The test embedment lengths were five, seven, and nine times the rebar diameter (db). For each rebar, the test results include the bond stress–slip response and the mode of failure. The test results showed that the bond strength of an FRP rebar is, on average, 40–100% the bond strength on a steel rebar for pullout failure mode. Based on this research, a proposal for the average bond strength of straight FRP rebars in normal strength concrete is made, which verifies an existing bond strength relationship (GFRP) and extends its application to AFRP and CFRP. It is an expression that is a function of the rebar diameter, and the concrete compressive strength.     

Realistic Bond Strength of FRP Rebars in NSC from Beam Specimens

The bond strength of reinforcing bars in concrete is a prerequisite for the evaluation of the development length in reinforced concrete structures. This study concerns these phenomena for fiber reinforced polymer (FRP) rebars in normal strength concrete (NSC). Three different types of rebars were tested using the beam specimen: Carbon, glass, and steel. This involved a total of 26 beam specimens containing 10, 16, and 19?mm rebars. The test embedment lengths were 10, 15, and 20 times the rebar diameter (db). For each rebar tested, the results concern load deflection curves, bond stress-slip responses, and the mode of failure. The results showed that the bond strength of a FRP rebar is, generally, lower than that of steel rebar. Based on this and previous research, proposals for the average bond strength and for the development length of straight FRP rebars under tension in NSC are made.     

日本标准SD390螺纹钢筋的研制与生产

日照钢铁公司在研制开发日标SD390钢筋过程中,分析了SD390钢筋的质量特性;设计了日照钢铁内控日标钢筋的化学成分;改进了连铸坯的生产工艺;制定了孔型设计方案和轧制生产工艺;并成功地开发出质量达到日标及合同要求的产品.