Experimental study on HRB500E seismic reinforcement bar produced by microalloying of high nitrogen ferrovanadium alloy
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摘要: 以转炉、连铸、轧钢工艺装备为基础,进行了高氮钒铁合金微合金化生产HRB500E高强抗震钢筋的试验研究,结果表明:与钒氮合金相比,使用高氮钒铁合金微合金化生产HRB500E抗震钢筋节钒22.2%,钒合金化成本降低17.98元/t。钢筋力学性能稳定,具有低应变时效性。Ø28 mm和Ø32 mm规格时效15天,ReL均降低15 MPa、Rm分别降低2 MPa和3 MPa, Agt分别提高0.7个百分点和0.8个百分点,之后力学性能不变,时效后的钢筋强屈比和屈标比更合理,抗震性能更好。钢筋金相组织为珠光体+铁素体,晶粒度等级10级,比使用钒氮合金提高1.0级。钢筋拉伸试验断口为等轴韧窝断口。钢筋帮条焊后进行拉伸在母材断裂,缩颈显著,焊接性能良好。疲劳检验200万次时未发生断裂,满足新国标GB/T 1499.2—2018的疲劳寿命要求。Abstract: Based on the process and equipment of converter, continuous casting and rolling, the experimental study on the production of HRB500E high strength anti-seismic steel rebar by microalloying with high nitrogen ferrovanadium alloy was carried out. The results show that compared with vanadium-nitrogen alloy, the production of HRB500E anti-seismic steel rebar by microalloying with high nitrogen ferrovanadium alloy can save 22.2% vanadium and reduce the cost of vanadium alloying by RMB 17.98/ ton steel. The mechanical properties of steel rebars are stable and have low strain aging. The yield strength of Ø28 mm and Ø32 mm specifications are both reduced by 15 MPa, and tensile strength decreased by 2 MPa and 3 MPa respectively after aging for 15 days. The uniform elongations are increased by 0.7% and 0.8%, respectively. The strength yield ratio and yield standard ratio of steel rebars after aging are more reasonable and the seismic performance gets better. The metallographic structure of the steel rebar consists of pearlite + ferrite, and the grain size is ASTM 10, 1.0 grade higher than that of vanadium-nitrogen alloy. The tensile fracture contains equiaxed dimple. For welding test the fracture located in base metal, showing good weldability. There was no fracture after 2 million times of fatigue test, which met the fatigue life requirements of the new national standard GB/T 1499.2—2018.
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Key words:
- HRB500E /
- high nitrogen ferrovanadium alloy /
- microalloying /
- mechanical properties
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表 1 高氮钒铁合金FeV30N14主要化学成分
Table 1. Main chemical composition of high nitrogen ferrovanadium alloy
% V N P S C 30 14.5 0.041 0.02 0.3 表 2
Ø28 mm~Ø32 mm规格HRB500 E使用不同合金时的成分控制 Table 2. Composition control of high nitrogen ferrovanadium and vanadium nitrogen alloy used in Ø28 mm~32 mm HRB500E reinforcement bar
项目 合金类别 w/% C Si Mn V P/S 试验
工艺高氮
钒铁0.22~0.25 0.40~0.50 1.35~1.45 0.068~0.072 ≤0.045 原工
艺钒氮
合金0.088~0.092 表 3 高氮钒铁合金化生产HRB500E实际成分控制
Table 3. Actual compositions control of HRB500E reinforcement bars produced by high nitrogen ferrovanadium alloy
规格/mm 类别 w/% C Si Mn P S V N Ø28 范围 0.23~0.25 0.43~0.47 1.39~1.43 0.015~0.038 0.028~0.039 0.068~0.072 0.0180~0.0195 平均值 0.235 0.46 1.41 0.029 0.034 0.070 0.0192 Ø32 范围 0.23~0.25 0.43~0.46 1.40~1.44 0.021~0.032 0.025~0.040 0.068~0.073 0.0181~0.0200 平均值 0.236 0.45 1.40 0.027 0.035 0.070 0.0190 表 4 高氮钒铁合金化生产HRB500E的试样力学性能统计
Table 4. Mechanical properties of HRB500E reinforcement bars produced by high nitrogen ferrovanadium alloying
规格/mm 屈服强度/MPa 抗拉强度/MPa Agt/% 强屈比 屈标比 正弯、反弯 Ø28 540~570 690~705 12.3~13.5 1.25~1.28 1.08~1.15 完好 Ø32 540~565 690~720 12.1~13.2 1.25~1.28 1.08~1.13 -
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