HTRB600级高强钢筋高温下的力学性能

Mechanical properties of high-strength HTRB600 steel bars under high temperature

为研究600 MPa级高强钢筋高温下的力学性能,对HTRB600级热处理高强钢筋进行高温下的拉伸试验,分别测得其在20,200,300,400,500,600,700及800℃高温下的弹性模量、比例极限、屈服强度、极限强度及应力-应变曲线.试验结果表明:HTRB600级高强钢筋高温下屈服强度、极限强度、比例极限与弹性模量均随着温度的升高而显著降低.500℃时其高温下的弹性模量、比例极限、屈服强度与极限强度降低为不足常温下的50%,800℃时已不足常温下的10%.高温下HTRB600级高强钢筋应力-应变曲线随温度的升高逐渐趋于圆滑,当温度达到200℃时,屈服台阶就已消失.600 MPa级钢筋高温下屈服强度和极限强度的降低程度明显大于其他钢筋500 MPa以下强度的钢筋.最后提出了适用于HTRB600级高强钢筋的高温下应力-应变曲线简化计算模型.

Tensile testing of HTRB600 steel bars under high temperature was conducted to determine the mechanical properties of the steel under high temperature. The elastic modulus,proportional limit,yield strength,ultimate strength,and stress-strain curves of steel bars at 20,200,300,400,500,600,700,and 800 ℃ were obtained. The experimental results show that the elastic modulus,proportional limit,yield strength,and ultimate strength of the bars obviously decrease with increasing temperature. The yield strength,ultimate strength,proportional limit,and elastic modulus of the steel bars at 500 and 800 ℃ decrease to less than 50% and10%,respectively,of those of the sample at room temperature. The stress-strain curve of the steel bars smoothens as the temperature increases,and the yield terrace disappears at 200 ℃. The degree of decrease in yield strength and ultimate strength of the 600 MPa steel bar is obviously larger than that of the 500 MPa steel bar. Finally,a simplified calculation method to determine the stressstrain curve of HTRB600 steel bars under high temperature was proposed.