温度对超声波在16MnR钢中传播速度的影响

研究了温度变化对超声波探伤定位的影响,以及在20~450℃范围内,超声波在16MnR钢内的横波传播速度规律。应用最小二乘法拟合了3种速度规律关系式,并对其进行了比较,得出精确计算横波声速拟合公式VT=3253.31-1.8114T+1.18193×10-2T2-3.51474×10-5T3+3.05267×10-8T4。同时得出了由于热膨胀造成的试件半径变化对速度测量误差的影响在10-1mm量级,对缺陷位置和尺寸的影响不大。给出了实际波速、量程修正和误差幅度关系式。分析了由于温度变化造成的弹性模量、泊松比和密度的变化对速度变化的影响,得到了超声波在高温钢种下的理论修正公式。

Influence of Temperatures on the Transmission Velocity of Ultrasonic Wave in 16MnR Steel

The influence of temperature change on the detection allocation of ultrasonic wave and the transmission velocity law of the shear wave of ultrasonic wave in 16MnR steel in the range of 20～450℃ were studied.Three kinds of relations of velocity law were fitted using the least square method,and compared.The accurately calculated fitted formula of the velocity of the shear wave was derived,i.e.VT = 3253.31-1.8114T+1.18193×10-2T2-3.51474×10-5T3+3.05267×10-8T4.Meanwhile,it is concluded that the influence of the radius change of the sample induced by the heat expansion on the speed measuring error is 10-1mm,its influence on the flaw position and sizes is not important.The relations of the actual wave velocity,the range correction,and the error amplitude were given. The influences of the changes of elastic ratio,Poisson's ratio and density change induced by temperature changes on the velocity change were analyzed,the theoretical correction formula of ultrasonic wave in high temperature steels was obtained.