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为了掌握这种管接头的应力状态,对一台400吨/时锅炉工作压力为155公斤/厘米~2(表)的锅筒热拔大直径下降管圆孔管接头用电阻应变片进行了应力测量。关键测点的折算应力指出,接头应力最高区域的内壁面在锅筒纵向截面左右各60毫米宽度上,已进入了屈服状态。但是最高折算应力未超过锅筒钢材屈服强度的3倍,并且参照美国机械工程师协会容器规范疲劳设计曲线,估计该管接头的低周疲劳寿命有7000次应力循环,应可适合我国电站锅炉的实用要求。然而这次圆孔管接头最高应力系数达2.93,比长短轴之比为2的椭圆孔管接头的高出约50%,结论中指出,如采用椭圆孔式管接头,当较圆孔式的更有利于获得较好的应力状态.
In order to grasp the stress state of this pipe joint, a 400 ton / hour boiler working pressure of 155 kg / cm ~ 2 (table) hot-drawn large diameter drop pipe round hole pipe joints with strain gauges were stress measuring. The conversion stress of the key measuring points indicates that the inner wall surface of the joint with the highest stress area has entered the yield state at the width of 60 mm around the longitudinal section of the drum. However, the maximum conversion stress does not exceed 3 times the yield strength of the drum steel, and with reference to the American Society of Mechanical Engineers container design fatigue design curve, it is estimated that the low cycle fatigue life of the pipe joint has 7000 stress cycles and should be suitable for the practical application of power station boilers in China Claim. However, the maximum stress coefficient of this round hole pipe joint reached 2.93, which was about 50% higher than that of the oval hole pipe joint with the ratio of the long shaft to the short one. In the conclusion, it was pointed out that if an oval hole pipe joint is used, More conducive to getting better stress state.