十万立方米浮顶式原油贮罐焊接残余应力分布规律的研究

DISTRIBUTION OF WELDING RESIDUAL STRESS IN A FLOATING ROOF 100,000m^3 CRUDE OIL TANK

本文采用盲孔法技术,实测了十万立方米浮顶式原油贮罐的焊接残余应力,找出了该油罐承载最大和最重要部位的焊接残余应力的分布规律。

The residual stress may seriously affect the fatigue strength, initiation and propagation of cracks and stress corrosion of pressure vessels. The welding residual stresses in a floating roof 100,000M crude oil storage tank were measured in the field by means of the Blind Hole Relaxation Technique. The principle of measurement and arrangement of measuring points are described in detail in this paper. This distribution of welding residual stress was obtained on the most important parts of the oil tank where the load was the greatest. The residual stresses in the horizontal and vertical directions for fillet welds, longitudinal welds and circumferential welds in the oil tank were measured accurately. The results of measurement indicates that the residual stress is concentrated in the weld and decrease sharply with a slight departure from the fusion line of weld. The maximum value of residual stress in the weld is close to the yield strength of the parent metal, and the residual stress along the weld direction is much higher than that across the weld direction. However, as the fillet welds by manual arc welding on the oil tank root are made under the condition of serious transverse restraint ,the residual stress perpendicular to the weld direction is also fairly high.