The impact of edge preparation on the stress-strain state of soldered connections of galvanized pipes of long-distance pipelines

Abstract

The main problem of the zinc-covered pipe connections, using arc welding, is providing the welded joint corrosion resistance and preserving of the protective cover on the adjacent areas. This problem may be solved using the arc brazing technology, allowing to reduce by 30 per cent the temperature impact and provide a rather high strength of joints at the level of the base metal. The stress-strain state of the pipeline is determined by the characteristics of internal and external pressures, the main of which is the internal pressure. In this article the stress-strain state of arc-brazed joints of galvanized pipes by simulation of the finite element method was studied. Brazed pipe joints with a diameter of 150 mm from the low-alloy steel 16 HS and joints of materials CuiAl8 and CuSi3, loaded by the internal pressure 9 MPa were studied. The research results showed that by using standard V-shaped edges, the largest concentration of a circular tension occurs on the pipe outer wall, between the welded joint and the base metal. To reduce the circular tension and change its concentration, the optimization of edges shape was conducted. The proposed optimized form of edges allowed to reduce the value of the circular tension and change its distribution. Namely, the circular tension is concentrated and evenly distributed along the bottom edge of pipes, thus, increasing their strength and service life