MECHANO-CHEMICAL CHARACTER OF WELDING JOINTS OF PIPE LAYING

The dependability and security of pipe laying in practical application are laid on not only the performance of metal,but also the electrochemical characteristics of inhomogeneous metal surface under the action of active solution.These external factors can accelerate the mechano-chemical effect.The welding joints possess high electrochemical inhomogeneity on macro and microcosmic configuration and the distribution of unequal residual stress on each area depends on the shape,size and defects of welding joints.The performance inhomogeneity of welding joints can be reduced by selecting joining materials and adjusting technics.