It puts forward reasonable adjustment to each parameter,improvement to process method,strengthening friction lubrication and rational operation to reach the purpose of increasing usage life of expanding head of expander through analysis to pipe expanding process.

Effect of friction on deforming condition during tube expanding process;

The method of Prediction for the spring back of cylinders in mechanical expanding;

The practice of deep well diameter extension and washing, blasting is introduced in this paper.

Based on such analysis,some criteria and methods have been proposed for judging the situation of honeycomb,segregation,reducing,diameter extension,breaking zone and sedimentation on the bed of pile,etc.