The material behavior analysis in joining non straight line weld by using friction stir welding;

It gropes and designs a method of three points bending roller type forming process design as per longitudinal welded pipe's transform rule.

In way of weld field,the article introduces application foreseeing of this technology,also discusses this technology application into 4 aspects:forming roller design and manufacturing,design of longitudinal welded pipe mill,the control of deform process and forming stress in longitudinal welded pipe in production,and the control of pipe residual stress in spiral welded pipe in production.

The inner burr removing technology is an integrant working procedure to produce high quality and high additional value longitudinal welded pipe.

A high-power and high-frequency inductive power supply used in ERW for medium-sized straight welded pipes is introduced.

Since the conventional single blade and double blade sawing method for the big ERW high frequency (resistance) straight welded pipe is restrained, the digital controlled profile modeling sawing technology develops.

From the point of view of our energy strategy, the authors introduce the production, application and market prospect of the weld steel pipe in our country, they also analysis the technical advantages and application of the spiral welded pipe and straight seam pipe respectively.