The different processing technique of two pipes:expanding technique and power spinning technique.
1- Expanding technique is to expand the thick tube to large diameter and thin wall;For example,they produce 80mm Out diameter and 20 thinkness tube and then expand the tube to 150 diameter and 5 thinkness tube.When expanding,the tube maybe cracked,and then have to be repaired by welding the cracks.So it can not be certain that the quality are under the required standards.
2- Power spinning technique is by the new equipment to stress the think tube.For example,we made 180mm diameter bar and drillhole of 140mm or forged directly 140mm inner diameter thick ring.Then put into the mould,by the power stressing and spinning of our equipment to control the thickness of tube till finished. In the whole processing, the tensile strength can not be destroyed,and the tube can not be cracked.
3- Our Advantages: The performance is excellent, organize uniform and stable structure.It has long time life for petroleum pipeline.And we also can make Grade 5 Ti Al V alloy tubes.