We often say that thermal expansion seamless pipe refers to steel pipe with relatively low density but high shrinkage. Seamless steel tube can be abbreviated as thermal expansion pipe. The roughing and finishing process of enlarging pipe diameter by cross rolling or stretching method. In a short period of time, the steel pipe is thicker, can produce non-standard, special seamless pipe, low cost, production efficiency is the development trend of international pipe rolling field.




Two-stage propulsive pipe expander adopts taper pipe expanding technology, digital intermediate frequency induction heating technology and hydraulic technology in one machine. It has reasonable technology, low energy consumption, low structure, good product quality and wide range of raw materials. Material and product specifications are flexible, easy to replace, low-input production batch adaptability, replacing the traditional steel pipe industry pull expansion technology.


What precautions should be taken in the production of thermal expansion seamless tubes?
1. When the initial cutting head and tail of the heat expansion pipe are straightened, it is impossible to cut only the shrinkage and empty part and the crack part of the tail, and the end face should be flat and not skewed.


2. Finishing grade shall be inspected on the surface of the expansion of the pipe in the inspection device. Outer folds, inner folds, cracks and junctions are small and shallow, with more or deeper outer folds. The direct judgment that can not be repaired can not be used as expansion pipe; after grinding, the wall thickness exceeds negative deviation, repairing and smoothing;


3. After the thermal expansion operator inspected the inner and outer surface of the pipeline, it was found that the grinding wheel had repaired the missing defects such as wrinkles and cracks, and the grinding depth had been filled and smoothed by welding.


4. When encountering a rigid head tube, mark it on the rigid part of the head.  During the expansion process, when the clamp is about to end, the speed is slowed down and the temperature is raised.


5. After the expansion is completed, the inner and outer surfaces should be inspected. Uncleared defects should be marked on steel pipes and recorded in production records. Grinding can be repaired and then transferred to annealing furnace.


6. After each expansion of the steel tube, the thickness of the expansion wall should be measured, and the specifications should be determined according to the standard requirements, and production records should be made.