11.How to distinguish between hot expanded steel pipe and seamless steel pipe?
Hot-expanded steel pipe is just a manufacturing process of steel pipe, and both welded pipe and seamless steel pipe can be hot-expanded. How to distinguish what is hot expansion: in the appearance of steel pipe, the hot expansion is red, and the inside diameter is lead powder. We often say that the hot-expanded pipe refers to the steel pipe with low density but strong shrinkage, and (seamless steel pipe) can be simply called hot-expanded pipe.
A kind of finished rolling process of waste pipe to enlarge the diameter of pipe by cross rolling or drawing. Thickening steel pipes in a short time can produce non-standard and special seamless pipes with low cost and high production efficiency, which is the development trend in the field of international pipe rolling at present. Seamlessing steel pipe (not real seamless): this product adopts high-quality coiled plate, which is automatically formed and welded by longitudinal cutting or coiling after passing the reinspection. While the computer controls the optimal fusion temperature, the internal and external burrs of the steel pipe are removed.
The steel pipe qualified for nondestructive testing is heated to 910℃-950℃ in an atmosphere of little oxidation and discharged from the furnace. After descaling, it is rolled by a tension reducer for multiple times, so that the metallographic structure, grain state, geometric size and mechanical properties of the steel pipe are all uniform.
2How to get rid of lead powder in hot expanded steel pipe?
It can be soaked in acid, which is helpful to remove rust from the steel pipe. Of course, it can also be polished with sandpaper and can also be removed.
3Tolerance of Hot Expanded Steel Pipe Diameter allowed?
Tolerance with 1% for OD, and wall thickness tolerance with 12.5%, and our company products tolerance can be much smaller then the standard.