One challenge for buyers is to get qualified pipe on request. But even veterans can be lost. Below 8 points will help you to assure steel pipe quality.
1.Fresh production
Pipes on fresh production are better than those stored over several months, in regard of surface rust and roundness shape. Pipes will get rust and oval gradually if stored in warehouse too long.
2.External surface
Clean external surface helps the next coating step. If not clean enough, you’d better define the corrosion level as ISO8501. We don’t suggest choosing surface of Grace C and Grade D, because a big effort will be taken to remove rust, such as sanding, shot blasting, etc.
Corrosion as follows:
Steel surface largely covered with adhering mill scale but little, if any rust.
Steel surface which has begun to rust and from which the mill scale has begun to flake.
Steel surface on which the mill scale has rusted away or from which it can be scraped, but with slight pitting visible under normal vision.
Steel surface on which the mill scale has rusted away and on which general pitting is visible under normal vision.
3.Internal surface
Clean internal surface with fewer rust scrap, dust, and welding slag inside the pipe is more desirable, for better water/ gas flow. It is easy to check the interior condition of pipe by flashlight.
4.Coating
The quality and lifetime of coating are determined by layer thickness, adhesive force and smoothness, regardless of black painting, hot dip galvanizing or red oxide painting. It is better to use coating thickness gauge, to test 4-6 different points of each pipe.
Normally the minimum thickness of coating shall not be under 20um.
5.Marking
Correct, clear and indelible marking is very helpful to define pipe, as well as trace quality. Our marking can make it. The font size, type, color and position of marking shall be clear with both sides beforehand.
6.End protection
Pipes must be welded or threaded for connecting other joints. So pipe end is crucial, but it is also fragile after beveling or threading. To keep good performance, plastic cap (insert or cover type), steel ring or end protector are used for protection.
7.Bundle and unit weight
Pipes shall be tied tightly into bundles, to avoid loosening in transportation and storage. But too many steel straps and steel bars will increase the weight significantly (mills take it as Net Weight to charge buyers). Also it can damage pipe coating or water-proof cloth wrapped nearby when loading.
Our packaging of pipes shall contain 6-8 smooth steel straps on each bundle: 3 X strap on each end, and 2 X strap in the middle.
Then two steel bars or nylon slings are required for crane loading. One bundle weight is roughly 1 ton.
Make sure the sharp ends of steel bars are bent, to avoid scratching pipe coating or packaging of nearby bundle.
8.Store in warehouse
Pipe shall always be stored in indoor warehouse, no matter in mill or seaport, so as to avoid rain and dust damage.
