Due to their thin walls, thin-walled welded pipes are highly susceptible to deformation and weld cracking during transportation due to vehicle bumps and collisions. Therefore, basic protection measures must be taken during packaging. Flexible protective materials can be used to wrap the surface of the pipes, especially vulnerable areas such as the pipe ends and welds, which require focused reinforcement to prevent direct contact and friction/collision damage. For batch transportation of welded pipes, they can be bundled together, tightly binding several pipes into a single unit with flexible straps to reduce the movement of individual pipes. The tightness of the straps must be controlled during binding to ensure the pipes within the group remain secure without causing pressure damage to the pipe surface due to excessive tightness.
During loading, the welded pipes should be placed stably on the load-bearing surface of the transport vehicle, avoiding tilting that could shift the center of gravity.
For box-type transport vehicles, cushioning materials such as foam or pearl cotton can be filled between the welded pipes and the vehicle walls, ensuring a tight seal to prevent collisions between the pipes and the walls during transport. For open-top transport vehicles, in addition to bundling the pipes together, high-strength reinforcing ropes or straps should be used to securely connect the welded pipe assemblies to the vehicle's anchor points, ensuring the pipe assemblies do not shift during transport.

The national standard thickness for 3PE reinforced anti-corrosion grade is 2.5–3.7 mm. Generally, 3PE anti-corrosion steel pipes of the same specifications are 0.7 mm thicker than the ordinary grade.

The 3PE anti-corrosion coating consists of an epoxy powder layer, an adhesive layer, and a polyethylene layer. The epoxy powder layer provides adhesion and chemical resistance. The thickness of the epoxy powder layer varies depending on the pipe diameter and grade requirements: no less than 120 μm for DN≤500 mm and no less than 150 μm for DN>500 mm; the total thickness can reach 2.7–2.9 mm in reinforced anti-corrosion applications.

1. Dimensional Tolerance: This refers to the allowable dimensional deviation range during the production of shaped steel pipes. The size of the dimensional tolerance directly affects the quality and performance of the shaped steel pipe. Generally, the smaller the dimensional tolerance, the higher the quality of the shaped steel pipe.
2. Appearance Quality: This refers to the absence of obvious defects on the surface of the shaped steel pipe, such as cracks, inclusions, and rust. Good appearance quality not only improves the aesthetics of the product but also reduces problems during subsequent processing and use.
3. Mechanical Properties: This refers to the good strength, toughness, and hardness of the shaped steel pipe. The levels of these properties directly determine the safety and reliability of the shaped steel pipe during use.
4. Chemical Composition: This refers to the content of each element in the shaped steel pipe meeting specific standard requirements. A reasonable chemical composition not only ensures that the performance indicators of the shaped steel pipe meet the requirements but also improves its corrosion resistance and wear resistance.

Regarding the classification of special-shaped pipes:
https://www.chinasteelmarket.com/feature-pages/featureinfo/FEATURE%7C-The-Knowledge-Summary-of-Seamless,-Welded-Steel-Pipes,-Stainless-Steel-Pipes,-and-Special-shaped-Steel-Pipes_1166.html