1. What are the surface treatments for seamless carbon steel pipes?
* Black casing (original surface): Rust-preventive oil protection
* Painting: Red paint, yellow paint, blue paint, zinc-rich paint
* Powder coating, anti-corrosion coating
* Export commonly uses rust-preventive oil + woven bags/wooden crates for packaging.
2. How to judge the quality of seamless carbon steel pipes?
* Whether the hydrostatic test and non-destructive testing are qualified
* Reputable manufacturers can provide complete test reports for each batch.
3. Do seamless carbon steel pipes need to undergo a hydrostatic test?
Yes. All seamless pipes used for fluids, boilers, and pipelines must undergo a hydrostatic test. The pipes are pressurized to standard pressure for a certain period of time; no leakage or deformation indicates qualification. We conduct 100% hydrostatic testing before shipment to ensure safe use.
4. Does seamless carbon steel pipe undergo non-destructive testing (UT/RT)?
Used to detect internal defects, surface cracks, and weld defects (seamless pipes primarily test for internal defects), ensuring safe use in high-pressure and high-risk environments.
5. What is the difference between 20# steel and Q355B? How to choose?
20#: High-quality carbon structural steel, good plasticity and toughness, easy to weld, suitable for fluid transportation and medium-to-low pressure pipelines.
Q355B: Low-alloy high-strength steel, higher strength and better load-bearing capacity, suitable for structures, machinery, supports, and engineering machinery.
Choose according to application: Choose 20# for media transport, choose Q355B for structural applications.
