Small-diameter seamless steel pipe refers to precision pipes with an outer diameter usually between 10-159 mm and formed by hot rolling or cold drawing. Its unique manufacturing process gives it uniform mechanical properties and smooth inner wall characteristics. This seemingly ordinary industrial material plays a key role in the field of precision manufacturing, just like the "microvascular system" of the modern industrial system, supporting the precise operation of high-end equipment.
1. The core carrier in the field of high-end manufacturing
In the field of precision hydraulics, small-diameter seamless steel pipes constitute the "nerve fibers" of power transmission. The dimensional tolerance of the inner wall of the hydraulic cylinder of engineering machinery must be controlled within ±0.05mm, and the surface roughness Ra≤0.4μm. This precision requirement can only be met by cold-drawn seamless steel pipes. Test data from an international engineering machinery giant shows that the hydraulic system using precision seamless steel pipes has a 37% lower pressure fluctuation than traditional pipes and a 2.8 times longer service life.
The nuclear power equipment field has more stringent requirements on pipe performance. Nuclear-grade stainless steel seamless pipes must withstand 600℃ high temperature and 15MPa pressure, and the intergranular corrosion rate must be less than 1.2mm/year. In the CAP1400 nuclear power unit independently developed by my country, the steam generator heat transfer tube uses ultra-long thin-walled seamless steel pipes, with a single length of 22 meters and a wall thickness of only 1mm, achieving zero-defect delivery.
2. Key media of emerging technology industries
In semiconductor manufacturing equipment, high-purity gas delivery systems use 316L ultra-low carbon stainless steel seamless pipes, and the inner surface is electrolytically polished to Ra≤0.15μm. The gas pipeline system of a 12-inch wafer factory uses more than 50 kilometers of small-diameter seamless steel pipes to ensure that the gas purity is maintained at the ppt level (one trillionth). These pipes must pass helium mass spectrometry leak detection, and the leakage rate is less than 1×10-9 Pa·m³/s.
The hydrogen energy field puts forward revolutionary requirements for pipes. The inner liner of the 70MPa high-pressure hydrogen storage bottle is made of 34CrMo4 seamless steel pipe, which needs to maintain an impact energy greater than 80J at -40℃. The latest developed composite winding hydrogen storage bottle has a thinner inner liner wall thickness of 3.2mm, a 25% reduction in weight, and a range of 800 kilometers.
