Q: What is a seamless steel pipe, and what are its main manufacturing processes?
A: A seamless steel pipe is manufactured without a welded seam, typically through processes like hot rolling, hot extrusion, or cold drawing (cold rolling)-4. This makes it stronger and more reliable for high-pressure applications.
Q: Which Chinese standard and steel grades are used for general structural seamless pipes?
A: The common standard is GB/T 8162-2008. Representative steel grades include carbon steels like 20#, 45#, and alloy steels such as Q345, 20Cr, 40Cr, 20CrMo, 30-35CrMo, and 42CrMo-8.
Q: For structural applications like stadiums or airport terminals, what grades of SMLS pipes are typically specified, and what are their key mechanical properties?
A: Grades like Q345B, Q345C, Q390, Q420, and higher-strength grades up to Q690 are used-2. Their key properties are high yield strength, good toughness (especially at low temperatures for grades with suffixes C, D, E), and excellent weldability to ensure structural safety and stability-2.
Q: What is the difference between a "cold-drawn" and a "hot-rolled" seamless pipe in terms of application?
A: Cold-drawn pipes have higher dimensional accuracy, a smoother surface, and higher strength, making them suitable for precision mechanical parts. Hot-rolled pipes are more common for general structural and fluid transport applications-4.
5. Q: Which standard and grades are used for seamless pipes intended for fluid transportation?
* A: GB/T 8163-2008 is the primary standard. Common grades include 20# and Q345-8.
