| Q1: What is the X65QS grade designed for? | X65QS is a quenched and tempered (Q) grade with sour service (S) capability. It's designed for thick-walled, high-strength pipelines requiring excellent low-temperature toughness and resistance to Hydrogen Induced Cracking (HIC) in sour (H2S-containing) oil and gas environments -5. | |
| Q2: What is a key chemical feature of the X65QS grade for corrosion resistance? | It features an ultra-low carbon content (typically 0.05-0.09%) and very low Sulfur (≤0.003%) and Phosphorus (≤0.018%) levels. This, combined with micro-alloying (Nb, V, Ti, Mo), enhances its weldability and resistance to corrosion -5. | |
| Q3: What does the "DZ" prefix in grades like DZ50 indicate? | "DZ" is from the Chinese "Di Zhi" (Geology). It designates steel grades specifically for geological drill pipes. The number (e.g., 50) often relates to the minimum yield strength -3. | |
| Q4: What is the Chinese standard for general structural seamless steel pipes? | GB/T 8162 is the standard for seamless pipes used in general structures and mechanical parts -3. | |
| Q5: Which standard covers seamless pipes for fluid transportation in China? | GB/T 8163 covers seamless pipes for conveying fluids -3. |
