Q: Which grade of seamless steel pipe is suitable for chemical corrosion-resistant pipelines (such as dilute acid pipelines)?
A: ASTM A312 TP304 or TP316L stainless steel seamless pipes are suitable. They have excellent corrosion resistance to dilute acids, alkalis and other media, and are widely used in chemical, pharmaceutical and other industries.
Q: Can API 5L X42 seamless steel pipes be welded?
A: Yes. API 5L X42 seamless steel pipes have good weldability. They can be welded by arc welding, gas shielded welding and other methods, but preheating and post-weld heat treatment should be carried out according to the welding process requirements to avoid welding cracks.
Q: What is the common heat treatment method for ASTM A335 P91 seamless steel pipes?
A: The common heat treatment method is normalizing + tempering. Normalizing (950-1050℃) can refine the grain and improve the strength; tempering (730-780℃) can eliminate internal stress and improve toughness.
Q: How to inspect the internal quality of seamless steel pipes (taking GB/T 8163 20# as an example)?
A: Common inspection methods include ultrasonic testing (UT) and radiographic testing (RT). Ultrasonic testing is used to detect internal defects such as cracks and inclusions; radiographic testing is used to further confirm the type and size of internal defects.
Q: Can 45# seamless steel pipes be quenched and tempered to improve their performance?
A: Yes. 45# seamless steel pipes can be quenched (840-860℃) and tempered (550-650℃) to improve their strength, hardness and toughness, making them suitable for mechanical parts that require high comprehensive performance.
