Q: Which grade is generally more expensive?
A: Q345 is more expensive per ton due to its alloying elements and higher performance.
Q: What are key inspection points upon delivery?
A: Verify certificate, markings, dimensions (OD, WT), visual surface quality (defects, straightness), and potentially re-test samples.
Q: What is a common material substitution issue?
A: Unauthorized substitution of Q235 for Q345 to cut costs, leading to potential structural failure.
Q: What causes delamination in these pipes?
A: Inclusions or segregation in the steel slab. More a concern in lower-quality mills. Proper ultrasonic testing can detect it.
Q: What is the risk of buying under-thickness pipes?
A: It reduces the load-bearing cross-section, decreasing pressure rating and structural strength, a serious safety hazard.
