Dear friends, when purchasing 15CrMoG seamless steel pipes or thick-walled large-diameter seamless steel pipes, do you often encounter these problems: Don’t understand the material properties? Can’t understand the specifications? Don’t know how to choose due to the large price difference?
First, the common pain points of 15CrMoG thick-walled large-diameter seamless steel pipes.
1. Material confusion: What does the “G” in 15CrMoG stand for? What is the difference with ordinary 15CrMo?
2. Specification selection: How thick is the appropriate thickness of thick-walled pipes? What will be the impact of a larger diameter?
3. Price trap: Why do the quotations for the same nominal steel pipes differ by 30% or even more?
4. Quality concerns: How to identify inferior steel pipes? Is ultrasonic flaw detection reliable?
Second, a practical guide to the purchase of 15CrMoG thick-walled large-diameter seamless steel pipes
1. Material property analysis: 15CrMoG is a chromium-molybdenum alloy steel for boilers. “G” means it is dedicated to boilers. Compared with ordinary 15CrMo:
- Stricter control of carbon content (0.12-0.18%)
- Lower phosphorus and sulfur content requirements (≤0.025%)
- High-temperature mechanical properties data must be provided
2. Specification selection skills
Thick-walled large-diameter pipes (usually refers to outer diameter ≥219mm, wall thickness ≥20mm) should pay attention to:
- For every 1mm increase in wall thickness, the pressure-bearing capacity increases by about 5-8%
- Large-diameter pipes are preferred to use thermal expansion technology to avoid weld problems
- Common misunderstandings: The thicker the wall thickness, the better. The weight cost and installation difficulty should be considered
3. Four-step quality identification method
① Look at the surface: The inner and outer walls of high-quality pipes are smooth, without cracks or folds
② Dimensions: Measure with a caliper, the tolerance should be within ±1%
③ Check the certificate: Material report and heat treatment record must be provided
④ Test: It is recommended to sample for a water pressure test or ultrasonic test
Third, the use and maintenance suggestions for 15CrMoG thick-walled large-diameter seamless steel pipes
① Welding points: 15CrMoG needs to be preheated to 150-200℃ before welding, and slowly cooled after welding
② Anti-corrosion measures: Both ends should be sealed during storage to avoid rust inside the pipe
③ Regular inspection: It is recommended to measure the wall thickness every 2 years under a high-pressure environment
Post time: May-23-2025