Steam drum crack
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This post was last edited by **hai** on 2020-5-22 at 10:01. It involves a steam vessel with a diameter of 1200 and a length of 6000; the material used is Q345R, with a thickness of 10 mm. The operating pressure is 5.5 kg, and the temperature is 210 degrees. The design meets all relevant requirements and specifications. It has been in use for 6 years now, and cracks have appeared in the base metal of one of the end caps. I would appreciate it if everyone could help analyze the reasons for this. Thank you
Weld crack or base metal? Pictures? Head thickness?
Replace it! Large drum-type steel plants and power stations generally operate under high temperature and high pressure. The crack in the base material is likely to have been present since it left the factory, unless it was damaged by external forces such as impacts during transportation or use.
If the steel plate is not produced by a large manufacturer, the stresses generated during the processing of the head can cause such cracks after years of use.
So how can cracks appear after 7 years of use?
You need to take a photo for a preliminary analysis; under normal circumstances, cracking does not occur in the base material. Most are cases where quality issues from the time of manufacture were not detected. It's also very difficult to find the cause.
The crack in the base material likely existed already at the time of production
The cracks that occur near the heat-affected zone are likely due to this issue; I’ve encountered the same problem here as well. At a company in Xinjiang, three steam drums cracked within 3 years, and those three were manufactured by different manufacturers. In the end, I repaired one of them here, and it has not had any problems since then. The specific reason cannot be analyzed. It’s nothing more than issues such as material defects, welding defects, and process defects; since the specific cause cannot be identified, preventive measures are taken for each possible cause. The material undergoes normalizing treatment, two types of inspections, pre-heating before welding, and stress-relief heat treatment after welding; 100% non-destructive testing is also carried out. Class 1 container, 16 thick.
With someone as dedicated as you, it’s hard to encounter problems.
Is there a record of regular thickness measurements for the equipment? If the equipment is operating properly, notify the manufacturer to conduct a reinspection. The service life of the steam drum equipment is typically set at 8 years, as indicated on the drawings.
What materials did you use to make that device? But what is the basis for you to do this? Is it because the original equipment developed cracks?