Problems with the expansion jointing of the horizontal tubes in the primary cooler?
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Our plant’s primary cooler has been in use for 6 years now, and most of the horizontal tubes are severely corroded; therefore, they need to be replaced. Seamless steel pipes with a diameter of φ57*2 and made of 10# steel will be used for this purpose. Some people suggest that annealing treatment should be applied – is this necessary? I’d like to ask everyone for advice.
If the tubes in a horizontal tube primary cooler are replaced but the tube sheet is not changed, it seems that tube expansion can no longer be carried out; welding is the only option. The biggest problem with pipe welding is that the tube sheet tends to deform.
It can be replaced, but it needs to go through an annealing process. Several primary coolers manufacturers can provide replacements, but the cost is relatively high. Last edited by Poor Farmer on 2009-3-25 00:22.]
Please explain upstairs the reasons for the need for annealing
The purpose of annealing is to eliminate stress.
Grade 10 steel is used, and annealing is not necessary. However, when our factory replaces the tubes in the primary cooler, we anneal the tube ends, as the tube sheets suffer severe deformation and there are significant variations in the size of the tube holes. Annealing helps to relieve stress and facilitates welding. Our factory has already carried out tube replacements on two occasions, giving us extensive experience in this area
An annealing is required for the position of the truncated pipe end. But it had to be replaced after just six years of use – how could it corrode to such an extent?
Why use butt welding? Isn’t welding better?
This task isn’t too difficult; some larger installation companies can handle it. Annealing is required; the purpose of the butt joint is to allow for replacement in the future.
Welding is quite good; Hansteel does it this way, and it’s excellent.
Corrosion in major water systems is a serious issue, and water treatment chemicals are crucial; poor water treatment in such systems leads to severe corrosion of the equipment
How long does it take to replace the tube once?
If it is fully welded, does this stress still need to be considered?
Hehe, the horizontal tubes of the primary cooler can be expanded or welded in order to replace them. However, if welding is done once and then replacement is attempted, there will be problems with the tube sheet. The steel tubes need to be annealed, and both tube ends must be cleaned before expansion