Material issues with hot water pipes
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In the project for company construction, there is a pipeline for transporting hot water (at a temperature of less than 120 degrees Celsius and under normal pressure). Our French experts insist on using stainless steel for this pipeline, while the design institute has chosen carbon steel. We would appreciate some advice from those with more experience.
Our pure hot water system uses stainless steel pipes. But our hot water is dechlorinated before entering the system. Without dechlorination, stainless steel pipes may corrode in little time. You should also consider your usage conditions, whether pure hot water is required. For ordinary uses, is the cost of stainless steel too high?
The Code for Design of Urban Heat Networks CJJ 34—2002 stipulates that pipes in urban heat networks should be made of seamless steel pipes, or steel pipes welded by arc welding or high-frequency welding. I have been working in the heating industry for decades, but I have yet to come across heating pipelines made of stainless steel. One reason is the cost; another is that welding such pipelines is not as straightforward as with carbon steel pipes. Moreover, there is no need to use stainless steel for pipelines that carry hot water. The outer surface of the steel pipe should be coated with an anti-corrosion coating. For directly buried hot water pipes, prefabricated pipes made of steel tubes, insulation layers, and outer protective tubes that are tightly integrated together should be used. Its technical requirements shall comply with the provisions of \"Pre-fabricated directly-buried insulation pipes made of polyurethane foam with high-density polyethylene outer sheath\" (CJ/T 114) and \"Pre-fabricated directly-buried insulation pipes made of polyurethane foam with glass fiber reinforced plastic outer layer\" (CJ/T 129).
If water quality requirements exist, stainless steel should be used; if there are no special requirements, carbon steel pipes can be employed
It depends on the water quality; whether there are any special elements in it that can corrode carbon steel. Furthermore, it must be pure hot water; carbon steel will develop rust over time if exposed to water. Analyze each specific issue individually.
By using corrosion prediction and simulation analysis software for analysis and comparison, it becomes quite clear which method is better and which is not. The name of the software is Corruption Analyzer; or you can join QQ group 32624819 where I will help you with the simulations for free
Generally, from a cost perspective, it is more appropriate to use galvanized pipes, as they do not corrode.
Stainless steel is generally not used, as halide ions in hot water can easily cause corrosion of stainless steel. Unless there is a special reason, carbon steel will suffice
For hot water pipelines, isn’t it sufficient to use polyester pipes at atmospheric pressure? They can also prevent corrosion such as oxidation. Last edited by nanjingdaxue on 2009-3-24 18:42.]
If the water does not require a very high level of purity, carbon steel will suffice
OP, can water at normal pressure exceed 100 degrees? If it exceeds 100 degrees, there should be a large number of gas-liquid interfaces inside the pipeline, which can cause corrosion to the pipeline as well as affect water quality.