316L pipe leaks after 6 months of operation
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The 316L pipes used in my plant’s secondary oil pipeline have leaked three times after being in use for 6 months. The temperature in this pipeline is 280 degrees, the sulfur content is 0.56%, the acidity level is around 30, and the chloride ion concentration is less than 0.5 ppm. Could everyone help analyze the reasons for these leaks? Thank you!
Where is the leakage occurring? Is it at the weld, or due to corrosion-induced perforations? Is it at the bottom or on the back of the elbow? Is there no pipeline thickness measurement? How is the thickness measurement?
It would be best to have a few photos showing the leaks, so that everyone can analyze and discuss them.
Don’t know the location or circumstances of the leak?
The pipeline has been upgraded to 316L, which meets the requirements according to the standards for material upgrades. Several scenarios have been preliminarily analyzed: 1. The upgraded pipeline material lacks sufficient components; if the titanium content is low, stress corrosion cracking is likely to occur； 2. If it is a new pipeline being installed, it is necessary to consider whether there is leakage at the welding site; if so, it is important to analyze whether stress has been generated at the weld, whether the appropriate type of welding rod was used, and whether sufficient heat treatment was carried out ； 3. If it is caused by medium corrosion, the corrosion caused by active sulfur must be taken into account; inert sulfur is easier to analyze and its corrosive effect is not significant, but active sulfur formed from certain sulfides when heated can cause severe corrosion to the pipeline matrix. Therefore, it is very important to analyze the corrosion pattern, corrosion products, and conduct subsequent tests; I hope this can be of some help to you.
It leaked 3 times in 6 months; it’s probably a leak in the weld. If it’s a leak in the pipe wall, then as for this material, haha
High temperature and sulfur content – we have encountered that too; 304 works fine in such conditions
Let’s first examine the quality issues related to pipes – material testing, as well as the evaluation of pipe manufacturers. This is because there are many small manufacturers in the market that do not conduct any flaw detection or pressure tests on the pipes before they leave the factory.
Two questions: 1. Does 316L contain titanium? Is there a relationship between titanium content and stress corrosion resistance? 2. Does welding such stainless steel pipes require heat treatment?