Doubts about the raw materials for pipe fittings
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I have been working in the pipe fittings industry for 10 years; at first I only had a basic understanding of it, and now I know a bit more, but I still have many questions. The raw materials used for pipe fittings continue to pose challenges for me, and I hope to share these issues so that we can discuss them together. Among pipe fittings, elbows are one of the most commonly used types. Before placing an order, customers specify standards such as GB/T8163, GB3087, GB5310, GB6479, and GB9948. The standard GB8163 is the most widely used in the market. Materials that conform to other standards are quite rare; even if they can be found, their price advantage is minimal. As a result, it’s difficult to determine the appropriate pricing when quoting for customers You say that the pipes for 9948 are hard to find, right? The customer will say that as long as they meet the requirements of 9948, it’s fine. If you say it will be expensive, the customer will reply that others have already given quotes, and it’s not that expensive after all. . . . I asked some experienced professionals in the industry; some said that using a normal grade would be sufficient, and if precision is really important, then heat treatment can be applied... Other experts said that 9948 has low sulfur and phosphorus content, so 20G of 5310 would work, but it’s quite expensive. I hope that both those who work in technology and those who are experts in production will actively participate in the discussions to help me answer my questions
I’m just a junior designer; in terms of material, GB/T8163 belongs to the medium-to-low quality category. The remaining GB3087, GB5310, GB6479, and GB9948 belong to the high-quality category. The material standards are determined based on the pressure and temperature of the medium from the initial design stage. In terms of design principles, it is better to opt for a higher standard rather than a lower one, and to leave some margin.
A slight difference can be seen from the standard names. GB/T8163–Seamless steel tubes for transporting fluids; GB3087–Seamless steel tubes for low and medium pressure boilers; GB6479–Seamless steel tubes for high-pressure fertilizer processing equipment; GB9948–Seamless steel tubes for petroleum cracking; GB/T5310–Seamless steel tubes for high-pressure boilers.
The standard numbers are different; I would like to ask how to distinguish the actual products? There are people who fake money; is it that difficult to alter the markings on steel pipes?
**The standards met are fine, and the design is also okay; the issue lies mainly in the supply stage – how can consumers tell the difference between inferior products and high-quality ones? In other words, whether it’s the 5310 or the 9948, the only factor that seems to distinguish them from the 8163 is probably the sulfur-phosphorus content The sulfur and phosphorus content of 8163 is also not high at the moment...
Indeed, manufacturing capabilities have improved significantly now, and some low-end standards should be removed