Regarding tubes for heat exchangers
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A type I heat exchanger, with the drawings specifying that the heat exchange tubes should be of 25x2 0Cr18Ni9 GB13296-2007 WC material. I would like to ask whether it is necessary to meet the requirements of NB/T47019.1 and 47019.5 when purchasing these pipes, and whether such requirements should be specified in the purchase contract Thank you!
When purchasing this pipe, it is necessary to ensure compliance with the requirements of NB/T47019.1 and 47019.5; such requirements must be specified in the purchase contract.
May I ask the moderator: If GB13296 is used as the basis for procurement, then NB/T 47019 should be used instead. However, according to clause 4.1 of NB/T 47019.5 for stainless steel, \"the outer diameter and wall thickness of seamless steel pipes shall comply with the provisions of GB/T 17395.\" The wall thickness requirements specified in GB/T17395 are inconsistent with those specified in GB 13296. What to do?
GB/T 17395-2008 specifies the dimensions, shape, weight, and allowable tolerances of seamless steel pipes, while GB13296-2007 deals with stainless steel seamless pipes used in boilers and heat exchangers. Therefore, GB13296 represents an improvement over GB/T 17395. In my view, when there are discrepancies between the wall thickness requirements specified in GB/T 17395 and those in GB13296 for use as heat exchange tubes, GB13296-2007 should be the governing standard.
As is customary, when several standards require different things, and those requirements differ from those in the order contract, the stricter one applies.