Questions regarding the bundle level

I’ve never heard of that; the tubes used for heat exchange are classified into different grades.

The specific explanation in GB151-1999 is as follows: This standard classifies carbon steel and low-alloy steel heat exchange tubes into Grade 1 and Grade 2 bundles based on the grade of their outer diameter tolerances. This classification originates from version 151-1989. At that time, 95% of the carbon steel and low-alloy steel heat exchange tubes used in China were of the ordinary-grade cold-drawn type, while both TEMA and JIS B8249 specified high-precision cold-drawn tubes. Therefore, in order to take into account the actual production conditions in China, high-precision cold-drawn tubes were included as Grade 1 heat exchangers for promotion, while ordinary-grade cold-drawn tubes remained as Grade 2 heat exchangers. After 10 years of use, high-precision heat exchange tubes have gained some popularity, but ordinary-grade cold-drawn tubes still dominate the domestic market. Thus, in the revision of 151-1999, aside from removing the descriptions of applicable applications, the Grade 1 and Grade 2 heat exchangers were retained; since the difference mainly lies in the bundles themselves, they were renamed Grade 1 bundles and Grade 2 bundles in this revision； Furthermore, since ordinary precision grades are no longer available for stainless steel heat exchange tubes, the first and second classification levels are limited to carbon steel and low-alloy steel tubes.

The answer is upstairs. The tube bundle category applies only to carbon steel tubes and low-alloy tubes; it is incorrect for some people to classify stainless steel tubes as belonging to the first category of tube bundles.

Listening to you speak is better than studying for ten years, haha! I’ve learned it.*

That’s exactly right! Stainless steel heat exchange tubes are available in certain grades, all of which are of high precision