problem about the manufacturing process of flanges

[luissandoval]

Dear All:

i'm manufacturing a Shell-Tubes Heat Exchanger, according to API 660, and also TEMA R., but i have a problem about the manufacturing process of 2 flanges, they had to be According to ASTM A105N, but in Peru, we don't fabricate them, because of the dimensions, we are talking about 25in. (diameter), and they doesn't match with the dimensions of the Standard Flanges A105 25in. 300#,so, that's why i have to manufacture them, because import them, will take so much time, and i don't have enough time.

I will be pleasure if some of you can help me about the difference between forged and casted flanges,

I'll change forged to casted flanges, i'll manufacture them according to the ASTM A216 Terms,for the WCB Grade, but i've seen that they mention some heat treatment that depends on the chemical composition, how can i select it?, is it correct just to normalized them?or they'll need also Quenched and Tempered, as they mention in ASTM A703?

I'll Want to know how can i select the correct heat treatment,including the temperatures, number of cicles, and the duration of each of them, and if it exists some risks on changing the manufacturing process, from ASTM ASTM A105N (Normalized), to ASTM A216 Gr. WCB?

[nnreddy]

Hi Luissandoval,

If manufacture using steel casting flanges and it will not have same strength of ASTM A105 and mainly it will not have grain flow. If have have thick plate meeting ASTM Standard either ASTM A516 Grade 60 or 70 OR ASTM A285 Grade C you can use to make flanges to your requirement and it will have strength.

Regards
NNREDDY