API/5L-A PIPE MATERIAL

Carbon steel.

The use of galvanized pipe for instrument air is not recommended, due to the zinc coating flaking off and causing problems with small orifices downstream.Copper,($) aluminum, Stainless,Nylon, or plastic is better choice, depending on temperature, pressure and flow.Even black pipe is preferred over galvanized for instrument air.

API/5L-A is a carbon steel pipe. The fact it was galvanized has nothing to do with the type of pipe it is. Galvanizing is a coating applied after it was manufactured. Sometimes hot dip galvanizing can effect the heat treatment of certain alloys but not usually carbon (mild) steel.

Dear Sanii,

you can use A312 Tp304 or ERW A53 -B (Gal) for instrument air service up to pressure 12 kg/cm2 .

with warm regards

Mkhan

Correct metallurgical terminology for what we call as carbon steel is ' Plain carbon steels'. All such steels have Fe, C, Mn, Si, P & S; and sometimes, some trace materials - easily ignorable. No other alloying elements (to have some specific properties). Most of this composition is due to steel making process adopted. Galvanizing is a secondary process, it does not alter the original composition. API 5L is plain carbon steel.