procurement of exchanger tubes - 3 items , heat exchanger tubes indian make tubes only seamless cold drawn stress relieved and annealed testing standard astm a 450 tube manufacturers only are allowed to supply; not from dealers / stockists vender to submit quotation along with mfl approved qap and the qap to be strictly followed for manufacturing, testing & supply.third party inspection is required.vendor to select any one of tpi given in qap , tube seamless for e1601 3a & 3b ( k1601-3rd stage inter cooler ) tube size: outside dia 19.00 mm minimum wall thickness : 2.77 mm length : 4540mm material : medium carbon steel as perastm a210 grade c carbon content:0.28% maximum to be annealed as per a210 gr.c standard , tube seamless for e1601-1a & 1b ( k1601 i stage inter cooler ) tube size:outside dia 19.00mm minimum wall thickness : 2.11 mmlength: 4040 mm material : low carbon steel as per astm a 179annealed at 650 deg.c or higher temperature , tube seamless for e1601-2a & 2b ( k1601 ii stage inter cooler ) tube size: outside dia 19.00mm minimum wall thickness : 2.11 mm length: 4640 mm material: low corbon steel as per astm a 179 annealed at 650 deg.c or higher temperature