Corrosion Allowance 5 W.O / 3 CLAD 3

[etsen]

The shell and channel material of a heat exchanger is SA 387 Gr.11 Cl.2+SA 240 TP.347 CLAD, the tube material is SA 213 TP.347. The corrosion allowance of shell side and tube side is 5 WO./3 CLAD. The shell and channel thickness is 22+3mm and 19+3.5mm respectively. The specification of the tube is 19.05mm×1.65mm. The thickness value of tube is lower than corrosion allowance of tube side. So I am confused now. Could anybody explain it and what corrosion allowance 5 W.O / 3 CLAD means. Thanks very much.

 

[SnTMan]

etsen, corrosion allowance is rarely applied to tubes, as they would be too thick for economical construction and performance.

"5 W.O / 3 CLAD" My guess is that this statement means the corrosion allowance would be 5 mm on bare base metal or is 3 mm of cladding, i.e zero corrosion allowance on the base metal.

Regards,

Mike

 

[AravindSujay]

etsen,

5 WO /3 Clad should be either WO or Clad. because generally tubes will have zero CA and moreover SA 213 TP 347 is of the composition - 18Cr-10Ni-Cb and CA is not needed. It is very difficult to give CA of 3.5mm to a tube thickness of 1.65mm.

 

[SnTMan]

AravindSujay, you are probably right, WO means "Weld Overlay", generally thicker than integral cladding, to produce proper chemistry.

Regards,

Mike

 

[vesselfab]

This most likely refers to the stainless steel corrosion resistant lining

5mm thick weld overlay....(3mm deep of good metal and 2mm allowance for dillution of the base metal)

3mm if it is roll bonded or explosion bonded clad.

 

[roca]

Spot on vesselfab