Replace tube material (A 192 & A 179) 1

[PAN]

Tube material of the existing heat exchanger is ASTM A 192. Due to the avaiability of material, ASTM A 179 is proposed to replace the tubes after long time service.

The design temperature of this exchanger is less than 700 F. From allowable stress table of ASME Sec. II, the allowable stress should not be the problem.

Any comment for this proposal. Please comment.

 

[metengr]

From a material substitution standpoint, I see no real problem. However, depending on your specific application, you better check your heat exchanger tube sizes, and compare with boiler tube sizes. The A 192 specification is intended for boiler tubes, and specifies 1/2" to 7" in OD, and 0.085" to 1" in wall thickness ranges.

The A 179 specification is for carbon steel heat exchanger tubing with a range of 1/8" to 3" in OD. Also, check tube finish requirements applicable to each specification (A 179 versus A 192).

 

[greenche]

From the perspective of the intended use of the tube specification, you might be better to consider using A 178A. A 178A is the equivalent ERW tube version of A 192, which is seamless. Both have the same stress values at the temperatures you are using.