TC Wilson

1-800-230-2636

BOILER TUBE EXPANDERS

REFERENCE CHART

Guidelines for Tube Expansion

Improperly rolled joints create considerable additional expense: under-rolled joints must be re-rolled, and over-rolled tubes must be removed and replaced. The optimum joint is one that develops a leak-tight joint with adequate strength for the intended service, but with the minimum amount of cold working (or tube wall reduction).

Application Tube Wall Reduction*
Non-ferrous tubes in surface condensers   3% to 4%
Steel tubes in heat exchangers 5% to 10%
Soft copper and aluminum tubes in heat exchangers 8% to 12%
Boiler tubes 12% to 14%
*After metal-to metal contact of the tube Outer Diameter with the tubesheet hole
Here is an example of the application of this method for a 2-inch Outer Diameter 10 Gauge tube in a boiler.
Tubesheet Hole:
   2.010
Tube Outer Diameter:
   -2.000
Clearance:
  
.010
Tube Inner Diameter:
   1.732
Clearance:
   +.010
Tube Inner Diameter @ Metal-to-Metal:
  
1.742
13% of .134 x 2:
   .035
Tube Inner Diameter @ Metal-to-Metal:
   +1.742
Expanded Tube Inner Diameter:
   1.777

 

Download a PDF of Tube Rolling Worksheet