STUD PERFORMANCE

that effectively protects the tube wall. Above the same piece shows dramatic difference

The variables that will make stud protection effective (or not) are basically three variables and they are explained below in a very simplified manner. For additional information please contact us.

Importance of proper balance length - diameter is demonstrated here. Overly long studs will burn quicker

Mass of smelt versus the mass of "heat sink elements" is the key factor to prevent liquid smelt touch the tube

Upper half of panel has higher density and studs are new after 7 years in operation. Notice the wear pattern of chromized studs, regardless of the density. They wear off as a cigarrete butts and are therefore self preparatory for future repair jobs.

	Recovery Boiler tube welded with resistance weld pattern 4x4 and for comparison also welded with drawn arc stud process with 5x5 pattern...
	when sectioned shows what appears to be good results for both methods...
	but when scanned the real metal bond (gray areas) fails to show on the resistance welded studs...

lack of actual metal bond results in ...limited contact and lack of protection in operation - leading to the need of panel replacement...

properly welded studs grant complete metal bond and even when the stud is consumed the tube is protected...

a properly studded tube can be restored becomint practically new whereas if the original stud is not properly welded the tube may be damaged before the stud calls for replacement.

Ribbed area increases the heat absorption.

The non ribbed zone tells the user that restudding is need, thus preventing premature or overdue repair.

Spikes at top (not shown) grant the stud tip its own frozen layer.

Weld tip is chromium free thus avoiding microhardness at the welded zone.

Higher densities of 90 and 100 studs/ft are feasible but they render inspection with ultrasonic probes very difficult. To accomodate this situation we have modified the studs distribution to create inspection lines already built into the panels. This forces the inspector to use the same reference line year after year and ensures that realistic wear rates are determined.

Sage panels are gradually becoming a new standard in this "hard to compete" market. So far (2/06) seven boilers have them installed with pressures from 600 to 1200 psi. All perform flawlessly.