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2-KHz wave really exists, maybe some MTMK\ZWVQK KWUXWVMV\ QV \PM ZMK\QÅMZ Q[ not working properly. There is a communications system
A
that sometimes uses cables or pipelines to transmit digital data superimposed on the AC voltage. Maybe your wave comes from a system like this.
Zinc anodes with bare steel straps
for 10-lb (4.5-kg) zinc anodes with bare steel straps for welding to 3.5-in (89-mm) square stainless steel tubu- lars.
want to have bare steel, I suggest you grind the galvanized surface off the insert in the area where you want to weld. You should contact the major anode suppliers for assistance.
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prevent the contamination of the alloy by the steel straps when casting the anodes.
due to attachment with a tack weld. If you only grind the galvanized surface, you will very likely crack the stainless during weld-
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NACE International, Vol. 51, No. 3 March 2012 MATERIALS PERFORMANCE 13
Zinc contamination in stainless welds can be tricky stuff. I've seen trace amounts cause cracking through 1/4-in (6.4-mm) plate
Zinc anodes can be fabricated without the galvanizing. You should be aware that the purpose of the galvanized inserts is to
The inserts are galvanized to improve bonding between the anode alloy and insert; this is not done on aluminum anodes. If you
Most anodes come with a galvanized core or galvanized steel straps. I am looking
A high-frequency wave for a short period may indicate some kind of noise when you turn some equipment on and off. If the
ing. Grinding will load the grinder wheel and smear some of the zinc into the sur- face. The small amount that remains is more than enough to cause cracking. Etching with an acid after grinding is recommended if you plant to remove zinc from steel and weld it to stainless.
Editor's Note: Additional MP Blog items
appear in the individual technical sections: cathodic & anodic protection (p. 37), coatings & linings (p. 41), and chemical treatment (p. 54).