For Joining Of Dissimilar & Problem Steel
NST-312
CLASSIFICATION
AWS A5.4 E312-17 | JIS Z 3221 D312-16
PRODUCT DESCRIPTION
A manual metal arc welding electrode using a predominantly alloyed core wire with a rutile alumina-silicate flux concentrically extruded flux coating. The weld metal composition of 29%Cr–9%Ni and containing a large percentage of ferrite, it has very high tensile strength and excellent crack resistance. It is extensively used on a maintenance basis for welding of unknown specification and for dissimilar weld between ferritic and austenitic.
WELDING FEATURES OF THE ELECTRODE
This unique flux formulation ensures excellent arc stability, ease of initial arc strike and re-strike, minimal spatter on AC and virtually none on DC+. The resultant weld seams are smooth, evenly rippled and free from undercut while slag detachability is excellent. Metal recovery is some 103% with respect to core wire weight. For all-positional welding ideally use smaller diameters.
APPLICATIONS AND MATERIALS TO BE WELDED
Primarily designed for high carbon steels, cast or wrought, which are well known as difficult to weld or problem steels. The duplex microstructure of the weld metal will tolerate high dilution with such steels while still maintaining its strength ductility and thus resistance to cracking. It can also be used very successfully for joining carbon steels to stainless steels, the only exception to its extensive use on such applications is that at service temperatures above 300 ºC a drop in weld metal ductility occurs.
WELDING AMPERAGE AC and DC
OTHER DATA
Electrodes that have become damp should be re-dried at 120oC for 30 minutes.
