Hot Cracking Susceptibility of Austenitic Manganese Steel Welds

Mainly on Effects of Silicon and Phosphorus in Base Metal

Abstract

To investigate the effect ofsilicon and phosphorus content in base metal on the hot cracking susceptibility of welds, slit type cracking tests and angle expanding type (the modified Murex type) cracking tests were carried out. The materials used here were two series of austenitic manganese steel base metal, one varying in silicon (0.18-1.85%) and the other in phosphorus content (0.035-0.086%), and 16 Mn-16 Cr type electrodes. 17 Cr-7 Ni stainless steel (AISI 301 type) base metal and 16 Mn-16 Cr, 19 Cr-9 Ni and 25 Cr-20 Ni type electrodes were also used for comparative test with austenitic manganese steel base metal which had normal silicon and phosphorus content.
In the slit type cracking test on Si series base metal, a few micro cracks were observed in weld heat-affected zone (HAZ), but they seldom extended into the weld metal even if 1.86% Si base metal was used, while conspicuous cracks were observed in the HAZ and weld metal when the phosphorus content of base metal exceeded 0.065% as reported previously by the authors.
In the angle expanding type cracking test, the cracking susceptibility of weld bead increased as increasing the silicon as well as phosphorus content of base metal. It is also substantially affected by the difference of 0.025% in phosphorus content of the electrodes.