Oxide Inclusions in 19Cr-9Ni Stainless Steel Weld Metal

Abstract

An investigation was made of oxide inclusions in 19Cr-9Ni stainless steel weld metal which was produced using a electrode covered with lime-titania.
2MnO·SiO₂ (tephroite), MnO·SiO₂ (rhodonite), FeO·Cr₂O₃ (chromite), FeO·Ti₂O₃, Cr₂₃C₆, TiC, and TiN were identified by the X-ray analysis of the residue separated from the weld metal by ultrasonic agitating dissolution method using 14% I₂-CH₃OH solution.
The inclusion particles extracted were classified according to the size (5 μ over and under) by ultrasonic sieving method, and observed by optical microscope.
Typical inclusion particles over 5 μ were analyzed by electronprobe X-ray microanalyzer.
It was found that inclusion particles over 5 μ were mainly spheroidal MnO·SiO₂, 2MnO.SiO₂, angular SiO₂, massive SiO₂, plate-like SiO₂, rod-like Al-silicate, needle-like TiN, and stringer-like Ca-phosphate.
Inclusion particles less than 5 μ amount to about 90% of oxide inclusions, and they contain mainly Mnsilicate, FeO·Cr₂O₃, and FeO·Ti₂O₃, the size of which was 1 μ or under.