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.