Exploratory Study of Sensitization in Cryogenically Cooled Ferritic Stainless Steel Welds

Table 3

Classification of etched structure in oxalic acid electrolytic etch [16].

Classification	State of the microstructure
Acceptable	(i) Step  structure: step only between grains, no ditches at the grain boundary
	(ii) Dual  structure: some ditches at the grain boundary in addition to steps; however, no single grain is completely surrounded by ditches
Unacceptable	Ditch  structure: one or more grains are completely surrounded by ditches