Dependence of Carbide Precipitation on Grain Boundary Structure in Sensitized Austenitic Stainless Steel

Improvement of Transpassive Intergranular Corrosion Resistance of 304 Austenitic Stainless Steel by Thermomechanical Processing for Twin-induced Grain Boundary Engineering

“…29) Although the relationship between the grain boundary energy and the S-value is not simple depending on the grain boundary plane, etc., the present authors reported that the grain boundaries with SՅ29 CSL misorientations were prone to show higher resistance to intergranular carbide precipitation and corrosion than the other grain boundaries in a sensitized 304 austenitic stainless steel. 5,30,31) Therefore, in the present study, grain boundaries with SՅ29 were classified as CSL boundaries with low-energy, the others being classified as random boundaries with high energy.…”

“…29) Although the relationship between the grain boundary energy and the S-value is not simple depending on the grain boundary plane, etc., the present authors reported that the grain boundaries with SՅ29 CSL misorientations were prone to show higher resistance to intergranular carbide precipitation and corrosion than the other grain boundaries in a sensitized 304 austenitic stainless steel. 5,30,31) Therefore, in the present study, grain boundaries with SՅ29 were classified as CSL boundaries with low-energy, the others being classified as random boundaries with high energy.Transpassive intergranular corrosion susceptibility was assessed by the Coriou test 21,27) to measure the weight loss of the specimens after they were immersed in a boiling 5 mol/L HNO 3 ϩ0.15 mol/L Cr 6ϩ solution for 10 h, 20 h and 30 h. Before the Coriou test, specimens were heat treated for 24 h at a temperature of 973 K to enhance phosphide precipitation, and then all surfaces of the specimens had been polished with #400 emery paper. After ultrasonic cleaning and drying, the surface area and weight of the specimens were measured with a precision of 0.0001 mm 2 and 1 mg, respectively.…”