Transgranular corrosion

Figures 14.16 and 14.17 are examples of intergranular corrosion and transgranular corrosion of stainless steels, respectively. Transgranular corrosion refers to the corrosion of the metallic grains, while intergranular corrosion refers to the corrosion in the grain boundary region. Although carbon steel is considered to be unaffected by transgranular corrosion, transgranular SCC was observed with mild steels and low alloy steels in a H2O-CO-CO2 environment [18,19].

Sensitivity of Aluminium Alloys to Pitting Corrosion Transgranular and Intergranular (Intercrystalline) Corrosion... 

The appearance of stress corrosion cracking may be either intergranular or transgranular in nature. 

Microstructural examinations revealed that the cracks originated on the external surface (Fig. 9.15). The cracks were highly branched and transgranular. The branched, transgranular character of these cracks is typical of stress-corrosion cracking of austenitic stainless steels. The thick-walled fracture faces are also typical of cracking by this mode. 

Microscopic examinations revealed that the cracks were unbranched and transgranular, t3q)ical of corrosion-fatigue cracks. These examinations also... 

Microscopic examinations revealed tight, unbranched, transgranular cracks originating on the external surface. Many of these cracks originated at shallow pockets of corrosion. 

The fracture mode of stress-corrosion cracks in austenitic stainless steels can be transgranular, intergranular or a mixture of both. One of the earliest environments found to cause problems was solutions containing chlorides or other halides and the data due to Copson (Fig. 8.30) is very informative. The test solution for that data was magnesium chloride at 154°C the alloys contained 18-20alloy with a composition of approximately 18Cr-8Ni has the least resistance to cracking in this environment. 

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