Hello, I would like to provide a SS 316L lining on carbon steel which will be achieved byplug welding. The process medium contain aquous 5% chloride solution and pH 5-8 and temp 85-90 °C. The general corrosion rate is quite low (<0.2mm/yr). As SCC is known to be a fuction of chloride , pH, dissolved oxygen,temp and also the stress present in SS 316L, I would like to know whether 3mm or 6mm thickness should be opted as a safe option to prolong SCC. thanks for your response raju

You can use 3mm SS316 sheet. As the pitting corrosion resistance of 316 is high, low thickness is sufficient. In fact, such stainless steel covering is normally used in process vessels in petrochemical industries by bud-welding.

Though 316 or 316L is said to be resistant to pitting due to it's Mo content still it has got differential pitting resistance due to interdendritic high/low segregation of Mo . After all chloride ion can damage passivity as per it's concentratiion and stress level. As such either use duplex SS lining or simply put rubber lining. In case if you donot want to put rubber lining you MAY go for Moisture cured high solid Elastomeric Polyurethant Coating which can have good resistance .