Stress Corrosion Cracking in Tubing Bundles （应力腐蚀开裂在油管包）.pdfVIP

Stress Corrosion Cracking in Tubing Bundles A recent laboratory summary from a failure of a tube in a tubing This list assumes there is heat. SCC usually takes place at el- bundle concluded that there was a PVC coated wire in direct evated temperatures above 140ºF (60ºC) and below 300ºF contact with the 316 stainless steel tubes. Heat from the steam (149ºC). Elevated temperatures cause rapid water evaporation, tracer degraded the PVC resulting in chloride deposits on the which concentrates chloride ions. Also, heat speeds up the cor- tube which ultimately lead to tube rupture from chloride ion in- rosion reaction rate. duced stress corrosion cracking (SCC). 18-8 austenitic stainless steel is most sus- Our experience has been that SCC in tub- ceptible to SCC. This includes the 300 se- ing bundles has been a rare occurrence. ries stainless steels and the commonly used We have only witnessed a few cases in 316, 316L, 304 and 304L grades. This sug- over 20 years of manufacturing these gests that other alloys like the 400 series products. Twenty years of tubebundle and 800 series would be more resistant. manufacturing represents millions of feet Grades with lower nickel and higher of tubebundle. The laboratory summaries