Carburization 1

[Rajasekaransogec]

(1)What is the diffrent between carburizing and carburization?
(2)The objective of this service is to find whether carburization has taken place into the following SS pipng line nos due to temperature and the fluid services?

 

[TVP]

Carburizing is a heat treating process where carbon is intentionally diffused into the steel surface for beneficial purposes such as increasing resistance to contact stresses, bending fatigue, abrasive wear, etc. Carburization, also called metal dusting, is the unintentional diffusion of carbon into the surface of a metal (often austenitic stainless steel) during the service phase of a part/assembly, and is considered deleterious. Here are some references that you can review for more information:


Chapter 5 Carburization and Metal Dusting

http://books.google.com/books?id=tf...a=X&ei=_dpaUbC8PIGhqgGT-4HYDg&ved=0CDcQ6AEwAA

What to Do About Metal Dusting

http://theheattreatdoctor.com/documents/MetalDusting2.pdf

Metal Dusting Causes HRA Headaches

http://www.industrialheating.com/articles/85746-metal-dusting-causes-hra-headaches

 

[metengr]

Actually, we had in-situ corrosion of 304H austenitic stainless steel on one of our superheater assemblies that was attributed to carbon diffusion (similar to carburization) into the surface of the 304H tube material. This phenomenon resulted in reduced corrosion resistance to flue gas containing sulfur compounds that wasted the tube OD surface. The surface appearance was similar to pock marks and the reason for the corrosion was that the chromium combined with carbon deposited on the tube surface from poor coal combustion in a reducing atmosphere at 1800 deg F. The depleted chromium on the tube surface altered the corrosion resistance.