Leak policy is that it cannot happen! Tanks do have 100% secondary containment, just in case.
Pit depth was measured and compared with allowable depth per API 653. This showed the remaining tank wall thickness was greater than the minimum requirement per API 653 for "scattered pitting"...
Thank you metengr and stanweld for your prompt and thorough responses. In answer to some questions raised, the pitting does coincide with the sludge level near the bottom of the tank. There is general corrosion occurring as well as measured by ultrasonic inspection and comparison with original...
A recent ultra-sonic inspection determined several clusters of pitting in a carbon steel storage tank. Tank holds approx. 200,000 gallons of liquid waste containing organic compounds in water. pH is 11-12, but composition is likely to contain chlorides(to be verified).
The operating company...
A 420 SS overlay is being applied to carbon steel vessel (.35% C) using submerged arc welding. Pre and post weld heat treatment are being used and surface is physically acceptable (no cracking). It takes approximately 3 passes to buildup to desired 3/8" thickness of 420 layer. The desired...
Thanks for your inputs. Yes, the plated parts are "baked" at approximately 200 C for hydrogen release soon after they are removed from the plating bath.
How can I tell if the steel I am working with is susceptible to Tempered Martensite Embrittlement? According to ASM Metals Handbook Desk Reference, (online - Carbon and Alloy Steels; Service Characteristics of Carbon and Alloy Steels; Embrittlement of Steels) tempering in the region of 200 C -...
Thank you all for your inputs. To answer some questions posed on further details:
Steel composition is
.51% C
1.01% Cr
.93% Mn
.23% Si
.23% Mo
.09% Cu
.013% V
.012% P
.001% S
Steel is forged then heat treated 8 hrs at 850 F prior to intial grinding.
I am not sure of the history/reasoning...
Thank you Metalguy. Another question, if I may...
If the surface is rough ground to dimension, then laser hardened, then finished ground to final dimension - at what point should the tempering be done? Before or after finish grinding?
Also, any recommendations on temp/time to relieve the...
The application is a laser hardened steel corrugated roll that is cracking and peeling a small layer of material at the top of the flute - slightly off center. Locations of failures do not appear to follow any geometric pattern, but each crack is identical. The failures are occurring during the...
