Flange cracking

The current wheel monitoring practices are described in section 20.2, but gaps exist in automatic detection and/or measuring of the following cracked/broken flange, thermal flange crack, cracked/broken/shattered/spread rim, cracked/broken plate, thermal plate crack, hole in plate, loose wheel, wheel gouge, subsurface defect, etc. 

Bolting a raised-face flange to a flat-faced, cast-iron flange can create bending moments in the less ductile cast-iron flange, which could cause it to crack. 

Flange face areas experience stagnant conditions. Additionally, some gasket materials, such as asbestos fiber, contain leachable chloride ions. This creates crevice and stress corrosion cracking problems on sealing surfaces. Where necessary, flange faces that are at risk can be overlaid with nickel-based alloys. Alternatively, compressed asbestos fiber gaskets shrouded in PTFE may be used. 

Sleeve flange gaskets must be whole, in good condition, clean, and free of nicks or cracks. 

Limited aperture releases are conceptualized in Figure 4-2. For these releases material is ejected from holes and cracks in tanks and pipes, leaks in flanges, valves, and pumps, and severed or ruptured pipes. Relief systems, designed to prevent the overpressuring of tanks and process vessels, are also potential sources of released material. 

Some cadmium-plated bolts and nuts were purchased and installed as a test in the plant. More bolts were purchased and eventually some of the cadmium-plated bolts were installed on the outlet piping flanges of a cracking furnace. The high temperature outlet flanges on the furnace started to weep a bit. An experienced, intelligent pipefitter attempted to snug up a few bolts and the nuts crumbled. (The cause of the failure was later determined to be due to corrosion phenomena called liquid metal embrittlement. )... 

Chemical resistance test for rubber linings by Atlas blind flange test Determination of effects of liquid chemicals on plastics Determination of environmental stress cracking (ESC) by the bent strip method... 

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