CWB Welding Inspector Level 2 Exam (New 2023/ 2024 Update) Questions and Verified Answers_ 100% Correct_ Graded A

CWB Welding Inspector Level 2 Exam (New 2023/ 2024 Update) Questions and Verified Answers_ 100% Correct_ Graded A QUESTION How can you inspect galvanic corrosion? Answer: Visual inspection UT thickness gauging are very effective methods. QUESTION Describe Corrosion Under Insulation (CUI)? Answer: Corrosion in piping, pressure vessels, and structual components resulting from water trapped under insulation or fireproofing QUESTION What kind of material can be affected from Corrosion Under Insulation? Answer: Carbon Steel, Low alloy steels, 300 Series SS, and duples stainless steels QUESTION What are some critical factors for Corrosion Under Insulation? Answer: It affects externally insulated piping and equipment and those that are in intermittent service or operate between: 10F(-12C) and 350F(175C) for carbon and low alloy 140F(60C) and 400F(205C) for austenitic stainless steels and duplex stainless steels. Corrosion rates will increase with increasing metal temperature up to the point where the water evaporates quickly (ex. Corrosion becomes more severe at metal temperatures between boiling point 212F(100C) and 350F(121C), where water is less likely to vaporize and insulation stays wet longer. Insulating material that hold moisture (wick) is a problem Equipment that operates below water dew point creates condense water on metal surfaces Cyclic thermal operation or intermittent service can increase corrosion Plants located in areas with high rain fall Environments that provide airborne containments such as chlorides, stack emissions (SO2), cooling tower drift QUESTION What kind of equipment is affected by corrosion under insulation? Answer: All equipment is susceptible to CUI QUESTION What are some examples where corrosion under insulation can occur? Answer: Can be found on equipment with damaged insulation, vapor barriers, weatherproofing or mastic, or protrusions through the insulation or at insulation termination points such as flanges. Piping or equipment with damaged/leaking steam tracing. Localized damage to coating or paint systems Where water/moisture will naturally collect. Deadlegs (vents, drains, and other similar items) Pipehangers Caulking that has hardened, has separated, or is missing QUESTION What is the appearance of corrosion under insulation? Answer: Carbon and low alloy steels are subject to localized pitting corrosion and loss of thickness 300 Series SS are subject to stress corrosion cracking is chloride is present 300 Series SS and Duplex SS are subject to pitting and localized corrosion After insulation is removed from carbon and low alloy steels CUI often appears as loose flaky scale covering corroded components. QUESTION What is some prevention for corrosion under insulation? Answer: Best achieved by appropriate paints/coatings and maintaining insulation/sealing/vapor barriers to prevent moisture ingress. Flamed-Sprayed alluminum coatings have been used for carbon steels Using aluminum foil wrap on stainless steel piping under insulation Closed-cell foam glass materials will hold less water against vessel/pipe wall QUESTION What are some ways to inspect corrosion under insulation? Answer: Should be structured and systematic approach starting with prediction, then looking at more invasive procedures. Inspectors should consider areas that