CWB Level 2 Exam Questions with Correct Answers

CWB Level 2 Exam Questions with Correct Answers Heat ex changers utilize impingement plates and occasionally tube ferrules to minimize erosion What is used to detect refractory loss on stream when erosion is suspected? - Answer-IR scan What are 3 ways to inspect an area of erosion - Answer-Visual UT checks RT to check extent of metal loss What is the description of Mechanical Fatigue? - Answer-Mechanical fatigue is a form of degradation that occurs when a component is exposed to cyclical stresses for an extended period, often resulting in sudden unexpected failure. What type of material is subject to Mechanical fatigue? - Answer-All engineering alloys are subject to fatigue cracking What are the predominant factors in determining the fatigue resistance of a component? - Answer-Geometry, Stress Level, Number of cycles and material properties ( strength, hardness, micro-structure) With mechanical fatigue where do fatigue cracks usually initiate? - Answer-Surface of mechanical notches, stress raisers under cyclic loading, Weld joints, tool markings, grinding marks, corrosion areas, key holes on drive shafts With what 3 types of material does fatigue fractures decrease with stress amplitude until an endurance limit is reached? Regardless of the number of cycles - Answer-Titanium, Carbon Steel, and Low Alloy Steel. What are some affected units/equipment from mechanical fatigue? - Answer-Thermal Cycling; *Equipment that cycles daily like coke drums *Equipment that is on continuous standby but sees intermittent service such as auxiliary boilers. *Quench nozzle connections that sees significant temperature deltas during operation like a water washing system. Mechancial Loading ; *Pressure swing Absorbers on hydrogen purification units *Rotating shafts on centrifugal pumps and compressors that have stress concentrations dur to changes in radii and key ways *Components like small diameter piping that may see vibration from adjacent equipment and/or wind. *High pressure drop control valves or steam reducing stations can cause serious vibration problems in connecting piping.