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Which expert has encountered stress corrosion in steam pipelines? What do the specific phenomena look like? Has any expert encountered dense cracks at the π-shaped bends of steam pipelines (LLS), with the crack direction being perpendicular to the weld?
Most studies on the surface morphology of cavitation are based on SEM observations. The findings of many researchers indicate that cavitation on the surface causes severe plastic deformation; the impact of fluid micro-jets creates cavitation pores on the material surface, after which cracks initiate at the walls of these pores. These cracks propagate inward in a fatigue-related manner and eventually extend parallel to the surface. When several cracks connect, it leads to the peeling off of small sections of the surface layer. This process repeats itself, resulting in continuous peeling of the surface material. Cavitation erosion is a consequence of cavitation, but not all cavitation causes damage to materials; only unstable cavitation, such as that that occurs in unsteady flows or at the tail end of closed bubbles, leads to cavitation erosion. Therefore, cavitation often occurs in localized areas of an object. The mechanism of cavitation is different from the damage to materials caused by the impact of solid particles or liquid droplets. To eliminate and reduce cavitation damage, moving parts should operate under as stable conditions as possible. A passive approach involves applying or covering the areas prone to cavitation with materials with high elasticity, or injecting gas to absorb the energy released when bubbles collapse; chemical anti-corrosion methods can also be used to reduce the corrosive effects of the cavitation process.
Please check the water quality of the boiler to see if the alkalinity level is too high, and to determine whether there is a risk of \"alkaline embrittlement\"