在現(xiàn)實生活中，鍋爐壓力管道和壓力容器面臨復雜的內(nèi)外環(huán)境，這些裂縫是混合的。一般情況下，是根據(jù)裂縫產(chǎn)生和發(fā)展的原因來分類的，而裂縫的形成與鍋爐的使用、結構、材料、部件等有關，不同的部件、不同的材料、不同的用途，鍋爐壓力容器壓力管道裂縫的形成是不同的。
　　In real life, boiler pressure pipes and pressure vessels are faced with complex internal and external environment, and these cracks are mixed. In general, it is classified according to the causes of crack generation and development, and the formation of crack is related to the use, structure, materials, components, etc. different parts, different materials, different purposes, the formation of crack in pressure pipe of boiler and pressure vessel is different.
　　應力腐蝕裂紋的產(chǎn)生是應力與腐蝕性介質(高濃度堿性水)相互作用的結果。這種裂縫主要發(fā)生在鍋爐蒸汽管和容器管基礎上。當這些成分與堿液接觸時，堿液的腐蝕性引起了金屬微觀世界的化學變化，即金屬晶體與晶界之間的電位差造成兩者之間的弱電流，導致金屬產(chǎn)生裂紋。通過對裂紋的微觀觀察，發(fā)現(xiàn)裂紋有兩個主裂紋和兩個二次裂紋，主裂紋的發(fā)展趨勢是通過晶內(nèi)，二次裂紋的發(fā)展趨勢是沿晶界輻射。易產(chǎn)生這種裂紋的材料是奧氏體不銹鋼，它是在水蒸氣作用下通過應力形成的。
　　The generation of SCC is the result of the interaction between stress and corrosive medium (high concentration alkaline water). This kind of crack mainly occurs on the basis of boiler steam pipe and vessel pipe. When these components are in contact with alkali liquor, the corrosiveness of alkali liquor causes the chemical changes in the micro world of metal, that is, the potential difference between the metal crystal and the grain boundary causes the weak current between the two, which leads to metal cracks. Through the microscopic observation of the cracks, it is found that there are two main cracks and two secondary cracks in the cracks. The development trend of the main cracks is through the crystal, and the development trend of the secondary cracks is along the grain boundary radiation. The material easy to produce this kind of crack is austenitic stainless steel, which is formed by stress under the action of water vapor.

　　疲勞裂紋是鍋爐壓力容器壓力管道檢測中經(jīng)常遇到的問題之一。它通常發(fā)生在應力集中的設備中。這種裂縫開始時相對較小，在中后期會繼續(xù)擴展和擴展。疲勞裂紋有三種類型:機械疲勞裂紋、熱疲勞裂紋和腐蝕疲勞裂紋。
　　Fatigue crack is one of the common problems in the inspection of boiler pressure vessel pressure pipeline. It usually occurs in equipment with stress concentration. This kind of fracture is relatively small at the beginning, and will continue to expand and expand in the middle and later period. There are three types of fatigue crack: mechanical fatigue crack, thermal fatigue crack and corrosion fatigue crack.
　　機械疲勞裂紋的常見部位有葉輪、葉片、輔助旋轉設備等部件，而這些裂紋大多是從設備的表面開始，呈一條直線，開始相對較短，逐漸向內(nèi)擴展，直至連續(xù)變成一條長裂紋，穩(wěn)定增長。這種裂紋的來源一般是材料缺陷區(qū)、刀痕、接頭、尖角、孔的位置。
　　The common parts of mechanical fatigue cracks are impeller, blade, auxiliary rotating equipment and other components, and most of these cracks start from the surface of the equipment, in a straight line, relatively short at the beginning, and gradually expand inward, until they become a long crack continuously and grow steadily. The source of this kind of crack is generally the defect area of the material, the knife mark, the joint, the sharp angle and the position of the hole.