Pressure metal hose cracking analysis

Chemical composition of the base metal hoses meet the standard requirements, microstructure normal. Failure hose member and the base metal and weld finished piece unused micro-cracks are present on the hose, the hose which indicates that micro-cracks before they are used.According to the position and shape of micro-cracks can be divided into two categories: one is located on the weld, the weld along the direction of the main direction of the crack, in addition to many cracks perpendicular to the main secondary cracks, these cracks are located weld intergranular columnar crystal position is formed when the welding weld cracking; second crest of microcracks in Hydraulic pipe fittings of the hose, these micro-cracks in the circumferential direction along the hose (Up direction perpendicular to the weld). and substantially parallel to each other, since the majority of these micro-cracks exist in the inner surface of the crest, and the analyzes were performed by location and morphology with regularity, so these cracks should be rolling waves generated when processing cracks. In welding and molding process, the micro crack initiation at the inner surface of the hose in the subsequent assembly process of trial and the use of extended fatigue microcracks, finally cracked through, causing oil spills. Recommended welding hose and processing to improve, in order to avoid the generation of microcracks.