FAQ

　　A high acoustic impedance indicates that the material has greater resistance to the transmission of sound waves. This results in higher reflection and lower transmission at the interface.

　　The acoustic impedance level determines how ultrasound propagates when it encounters the interface of two substances. If the acoustic impedances of the two substances are the same, all sound waves are transmitted without reflection.

　　Yes, by measuring the acoustic impedance of a material, information about its density and sound speed can be inferred, which helps in identifying the material or assessing its properties.

　　Weld classification refers to the classification of the welds in the pressure-bearing part of pressure vessels based on their location and joint form. It is divided into four categories: A, B, C, and D.
　　Category A welds refer to the longitudinal butt welds in the pressure-bearing part of the vessel (excluding the longitudinal seams of the layer plates in multilayer wrapped vessels). It also includes all joint welds of various convex heads, circumferential welds connecting spherical heads to cylinders, and butt welds between embedded nozzles (referring to the forgings at the nozzle connection) and the cylinder or head.
　　Category B welds refer to the circumferential butt welds in the pressure-bearing part of the vessel, and the butt welds connecting the small end of conical heads to nozzles (excluding those that can be clearly specified as categories A, C, or D).
　　Category C welds are the welds connecting pressure-bearing components (such as flanges, heads, tube sheets, etc.) to the shell or to nozzles, the fillet welds of the internal heads and the cylinder, as well as the longitudinal welds of the layer plates in multilayer wrapped vessels.
　　Category D welds refer to the welds connecting nozzles, manholes, flanges, and other components to the shell. These inserted pressure-bearing components are generally connected to the shell with fillet welds (excluding those specified as categories A or B).