SHEET MEMBER AND MANUFACTURING METHOD THEREOF, EXHAUST GAS TREATING APPARATUS AND MANUFACTURING METHOD THEREOF, AND SILENCING DEVICE

摘要

A sheet member and a manufacturing method thereof, an exhaust gas treating apparatus, a manufacturing method thereof, and a silencer are provided to reduce a large fold caused by the circumference difference of the sheet members while increasing the thickness of the sheet member. A sheet member(30) includes first and second surfaces. The first and second surfaces are perpendicular to a thickness direction of the sheet member. The first surface includes a first sheet part(420) having a first volume density. The second surface includes a second sheet part(430) having a second volume density higher than the first volume density. The first and second sheet parts are stacked on each other in a thickness direction. The sheet member includes a needle mark. The density of the needle mark of the first surface is lower than that of the second surface.