Abstract: From the exhaust tube of automobiles the power source sounds and travelling sounds are radiated as noises. A heat-resistant intermediate layer is disposed partly around the inner tube of dual metal tubing and achieves decreases in the radiated noise from the exhaust pipe due to the vibration damping of the inner and outer tubes.

Abstract: A steel tubing and more particularly a composite dual tubing which can be suitably used for an exhaust pipe capable of effectively reducing the radiated noise from the exhaust pipe of automobiles. A metallic dual tubing of the present invention comprises: lugs (20a); lugs (20a) and heat-resistant filler material (24); or, the spacer member (16) and the heat-resistant filler member (17).

Abstract: The present invention relates to a steel tubing and more particularly a composite dual tubing which can be suitably used for an exhaust pipe capable of effectively decreasing the radiated noise from the exhaust pipe of automobile.Several known dual tubings are effective occasionally for the reduction of radiated noise, but their effects are drastically reduced at high temperature. A metallic dual tubing of the present invention comprises an inner tube (10) and an outer tube (20) and is, characterized in that the metallic dual tubing is provided with an intermediate layer (18) comprising combustible material filled between the inner tube (10) and the outer tube (20). This layer may be single layer consisting of the combustible material or of the mixture of such material with a heat-resistant material. The intermediate layer may be a dual layer of the combustible material and the heat-resistant material.