Method for producing a metallic substrate used for automobile exhaust gas purifying device

A method for producing a metallic substrate used for an automobile exhaust gas purifying device, the metallic substrate having a length necessary for said use and substantially consisting of a honeycomb and an outer sleeve, both of which extend along the entire length of the the metallic substrate, wherein said method comprises the steps of:

• preparing a heat-resisting steel member having a length and capable of containing therein easy-soluble material members and stainless steel members extending along the entire length thereof;
• densely filling the heat-resisting steel member with said easy-soluble material members extending along the entire length of the heat-resisting steel member and with said stainless steel members for separating the easy-soluble material members from each other over the entire length thereof, to form a filled body;
• hot-working the filled body to reduce the cross sectional area thereof at a reduction ratio necessary for achieving a metallic bond between the stainless steel members;
• cutting the filled body to a predetermined length sufficient for the metallic substrate;
• and
• removing the easy-soluble material from the filled body by at least one of a chemical and an electrochemical treatment for boring throughholes extending along the entire length of the filled body to expose catalyst carrier-destined surfaces of the stainless steel.