Heat transfer element for manifold

Abstract

A heat transfer element for manifold prevents thermal fatigue of a manifold main body and has good high-temperature strength and oxidation resistance. At least one part of the heat transfer element for manifold is formed from ferritic stainless steel. The ferritic stainless steel contains at least one element, in terms of mass %, of: C: 0.03% or less; Si: 2.0% or less; Mn: 2.0% or less; Cr: 10 to 30%; Nb: 0.8% or less; and Ti: 0.8% or less, and N: 0.03% or less, and the remaining part thereof is formed from Fe and inevitable impurities. _Further, an alloy content of the ferritic stainless steel is adjusted so that an A value in equation (1), where A value=Nb+Ti−4(C+N), is 0.10 or more, and a B value in equation (2), where B value=Cr+15Si, is 18 or more.

1 . A heat transfer element for manifold which is located at least at the upstream side of a manifold main body through which exhaust gas from an engine flows in an exhaust manifold, and which transfers heat of the exhaust gas from the engine to the manifold main body, wherein
 at least one part thereof contains at least one element, in terms of mass %, of: C: 0.03% or less; Si: 2.0% or less; Mn: 2.0% or less; Cr: 10 to 30%; Nb: 0.8% or less, and Ti: 0.8% or less, and N: 0.03% or less, and the remaining part thereof is formed from Fe and inevitable impurities, and the heat transfer element for manifold is formed from ferritic stainless steel in which an alloy content is adjusted so that an A value expressed in equation (1) below is 0.10 or more and a B value expressed in equation (2) below is 18 or more.
     A  value=Nb+Ti−4(C+N)   Equation (1):
 
     B  value=Cr+15Si   Equation (2):
 
   
     
     
         2 . The heat transfer element for manifold according to  claim 1 , wherein the ferritic stainless steel contains at least one element, in terms of mass %, of: Cu: 3.0% or less; Mo: 3.0% or less; and W: 3.0% or less.