Design of Stainless Steel Automotive Exhaust Manifolds

Santacreu, Pierre-Olivier; Cleizergues, O.; Simon, Christian; Duroux, Patrick

doi:10.4271/2003-01-2848

Cited by 5 publications

(3 citation statements)

References 3 publications

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“…Exhaust gas temperature reaches up to 1000°C for new vehicles with high performance engines. Santacreu et al (2004Santacreu et al ( , 2006 presented a new design approach to replace traditional manifolds made of cast iron to stainless steel tubes which are formed and welded.…”

Section: Introductionmentioning

confidence: 99%

Influence of filler wire composition on weld microstructures of a 444 ferritic stainless steel grade

Villaret

Deschaux-Beaume

Bordreuil

et al. 2013

Journal of Materials Processing Technology

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Section: Introductionmentioning

confidence: 99%

Influence of filler wire composition on weld microstructures of a 444 ferritic stainless steel grade

Villaret

Deschaux-Beaume

Bordreuil

et al. 2013

Journal of Materials Processing Technology

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“…Ferritic stainless steels (FSS) had been widely used in many elevated temperature applications (automotive exhaust systems, steam generators of power plants, and so on) due to its superior resistance to pitting corrosion, good machinability, and high thermal conductivity, as compared with conventional austenitic stainless steels [1][2][3][4][5]. During application, they were inevitably exposed to the temperature range above recrystallization temperature; the thermal cycles would lead to the grain growth and sensitization, causing the intergranular corrosion (IGC) followed by the failure of the appliances [6].…”

Section: Introductionmentioning

confidence: 99%

Intergranular Corrosion of Low Cr Ferritic Stainless Steel 429 Evaluated by the Optimized Double Loop Electrochemical Potentiokinetic Reactivation Test

Jiang

et al. 2015

Advances in Materials Science and Engineering

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Intergranular corrosion (IGC) of Nb-Ti stabilized ferritic stainless steel (FSS) 429 was investigated using the double loop electrochemical potentiokinetic reactivation (DL-EPR) test combined with the microstructure observation. The results indicated that the optimized DL-EPR test condition for FSS 429 was the solution of 0.5 M H2SO4+ 0.0001 M KSCN with a scanning rate of 100 mV/min at 30°C. Based on this condition, the specimens aging at 400–700°C for different duration were tested and a time-temperature-sensitization (TTS) curve for FSS 429 was obtained, which reveals the sensitization nose was located around 550°C. The criticalIr/Iavalue was determined to be about 3% above which IGC occurred. After aging treatment, Cr depletion zone was detected using energy dispersive spectroscopy (EDS), most possibly due to Cr segregation around intergranular TiC and NbC.

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“…Some of the investigations carried out to reach these objectives concerns the exhaust system, that have to be lighter and more resistant to high temperatures produced by the increase of engine efficiency. The exhaust manifold is a critical part of the exhaust system, because it supports very high temperatures and corrosive atmosphere [1][2][3][4]. Traditionally made of cast iron in the form of massive components, manifolds can now be made of stainless steel, using tubes or thin sheets rolled and welded [2].…”

Section: Introductionmentioning

confidence: 99%

Characterization of Gas Metal Arc Welding welds obtained with new high Cr–Mo ferritic stainless steel filler wires

et al. 2013

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Several compositions of metal cored filler wire were manufactured to define the best welding conditions for homogeneous welding, by Gas Metal Arc Welding (GMAW) process, of a modified AISI 444 ferritic stainless steel dedicated to automotive exhaust manifold applications. The patented grade is know under APERAM trade name K44X and has been developed to present improved high temperature fatigue properties. All filler wires investigated contained 19%Cr and 1.8%Mo, equivalent to the base metal K44X chemistry, but various titanium and niobium contents. Chemical analyses and microstructural observations of fusion zones revealed the need of a minimum Ti content of 0.15% to obtain a completely equiaxed grain structure. This structure conferred on the fusion zone a good ductility even in the as-welded state at room temperature. Unfortunately, titanium additions decreased the oxidation resistance at 950°C if no significant Nb complementary alloying was made. The combined high Ti and Nb additions made it possible to obtain for the welded structure, after optimized heat treatment, high temperature tensile strengths and ductility for the fusion zones and assemblies, rather close to those of the base metal. 950°C aging heat treatment was necessary to restore significantly the ductility of the as welded structure. Both fusion zone and base metal presented rather homogenized properties. Finally, with the optimized composition of the cored filler wire -0.3 Ti minimum (i.e. 0.15% in the fusion zone) and high Nb complementary additions, the properties, including the thermal fatigue strength, of the K44X assemblies are excellent.

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Design of Stainless Steel Automotive Exhaust Manifolds

Cited by 5 publications

References 3 publications

Influence of filler wire composition on weld microstructures of a 444 ferritic stainless steel grade

Influence of filler wire composition on weld microstructures of a 444 ferritic stainless steel grade

Intergranular Corrosion of Low Cr Ferritic Stainless Steel 429 Evaluated by the Optimized Double Loop Electrochemical Potentiokinetic Reactivation Test

Characterization of Gas Metal Arc Welding welds obtained with new high Cr–Mo ferritic stainless steel filler wires

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