Stainless Steel Grade 409 Annealed Tube Of ASTM A268

Stainless Steel Grade 409 Annealed Tube Of ASTM A268

    Stainless steel grade 409 ( UNS S40900 )

Applications

 This type of grade 409 stainless steels are widely used for :

•  Automotive exhaust tubing

•  Catalytic converter systems

  
  

Chemical Formulation 

 C:= 0.08  ,   Mn:=1.00,  Si:=1.00,  Cr:10.5~11.75,  Ni :=0.50,  P:=0.045,  S:=0.03,  Ti:(6C~0.75)

     Type 409 steels are available in highly stabilized forms, such as S40910, S40920, S40930, which stability of is provided by the presence 

of niobium, titanium in the composition.

Introduction

   409 stainless steels used to be called “ the cheapest stainless steels ”. 

   It is commonly considered as a chromium stainless steel, which have excellent corrosion 

 resistance, heat resistance and fatigue resistance. It can realize the exhaust system components 

 for a longer life time and a lightweight designs.

   With high temperature resistance, the engine can work in high efficiency, at the same time, 

 reduce the thickness of exhaust system , can reduce the emissions. 409 stainless steels are 

 cheaper than other stainless steels, with a good flexibility, high yield, easy to replace, are 

 recyclable and environmentally friendly new materials. At present, Most famous major automobile 

 manufacturers have used type 409 stainless steel materials for their production.

 The automobile exhaust system can collect and disposal the emissions, which is high temperature,

 high speed combustion come from the engine. Then exhausts gas overboard and reduces the noise level 

 of the high velocity gas flow. The automobile exhaust system is the longest components of the auto 

 parts, which must bear strict temperature change ( from -20? to 850? ) and high frequenvy 

 vibration. The 409 stainless steels can work as the heat from -20? to 650?.

   Recently, as the global increasingly stringent environment target, the short distance urban 

 driving increasing, and the spread of Winter snow remover, the standard of using exhaust system is 

 getting more and more stringent. From standard Europe ? to Europe ?, the traditional steel can 

 not meet the technical requirements. We estimate each car need 409 stainless steels appr 35kgs - 

 65kgs in the futuer.

Composition 

                Table 1 -  Composition ranges of type 409 stainless steels

Mechanical Properties

              Table 2 - Mechanical properties of type 409 stainless steels         

Physical Properties

             Table 3 - Physical properties of annealed type 409 stainless steels

Type Specification Comparison

Possible replace with:

Heat Resistance

  Type 409 stainless steels can work at tempertatures up to 675? during continuous operation, and up to 815? under intermittent conditions. This is very important to service environments.

Heat Treatment

    For 409 stainless steels, annealing is carried out at temperatures from 790? to 900?, followed by air cooling.

Welding Performance

   Type 409 stainless steels must be pre-heated to temperatures of 150 to 260°C before welding. Care should be taken to weld grade 409 steels with minimum heat, in order to mitigate grain growth.Ductility of the welded products can be improved by annealing post-welding at temperatures of 760 to 815°C.