Ferritic stainless steel pipes (409 / 430 / 439 / 444) are chromium‑based stainless steels with low carbon content and a body‑centered cubic (BCC) structure. They offer excellent heat resistance, good oxidation resistance, and cost‑effective performance, making them widely used in automotive exhaust systems, heat exchangers, and industrial ventilation.
409 Stainless Steel Pipe
Ti‑stabilized ferritic stainless steel
Excellent heat resistance
Widely used in automotive exhaust systems
430 Stainless Steel Pipe
Basic ferritic stainless steel
Good corrosion resistance in mild environments
Cost‑effective alternative to 304
439 Stainless Steel Pipe
Nb‑stabilized ferritic grade
Better weldability and corrosion resistance than 430
Used in automotive exhaust and heat exchangers
444 Stainless Steel Pipe
Mo‑alloy ferritic stainless steel
Excellent pitting and crevice corrosion resistance
Suitable for hot‑water tanks, heat exchangers, and marine environments
Key Advantages:
Lower cost than austenitic stainless steels
Good heat and oxidation resistance
Magnetic, stable structure
Good weldability (especially 439 / 444)
Suitable for high‑temperature exhaust and heating systems
🟧 Standards
ASTM A268
EN 10296‑2
JIS G4305
GB/T 14976
🟧 Grades
409 (UNS S40900)
430 (UNS S43000)
439 (UNS S43035)
444 (UNS S44400)
🟧 Product Specifications & Available Sizes
Outer Diameter (OD)
Welded: 12–630 mm
Seamless (limited availability): 10–120 mm
Wall Thickness (WT)
0.5–8 mm
Length
6 m / 12 m / custom
Type
Welded (ERW / TIG)
Seamless (limited grades)
Surface Finish Options
2B
BA
Polished (180–400 grit)
Annealed
Pickled
Dimensions (mm)
Ф21×4
Ф87×17.5
Ф121×19
Ф168×19
Ф21×4.5
Ф89×6-12
Ф124×6.5
Ф168×8
Ф22×6.5
Ф89×15
Ф127×10
Ф170×25
Ф25×8
Ф89×17
Ф127×13
Ф172×18
Ф28×8
Ф91×7.5
Ф127×8
Ф180×10
Ф30×10
Ф92×12
Ф130×12
Ф180×18
Ф30×8
Ф95×10
Ф130×18
Ф180×6
Ф32×8
Ф95×12
Ф133×6-12
Ф180×8
Ф34×6
Ф95×16
Ф133×18
Ф183×18
Ф34×8
Ф95×20
Ф140×8-12
Ф185×18
Ф38×10
Ф95×5.5
Ф140×15
Ф185×20
Ф38×8
Ф95×8
Ф140×20
Ф192×18
Ф40×10
Ф100×8.5
Ф142×18
Ф194×10
Ф40×8
Ф100×13
Ф145×18
Ф194×16
Ф42×5-10
Ф102×6-10
Ф146×10
Ф196×16
Ф45×6-12
Ф102×15
Ф146×12
Ф196×24
Ф48×5-10
Ф104×8.5
Ф152×10
Ф200×20
Ф50×8-12
Ф108×6-10
Ф152×12
Ф219×6-12
Ф51×10
Ф108×13
Ф152×14
Ф219×15
Ф55×10
Ф108×15
Ф152×20
Ф245×10
Ф57×6-10
Ф110×6
Ф152×6
Ф250×25
Ф60×6-12
Ф114×6-10
Ф152×8
Ф273×6-12
Ф65×6-12
Ф114×13
Ф159×6-10
Ф273×34
Ф68×6-12
Ф114×17.5
Ф159×12
Ф325×8-10
Ф70×8
Ф116×12
Ф159×15
Ф355×14
Ф70×10
Ф116×8
Ф159×18
Ф377×10
Ф76×6-12
Ф118×2
Ф159×22
Ф406×14
Ф80×8-12
Ф121×6-11
Ф168×10
Ф457×14
Ф83×8-12
Ф121×16
Ф168×12
Ф508×15
🟧 Chemical Composition
（ASTM A268）
409
Element
Content (%)
C
≤ 0.03
Si
≤ 1.00
Mn
≤ 1.00
P
≤ 0.040
S
≤ 0.030
Cr
10.5–11.75
Ni
≤ 0.50
Ti
≥ 6 × C%
430
Element
Content (%)
C
≤ 0.12
Si
≤ 1.00
Mn
≤ 1.00
P
≤ 0.040
S
≤ 0.030
Cr
16.0–18.0
Ni
≤ 0.50
439
Element
Content (%)
C
≤ 0.03
Si
≤ 1.00
Mn
≤ 1.00
P
≤ 0.040
S
≤ 0.030
Cr
17.0–19.0
Ni
≤ 0.50
Nb
≥ 10 × C%
444
Element
Content (%)
C
≤ 0.025
Si
≤ 1.00
Mn
≤ 1.00
P
≤ 0.040
S
≤ 0.030
Cr
17.5–19.5
Ni
≤ 1.00
Mo
1.75–2.50
Ti + Nb
Stabilized
🟧 Mechanical Properties
（Ferritic grades similar）
Property
Requirement
Tensile Strength
380–450 MPa
Yield Strength
205–260 MPa
Elongation
≥ 20%
Hardness
≤ 200 HB
🟧 Physical Properties
Property
Value
Density
7.70 g/cm³
Thermal Conductivity
25–30 W/m·K
Electrical Resistivity
0.60–0.70 μΩ·m
Magnetic
Yes
🟧 Manufacturing Processes
ERW Welding
TIG Welding
Cold Rolling
Annealing
Pickling
Polishing
Eddy Current Testing
🟧 Primary Industry Usage
Automotive exhaust systems（409 / 439）
Heat exchangers（439 / 444）
Hot‑water tanks（444）
Industrial ventilation ducts
Household appliances（430）
Furnace components
🟧 Why Use Ferritic Stainless Steel Pipe
Cost‑effective alternative to austenitic grades
Good heat and oxidation resistance
Magnetic and dimensionally stable
Excellent weldability (439 / 444)
Suitable for automotive and heating applications
🟧 Why Choose WelSteels
Full range of ferritic stainless steel grades
Strict quality control with MTC 3.1
Expertise in automotive and heat‑resistant applications
Welded & seamless options available
Global shipping with professional loading supervision
Competitive pricing for large‑volume industrial projects
