Ferritic stainless steel tubes are essential for industries requiring robust corrosion resistant tubes and high temperature tubing, particularly in boiler pipeline protection where oxidation and erosion pose significant threats. These tubes, characterized by high chromium content (10.5-30%) and low carbon ( Conforming to standards like ASTM A268 and A240, grades such as 409, 430, and 439 ensure reliable performance in power generation, petrochemical processing, and automotive exhaust systems, with seamless or welded constructions optimized for pressures up to 10 MPa and temperatures exceeding 800°C.

Produced through hot extrusion or cold pilgering, ferritic stainless steel tubes benefit from annealing treatments that enhance ductility while preserving their ferritic microstructure and magnetic properties. The absence of nickel reduces costs compared to austenitic alternatives, yet provides superior thermal conductivity—up to twice that of 304 stainless steel—and lower thermal expansion, minimizing distortion in fluctuating heat cycles typical of heat exchanger tubes. Stabilized variants like Type 439, with titanium additions, prevent sensitization and carbide precipitation during welding, making them ideal for erosion resistant steel pipes in flue gas desulfurization units and furnace components where abrasive particulates accelerate wear.

In boiler pipeline protection, these tubes excel by mitigating steam-side erosion and fireside corrosion from sulfurous environments, with high-chromium grades like 446 offering scaling resistance up to 1100°C. Rigorous quality controls include ultrasonic testing, hydrostatic pressure verification, and flattening tests, yielding minimum tensile strengths of 380-600 MPa and elongations of 20-30% for sustained integrity under cyclic loading. Surface options range from annealed and pickled to bright annealed, with protective coatings like electropolishing for enhanced hygiene in food processing lines.

Relative to martensitic steels, ferritic stainless steel tubes demonstrate better intergranular corrosion resistance and formability, supporting fabrication into elbows, reducers, and custom bends per ASTM A403. Their eco-friendly profile—fully recyclable and free of costly alloys—aligns with sustainable practices, while moderate toughness suits non-impact applications like catalytic converters and water heaters. Available in diameters from 6-610 mm and wall thicknesses of 1-30 mm, they cater to diverse industrial piping needs, from marine exhausts to chemical reactors.

Tackling prevalent issues such as tube wall thinning from fly ash erosion or chloride-induced pitting, corrosion resistant tubes like these extend operational life by 40-60% in harsh settings, lowering downtime and repair expenses. For engineers addressing boiler pipe protection solutions or seeking high temperature tubing for reformers, ferritic stainless steel tubes offer a versatile, high-value choice, backed by proven efficacy in global energy infrastructures.

Chemical Composition

Typical composition for common ferritic grades (wt. % max unless specified; balance Fe).

Chemical Composition of Ferritic Stainless Steel Tubes
Grade	C	Mn	Si	P	S	Cr	Ni	Ti or Others
409	0.08	1.00	1.00	0.045	0.045	10.5-11.75	0.50	Ti: 6xC min - 0.75 max
430	0.12	1.00	1.00	0.040	0.030	16.0-18.0	0.75	-
439	0.03	1.00	1.00	0.040	0.030	17.0-19.0	0.50	Ti: 0.15-0.45
444	0.025	1.00	1.00	0.040	0.030	17.5-19.5	1.00	Mo: 1.75-2.50; Ti: 5x(C+N) min - 0.8 max; Nb: 0.3-0.8
446	0.20	1.25	1.00	0.040	0.030	23.0-27.0	0.25	Al: 0.10-0.50 (optional)

Mechanical Properties

Minimum values at room temperature for annealed condition.

Mechanical Properties of Ferritic Stainless Steel Tubes
Grade	Tensile Strength (MPa)	Yield Strength (MPa)	Elongation (%)	Hardness (HB max)
409	380	205	20	179
430	450	205	22	183
439	415	205	28	179
444	415	205	20	190
446	435	275	20	217

Key Benefits

Exceptional Corrosion Resistance

High chromium forms a protective oxide layer, shielding against pitting and oxidation in harsh industrial settings.

High-Temperature Stability

Maintains integrity up to 800°C with low expansion, ideal for boiler and furnace applications.

Erosion and Wear Resistance

Resists abrasive flows and thermal fatigue, extending lifespan in erosion-prone pipelines.

Superior Weldability

Stabilized grades enable easy fusion welding without post-heat treatment in many cases.

Cost-Effective Durability

Nickel-free composition lowers costs while delivering austenitic-level performance.

Eco-Friendly Recyclability

Magnetic and fully recyclable, supporting sustainable manufacturing practices.

Main Standards Covered

ASTM A268 – Seamless and Welded Ferritic and Martensitic Stainless Steel Tubing for General Service
JIS G3463 – Stainless Steel Tubes for Boiler and Heat Exchangers
GB/T 30065 – Welded Ferritic Stainless Steel Tubes for Feedwater Heaters
GB/T 30066 – Welded Ferritic Stainless Steel Tubes for Heat Exchangers and Condensers

Ferritic Stainless Steel Grades – Features & Applications
Grade	Key Feature	Typical Applications
430	Basic ferritic grade with good resistance to nitric acid, sulfur gases, and organic/food acids	Food processing equipment, chemical environments, decorative applications
405	Lower chromium with added aluminum to prevent hardening when cooled from high temperatures	Heat exchangers, thermal components
409	Lowest chromium content; most economical ferritic grade	Mufflers, automotive exhaust components, exterior non-critical parts
434	Improved corrosion resistance with added molybdenum	Automotive trim, fasteners, architectural components
436	Enhanced corrosion and heat resistance with columbium (niobium)	Deep-drawn parts, industrial components
442	Higher chromium content for improved scaling resistance	Furnace parts, heater components
446	Highest chromium among listed grades; excellent high-temperature corrosion resistance	Oxidizing and sulfuric atmospheres, high-temperature furnace applications

Comparison Chart

Stainless Steel Grade Cross-Reference Table
GB	ISO Unified Digital Code	ASTM / ASME	UNS Code	EN Code	Company Commercial Grade
06Cr13Al	S11348	405	S40500	1.4002	–
	–	409 409L	S40900	1.4512
0Cr13SiAl	–	–	–	1.4724	SIC9(Sanyo)/ 1C256(Sandvik)
10Cr17	S11710	430	S43000	1.4016	–
022Cr18Ti	S11863	439	S43035	1.451	–
019Cr19Mo2NbTi	S11972	444	S44400	1.4521	–
0Cr18SiAl	–	–	–	1.4742	SIC10(Sanyo)/ 1C356(Sandvik)
0Cr24SiAl	–	–	–	1.4762	SIC12(Sanyo)
16Cr25N	S12550	TP446-1/TP446-2	S44600	1.4762	2C52/2C48(Sandvik)
1Cr25Ti	–	–	–	–	QS25T(Sanyo)
00Cr27Mo3Ni2TiNb	–	S44660	S44660	–	Sea-Cure(Plymouth Tube)
00Cr29Mo4TiNb	–	S44735	S44735	–	AL29-4C(ATI)
00Cr29Mo4Ni2TiNb	–	S44736	S44736	–	AL29-4-2(ATI)
	–	S44300	S44300	1.4522	443

Ferritic stainless steels, which are part of the 400 series of stainless alloys, have chromium as their major alloying element and are typically low in carbon content. Their ductility and formability are lower than those of the austenitic grades. The corrosion resistance is comparable to that of austenitic stainless steels in certain applications. Thermal conductivity is about half that of carbon steels.

Ferritic stainless steels are magnetic and generally have good ductility. They can be welded or fabricated without difficulty. These grades can be processed to develop an aesthetically pleasing, bright finish and are therefore sometimes used for automotive trim and appliance molding.

They are also commonly used in functional applications where cost is a significant factor, such as automotive exhaust systems, catalytic converters, radiator caps, and chimney liners. These grades can be hardened by cold rolling, although not to the same extent as austenitic alloys.

Application Industries

Power Generation

Petrochemical & Refinery Systems

Heat Exchangers & Condensers

Boilers & Pressure Equipment

Automotive Components

Food Processing & Organic Chemicals

Feedwater Heater Systems

Industrial Exhaust & Gas Treatment

FAQs

Their high chromium enables a stable oxide layer for oxidation and erosion resistance up to 800°C, outperforming carbon steels in corrosive flue gases.

Ferritic offer better stress corrosion cracking resistance and lower cost, with comparable pitting protection but higher thermal conductivity for heat transfer.

Yes, stabilized grades like 439 weld easily via TIG or ERW, minimizing cracking risks in high-temperature applications.

Ferritic stainless steel is frequently used in the manufacture of waterheating appliances due to its excellent formability and its extremely high resistance to such shortcomings as pitting and stress corrosion cracking associated with austenitic stainless steel.

Ferritic stainless steel tubes