309 Stainless Tube Shields are high-performance protective components manufactured from SS309, an advanced austenitic stainless steel alloy containing approximately 23% chromium and 13% nickel. These shields are engineered for extreme heat applications, offering superior resistance to oxidation, thermal fatigue, and chemical corrosion.

Designed to operate continuously in temperatures up to 1000–1100°C (1832–2012°F), SS309 shields outperform conventional stainless steels such as SS304 or SS321, especially in flue gas paths, radiant zones, and high-temperature heat recovery environments.

Their primary function is to protect heat exchange tubes from direct impacts by fly ash, soot, flue gases, and flame impingement. By absorbing mechanical and chemical stresses, these shields extend tube life and ensure consistent thermal performance, while reducing the frequency of unscheduled outages.

Why Choose SS309 Tube Shields?

Exceptional Heat Resistance: Withstands radiant heat and cyclic thermal loading without deformation or scaling.
Superior Corrosion Protection: Effective against oxidation, flue gas corrosion, and high-velocity gas erosion.
Improved Durability: Outperforms SS304 and 1Cr18Ni9Ti in high-temperature, aggressive conditions.
Extended Service Life: Reduces tube wear, prevents premature failure, and lowers maintenance frequency.
Application Versatility: Ideal for power plant boilers, incinerators, and high-efficiency waste heat systems.

SS309 tube shields are recommended for use in boiler zones exposed to radiant heat, corrosive gas flow, and repeated thermal cycling. Available in curved, straight, or custom-formed profiles for diameters ranging from 32mm to 89mm.

Stainless Steel 309 / 309S / 309H

Technical specifications including chemical composition, mechanical and thermal properties.

Chemical composition of grade 309 stainless steels.
Grade	C	Mn	Si	P	S	Cr	Ni	Fe
SS 309	0.20 max	2.0 max	0.75 max	0.045 max	0.030 max	22.0 – 24.0	12.0 – 15.0	Balance
SS 309S	0.08 max	2.0 max	0.75 max	0.045 max	0.030 max	22.0 – 24.0	12.0 – 15.0	Balance

Physical properties of SS 309 stainless steels.
Property	Metric	Imperial
Density	8 g/cm³	0.289 lb/in³
Melting Point	1455°C	2650°F

Physical properties of SS 309 stainless steels, including density, thermal expansion, and specific heat.

Mechanical properties of SS 309 stainless steels.
Property	Metric	Imperial
Tensile Strength	620 MPa	89,900 psi
Yield Strength (0.2%)	310 MPa	45,000 psi
Izod Impact	120–165 J	88.5–122 ft-lb
Shear Modulus	77 GPa	11,200 ksi
Elastic Modulus	200 GPa	29,008 ksi
Poisson’s Ratio	0.27 – 0.30	0.27 – 0.30
Elongation at Break	45%	45%
Hardness, Brinell	147	147
Hardness, Rockwell B	85	85
Hardness, Vickers	169	169

Thermal properties of SS 309 stainless steels.
Property	Metric	Imperial
Thermal Expansion Coefficient (0–100°C)	14.9 μm/m·°C	8.28 μin/in·°F
Thermal Conductivity (0–100°C)	15.6 W/m·K	108 BTU in/hr·ft²·°F

Equivalent standards for SS 309 stainless steels.
Standard 1	Standard 2	Standard 3	Standard 4
ASTM A167	ASME SA249	ASTM A314	ASTM A580
ASTM A249	ASME SA312	ASTM A358	FED QQ-S-763
ASTM A276	ASME SA358	ASTM A403	FED QQ-S-766
ASTM A473	ASME SA403	ASTM A409	MIL-S-862
ASTM A479	ASME SA409	ASTM A511	SAE J405 (30309)
DIN 1.4828	ASTM A312	ASTM A554	SAE 30309