SUS347 vs SUS317L:High-Temperature Applications

When selecting materials suitable for high-temperature applications, understanding the properties of SUS347 and SUS317L stainless steel is crucial. Both materials offer excellent high-temperature resistance and corrosion resistance, but they differ in their chemical composition, mechanical properties, and application areas.

 

What is SUS347 Stainless Steel?

SUS347 stainless steel, due to the addition of niobium, maintains excellent oxidation resistance and intergranular corrosion resistance at high temperatures. Its operating temperature typically reaches 900–1150°C. It is particularly suitable for high-temperature applications such as furnaces, heat treatment equipment, and petrochemical reactors.

 

What is SUS317L Stainless Steel?

SUS317L stainless steel is a type of stainless steel containing a higher molybdenum content, offering better resistance to chloride corrosion, making it particularly suitable for marine and chemical environments. Its high-temperature resistance is typically in the range of 800–900°C, making it suitable for corrosive environments involving acidic gases and chlorides.

 

What are the main differences between SUS347 and SUS317L?

SUS347 is designed for high-temperature environments with better oxidation resistance, while SUS317L offers superior corrosion resistance due to its higher molybdenum content, making it ideal for chloride and acidic environments.

 

SUS347 vs SUS317L: Chemical Composition​

Element	SUS347 (JIS G3459 / ASTM A312 TP347)	SUS317L (JIS G3459 / ASTM A312 TP317L)
C (Carbon)​	≤ 0.08 %	≤ 0.03 %
Cr (Chromium)​	17.00 – 19.00 %	18.00 – 20.00 %
Ni (Nickel)​	9.00 – 13.00 %	11.00 – 15.00 %
Mo (Molybdenum)​	–	3.00 – 4.00 %
Nb (Niobium)​	0.70 – 1.00 %	–
Mn (Manganese)​	≤ 2.00 %	≤ 2.00 %
Si (Silicon)​	≤ 1.00 %	≤ 1.00 %
P (Phosphorus)​	≤ 0.045 %	≤ 0.045 %
S (Sulfur)​	≤ 0.030 %	≤ 0.030 %
Fe (Iron)​	Balance	Balance

 

SUS347 vs SUS317L: Mechanical Properties​

Property	SUS347	SUS317L
Tensile Strength (min)​	515 MPa	485 MPa
Yield Strength, 0.2% offset (min)​	205 MPa	170 MPa
Elongation (min, in 50 mm)​	35 %	40 %
Hardness (Brinell, max)​	~160–190 HB	~160–180 HB
Density​	~8.0 g/cm³	~8.0 g/cm³
Modulus of Elasticity​	~190–210 GPa	~193 GPa
Standard​	ASTM A312 / JIS G3459	ASTM A312 / JIS G3459

 

What is the temperature range for 347 stainless steel?

347 stainless steel exhibits excellent performance in high-temperature environments and is typically used in the temperature range of 800°F to 1650°F (427°C to 900°C), with a continuous service temperature limit of approximately 1600-1650°F (870-900°C). Furthermore, it maintains good toughness in low-temperature environments, and its melting point is approximately 2550-2600°F (1400-1425°C).

 

SUS347 vs SUS317L:High-Temperature

Even after prolonged heating, SUS347 stainless steel maintains a tensile strength of 515 MPa and a yield strength of 205 MPa. In contrast, SUS317L, which does not contain niobium as a stabilizing element and has a lower carbon content (≤ 0.03%), lacks specific high-temperature grain boundary protection measures, resulting in reduced intergranular corrosion resistance at temperatures above 500 °C.

Property	SUS347 (JIS G3459 / ASTM A312 TP347)	SUS317L (JIS G3459 / ASTM A312 TP317L)
Stabilizing Element​	Niobium (Nb): 0.7–1.0 %	None (low‑carbon only)
Critical Temp. Range for Carbide Precipitation​	427–816 °C	427–650 °C (higher risk without Nb)
Intergranular Corrosion Resistance (427–816 °C)​	Excellent (Nb prevents Cr depletion)	Fair (relies on low C, less stable long‑term)
Strength Retention at 600 °C (approx.)​	~85 % of RT tensile	~80 % of RT tensile
Typical High‑Temp Applications​	Boiler tubes, superheaters, furnace parts (≥ 500 °C sustained)	Heat exchangers, chemical reactors (< 500 °C intermittent)

 

If you have project requirements for 347 stainless steel, we welcome your order. GNEE has a large inventory of popular products for you to choose from. It can be processed into various practical product forms, including plates, coils, tubes, bars, wires, etc. For detailed chemical composition and free samples, please contact our factory immediately. We offer competitive prices and excellent service.