High Quality SS 347/347H Round Bars & Rods

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Stainless Steel 347 / 347H Explained

Stainless Steel 347 and 347H are niobium-stabilized austenitic stainless steels engineered for excellent resistance to intergranular corrosion and high-temperature oxidation. The stabilization prevents chromium carbide precipitation during welding and prolonged thermal exposure. SS 347 offers superior corrosion resistance, while SS 347H, with higher carbon content, provides enhanced creep and rupture strength in continuous high-temperature service.

Commonly used in refinery systems, superheaters, high-temperature pressure vessels, petrochemical pipelines, and power generation equipment, SS 347/347H deliver exceptional structural stability under severe thermal and corrosive operating conditions.

Other Types of Stainless Steel 347 / 347H Bars

View SS 347 / 347H Square Bar

SS 347 / 347H Square Bar

Stainless Steel 347 / 347H square bars for precision machining
UNS S34700 / S34709 stabilized austenitic grades
Manufactured in accordance with ASTM A276 / ASME SA276
DIN 1.4550 square bar dimensional standards

View SS 347 / 347H Hex Bar

SS 347 / 347H Hex Bar

ASME SA276 SS 347 / 347H hexagonal bar supply
ASTM A276 certified stainless steel hex rods
DIN 1.4961 / UNS S34700 material compliance
Bright drawn and polished hex profiles available

SS 347 347H Stainless Steel Rectangular Bar

View SS 347 / 347H Rectangular Bar

SS 347 / 347H Rectangular Bar

Stainless steel 347 rectangular bar profiles
UNS S34700 / DIN 1.4550 grade specification
ASTM A276 compliant rectangular sections
Machined and polished rectangle bar finishes

View SS 347 / 347H Flat Bar

SS 347 / 347H Flat Bar

DIN 1.4961 stainless steel flat bar sections
UNS S34700 flat bars for heavy-duty applications
Produced as per ASTM A276 / ASME SA276 standards
Hot rolled, ground and polished surface options

View SS 347 / 347H Bright Bar

SS 347 / 347H Bright Bar

ASTM A276 SS 347H stainless bright bars
UNS S34700 / S34709 material grade availability
Cold drawn, peeled and centerless ground finish
High precision dimensional tolerance and smooth surface

View SS 347 / 347H Forged Bar

SS 347 / 347H Forged Bar

UNS S34700 stainless steel forged bar supply
ASTM A276 compliant SS 347 / 347H forged rods
Heat treated and rough machined forgings
High strength forged bars for pressure and thermal service

347/347H STAINLESS STEEL ROUND BAR EQUIVALENT GRADES

STANDARD	UNS	WNR.	JIS	EN
SS 347	S34700	1.4550	SUS 347	X6CrNiNb18-10
SS 347H	S34709	1.4961	SUS 347H	X6CrNiNb18-12

SPECIFICATION OF STAINLESS STEEL 347/347H ROUND BAR

Stainless Steel Round Bar Specification	ASTM A276 / A479, ASME SA276 / A479
Dimension Standard	EN, DIN, JIS, ASTM, BS, ASME, AISI
Size	14 mm – 300 mm
Thickness	50 mm to 6000 mm Long
Length	1 to 6 Meters, Custom Cut Length
Form	Round, Square, Hex (A/F), Rectangle, Billet, Ingot, Forging Etc.

CHEMICAL COMPOSITION OF STAINLESS STEEL 347/347H ROUND BAR

Grade	C%	Cr%	Mn%	Ni%	P%	S%	Si%	Nb + Ta%
347	0.08 max	17.0 – 20.0	2.0 max	9.0 – 13.0	0.04 max	0.03 max	0.75 max	Min 10×C, Max 1.00
347H	0.04 – 0.10	17.0 – 20.0	2.0 max	9.0 – 13.0	0.03 max	0.03 max	0.75 max	Min 10×C, Max 1.00

MECHANICAL PROPERTIES OF STAINLESS STEEL 347/347H ROUND BAR

Grade	Tensile Strength (ksi)	Yield Strength 0.2% (ksi)	Elongation (%) in 50 mm	Hardness (Brinell) MAX	Hardness (Rockwell B) MAX
347 / 347H	75 (515 MPa)	30 (205 MPa)	40	201	95

PHYSICAL PROPERTIES OF 347/347H STAINLESS STEEL ROUND BAR

Density lb/in³	Coefficient of Thermal Expansion (min/in)-°F	Thermal Conductivity BTU/hr-ft-°F	Specific Heat BTU/lb-°F	Modulus of Elasticity (psi)
0.286 at 68°F	9.2 at 68–212°F 20.5 at 68–1832°F	9.3 at 200°F	0.12 at 32–212°F	28 × 10⁶ (annealed, E)

💡 Practical Difference in Use

Use Stainless Steel 347 Round Bars when: excellent resistance to intergranular corrosion, strong oxidation stability, and reliable mechanical performance after welding are required in high-temperature and pressure environments. Niobium (Columbium) stabilization prevents chromium carbide precipitation during fabrication and prolonged service. → Example: heat exchanger rods, chemical processing shafts, pressure piping, refinery components, exhaust system parts, and structural fasteners.

Use Stainless Steel 347H Round Bars when: higher tensile strength, improved creep resistance, and superior durability are required for continuous operation at elevated temperatures, especially in thermal cycling and heavy load applications. → Example: furnace components, power plant hardware, superheater tubes, high-temperature piping, thermal equipment supports, and heavy-duty fasteners.

Applications of Stainless Steel 347 / 347H Round Bars

Stainless Steel 347 and 347H round bars are widely used in high-temperature, pressure, and welded applications where thermal stability, oxidation resistance, and long-term structural reliability are essential.

Power Generation & Thermal Systems: Heat exchanger rods, boiler supports, superheaters, turbine components, and exhaust assemblies.
Oil, Gas & Petrochemical: Refinery piping, reactor components, pressure vessels, valves, and fasteners.
Chemical & Process Industry: Shafts, piping systems, fabrication assemblies, and corrosion-resistant structures.

When to Choose Stainless Steel 347 vs. 347H Round Bars?

The selection mainly depends on operating temperature, strength requirement, pressure exposure, welding conditions, and long-term thermal performance.

Choose SS 347 Round Bars when:

Resistance to sensitization and intergranular corrosion is critical
Welded fabrication without post-weld heat treatment is required
Stable mechanical properties are needed at moderate-to-high temperatures
Used in piping systems, pressure parts, frames, and welded assemblies
Excellent oxidation resistance improves service life
Balanced performance and cost efficiency are preferred

Choose SS 347H Round Bars when:

Continuous exposure to very high temperatures is expected
Higher carbon content delivers increased strength and creep resistance
Long-term performance in thermal cycling environments is essential
Used in furnaces, power plants, refineries, and thermal processing equipment
Superior load-bearing capacity at elevated temperatures
Enhanced durability under high pressure and heat conditions

Industries That Use Stainless Steel 347 / 347H Round Bars

These grades are preferred in industries where heat resistance, pressure strength, welding reliability, oxidation protection, and long operational service life are required.

Power & Energy Industry

Used in high-temperature and high-pressure mechanical systems.

Uses

Boiler parts, superheater components, turbine supports, heat exchangers.

Why SS 347 / 347H?

Excellent thermal stability and oxidation resistance under pressure.

Oil, Gas & Petrochemical

Used in extreme operating conditions involving heat and pressure.

Uses

Refinery piping, pressure vessels, valves, fasteners, reactor supports.

Why SS 347H?

Superior creep strength and durability for continuous high-temperature service.

Chemical & Process Industry

Used in corrosive and welded process environments.

Uses

Piping systems, shafts, structural frames, fabricated assemblies.

Why SS 347?

Niobium stabilization prevents intergranular corrosion after welding.

Aerospace & Heavy Engineering

Used in heat-resistant structural and load-bearing components.

Uses

Engine supports, brackets, high-temperature fasteners.

Why SS 347H?

Maintains strength and stability at elevated temperatures.

Fabrication & Pressure Equipment

Used in welded pressure and thermal equipment.

Uses

Pressure parts, frames, industrial assemblies.

Why SS 347?

Excellent weldability with resistance to carbide precipitation.

Heat Treatment & Furnace Systems

Used in continuous high-temperature operating environments.

Uses

Furnace fixtures, supports, thermal carriers.

Why SS 347H?

Enhanced creep resistance for prolonged thermal exposure.

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