What Is 347H (UNS S34709) Stainless Steel

347H (UNS S34709, 1.4550, SUS347H) is high-carbon niobium-tantalum stabilized stainless steel, designed for high-temperature creep strength and stability.

Equivalent Grades (Horizontal)

UNS: S34709 | JIS: SUS347H | GB: 07Cr18Ni11Nb | EN: X7CrNiNb18-10

Chemical Composition (wt%, Horizontal)

C: 0.04-0.10 | Si: ≤1.00 | Mn: ≤2.00 | P: ≤0.045 | S: ≤0.030 | Cr: 17.00-19.00 | Ni: 9.00-13.00 | Nb+Ta: 8×C-1.00 | Fe: Balance

Grade	UNS No	Old British		Euronorm		Swedish SS	Japanese JIS
		BS	En	No	Name
321	S32100	321S31	58B, 58C	1.4541	X6CrNiTi18-10	2337	SUS 321
321H	S32109	321S51	-	1.4878	X10CrNiTi18-10	-	SUS 321H
347	S34700	347S31	58G	1.4550	X6CrNiNb18-10	2338	SUS 347

Key Properties (20°C, Annealed, Horizontal)

Density: 7.93g/cm³ | Melting Point: 1400-1450°C | Tensile Strength: ≥515N/mm² | 0.2% Yield Strength: ≥205N/mm² | Elongation: ≥40% | Hardness (HB): ≤201

Core Characteristics

Superior high-temperature creep strength (600-900°C); excellent post-weld corrosion resistance; mandatory post-weld annealing; for high-temp stress-bearing nuclear/industrial components.

347 vs 347H (Horizontal)

Carbon Content: 347 (≤0.08%) | 347H (0.04-0.10%) | High-Temp Creep: 347 (Good) | 347H (Excellent) | Post-weld Annealing: 347 (Optional) | 347H (Mandatory)

 

 

Stainless Steel Suppliers

If you have project requirements for 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 information and free samples, please contact our factory immediately. We offer competitive prices and excellent service.Email: info@gneestainless.com

 

Testing and Documentation: Factory test certificate, EN 10204 3.1, chemical report, mechanical report, destructive testing report, non-destructive testing report, PMI test report, visual inspection report, third-party inspection report, NABL certified laboratory report.
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