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SS 347 / 347H Studs Manufacturer & Exporter in India

Explore SS 347 / 347H Studs Manufacturer & Exporter in India manufactured for demanding industrial applications with reliable strength, corrosion resistance and compliance with international standards.
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-196

Min Temp

870

Max Temp

🌡

870

Suitable for continuous service up to approximately 870°C under typical operating conditions.

⚡

620

Typical tensile strength around 620 MPa depending on product form and heat treatment.

🛡

Very Good

Very Good corrosion resistance in a wide range of industrial environments.

⚖

8

Typical density is approximately 8.0 g/cm³.

Product Overview

What are SS 347 / 347H Studs?

SS 347 / 347H studs are high-temperature austenitic stainless steel fasteners manufactured from stabilized grades UNS S34700 and UNS S34709. These studs are alloyed with columbium (niobium) to prevent chromium carbide precipitation, ensuring excellent intergranular corrosion resistance even after welding or exposure to high temperatures. The 347H variant features a higher carbon content for enhanced creep strength above 500°C, making it ideal for critical bolted joints in heat exchangers, pressure vessels, and refinery piping.

SS 347 / 347H studs are specified in ASME, ASTM, and EN standards for use in petrochemical, power generation, and thermal processing industries where resistance to polythionic acid stress corrosion and high-temperature oxidation is essential.

Quick Specifications

MaterialStainless Steel 347 / 347H
UNS NumberS34700 / S34709
DIN Number1.4550 / 1.4961
Material StandardASTM A193 B8 Class 1 / Class 2
Stud Standard (Metric)DIN 976 / DIN 975 / ISO 898-1
Stud Standard (Inch)ASME B16.5 / ASME B18.31.2
Thread FormISO Metric / UNC / UNF
Diameter RangeM6-M100 / ¼"-4"
Tensile Strength515 MPa (75 ksi) min
Yield Strength205 MPa (30 ksi) min
HardnessMax 223 HB / 95 HRB
? All material certified by NABL-accredited laboratory. PMI and IGC test available on request.

Complete the Fastener Set

Other SS 347 / 347H Fastener Products Available from RealBolt

RealBolt also manufactures the complete SS 347 / 347H fastener range — SS 347 / 347H Bolts, SS 347 / 347H Nuts, SS 347 / 347H Screws, SS 347 / 347H Washers, SS 347 / 347H Threaded Rods — from certified bar stock per ASTM with full EN 10204 MTC 3.1/3.2 documentation and fast Mumbai dispatch.
SS 347 / 347H Bolts
SS 347 / 347H Nuts
SS 347 / 347H Screws
SS 347 / 347H Washers
SS 347 / 347H Threaded Rods

Technical Data

SS 347 / 347H Studs Dimensions, Sizes & Thread Standards

SS 347 / 347H Studs are available in metric M6–M100 and inch ¼″–4″ as standard. Per DIN 976 (full thread) / DIN 975 (threaded rod) / ASME B16.5 (stud bolts for flanges). Custom cut lengths available in 5mm increments. Inch dimensions per ASME B18.31.2.

Stud Bolt Dimensions - Metric (DIN 976)

Size (M)Pitch (mm)Across Flats (mm)Stud Length (mm)Min L (mm)Max L (mm)
M61.01020-2000202000
M81.251320-2500202500
M101.51720-3000203000
M121.751925-3000253000
M162.02430-3000303000
M202.53035-3000353000
M243.03640-3000403000
M303.54650-3000503000
M364.05560-3000603000
M424.56580-3000803000
M485.075100-30001003000
M565.585120-30001203000
M646.095140-30001403000
M726.0105160-30001603000
M806.0115180-30001803000
M1006.0145200-30002003000

Dimensional & Material Standards

StandardCoversThread
DIN 976Stud bolts, full threadMetric
DIN 975Threaded rodsMetric
ASME B16.5Stud bolts for flangesUNC
ASME B18.31.2Continuous thread studsUNC/UNF
ISO 898-1Mechanical propertiesMetric
Material StandardRequirement
ASTM A193 B8 Cl.1Studs - SS 347
ASTM A193 B8 Cl.2Studs - SS 347H
ASTM A194 Gr.8Heavy hex nuts
EN 10204 3.1Mill test certificate
EN 10204 3.2TPI-witnessed MTC

Material Chemistry

SS 347 / 347H Chemical Composition

SS 347 / 347H Studs are manufactured from an iron-chromium-nickel alloy with chromium (16–26%), nickel (8–28%), and grade-specific molybdenum additions per ASTM and ASTM A193/A194. Chromium content governs the self-healing passive oxide film; molybdenum (2–6%) enhances chloride pitting resistance; and carbon content determines sensitization risk in welded assemblies.

Chemical Composition per ASTM A276 / A193

ElementSS 347 (%)SS 347H (%)
Chromium (Cr)17.0-19.017.0-19.0
Nickel (Ni)9.0-13.09.0-13.0
Carbon (C)0.08 max0.04-0.10
Manganese (Mn)2.00 max2.00 max
Silicon (Si)1.00 max1.00 max
Phosphorus (P)0.045 max0.045 max
Sulfur (S)0.030 max0.030 max
Niobium (Nb)10xC-1.010xC-1.0
Iron (Fe)BalanceBalance
? All heats verified by NABL-accredited spectrometry. IGC and PMI available on request.

Why SS 347 / 347H Alloy Composition Matters for Studs

Nb Stabilization — Intergranular Corrosion Resistance
Niobium (columbium) additions tie up carbon, preventing chromium carbide precipitation at grain boundaries. This ensures SS 347 / 347H studs resist intergranular attack after welding or high-temperature service, unlike standard 304/316 grades.
347H — High Carbon for Creep Strength
The higher carbon content in 347H (0.04–0.10%) increases creep and rupture strength above 500°C, making it the preferred choice for refinery, power, and petrochemical bolted joints exposed to sustained high temperatures.
Excellent Weldability
SS 347 / 347H studs can be welded without risk of sensitization or loss of corrosion resistance, supporting reliable fabrication of pressure vessels and piping systems.

Fastener Performance

SS 347 / 347H Studs Mechanical Properties & Torque Reference

The table below lists mechanical properties and torque reference for SS 347 / 347H Studs per ASTM. SS 347 / 347H studs achieve 620 MPa tensile strength, with hardness, yield, and elongation values verified by NABL-accredited testing and reported in the EN 10204 MTC.

Stud SizeDry (Nm)Lubricated (Nm)Clamp Load (kN)
M12705625
M1617013652
M2034027282
M24590472119
M301200960192
M3621001680278
M4233002640380
M4848003840520
?? Anti-galling: Use molybdenum-based or PTFE anti-seize. Lubricated values assume K=0.16. Avoid copper-based anti-seize in chloride service.

Industry Applications

SS 347 / 347H Studs Applications — Industries & End Uses

SS 347 / 347H Studs from RealBolt are specified across food and dairy, pharmaceutical, marine, chemical processing, and oil and gas where very good corrosion resistance and 620 MPa tensile strength are required for reliable fastener performance. Click each industry below for detailed application examples.
SS 347 / 347H studs are the preferred choice for ASME B16.5/B16.47 flange connections, reactor closures, and heat exchanger channel covers in hydroprocessing, catalytic reforming, and sulfur recovery units. Their resistance to polythionic acid and high-temperature oxidation ensures long-term reliability in aggressive refinery environments.
Stud bolts for superheater, reheater, and economizer header connections in coal-fired and combined cycle power plants. 347H is specified for its superior creep strength and resistance to stress rupture at elevated temperatures, supporting safe operation of high-pressure steam systems.
Used in pressure vessel nozzles, agitator drives, and process piping in nitric acid, urea, and organic acid plants where standard 304/316 studs are prone to intergranular attack or stress corrosion cracking.
SS 347 / 347H studs are used for securing furnace linings, burner assemblies, and radiant tube supports in continuous annealing, heat treatment, and carburizing furnaces due to their oxidation resistance up to 870°C.

SS 347 / 347H Studs Standards & International Certifications

SS 347 / 347H Studs from RealBolt Engineering Industries are manufactured to internationally recognised fastener dimensional standards covering thread form, tolerances, strength grades, and quality requirements. Every batch ships with EN 10204 MTC 3.1/3.2, IS 12427 compliance, ISO 3506 material certification, NACE MR0175, and PMI (XRF) reports — available on request for all orders.
Standards
DIN 938 DIN 939 DIN 976-1 ASME B18.31.2 IS 1364 IS 1367 IS 12427
Certifications
ISO 9001:2015PED 2014/68/EUNABL LabEN 10204 3.1 / 3.2

Buy SS 347 / 347H Studs from India's Leading Manufacturer — Get a Competitive Quote Today

Partner with RealBolt — India’s leading manufacturer of certified SS 347 / 347H Studs — for competitive pricing, EN 10204 MTC 3.1/3.2 documentation, and fast Mumbai dispatch. Standard sizes are ex-stock; custom dimensions accepted with 2–3 week lead time. Request your quote today.
022-6743-7972
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Answers for Buyers

SS 347 / 347H Studs — Frequently Asked Questions

Browse expert answers to common questions about SS 347 / 347H Studs from RealBolt — covering ASTM A193/A194 grades, chloride resistance, temperature limits, sensitization, sizes, and MTC documentation. Contact our technical team directly for project-specific guidance on SS 347 / 347H studs selection and pricing.
SS 347 / 347H stud bolts are available to DIN 976 (full thread), DIN 975 (threaded rod), ASME B16.5 (flange studs), and ASME B18.31.2 (continuous thread). Custom thread forms (UNC, UNF, BSW, BSF) and cut lengths are available on request with a typical lead time of 10-15 working days.
Use a molybdenum-based or PTFE anti-seize compound (such as Molykote 1000 or Loctite LB 8008 C5-A) to prevent galling and facilitate disassembly. Avoid copper-based anti-seize in chloride or sulfur service to prevent galvanic corrosion. Lubricated torque values should be reduced by 20% compared to dry assembly.
Yes – SS 347 / 347H studs are stabilized with niobium, providing excellent resistance to intergranular corrosion after welding and during high-temperature service up to 870°C. 347H is specifically designed for improved creep strength in continuous high-temperature applications. Both grades are widely used in refinery, power, and chemical plant bolted joints.
No formal MOQ for standard sizes (M12-M36) held ex-stock – we supply from single pieces for urgent maintenance. Custom cut lengths or non-standard threads have an MOQ of 10 kg. Flange stud bolt sets are supplied by the set with no minimum. Quantity price breaks at 50 pcs, 200 pcs, and 500 pcs.

Industrial Cities We Serve:

  • Ahmedabad
  • Aurangabad
  • Bengaluru
  • Chennai
  • Coimbatore
  • Faridabad
  • Gandhidham
  • Greater Noida
  • Gurugram
  • Hazira
  • Hosur
  • Hyderabad
  • Jamnagar
  • Jamshedpur
  • Ludhiana
  • Mumbai
  • Mundra
  • Mysuru
  • Nagpur
  • Nashik
  • Navi Mumbai
  • Noida
  • Pune
  • Rajkot
  • Sanand
  • Surat
  • Thane
  • Tiruppur
  • Vadodara
  • Visakhapatnam

Countries We Export To:

  • US
  • Canada
  • Mexico
  • Germany
  • UK
  • France
  • Italy
  • Spain
  • Netherlands
  • Belgium
  • Poland
  • Sweden
  • Norway
  • Denmark
  • Turkey
  • UAE
  • Saudi Arabia
  • Qatar
  • Oman
  • Kuwait
  • Bahrain
  • South Africa
  • Egypt
  • Nigeria
  • Australia
  • New Zealand
  • Singapore
  • Malaysia
  • Indonesia
  • Thailand
  • Vietnam
  • South Korea
  • Japan
  • Brazil