347H Stainless Steel Seamless Hydraulic & Instrumentation Tubes

Niobium-Stabilized High Carbon Grade • Superior High-Temperature Strength • Excellent Intergranular Corrosion Resistance

Manufacturers and suppliers of 347H Stainless Steel Seamless Hydraulic & Instrumentation Tubes, engineered for extreme high-temperature, refineries, power generation facilities, and chemical processing systems.

ISO 9001:2015 • ISO 14001:2015 • ISO 45001:2018 • PED 2014/68/EU • EN 10204 3.1/3.2 Certified

347H Stainless Steel Seamless Hydraulic & Instrumentation Tubes

Our 347H Stainless Steel Seamless Hydraulic & Instrumentation Tubes are engineered for extreme high-temperature and corrosive service environments where superior mechanical strength, enhanced creep resistance, and long-term operational reliability are critical. The high-carbon, niobium-stabilized composition of Grade 347H prevents carbide precipitation during welding and prolonged heat exposure, ensuring outstanding resistance to intergranular corrosion, oxidation, and thermal fatigue.

The seamless, precision-manufactured construction provides uniform wall thickness and smooth internal surfaces, reducing pressure losses and enhancing flow efficiency in critical hydraulic and instrumentation systems. These tubes maintain exceptional performance under high pressure, severe thermal cycling, and continuous elevated temperatures, making them ideal for safety-critical fluid control and precision measurement applications.

Widely used in petrochemical and chemical processing plants, refineries, power generation facilities, aerospace systems, and high-temperature industrial operations, our 347H stainless steel seamless tubes are manufactured and tested to international standards to deliver a durable, high-performance, and cost-effective solution for harsh, heat-intensive, and corrosive service environments.

347H Stainless Steel Seamless Hydraulic and Instrumentation Tubes

Comprehensive Global Reach

Our 347H Stainless Steel Seamless Hydraulic & Instrumentation Tubes are trusted across major industrial cities in India, including Mumbai, Chennai, Pune, and Ahmedabad, supporting petrochemical plants, refineries, power generation facilities, and critical infrastructure projects that demand reliable, high-temperature and corrosion-resistant tubing solutions.

Throughout the Middle East, we supply the UAE (Dubai, Abu Dhabi, Sharjah, Ajman, and Ras Al Khaimah), Saudi Arabia, Qatar, Kuwait, Oman, Bahrain, Iraq, Jordan, and Lebanon. Our 347H stainless steel seamless tubes are widely used in oil & gas processing, water treatment facilities, and EPC projects operating under extreme heat, pressure, and corrosive service conditions.

Europe, Africa, Americas & Asia-Pacific

In Europe, our tubes serve Italy, Germany, Spain, France, the United Kingdom, Turkey, Greece, Austria, and Eastern European markets, where precision engineering and high-temperature performance are essential. Across Africa, the Americas, and the Asia-Pacific region—including the United States, Canada, Brazil, Mexico, South Africa, Nigeria, Singapore, Malaysia, Thailand, and Australia—our 347H Stainless Steel Seamless Hydraulic & Instrumentation Tubes support chemical processing plants, power stations, offshore platforms, heavy manufacturing, and thermal processing industries.

Commitment to Quality

Wherever you operate—Doha, Dubai, London, Houston, Singapore, or Sydney—Seminox Pipes & Tubes delivers premium-quality 347H Stainless Steel Seamless Hydraulic & Instrumentation Tubes, manufactured and certified to international standards to ensure precision, full traceability, and long-term performance in critical fluid control and high-temperature instrumentation applications worldwide.

Key Features of 347H Stainless Steel Seamless Hydraulic & Instrumentation Tubes

Precision Seamless Manufacturing

Manufactured using advanced cold drawing and seamless forming processes to ensure uniform wall thickness, tight dimensional tolerances, and smooth internal surfaces for consistent fluid flow and accurate instrumentation performance.

Niobium-Stabilized High-Carbon Grade

The high-carbon, niobium-stabilized composition of 347H stainless steel prevents carbide precipitation at elevated temperatures, improving creep strength and ensuring reliable performance in high-heat and high-pressure hydraulic and instrumentation systems.

Superior Intergranular Corrosion Resistance

Stabilization with niobium provides outstanding resistance to intergranular corrosion after welding or prolonged exposure to high temperatures, making these tubes ideal for petrochemical, power generation, and chemical processing environments.

Smooth Bore for Accurate Flow Control

Precision-finished internal surfaces reduce friction, minimize pressure loss, and enhance flow stability for sensitive instrumentation and critical process control systems.

High-Temperature & Oxidation Resistance

Maintains mechanical integrity, oxidation resistance, and structural stability under extreme temperatures, thermal cycling, and aggressive industrial service conditions.

Long Service Life & Reduced Maintenance

Engineered for extended durability, reduced downtime, and lower lifecycle costs in refineries, petrochemical plants, power stations, and high-temperature process industries.

Product Specification – 347H Stainless Steel Seamless Hydraulic & Instrumentation Tubes

Outside Diameter
6.00 mm to 114.30 mm (1/4” to 4.5”)
Wall Thickness
0.71 mm to 12.70 mm (0.028” to 0.500”)
Grade / Material
Austenitic Stainless Steel (High Carbon, Niobium Stabilized)
AISI 347H
UNS S34709
EN 1.4961 (Closest Equivalent)
Manufacturing Process
Seamless (Cold Drawn / Cold Rolled) • Solution Annealed • Pickled / Bright Annealed
Standards & Specifications
ASTM A213 / A213M – Seamless Stainless Steel Tubes (Instrumentation & Heat Transfer)
ASTM A269 – General Service Stainless Steel Tubing
ASTM A511 – Mechanical Tubing
ASME SA213 / SA269
EN 10216-5 (Seamless Precision Tubes)
Customer Drawings & EPC / Project Specifications
Length
Standard: 6 meters • Random Lengths • Up to 18 meters
Custom cut lengths as per Project / Instrumentation Requirements
Surface Finish
Annealed & Pickled (AP), Bright Annealed (BA),
Polished (180 / 240 / 320 / 400 / 600 Grit), Electropolished
Mechanical Properties (Typical)
Yield Strength: ≥ 205 MPa
Tensile Strength: 515–690 MPa
Elongation: ≥ 40%
Enhanced Creep Strength at Elevated Temperatures
Applications
High-Temperature Hydraulic & Pneumatic Systems
Instrumentation & Process Control Lines
Petrochemical & Refinery Piping Systems
Chemical Processing & Corrosive Fluid Handling Units
Power Generation & Thermal Energy Systems
Heat Exchangers & Furnace Equipment
High-Pressure, High-Temperature & Critical Service Environments

Manufacturing, Testing & Quality Assurance – 347H Stainless Steel Tubes

Advanced Manufacturing

347H Stainless Steel Seamless Hydraulic & Instrumentation Tubes are manufactured using precision cold drawing and cold rolling processes, followed by controlled solution annealing and pickling or bright annealing. The niobium-stabilized, high-carbon austenitic structure prevents carbide precipitation during welding and prolonged high-temperature exposure, ensuring superior creep strength, oxidation resistance, and dimensional stability for high-pressure and high-heat hydraulic and instrumentation service applications.

Inspection & Testing

Each tube undergoes comprehensive quality control including Eddy Current Testing (ECT), Hydrostatic or Pneumatic Pressure Testing, Positive Material Identification (PMI), chemical composition verification, mechanical and high-temperature performance testing, dimensional inspection, and 100% visual examination. These procedures ensure full compliance with ASTM A213 / A269 and ASME SA213 / SA269 standards for safe and reliable performance in critical, corrosive, and elevated-temperature environments.

Certifications & Compliance

Manufactured in accordance with ASTM A213, ASTM A269, ASME SA213, ASME SA269, EN 10216-5, ISO 9001:2015, ISO 14001:2015, ISO 45001:2018, and PED 2014/68/EU directives. Tubes are supplied with EN 10204 3.1 / 3.2 Mill Test Certificates (MTC), ensuring full traceability, regulatory compliance, and acceptance for EPC, petrochemical, power generation, refinery, chemical processing, and offshore projects worldwide.

Typical Applications of 347H Stainless Steel Seamless Hydraulic & Instrumentation Tubes

High-Temperature Hydraulic & Pneumatic Control Systems
Instrumentation & Process Control Lines
Petrochemical & Refinery Piping Systems
Chemical Processing & Corrosive Fluid Handling Units
Power Generation & High-Heat Energy Systems
Industrial Heating & Furnace Equipment
High-Pressure & High-Temperature Fluid Transfer
Heat Exchangers & Thermal Control Systems
Corrosive, High-Temperature & Critical Service Environments

Need 347H Stainless Steel Seamless Hydraulic & Instrumentation Tubes for Your Project?

Partner with Seminox Pipes & Tubes for certified, project-ready 347H Stainless Steel Seamless Hydraulic & Instrumentation Tubes manufactured to international standards and supplied with EN 10204 3.1 / 3.2 Mill Test Certificates. Trusted worldwide for petrochemical, chemical processing, power generation, and high-temperature industrial applications requiring superior oxidation resistance, excellent intergranular corrosion protection, and long-term reliability in heat-intensive and critical service environments.

Get in Touch

Phone Number

022 6659 5296
+91 9987403801
+918433943801

Email

domestic@seminoxpipes.com
export@seminoxpipes.com

Address

1219 / 1220, 12th Floor, Prasad Chambers, Girgaon, Mumbai- 400004

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Saturday — 10am – 3pm
Sunday — Closed

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