Super Duplex Steel Tube Plug Manufacturer & Supplier
The super duplex steel tube plugs are highly important materials that are used to close and isolate leaky or damaged tubes of heat exchangers, condensers, boilers, and coolers. In the event of a tube failure in a high-pressure or corrosive setting, it is necessary to provide reliable isolation to avoid cross-contamination to maintain the safe functioning of the equipment.
At Unifit, we manufacture precision-machined super duplex steel S32750 / S32760 tube plugs designed to provide a secure metal-to-metal seal. Our plugs are engineered for long service life and trouble-free installation during maintenance shutdowns. By effectively plugging damaged tubes, operators can bring critical equipment back online quickly without the immediate need for complete retubing.
Every tube plug we supply is produced from certified bar stock, with strictly controlled chemistry and mechanical properties. We provide full documentation and traceability, making Unifit a trusted partner for critical process industries where material integrity is non-negotiable.
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What Is a Super Duplex Steel Tube Plug?
A tube plug is a small tapered mechanical device that fits into the open end of a heat exchanger or condenser tube. It is used mainly to prevent the flow of fluids and permanently seal a particular tube that exhibits a leakage or wall thinning, and the remainder of the tube bundle is still serviceable.
Super Duplex Steel has a blend of the superior characteristics of both austenitic and ferritic stainless steel. The benefits of this dual-phase microstructure include:
- Increased Strength: Improved tensile as well as yield strength over regular stainless grades.
- Corrosion Resistance: Since it is needed to resist stagnant conditions within a plugged tube, it has very high resistance to both pitting and crevice corrosion.
- Stress Corrosion Cracking Resistance: Superb resistance to chloride-induced stress corrosion cracking (SCC).
- Durability: Great toughness and also weldability so that the plug does not lose its integrity due to pressure.
These properties enable our Super Duplex tube plugs to be used in applications where seawater, high chloride cooling water, brine, and aggressive chemical media can be used and the more conventional materials would fail prematurely.
Grades & Technical Specifications
We specialize in the two most common and effective grades of Super Duplex Steel for industrial applications. Both grades feature high levels of chromium, molybdenum, and nitrogen to deliver superior corrosion resistance in marine and chemical environments.
Material Grades
- Super Duplex Steel UNS S32750 (2507): The most widely used super duplex grade, offering excellent mechanical strength and corrosion resistance.
- Super Duplex Steel UNS S32760: Contains added tungsten for enhanced resistance in specific aggressive environments, such as sour gas service.
- Manufacturing Specifications
- Parent Material: Super Duplex forged or rolled bar conforming to relevant ASTM / ASME standards (e.g., ASTM A479, ASTM A276).
- Condition: Supplied in the solution-annealed and quenched condition to ensure optimal corrosion resistance and microstructure balance.
- Hardness: Strictly controlled to avoid galling during installation and to ensure proper seating into the tube sheet.
- Taper Design: Typically machined with a 2° to 2.5° taper, ensuring a reliable interference fit that seals tightly as the plug is driven in.
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Advantages of Super Duplex Steel Tube Plugs
Choosing Super Duplex Steel S32750 / S32760 for tube plugs offers significant long-term benefits for plant reliability and safety:
- Extended Service Life: Outlasts standard stainless steel plugs in seawater, brine, and chlorinated cooling water systems.
- Superior Pitting Resistance: High PREN (Pitting Resistance Equivalent Number) ensures the plug does not corrode in high-chloride environments.
- SCC Resistance: Virtually immune to chloride stress corrosion cracking, reducing the risk of sudden plug failure under thermal cycling.
- High Strength Sealing: The material's high yield strength allows for reliable sealing under high pressure and temperature fluctuations.
- Cost-Effective Maintenance: Helps extend the operating life of heat exchangers and condensers between major retubing operations.
For coastal refineries, offshore platforms, desalination plants, and facilities handling aggressive chemicals, Super Duplex tube plugs represent the most economical long-term solution for equipment isolation.
Why Choose Unifit for Super Duplex Steel Tube Plugs?
Unifit combines technical manufacturing expertise with a deep understanding of metallurgical requirements. Here is why procurement teams trust us:
- In-House Machining: Our plugs are machined on modern CNC equipment to ensure consistent taper angles, precise lengths, and excellent surface finishes. Every plug is dimensionally checked against approved drawings or standard industry sizes before dispatch.
- Quality & Traceability: We source raw material only from approved mills that provide full heat-number traceability. Every batch is supplied with Material Test Certificates (MTC) as per EN 10204 3.1. We also offer optional PMI (Positive Material Identification), hardness testing, and other mechanical or NDT testing based on customer requirements.
- Flexible Supply: We understand the urgency of plant maintenance. We have the capability to supply small urgent quantities for shutdowns as well as bulk production runs for OEMs and large projects. We can also manufacture custom designs exactly to your tube sheet or engineering drawing specifications.
- Global Export Experience: Unifit regularly exports to customers in the Middle East, Europe, Asia, and beyond. Our team is experienced in export-standard packing and documentation, ensuring your order arrives safely and clears customs without delay.
- Packing, Marking & Documentation: To protect the plugs during transit and storage, we follow a rigorous packing and marking procedure
- Cleaning: All plugs are thoroughly cleaned and lightly oiled or passivated as required.
- Packaging: Packed in polythene bags or small cartons with clear labels indicating size and quantity.
- Export Crating: Larger quantities are packed in strong wooden boxes or crates suitable for sea or air shipment.
- Identification: Each box is marked with the material grade, plug size, heat number, and order number for easy identification.
- Documentation: Dispatch documents include a detailed packing list, MTCs, and any agreed inspection reports.
Applications of Super Duplex Steel Tube Plugs
Super Duplex steel tube plugs from Unifit are deployed across critical infrastructure sectors worldwide. They are essential for:
- Refineries & Petrochemical Plants: Sealing leaking tubes in heat exchangers handling sour crude, chlorides, or acids.
- Power Generation: Isolating damaged tubes in condensers and coolers within power plants.
- Desalination & Water Treatment: Critical for plants handling seawater, brine, and reject water where corrosion rates are high.
- Offshore Oil & Gas: Used on platforms and FPSOs for process cooling systems exposed to marine environments.
- Marine & Shipbuilding: Sealing seawater cooling lines and central coolers on vessels.
- Chemical Processing: Any service involving high-chloride or acidic media requiring reliable isolation.
Whether you need to plug a few leaking tubes during an emergency shutdown or require a large quantity for a scheduled maintenance campaign, Unifit can supply the exact specification required.
Send Your Enquiry for Super Duplex Steel Tube Plugs
To help us provide a quick and accurate quote, please share the following details about your requirement:
- Tube Dimensions: Tube outside diameter (OD) and gauge / wall thickness.
- Operating Conditions: Tube material, medium, temperature, and pressure.
- Plug Material: Specify Super Duplex S32750 or S32760.
- Quantity & Location: Required quantity and delivery destination.
- Drawings: Any specific drawings or special plug geometry (if applicable).
You can send your enquiry via email, our contact form, or phone. Our technical team will review your tube data and respond promptly with suitable plug sizes, delivery times, and competitive pricing.