Stainless Steel 304 / 304L Tube Plugs from Unifit Fasteners are essential materials that ensure safety, efficiency, and leakproof performance of heat exchangers, boilers, condensers, and industrial piping systems. These plugs are meant to close the ends of the tubes permanently to avoid fluid leaks, lessen the decline in time and ensure a seamless operation of systems even in moderate temperatures and slightly corrosive environments.
In plain terms, stainless steel 304 and stainless steel 304L tube plugs are small plug-shaped parts used to close the ends of tubes or pipes. They are made from strong SS 304/304L material that prevents leakages and helps to contain the items.
These tube plugs are manufactured out of high-grade austenitic stainless steel, and they have high corrosion resistance, good mechanical properties and high dimensional accuracy. They can be customised to fit perfectly in systems of different sizes, diameters, lengths, and designs, and do not create any complications during installation because they do not damage tube sheets and do not interfere with performance.
Adjusting to ASTM A182, ASME SA182 and DIN 1.4301 / 1.4307, SS 304 / 304L Tube Plugs are popular in chemical plants, water, pharmaceutical, food and beverage plants, and other general industrial applications. All of the plugs are backed with complete material trace, quality inspection, and dependable testing – a solution to the serious operations that engineers and procurement departments would find lasting and maintenance-free in sealing.
Request QuoteStainless Steel 304 / 304L Tube Plugs are mechanical sealing components used to isolate, block, or seal damaged or unused tubes in heat exchangers, condensers and boilers. Unlike temporary sealing methods, these plugs provide a maintenance-free, long-lasting solution that maintains system efficiency and prevents fluid leakage.
Available in tapered and parallel designs, these plugs are easy to install and minimize the risk of tube sheet damage while providing maximum sealing effectiveness.
Selecting the right tube plug is essential for ensuring optimal sealing, preventing leakage and maintaining the efficiency of industrial systems. We offer a comprehensive range of precision-engineered tube plugs to suit various industrial applications:
Understanding the specifications of stainless steel 304 tube plugs and stainless steel 304L tube plugs is critical for selecting the right component for your industrial systems. By choosing plugs with verified standards and precise tolerances, engineers and procurement teams can ensure reliable performance, long service life, and compliance with international quality standards.
| Standard | Material Grade | Designs Available | Size Range | Finish | Tolerance |
|---|---|---|---|---|---|
| ASTM A182, ASME SA182, DIN 1.4301 / 1.4307 | Stainless Steel 304 / 304L (UNS S30400 / S30403) | Tapered, Parallel, Threaded, Custom | As per requirement | Smooth Machined / Polished | ±0.05 mm or as specified |
To ensure compatibility across global industrial applications, stainless steel 304 tube plugs and stainless steel 304L tube plugs are manufactured to meet a variety of international standards and equivalent grades.
| Standard | Grade / Equivalent | Description |
|---|---|---|
| UNS | S30400 / S30403 | Austenitic stainless steel with excellent corrosion resistance |
| WERKSTOFF NR. | 1.4301 / 1.4307 | German standard designation |
| EN | X5CrNi18-10 | European standard name |
| JIS | SUS 304 | Japanese Industrial Standard |
| BS | 304S15 / 304S16 | British Standard specification |
| GOST | 08Х18Н10 | Russian equivalent grade |
| AFNOR | Z6CN18-10 | French standard equivalent |
The chemical composition of Stainless Steel 304 / 304L Tube Plugs is carefully controlled to ensure optimal corrosion resistance, mechanical strength, and thermal stability in industrial applications. Selecting the right composition ensures that tube plugs maintain performance and dimensional stability even under prolonged exposure to moderate temperatures and mildly corrosive environments.
| Element | Minimum (%) | Maximum (%) |
|---|---|---|
| Carbon (C) | – | 0.08 (304) / 0.03 (304L) |
| Manganese (Mn) | – | 2.00 |
| Silicon (Si) | – | 0.75 |
| Phosphorus (P) | – | 0.045 |
| Sulfur (S) | – | 0.030 |
| Chromium (Cr) | 17.00 | 19.00 |
| Nickel (Ni) | 8.00 | 12.00 |
| Iron (Fe) | Balance | Balance |
Why it matters: Maintaining this precise chemical balance ensures that SS 304 / 304L Tube Plugs deliver reliable sealing, resist corrosion and sustain mechanical integrity, making them suitable for applications in heat exchangers, boilers, condensers and industrial piping systems.
The mechanical properties of Stainless Steel 304 / 304L Tube Plugs determine their ability to withstand pressure, stress, and thermal cycling in industrial applications. Here’s the detailed breakdown:
| Property | Metric | Imperial |
|---|---|---|
| Tensile Strength (min) | 505 MPa | 73,000 psi |
| Yield Strength (0.2% Proof, min) | 215 MPa | 31,000 psi |
| Elongation (min) | 40% | 40% |
| Hardness (Brinell, max) | 201 HB | 201 HB |
| Modulus of Elasticity | 193 GPa | 28,000 ksi |
Selecting the right tube plug is critical to ensuring system reliability, efficiency, and safety in industrial applications. Using these plugs helps minimize operational downtime, prevent fluid leakage, and extend the lifespan of heat exchangers and piping systems:
Key reasons to choose stainless steel 304 tube plugs and stainless steel 304L tube plugs include:
With this grade, the combination of corrosion resistance and mechanical strength allows plugs to perform reliably in moderate temperature and mildly corrosive environments, making accurate sizing critical for both standard and custom industrial applications:
| Metal Tapered Tube Plugs – Tube Plug Sizing Chart | ||||
|---|---|---|---|---|
| Tube OD | Gauge | Dimension (Inches) | ||
| “A” | “B” | “L” | ||
| Small End | Large End | Length | ||
| 1/4″ | 18-24 | 0.141″ | 0.235″ | 1-1/4″ |
| 3/8″ | 12-24 | |||
| 3/8″ | 15-24 | 0.213″ | 0.371″ | 1-3/4″ |
| 1/2″ | 13-15 | |||
| 1/2″ | 15-24 | 0.337″ | 0.495″ | |
| 5/8″ | 12-14 | |||
| 5/8″ | 14-24 | 0.449″ | 0.625″ | |
| 3/4″ | 10-14 | |||
| 3/4″ | 14-24 | 0.564″ | 0.750″ | |
| 7/8″ | 10-13 | |||
| 1″ | 8-9 | |||
| 7/8″ | 15-24 | 0.706″ | 0.875″ | |
| 1″ | 10-15 | |||
| 1″ | 13-18 | 0.776″ | 0.934″ | |
| 1″ | 18-24 | 0.892″ | 1.050″ | |
| 1-1/8″ | 13-17 | |||
| 1-1/8″ | 15-24 | 0.949″ | 1.125″ | 2″ |
| 1-1/4″ | 10-14 | |||
| 1-1/4″ | 13-19 | 1.010″ | 1.186″ | |
| 1-1/4″ | 19-24 | 1.147″ | 1.323″ | |
| 1-1/2″ | 10-24 | 1.200″ | 1.495″ | 3″ |
| 1-1/2″ | 14-24 | 1.305″ | 1.600″ | |
| 1-3/4″ | 6-13 | |||
| 1-3/4″ | 14-22 | 1.575″ | 1.870″ | |
| 2″ | 6-13 | |||
| 2″ | 12-22 | 1.700″ | 1.995″ | |
| 2-1/4″ | 6-13 | 1.805″ | 2.100″ | |
| 2-1/2″ | 5-18 | 2.000″ | 2.375″ | |
| 2-3/4″ | 4-10 | 2.232″ | 2.500″ | |
| 3″ | 5-12 | 2.524″ | 2.834″ | 4″ |
| 3″ | 10-23 | 2.625″ | 3.000″ | |
| 3-1/4″ | 7-14 | 2.875″ | 3.125″ | |
| 3-1/4″ | 13-23 | 3.010″ | 3.250″ | |
| 3-1/2″ | 7-12 | 3.125″ | 3.375″ | |
| 3-1/2″ | 13-23 | 3.260″ | 3.500″ | |
| 3-3/4″ | 5-12 | 3.274″ | 3.567″ | |
| 3-3/4″ | 13-23 | 3.510″ | 3.750″ | |
| 4″ | 5-12 | 3.524″ | 3.817″ | |
| 4″ | 13-23 | 3.782″ | 4.000″ | |
Stainless Steel 304 / 304L Tube Plugs are widely used in industries where reliable sealing, corrosion resistance, and dimensional accuracy are critical. Their robust performance in moderate temperature and mildly corrosive environments makes them a preferred choice for various industrial systems.
Common applications include:
| Threaded Tapered Plugs | |||
| Max Hole Size | Part No. | Width | Hex Size |
|---|---|---|---|
| 0.350″ | TTP-375 | 0.365″ | 3/8″ |
| 0.450″ | TTP-500 | 0.480″ | 1/2″ |
| 0.580″ | TTP-625 | 0.615″ | 5/8″ |
| 0.710″ | TTP-750 | 0.730″ | 3/4″ |
| 0.835″ | TTP-875 | 0.855″ | 7/8″ |
| 0.950″ | TTP-1000 | 0.975″ | 1″ |
| 1.150″ | TTP-1125 | 1.100″ | 1 1/8″ |
| 1.200″ | TTP-1250 | 1.220″ | 1 1/4″ |
| 1.320″ | TTP-1375 | 1.345″ | 1 3/8″ |
| 1.450″ | TTP-1500 | 1.470″ | 1 1/2″ |
| Tube OD | Tube ID Range | Pin Size | Ring Size |
|---|---|---|---|
| 3/8″ | 0.283 – 0.377 | TP – 1 | TPR-0375 |
| 1/2″ | 0.283 – 0.377 | TP – 1 | TPR-0500-1 |
| 0.384 – 0.503 | TP – 2 | TPR-0500-2 | |
| 5/8″ | 0.384 – 0.503 | TP – 2 | TPR-0625-2 |
| 0.480 – 0.635 | TP – 3 | TPR-0625-3 | |
| 3/4″ | 0.480 – 0.635 | TP – 3 | TPR-0750-3 |
| 0.616 – 0.759 | TP – 4 | TPR-0750-4 | |
| 1″ | 0.616 – 0.759 | TP – 4 | TPR-1000-4 |
| 0.730 – 0.840 | TP – 5 | TPR-1000-5 | |
| 0.830 – 1.008 | TP – 6 | TPR-1000-6 | |
| 1 1/8″ | 0.730 – 0.840 | TP – 5 | TPR-1125-5 |
| 0.830 – 1.008 | TP – 6 | TPR-1125-6 | |
| 0.930 – 1.130 | TP – 7 | TPR-1125-7 | |
| 1 1/4″ | 0.930 – 1.130 | TP – 7 | TPR-1250-7 |
| 0.992 – 1.261 | TP – 8 | TPR-1250-8 | |
| 1 1/2″ | 1.180 – 1.240 | TP – 9 | TPR-1500-9 |
| 1.242 – 1.342 | TP – 10 | TPR-1500-10 | |
| 1.344 – 1.495 | TP – 11 | TPR-1500-11 | |
| 1.380 – 1.510 | TP – 12 | TPR-1500-12 | |
| 2″ | 1.680 – 1.856 | TP – 13 | TPR-2000-13 |
| 1.742 – 2.020 | TP – 14 | TPR-2000-14 |
The price of Stainless Steel 304 / 304L Tube Plugs depends on several factors, including dimensions, design type, quantity, manufacturing tolerances, and any special surface treatments. Custom sizes, high-pressure variants, or plugs with stringent industry specifications may have higher pricing due to precision machining, material quality, and rigorous testing requirements.
At Unifit Fastener, we offer competitive pricing by sourcing premium-grade stainless steel directly from trusted mills and maintaining efficient production processes. Each tube plug is supplied with material test reports (MTRs), traceability, and quality assurance, ensuring you receive reliable, high-performance components at the best value for your application.
Why it matters: Investing in quality SS 304 / 304L Tube Plugs reduces operational downtime, minimizes maintenance costs, and extends system life, providing a higher return on investment over standard or substandard alternatives.
Unifit Fastener is a leading manufacturer and supplier of premium Stainless Steel 304 / 304L Tube Plugs, trusted by industries worldwide for precision, durability and reliable performance. Each tube plug is engineered to provide leak-proof sealing, dimensional accuracy, and corrosion resistance in heat exchangers, boilers, condensers and piping systems operating under moderate temperature and mildly corrosive conditions.
Our ISO-compliant manufacturing processes ensure that every SS 304 / 304L Tube Plug meets ASTM, ASME and DIN standards. We offer a wide range of sizes, designs and pressure ratings, including tapered, parallel, threaded, and custom plugs.
By choosing Unifit Fastener, clients gain high-performance SS 304 / 304L Tube Plugs backed by material test reports (MTRs), rigorous quality checks and traceability ensuring long service life, reduced downtime and optimal system efficiency. Our commitment to precision engineering and dependable supply makes us the preferred partner for businesses seeking reliable, maintenance-free tube sealing solutions.
Request QuoteSS 304 / 304L Tube Plugs are used to seal, block, or isolate tubes in heat exchangers, boilers, condensers, and industrial piping systems, preventing fluid leakage and maintaining operational efficiency.
SS 304 / 304L offers excellent corrosion resistance, mechanical strength, and dimensional stability under moderate temperatures and mildly corrosive environments, making it ideal for long-term, maintenance-free applications.
SS 304 / 304L Tube Plugs are suitable for moderate temperature applications (up to ~870°C intermittently). For continuous exposure to very high temperatures, specialized grades like SS 321 may be preferred.
Yes, these plugs offer excellent corrosion resistance to water, mild acids, and other moderately corrosive media, making them suitable for chemical processing, water treatment, and food & beverage applications.
Installation depends on the type: tapered plugs are driven into the tube for a tight fit, threaded plugs are screwed in, and expandable plugs adjust to tube diameter, all ensuring leak-proof sealing with minimal risk of tube sheet damage.
Yes, Unifit Fastener provides customized tube plugs in terms of diameter, length, taper, pressure rating, and design type, ensuring a perfect fit and optimal performance for specialized industrial requirements.