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Union Tube Fitting Manufacturer & Exporter — India

Q: What brand of union tube fitting does Tesco Steel manufacture?

Tesco Steel manufactures union tube fittings under the TES-LOK brand. TES-LOK fittings are compatible in form, fit, and function with major industry brands including Swagelok, Parker A-LOK, and Ham-Let, and are produced to ASTM D1710 and ASTM D3294 standards.

Q: What thread standards are supported?

TES-LOK union tube fittings are available with NPT (National Pipe Taper), BSP (British Standard Pipe), BSPT (British Standard Pipe Taper), UNF (Unified Fine), ISO, and SAE thread forms, allowing use in North American, European, and Asian piping systems.

Q: What is the difference between SS 304 and SS 316 union tube fittings?

SS 304 union tube fittings offer excellent general-purpose corrosion resistance for most non-chloride environments. SS 316 contains 2–3% molybdenum, providing superior resistance to chlorides, marine environments, acidic media, and higher pitting resistance. SS 316 is preferred in offshore, chemical, and food-grade applications where SS 304 may suffer pitting or crevice corrosion.

Q: What industries use union tube fittings?

Union tube fittings are widely used in oil and gas (wellhead instrumentation, analyzer systems), chemical and petrochemical process lines, power generation, semiconductor manufacturing (ultra-high purity), food and beverage (hygienic SS 316), shipbuilding, and hydraulic systems. Their re-makeable design is especially valued wherever lines need regular maintenance or inspection.

Q: What is the difference between a single-ferrule and double-ferrule union tube fitting?

A single-ferrule design uses one ferrule that both grips and seals the tube — simpler but less suitable for hard tubing or vibration. A double-ferrule design uses a front ferrule (sealing) and a back ferrule (gripping), providing superior pull-out resistance, vibration resistance, and leak-tightness. TES-LOK double-ferrule unions are the industry standard for instrumentation-grade applications.

TES-LOK brand | SS 304 / SS 316 / Brass / Special Alloys | 6000 PSI Rated | ISO 9001:2015

1/16"–2" OD & 2–50 mm OD NPT · BSP · BSPT · UNF · ISO · SAE 150–400 °C ASTM D1710 / D3294

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SS 304 SS 316 Brass Special Alloys NPT BSP BSPT UNF ISO SAE 6000 PSI Double Ferrule

TES-LOK Union Tube Fittings — SS 304, SS 316, Brass

What is a Union Tube Fitting?

A union tube fitting is a compression-type instrument fitting that creates a secure, leak-tight, and re-makeable connection between two lengths of tubing. Unlike permanent butt-weld joints, a union allows the line to be fully disconnected and reconnected without cutting the tube — an essential feature for instrumentation loops, analyzer sampling systems, and process lines that require periodic maintenance or re-routing.

Tesco Steel manufactures union tube fittings under the TES-LOK brand using a precision double-ferrule design: a front (sealing) ferrule and a back (gripping) ferrule are progressively loaded by the nut, delivering simultaneous gripping force and a metal-to-metal seal at the fitting body seat. TES-LOK unions are dimensionally compatible with Swagelok, Parker A-LOK, Ham-Let, and similar premium brands, enabling direct drop-in replacement.

Specifications

TES-LOK Union Tube Fitting — Technical Data
Brand	TES-LOK (Tesco Steel & Engineering)
Fractional Sizes	1/16" OD to 2" OD
Metric Sizes	2 mm OD to 50 mm OD
Material Grades	SS 304 (1.4301), SS 316 (1.4401), Brass, Monel 400, Inconel 600, Hastelloy C-276, Titanium Gr. 2
Thread Standards	NPT (ANSI/ASME B1.20.1), BSP (ISO 228), BSPT (ISO 7), UNF (ANSI/ASME B1.1), ISO, SAE
Pressure Rating — SS	Up to 6000 PSI (413 bar)
Pressure Rating — Brass	300 PSI / 1000 PSI / 3000 PSI (size-dependent)
Temperature Range	150 °C to 400 °C (material and seal dependent)
Standards	ASTM D1710, ASTM D3294
Design	Double-ferrule compression (front ferrule + back ferrule)
Surface Finish	Electropolished / Passivated / As-machined
Certifications	ISO 9001:2015, NABL-traceable material test reports available

Why Choose TES-LOK Union Tube Fittings?

Re-makeable Design

Full disconnection and reconnection without cutting tubing — critical for instrumentation loops requiring regular maintenance.

Leak-Tight Seal

Double-ferrule progressive action creates a metal-to-metal seat seal — rated to 6000 PSI with zero leak tolerance.

Brand Compatible

Dimensionally interchangeable with Swagelok, Parker A-LOK, and Ham-Let — drop-in replacement with no line modification.

Corrosion Resistance

SS 316 with molybdenum addition resists chlorides, acids, and marine environments. Alloy options for H₂S and aggressive media.

Wide Material Range

SS 304, SS 316, Brass for standard service; Monel, Inconel, Hastelloy for corrosive and high-temp specialty applications.

Global Thread Variants

NPT for North American systems, BSP/BSPT for European and Middle East installations, SAE/ISO for hydraulic systems.

Thread Standard Reference

Thread Type	Standard	Seal Type	Primary Market
NPT	ANSI/ASME B1.20.1	Tapered thread seal (PTFE tape)	North America, India
BSP (BSPP)	ISO 228	Parallel thread + face seal / bonded washer	Europe, UK, Middle East
BSPT	ISO 7	Tapered thread seal	UK, Asia-Pacific
UNF	ANSI/ASME B1.1	O-ring or face seal	North America (hydraulic)
ISO	ISO 228-1	Parallel, face or O-ring	International / Europe
SAE	SAE J514	37° flare or O-ring boss	Hydraulic / automotive

Union Fitting Family

Fitting Type	Function	Typical Use
Union (Straight)	Inline connection / disconnection of two equal-diameter tubes	Instrumentation, process lines
Union Elbow	90° directional change with union disconnection at the turn	Panel instrument connections
Union Tee	T-branch with union ends on all three ports	Sampling loops, distribution
Union Cross	Four-way junction with union connections	Complex manifold headers
Bulkhead Union	Feed-through panel union for enclosure or panel mounting	Analyzer shelters, junction boxes
Reducing Union	Inline connection between two different tube ODs	Size transitions, gauge connections
Socket Weld Union	Weld-end connection with union nut for disconnection	High-pressure permanent + serviceable lines
AN Union Connector	Aerospace / AN-standard union connector	Aviation, defence, motorsport

Industries Served

Industry	Application	Preferred Material
Oil & Gas	Wellhead instrumentation, analyzer sample conditioning, flow measurement	SS 316, Monel, Inconel
Chemical & Petrochemical	Corrosive fluid instrumentation, pH / conductivity probe lines	SS 316L, Hastelloy C-276
Power Generation	Boiler instrument lines, condensate sampling, cooling water monitoring	SS 316, Carbon Steel
Semiconductor	Ultra-high purity gas distribution, process chemical delivery	SS 316L EP (electropolished)
Food & Beverage	Hygienic process instrumentation, CIP/SIP sampling lines	SS 316L (3-A / EHEDG)
Shipbuilding & Offshore	Hydraulic control lines, deck instrument panels, ballast monitoring	SS 316, Cupro-Nickel

Frequently Asked Questions

What is a union tube fitting?

A union tube fitting is a compression-type fitting that creates a leak-tight, re-makeable joint between two tube ends. It consists of a body, front ferrule, back ferrule, and nut. Tightening the nut progressively loads both ferrules to grip the tube OD and seal against the body seat. Unions allow full disconnection and reconnection without cutting the tube — essential for instrumentation and process lines requiring periodic maintenance.

What brand of union tube fitting does Tesco Steel manufacture?

Tesco Steel manufactures union tube fittings under the TES-LOK brand. TES-LOK fittings are designed to be compatible in form, fit, and function with major brands including Swagelok, Parker A-LOK, and Ham-Let, and are produced to ASTM D1710 and ASTM D3294 standards. All fittings carry ISO 9001:2015 certification with full material traceability.

What sizes are available for TES-LOK union tube fittings?

TES-LOK union tube fittings are available in fractional sizes from 1/16" OD to 2" OD and metric sizes from 2 mm OD to 50 mm OD, covering the complete range of instrumentation and process tubing used in industrial applications.

What thread standards are supported by TES-LOK unions?

TES-LOK union tube fittings are available with NPT (ANSI/ASME B1.20.1), BSP (ISO 228), BSPT (ISO 7), UNF (ANSI/ASME B1.1), ISO, and SAE thread forms — enabling compatibility with North American, European, Middle Eastern, and Asian piping systems.

What is the pressure rating of stainless steel union tube fittings?

SS 304 and SS 316 TES-LOK union tube fittings are rated up to 6000 PSI (413 bar), suitable for high-pressure instrumentation and hydraulic lines. Brass union tube fittings are available in 300 PSI, 1000 PSI, and 3000 PSI ratings depending on tube size. Actual working pressure depends on tube OD, wall thickness, and temperature.

What is the difference between SS 304 and SS 316 union tube fittings?

SS 304 offers excellent general-purpose corrosion resistance for most non-chloride environments at lower cost. SS 316 contains 2–3% molybdenum, providing superior resistance to chlorides, marine environments, acidic media, and significantly better pitting and crevice corrosion resistance. SS 316 is the standard choice for offshore, chemical, and food-grade applications where SS 304 would be susceptible to localised corrosion.

What industries use union tube fittings?

Union tube fittings are essential in oil & gas (wellhead instrumentation, analyzer systems), chemical & petrochemical process lines, power generation (boiler monitoring, condensate sampling), semiconductor manufacturing (ultra-high purity gas delivery), food & beverage (hygienic sampling loops), and shipbuilding & offshore hydraulic panels. Their re-makeable design is especially valued wherever lines need regular maintenance or instrument calibration.

What is the difference between a single-ferrule and double-ferrule union tube fitting?

A single-ferrule design uses one ferrule that both grips and seals the tube — simpler and lower cost, but less suited to vibrating environments or hard tubing materials. A double-ferrule design (as used in TES-LOK) uses a front ferrule for sealing and a back ferrule for gripping, delivering superior pull-out resistance, vibration fatigue resistance, and reliable high-pressure leak-tightness. Double-ferrule is the preferred design for instrumentation-grade, oil and gas, and high-pressure applications.

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ISO 9001:2015 certified | 6000 PSI rated | SS 304 · SS 316 · Brass · Special Alloys | Fast global shipment

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'SHAPING INDUSTRIES WITH THE FINEST STEEL'

Union Tube Fitting Manufacturer & Exporter — India

What is a Union Tube Fitting?

Specifications

Why Choose TES-LOK Union Tube Fittings?

Re-makeable Design

Leak-Tight Seal

Brand Compatible

Corrosion Resistance

Wide Material Range

Global Thread Variants

Thread Standard Reference

Union Fitting Family

Industries Served

Frequently Asked Questions

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