In process plants, refineries, offshore platforms, and analytical laboratories, reliable tube fittings are essential for maintaining leak-free connections and safe fluid transfer. Kalpataru Piping Solution is a stainless steel tube fittings manufacturer and exporter in India, offering a wide range of ferrule compression fittings, instrumentation fittings, and high-pressure hydraulic tube fittings manufactured from premium stainless steel grades, including SS 304, 304L, 316, 316L, 316Ti, 317L, 321, 347H, 310S, and 904L.
Our stainless steel tube fittings are manufactured to meet applicable ASTM A276, ASTM A479, and ASME SA276 material requirements. Available in single-ferrule and double-ferrule configurations from 1/16″ to 2″ OD (2 mm to 50 mm), these fittings support pressure ratings from 3,000 PSI to 20,000 PSI, depending on the fitting design and material grade. End connection options include NPT, BSP, SAE, AN, ISO, and weld types. Kalpataru Piping Solution provides tube fittings designed for secure, leak-resistant connections and reliable performance in demanding industrial applications. Material test certificates conforming to EN 10204 3.1 and dimensional inspection records are available as applicable.
What Are Stainless Steel Tube Fittings?
Stainless steel tube fittings are precision-machined mechanical connectors used to join, branch, terminate, or redirect stainless steel tubing in fluid and gas systems. Unlike pipe fittings that rely on cut threads for sealing, tube fittings create a seal through a mechanical clamping action — either via ferrules (the compression principle) or push-to-connect mechanisms — eliminating the need for welding or thread sealants in many applications and enabling fast, repeatable assembly and disassembly.
The two dominant connection technologies in the instrumentation and process industry are:
- Double-Ferrule (Twin-Ferrule) Compression Fittings — A front ferrule and back ferrule compress against the tube OD when the nut is tightened, creating a gas-tight, vibration-resistant seal. This is the Swagelok® / Parker A-LOK® principle, and Kalpataru’s double-ferrule SS tube fittings are fully interchangeable with both brands.
- Single-Ferrule (Push-Lock / Bite-Type) Fittings — A single ferrule bites into the tube OD. Simpler assembly but slightly lower vibration resistance. Widely used in pneumatic and low-to-medium pressure hydraulic systems.
Kalpataru Piping Solution manufactures both types across the full range of stainless steel grades and sizes. Our fittings are machined from hexagonal bar stock per ASTM A276/A479 on high-speed CNC Swiss-type automatic lathes, delivering consistent wall thickness and thread quality across every batch.
Explore our complete tube fittings range: Tube Fittings | Titanium Tube Fittings | Inconel Tube Fittings | Monel Tube Fittings | Copper Nickel Tube Fittings | Duplex Steel Tube Fittings | Hastelloy Tube Fittings
Stainless Steel Grades & Material Data
Kalpataru Piping Solution stocks and manufactures stainless steel tube fittings in all major austenitic grades. Each grade is selected for specific corrosion, temperature, and strength requirements. Bar stock is sourced from certified mills with EN 10204 3.1 MTCs, and every heat is PMI-verified before machining.
For grade-specific listings, explore our dedicated pages:
Technical Data
Stainless Steel Tube Fittings Technical Specifications
| Fitting Type | Double-Ferrule (Twin-Ferrule), Single-Ferrule, Push-Lock, Weld-End |
| Tube OD Range | 1/16″ to 2″ (imperial); 2 mm to 50 mm (metric) |
| Material | SS 304, 304L, 316, 316L, 316Ti, 317L, 321, 347, 347H, 310S, 904L |
| Body Form | Machined from hex barstock per ASTM A276 / ASTM A479 / ASME SA276 |
| Pressure Ratings | Low: up to 11,000 PSI (757 bar) \ Medium: up to 20,000 PSI (1,378 bar) \ High: up to 60,000 PSI (4,134 bar) |
| Temperature Rating | 150°C to 537°C (depending on grade and seat material) |
| Applicable Standards | ASTM A276/A479, ASME SA276/SA479, ASME A182/SA182 |
| Thread Standards | NPT (ASME B1.20.1, MILL-P-71058), BSPP (BS 2779, ISO 228), BSPT (BS 21, ISO 7), SAE/AN (ASME B1.1) |
| End Connection Types | Tube-to-tube, tube-to-male, tube-to-female, weld end, bulkhead, port connector |
| Configurations | Straights, elbows, tees, crosses, caps, plugs, nuts, ferrules, adapters, reducers |
| Testing & Certification | ECE R110, EC-79, NACE MR0175/ISO 15156, MR0103 |
| Equivalent Brands | Swagelok®, Parker A-LOK®, DK-LOK, Ham-Let, Gyrolok, Tylok, Bilok, Duolok |
Seamless Tube Fittings Specifications
| Specification | Value |
| Size Range | 1/8″ to 2″ OD |
| Pressure Rating | 3,000 PSI to 10,000 PSI |
| Threads | NPT, BSPT, BSPP |
| Connection | Compression (double ferrule) |
High-Pressure Stainless Steel Tube Fittings
| Specification | Value |
| Pressure Rating | Up to 60,000 PSI (4,134 bar) |
| Temperature Rating | Up to 537°C (1,000°F) |
| Materials | SS 316 Stainless Steel, Alloy 2507, Inconel 625 |
| Applications | Hydraulic testing, CNG/HPNG gas, deepwater, laboratory high-pressure rigs |
Grade Cross-Reference & Equivalents
| ASTM Grade | UNS | Werkstoff Nr. | AFNOR | EN / DIN | JIS | BS | GOST |
| SS 304 | S30400 | 1.4301 | Z7CN18-09 | X5CrNi18-10 | SUS 304 | 304S31 | 08X18H10 |
| SS 304L | S30403 | 1.4306/1.4307 | X2CrNi18-9 | Z3CN18-10 | SUS 304L | 304S11 | 03X18H11 |
| SS 316 | S31600 | 1.4401 | Z7CND17-11-02 | X5CrNiMo17-12-2 | SUS 316 | 316S31 | 08X17H13M2 |
| SS 316L | S31603 | 1.4404 | Z3CND17-11-02 | X2CrNiMo17-12-2 | SUS 316L | 316S11 | 03X17H14M2 |
| SS 316Ti | S31635 | 1.4571 | Z6CNDT17-12 | X6CrNiMoTi17-12-2 | SUS 316Ti | 320S31 | 08X17H13M2T |
| SS 317L | S31703 | 1.4438 | Z3CND19-14-04 | X2CrNiMo19-14 | SUS 317L | — | — |
| SS 321 | S32100 | 1.4541 | Z6CNT18-10 | X6CrNiTi18-10 | SUS 321 | 321S31 | 08X18H10T |
| SS 321H | S32109 | 1.4878 | — | X10CrNiTi18-10 | — | — | — |
| SS 347 | S34700 | 1.4550 | Z6CNNb18-10 | X6CrNiNb18-10 | SUS 347 | 347S31 | 08X18H12B |
| SS 347H | S34709 | 1.4961 | — | X8CrNiNb16-13 | — | — | — |
| SS 310S | S31008 | 1.4845 | Z12CN25-20 | X8CrNi25-21 | SUS 310S | 310S24 | 12X25H20 |
| SS 904L | N08904 | 1.4539 | Z2NCDU25-20 | X1NiCrMoCu25-20-5 | SUS 890L | — | — |
Stainless Steel Tube Fittings Chemical Composition
| Grade | C max | Cr | Ni | Mo | Other |
| SS 304 | 0.08 | 18–20 | 8–12 | — | — |
| SS 304L | 0.03 | 18–20 | 8–13 | — | — |
| SS 316 | 0.08 | 16–18 | 10–14 | 2.0–3.0 | — |
| SS 316L | 0.03 | 16–18 | 10–14 | 2.0–3.0 | — |
| SS 317L | 0.03 | 18–20 | 11–15 | 3.0–4.0 | — |
| SS 321 | 0.08 | 17–19 | 9–12 | — | Ti ≥ 5×C |
| SS 347 | 0.08 | 17–19 | 9–13 | — | Nb ≥ 10×C |
| SS 310S | 0.08 | 24–26 | 19–22 | — | — |
| SS 904L | 0.02 | 19–23 | 23–28 | 4.0–5.0 | Cu 1.0–2.0 |
Stainless Steel Tube Fittings Mechanical Properties
| Grade | UTS MPa (min) | YS MPa (min) | Elongation % min | Hardness HRB max | Heat Treatment |
| SS 304 | 515 | 205 | 35 | 90 | Solution anneal 1000–1100°C, cool rapidly |
| SS 304L | 485 | 170 | 35 | 90 | Solution anneal 1000–1100°C, cool rapidly |
| SS 316 | 515 | 205 | 35 | 90 | Solution anneal 1000–1100°C, cool rapidly |
| SS 316L | 485 | 170 | 35 | 90 | Solution anneal 1000–1100°C, cool rapidly |
| SS 317L | 515 | 205 | 35 | 96 | Solution anneal 1010–1121°C, cool rapidly |
| SS 321 | 515 | 205 | 40 | 95 | Solution anneal 950–1120°C, cool rapidly |
| SS 347 | 515 | 205 | 40 | 95 | Solution anneal 950–1120°C, cool rapidly |
| SS 310S | 515 | 205 | 40 | 95 | Solution anneal 1040–1150°C, cool rapidly |
Alloy 20 Ball Valves Equivalent Grades
| UNS | Werkstoff | AFNOR | EN | Common Names |
| N08020 | 2.4660 | Z2NCUD31-20AZ | NiCr20CuMo | Carpenter 20, Alloy 20, CN7M (cast), F20 |
Check the chemistry limits against the specific product standard on your purchase order (ASTM B462 / B473 for forgings and bar, ASTM A351 CN7M for castings). Values vary slightly by form.
NPT/ISO Pressure Ratings (per ASME B31.3 — Ambient Temperature)
| NPT/ISO Pipe Size | Male PSIG (Bar) | Female PSIG (Bar) |
| 1/16 | 11,000 (757) | 6,700 (461) |
| 1/8 | 10,000 (689) | 6,500 (447) |
| 1/4 | 8,000 (551) | 6,600 (454) |
| 3/8 | 7,800 (537) | 5,300 (365) |
| 1/2 | 7,700 (530) | 4,900 (337) |
| 3/4 | 7,300 (502) | 4,600 (316) |
| 1 | 5,300 (365) | 4,400 (303) |
| 1-1/4 | 6,000 (413) | 5,000 (344) |
| 1-1/2 | 5,000 (344) | 4,600 (316) |
| 2 | 3,900 (268) | 3,900 (268) |
Push-Lock Mechanical Properties
| Property | Value |
| Density | 8.0 g/cm³ |
| Melting Point | 1,400°C (2,550°F) |
| Tensile Strength | Psi ~75,000 (MPa ~515) |
| Yield Strength (0.2%) | Psi ~30,000 (MPa ~205) |
| Elongation | 40% |
Stainless Steel Tube Fittings — Dimensions & Size Range
Standard OD Sizes & Thread Designation
OD (Fraction Inch) | OD Actual (Inches) | Thread Designation – Nominal Size (Inches) | Threads per Inch NPT | Threads per Inch BSP |
5/16 | 0.3125 | 1/16 | 27 | 28 |
13/32 | 0.405 | 1/8 | 27 | 28 |
35/64 | 0.540 | 1/4 | 18 | 19 |
43/64 | 0.675 | 3/8 | 18 | 19 |
27/32 | 0.840 | 1/2 | 14 | 14 |
1-3/64 | 1.050 | 3/4 | 14 | 14 |
1-5/16 | 1.315 | 1 | 11-1/2 | 11 |
1-21/32 | 1.660 | 1-1/4 | 11-1/2 | 11 |
1-29/32 | 1.900 | 1-1/2 | 11-1/2 | 11 |
2-3/8 | 2.375 | 2 | 8 | 11 |
2-7/8 | 2.875 | 2-1/2 | 8 | 11 |
3-1/2 | 3.5 | 3 | 8 | 11 |
4 | 4.0 | 3-1/2 | 8 | 11 |
4-1/2 | 4.5 | 4 | 8 | 11 |
5-5/8 | 5.563 | 5 | 8 | 11 |
6-5/8 | 6.625 | 6 | 8 | 11 |
Metric Size Range
Tube OD (mm) | Nominal Pipe Thread (BSP) |
2 mm | 1/16″ BSP |
4 mm | 1/8″ BSP |
6 mm | 1/4″ BSP |
8 mm | 1/4″ BSP |
10 mm | 3/8″ BSP |
12 mm | 3/8″ BSP |
14 mm | 1/2″ BSP |
16 mm | 1/2″ BSP |
18 mm | 3/4″ BSP |
22 mm | 3/4″ BSP |
25 mm | 1″ BSP |
28 mm | 1″ BSP |
32 mm | 1-1/4″ BSP |
38 mm | 1-1/2″ BSP |
50 mm | 2″ BSP |
Standard Configurations Supplied
Connection Category | Fittings Available |
Tube-to-Tube | Union, Elbow, Tee, Cross, Reducing Union, Bulkhead Union, Cap, Reducer |
Tube-to-Male Thread | Male Connector, Male Elbow (90°, 45°), Male Tee, Male Bulkhead, Male Run Tee, Male Branch Tee |
Tube-to-Female Thread | Female Connector, Female Elbow, Female Tee, Female Bulkhead, Female Adapter |
Weld End | Tube Socket Weld Union, Pipe Weld Connector, Weld Elbow |
Accessories | Front Ferrule, Back Ferrule, Nut, Hex Plug, Allen Key Plug, Hex Nipple, Hex Bushing |
Stainless Steel Tube Fittings Applications & Industries
Kalpataru Piping Solution’s stainless steel tube fittings are trusted in every major process, utility, and analytical industry. The combination of corrosion resistance, high-pressure capability, and Swagelok-equivalent interchangeability makes them the standard choice for instrument engineers and procurement teams worldwide.Industry Application Table
| Industry | Typical Application | Why SS Tube Fittings? |
| Oil & Gas (Onshore & Offshore) | Instrument impulse lines, gauge isolation, sample cylinders, HP hydraulic control | Corrosion resistance, high-pressure ratings, vibration resistance; NACE MR0175 compliant |
| Petrochemicals & Refineries | Analyser sample systems, process taps, heat exchanger instrument connections | High-temp service (SS 321/347H); leak-free seal in explosive atmospheres |
| Natural Gas & LNG | CNG dispenser systems, gas analyser connections, HPNG flow control | 10,000–20,000 PSI ratings; ECE R110 / EC-79 compliance |
| Power Generation | Steam line instrumentation, feedwater sampling, condenser connections | SS 321/347H for high-temperature creep resistance |
| Chemical Processing | Acid, alkali, and solvent line instrumentation; sample systems | SS 316L or 317L resists pitting and chloride attack |
| Pharmaceutical & Biotech | CIP/SIP instrument connections, sterile sampling, process gas lines | Crevice-free interior; electropolishable; biocompatible SS 316L |
| Food & Beverage | High-purity ingredient metering, carbonation gas lines, CIP connections | Smooth bore; SS 316L; no contamination of food-contact streams |
| Hydraulic Systems | Mobile hydraulic machines, presses, test benches, heavy equipment | Vibration-resistant two-ferrule seal; up to 60,000 PSI high-pressure series |
| Marine & Offshore | Ship instrumentation, ballast water treatment, seawater cooling instrument lines | SS 316L corrosion-resistant to seawater; NACE compliant |
| HVAC & Refrigeration | Refrigerant instrument lines, chiller pressure gauges, high-side/low-side monitoring | Leak-tight; wide temperature range; compact fittings for confined plant rooms |
Types of Stainless Steel Tube Fittings
Kalpataru Piping Solution manufactures a comprehensive range of stainless steel tube fitting configurations. All types are available in every listed SS grade and in both imperial (OD inch) and metric (OD mm) sizing.
Tube-to-Tube Connection Fittings
| Fitting Type | Description | Common Use |
|---|---|---|
| Union (Straight) | Joins two same-OD tubes end-to-end; fully removable | General instrument line connection |
| Union Elbow | 90° direction change, tube-to-tube | Panel routing, confined-space bends |
| Union Tee | Branch off a straight run; all three ports tube ends | Three-way flow splitting |
| Union Cross | Four-way fitting, all tube ends | Complex manifold headers |
| Reducing Union | Joins two different-OD tubes | Flow reduction, line downsizing |
| Bulkhead Union | Passes through a panel or bulkhead; hex on body for panel lock | Control panel wall penetration |
| Tube Cap / End Closure | Seals an open tube end | System pressure testing, dead-leg sealing |
Tube-to-Male Thread Fittings
| Fitting Type | Description |
|---|---|
| Male Connector | Tube compression one end, male NPT/BSP thread other end |
| Male Elbow | 90° turn — tube compression + male thread |
| 45° Male Elbow | 45° turn — tube compression + male thread |
| Positionable Male Elbow | Swivel male elbow for adjustable orientation |
| Male Run Tee | Straight-through male thread in the run; tube branch |
| Male Branch Tee | Male thread branch; tube-to-tube run |
| Male Bulkhead Connector | Through-panel fitting with male external thread |
Tube-to-Female Thread Fittings
| Fitting Type | Description |
|---|---|
| Female Connector | Tube compression one end, female NPT/BSP thread other end |
| Female Elbow | 90° turn — tube compression + female thread |
| Female Run Tee | Female thread in the run; tube branch |
| Female Branch Tee | Female thread branch; tube-to-tube run |
| Female Adapter | Tube end + female thread, used as port adapter |
| Bulkhead Female Connector | Through-panel fitting with female internal thread |
Accessories
| Item | Description |
|---|---|
| Front Ferrule (Cutting Ring) | First ferrule — bites into tube OD to create primary seal |
| Back Ferrule (Pressure Ring) | Second ferrule — provides axial compression force |
| Nut | Drives ferrules during tightening; hex for tool access |
| Blanking Plug | Hex plug to seal unused ports |
| Allen Key Plug | Low-profile socket-head plug for recessed port sealing |
| Hex Nipple | Male-to-male nipple for extending threaded connections |
| Hex Bushing | Reducing adapter — large female to small male thread |
Speciality & High-Pressure Configurations
| Type | Description |
|---|---|
| Positionable Male Run Tee | Swivel run tee for alignment-free installation |
| Reducing Union Tee | All three ports different ODs |
| Union Joint Ball | Swivel joint for rotating lines |
| High-Pressure (20,000 PSI) Fitting | Forged single-ferrule or cone-and-thread for HPNG/hydraulic testing |
Related Products — Complete Your Instrument Loop
- Stainless Steel Needle Valve — instrument isolation
- Stainless Steel Manifold Valves — 2-valve, 3-valve, 5-valve manifolds
- Stainless Steel Ball Valves — process isolation
- Stainless Steel Pipe Fittings — weld fittings for process piping
- Stainless Steel Flanges — flange connections for main process lines
- Check Valves — non-return valves for sampling and dosing lines
Manufacturing Excellence & Quality Assurance
Kalpataru Piping Solution operates a precision CNC machining facility dedicated to tube fitting manufacture. Our process is designed to deliver dimensional consistency, material authenticity, and sealing performance that matches or surpasses the equivalent imported brands.
Manufacturing Process
Step 1 — Raw Material & PMI Hex barstock (per ASTM A276/A479) and round barstock are sourced from certified Indian and European mills. Each heat arrives with EN 10204 3.1 material test certificates. PMI (XRF) testing is performed on every heat lot before machining begins.
Step 2 — CNC Swiss-Type Automatic Turning Fitting bodies, nuts, front and back ferrules are machined on Swiss-type CNC automatic lathes. These machines produce the close dimensional tolerances — particularly on ferrule ID, fitting body bore, and thread form — that determine sealing reliability. Tolerances are held to ±0.005 mm on critical dimensions.
Step 3 — Thread Cutting & Gauging NPT, BSPP, BSPT, and SAE threads are cut with precision form tools and 100% gauged using calibrated Go/No-Go thread gauges traceable to NABL-accredited references. Every nut undergoes cross-hole drilling if applicable.
Step 4 — Silver Coating of Nut Threads Nut internal threads are silver-coated to the required film thickness to prevent galling during make-up and allow repeated assembly/disassembly without thread damage.
Step 5 — Passivation All machined components undergo citric acid passivation per ASTM A967 to remove free iron from surfaces and strengthen the natural chromium oxide passive film, enhancing corrosion resistance.
Step 6 — Dimensional & Visual Inspection Full first-article inspection per applicable ASME/ASTM standards. Critical dimensions checked on CMM. Visual inspection per MSS SP-55. Lot-by-lot sampling inspection in production.
Step 7 — Pressure / Leak Testing Production samples from each lot are hydrostatically or pneumatically tested to rated pressure per API 598 / BS EN 12266-1. Test certificates issued for each tested lot.
Step 8 — Marking & Packaging Each fitting is stamped or laser-marked with: material grade, heat number, and manufacturer’s mark. Fittings are individually polypropylene-bagged, bulk-packed in cartons (21″×16″×14CM or 31″×21″×16CM or 36″×45″×50CM), and export-packed in wooden cases with HS code, COO, and barcode labelling.
Explore Related Products:
- Tube Fittings — all alloys
- SS 304 Tube Fittings
- SS 316 Tube Fittings
- SS 316L Tube Fittings
- SS 317L Tube Fittings
- SS 321 Tube Fittings
- SS 347H Tube Fittings
- SS 904L Tube Fittings
- SS 310/310S Tube Fittings
- Inconel Tube Fittings
- Monel Tube Fittings
- Duplex Steel Tube Fittings
- Nickel Alloy Tube Fittings
- Brass Tube Fittings
- DIN 2353 Bite-LOK Tube Fittings
- 37° Flare Tube Fittings
- Ermeto Fittings
Frequently Asked Questions (FAQs)
Stainless steel tube fittings are mechanical connectors that join stainless steel tubing by compressing one or two ferrules against the tube OD as the nut is tightened. The front ferrule cuts into the tube surface to create a gas-tight primary seal; the back ferrule provides axial load and resiliency for repeated make-up. No solder, thread sealant, or welding is required, making them ideal for instrumentation and process systems requiring frequent disassembly.
Yes. Kalpataru’s double-ferrule stainless steel tube fittings are fully interchangeable with Swagelok® and Parker A-LOK® fittings in the same size and thread configuration. The same tube preparation (deburring, squaring) and make-up procedure applies.
We supply SS tube fittings in NPT (ASME B1.20.1), BSPP (ISO 228 / BS 2779), BSPT (BS 21 / ISO 7), SAE / AN (ASME B1.1), JIC, and metric thread forms. Custom threads available on request.
Yes. SS 316L stainless steel tube fittings are available with NACE MR0175/ISO 15156 and NACE MR0103 compliance for use in sour gas and sour crude service environments. Hardness verification and NACE MTR documentation are provided.
Every order ships with: EN 10204 3.1 Material Test Certificate (MTC), dimensional inspection report, pressure test certificate, PMI (XRF) test records, and packing list. EN 10204 3.2 (third-party certified MTC) is available on request from BV, SGS, TÜV, or Lloyd’s Register.
Get a Quote — Stainless Steel Tube Fittings
- Direct CNC Manufacturer — No trader margin. Factory-direct pricing on every order, large or small
- Swagelok / Parker / DK-LOK Equivalent — Drop-in replacement with full dimensional interchangeability
- Full Grade Range — SS 304 through 904L in stock; special grades and alloys on request
- Full Traceability — EN 10204 3.1 MTC, PMI records, pressure test reports, dimensional inspection — all standard
- ISO 9001:2015 Certified — Consistent quality, documented processes, regular third-party audits
- OEM & EPC Ready — Vendor approval documentation, data books, and bulk blanket order support
- NACE / Sour Service — MR0175/ISO 15156 and MR0103 compliance documentation available
- Fast Lead Time — Stock items ship within days; standard production 2–4 weeks
- Export Packaging — Wooden cases, HS code, COO, barcoding — hassle-free customs clearance in 50+ countries
Have Any Questions ?
Please feel free to contact us. We will get back to you with 2 business days. Or just call us now.