Unilok® Tube Fitting & Valve Cross-Reference: Crestflo Interchange Equivalents in Stainless AND Exotic Alloys

Reviewed by the Crestflo Engineering Team

> Trademark & independence notice: "Unilok®" is a trademark of its respective owner. Crestflo is not affiliated with, authorized by, sponsored by, or endorsed by the owner of the Unilok mark. Every reference on this page is nominative, used only to identify the parts you already run so you can find the dimensionally equivalent Crestflo part. All claims are factual and dimensional. Crestflo supplies independently manufactured equivalents, not genuine Unilok products.

Crestflo manufactures dimensional equivalents to Unilok® instrumentation tube fittings and instrumentation valves, compression fittings whose interchange is qualified to ASTM F1387, with valves built to the applicable ASME B16.34 / API standards, in 316L stainless and exotic alloys including Hastelloy, Super Duplex, Inconel, and Monel, with 6–8 week delivery. Send us the Unilok part numbers you buy today and we return the interchange equivalent, the alloys it ships in, and a quote. Crestflo has already mapped 157 Unilok instrumentation tube-fitting part numbers to Crestflo equivalents, see the interchange table below.

Request your Unilok cross-reference & quote → · Send a part list, a print, or a sample, the Crestflo Engineering Team identifies the equivalent for you.

Scope: this cross-reference is for instrumentation twin-ferrule tube fittings and instrumentation valves in stainless steel and alloy, not hydraulic/JIC, plumbing compression, or electrical ferrules. Here "ferrule" means a fluid-system compression ferrule, "ball valve" and "needle valve" mean instrumentation valves, and "manifold" means a valve manifold.

What Unilok tube fittings and valves are

Unilok® tube fittings are instrumentation compression tube fittings that seal small-bore stainless and alloy tubing in analytical, process, and instrument-air lines, and Unilok also builds a matching family of instrumentation valves and regulators. A complete twin-ferrule fitting is a body, a nut, a front ferrule, and a back ferrule; pulling the nut up advances the ferrules onto the tube OD to make a gas-tight, mechanically gripped joint. Unilok is a Korean instrumentation fitting and valve brand, and its parts follow the standard imperial and metric size conventions used across the instrumentation category. Crestflo builds to the same ferrule geometry and the same size conventions, which is what makes a location-for-location swap possible.

Unilok part numbers follow a compact, letter-and-number ordering scheme, for example a male-connector series written as U1MC1, U2MC1, U1MC2, where the leading "U" denotes the brand, the digits denote tube-OD and thread sizes, and the letters denote the fitting type. Crestflo's own scheme substitutes its "C…" prefix and its size-and-type code, so U1MC1 interchanges to Crestflo CMC 1-1N, U2MC1 to CMC 2-1N, and U1MC2 to CMC 1-2N. The rest of the mapping, all 157 part numbers, is published in the interchange table on this page and in the cross-reference lookup tool.

Unilok designations this cross-reference also covers

Unilok buyers write the brand and the interchange in many forms, and every one of them points to the same Crestflo interchange.

Unilok interchange attributes: how the equivalent is defined

A cross-reference answers one question: for the Unilok part I buy today, what is the Crestflo part that dimensionally interchanges, and in which alloys? The 157-part mapping on this page resolves that for the tube-fitting range directly, and for anything outside the published list, Crestflo builds your cross-reference to order rather than guessing at a generic parts table. Every equivalent is verified against your exact series, size, and material so it stays accurate to your bill of materials.

Unilok-to-Crestflo interchange attribute set

Values per applicable standard; customizable to requirement. Per-part alloy and size confirmation is provided with your quote.

Unilok part number cross reference: how to request it

The 157-row interchange table below maps the core Unilok tube-fitting range part-for-part. For valves, specials, or any part number outside the published list, send us the Unilok part numbers, a line-card export, a drawing, or a physical sample. The Crestflo Engineering Team returns the interchange equivalent, the ferrule and connection parity notes, the available alloys, and a quote, no login, no gated tool.

Request your Unilok® cross-reference →

Unilok cross reference chart / PDF: what you get instead

Where competitors bury interchange data in gated tools or un-searchable PDFs, Crestflo publishes the mapping as a clean, verified, HTML-native table you can read on the page, and returns a document tied to your actual part list on request. Ask for it through the request-a-quote form or by emailing sales@crestflousa.com. You can also open the cross-reference lookup tool to search a part number directly.

Unilok product families cross-referenced: fittings, ferrules & valves

Crestflo equals the Unilok instrumentation catalog family for family, each with its own product line to link to.

The full valve range, 1/16" to 1", threaded or tube-fitting ends, sits under instrumentation valves.

Unilok equivalents in stainless AND exotic alloys: the Crestflo wedge

This is where Crestflo separates from stainless-only cross-references: the same dimensionally equivalent fitting is available not just in 316 SS but across exotic and corrosion-resistant alloys that a stock range does not lead with. Availability is by fitting type and alloy; per-part confirmation comes with your quote.

Alloy-availability matrix, Crestflo Unilok-equivalent fittings

✓ = available / made-to-order in that alloy. Ready stock for standard items · made-to-order for specials · 6–8 week delivery.

Unilok fitting in Hastelloy C-276

For wet-chlorine, sulfuric, and mixed-acid service, Crestflo equals the Unilok part in Hastelloy C-276 / C-22. These nickel-molybdenum-chromium alloys resist pitting, crevice attack, and stress-corrosion cracking where 316 stainless would fail. See Hastelloy C-276 tube fittings and the Hastelloy C-276 material page.

Unilok fitting in Super Duplex 2507 & Duplex 2205

For high-chloride and offshore seawater duty, the equivalent is available in Super Duplex 2507 and Duplex 2205. The duplex microstructure delivers roughly twice the yield strength of standard austenitic stainless with strong chloride stress-corrosion resistance. See Super Duplex 2507 tube fittings and the Duplex 2205 material page.

Unilok fitting in Inconel 625 / Inconel 825 & Monel 400

For high-temperature, sour-gas, and hydrofluoric service, Crestflo equals it in Inconel 625, Inconel 825, and Monel 400. These nickel alloys hold up where temperature, reducing acids, or HF exposure rule out stainless. See Inconel 625 tube fittings, Inconel 825 tube fittings, and Monel 400 tube fittings.

Unilok fitting in 254 SMO, Alloy 20 & 904L

For sulfuric-acid and high-chloride process lines, Crestflo also supplies the equivalent in 254 SMO, Alloy 20, and 904L, see the 254 SMO, Alloy 20, and 904L material pages. Default material is 316/316L, see the 316/316L material page.

Is Unilok interchangeable? Interchange vs. intermix

This is the question every specifying engineer should ask, and the honest answer earns trust:

• Interchange (correct): replace a complete Unilok fitting with a complete Crestflo fitting at the same location. Body, nut, and both ferrules are Crestflo. This is what "Unilok equivalent" and "drop-in replacement" mean here.
• Intermix (do not do this): mixing a Crestflo ferrule or nut with a Unilok body, or vice versa, inside a single joint. Twin-ferrule geometry and hardness are engineered as a set; mixing components across brands within one joint can compromise the seal and is not what "interchange" means.

Unilok and Swagelok are both instrumentation compression systems built to comparable dimensional envelopes, which is why buyers ask whether they interchange. The precise, safe answer is the same for every brand: use complete fittings of one brand as interchange equivalents; validate the specific part; and do not intermix components across brands within a joint. Crestflo publishes F1387-qualified equivalents for both, see the Swagelok cross-reference and the master interchange chart. For the geometry itself, see single vs double ferrule. For a feature-by-feature comparison, see Unilok vs Crestflo; for the switching case, Unilok alternative.

Why the interchange is proven: ASTM F1387 for fittings, ASME B16.34 / API for valves

The interchange claim is not a marketing assertion, it rests on published standards. Crestflo compression tube fittings are qualified to ASTM F1387, the performance qualification for mechanically attached (compression tube) fittings, covering the dimensional and performance behavior that is the basis for equivalence. Instrumentation valves are a different entity: they are built to the applicable ASME B16.34 and API 6D / 598 / 602 valve standards for the type, not to F1387 (which applies to fittings). That distinction is exactly the kind of documented rigor that separates a qualified equivalent from an uncontrolled marketplace "equivalent" with no proof or traceability.

Interchange-proof summary

Read more on the ASTM F1387 interchange qualification, the ASME B16.34 and NACE MR0175 standard pages, the EN 10204 MTC page, traceability, and testing & inspection.

How to request your Unilok cross-reference

1. Send your Unilok part numbers, a line-card export, a drawing, or a sample.
2. Tell us the alloy and size you need (or ask us to match what you run today).
3. We return the Crestflo equivalent, alloy availability, and quote, typically for delivery in 6–8 weeks.

Buyer paths: distributors → line-card / stocking program · equipment manufacturers → send a print for made-to-print interchange · OEMs → private-label program · end users, MRO & EPC → RFQ or sample. All routes start at the RFQ form.

RFQ form fields: Name · Company name · Email · Phone · Requirement description.

Request your Unilok® cross-reference & quote → · Request a sample · Or contact Crestflo: sales@crestflousa.com · +1 346 594 9005 · Houston, TX.

Why buyers switch to Crestflo

Crestflo is the alloy-aware, standards-backed alternative to Unilok, and the reasons buyers move are specific:

• Drop-in interchange, dimensionally equal and qualified to ASTM F1387, not a marketplace guess, with 157 Unilok tube-fitting part numbers already mapped on this page.
• Stainless AND exotic alloys, Hastelloy, Super Duplex, Inconel, Monel, 254 SMO, Alloy 20, a range a stock catalog does not lead with.
• 6–8 week delivery on made-to-order specials, versus the long lead times common on the majors.
• Cost-competitive even after US duties/tariffs, see the tariff cost advantage.
• Small MOQ and private-label / OEM programs, with a stated lead time.
• Heat/lot number on every part with EN 10204 3.1 MTC as standard.
• ISO 9001 / 14001 / 45001 & PED certified.

Crestflo is the instrumentation division of a four-decade, Government-of-India-recognized export house with a Middle-East delivery track record, established manufacturing heritage behind a focused US-serving instrumentation brand. Origin: Indian origin; US / European melt available on request, with full material traceability, see US-origin compliance. We Engineer Confidence.

Explore the underlying product line: Crestflo tube fittings, nut & ferrule sets, and instrumentation valves.

FAQ

Other brand tube-fitting cross-references

Not a Unilok user? Crestflo publishes interchange guides across the instrumentation category:

• Swagelok cross-reference
• Parker A-Lok cross-reference
• Hy-Lok cross-reference
• Fitok cross-reference
• DK-LOK cross-reference
• Hoke cross-reference · Gyrolok cross-reference
• All brand interchange guides · Master interchange chart

Related: Unilok alternative · Unilok vs Crestflo.

Unilok® is a trademark of its respective owner. Crestflo is not affiliated with, authorized by, or endorsed by the owner of the Unilok mark. All references are nominative and used only to identify equivalent parts. Crestflo supplies independently manufactured dimensional equivalents. Origin: Indian origin; US / European melt available on request, with full material traceability.