Back Ferrule (if dual ferrule design): Component Specs, Materials & Applications

Component Specifications

Definition

The back ferrule is the rear component in a dual-ferrule compression fitting system, typically used in industrial fluid and gas applications. When the fitting nut is tightened, it drives the front ferrule forward while compressing the back ferrule against the tubing. This creates a secondary mechanical grip and seal that prevents vibration-induced loosening and ensures long-term reliability. The back ferrule's design allows for controlled deformation that maintains seal integrity even under thermal cycling and pressure fluctuations.

Working Principle

The back ferrule operates on mechanical compression principles. When the fitting assembly is tightened, the back ferrule is compressed radially against the tubing outer diameter, creating a strong mechanical grip. Simultaneously, it pushes against the front ferrule, forcing it to bite into the tubing and form the primary seal. This dual-action provides both secure holding force and redundant sealing capability.

Materials

Typically manufactured from corrosion-resistant materials: 316 stainless steel (most common), brass, carbon steel, or specialty alloys like Monel or Hastelloy for corrosive environments. Hardness typically ranges from 80-90 HRB for optimal deformation characteristics.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Surface Finish	16-32 μin Ra (0.4-0.8 μm Ra)
Pressure Rating	Up to 10,000 psi (690 bar)
Tubing OD Range	1/8" to 2" (3mm to 50mm)
Temperature Range	-65°F to 450°F (-54°C to 232°C)
Concentricity Tolerance	±0.002" (±0.05mm)

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards

ISO 8434-1, DIN 2353, SAE J514

Parent Products

This component is used in the following industrial products

Compression Fitting

A mechanical fitting that creates a leak-tight seal by compressing a ferrule or sleeve onto a tube or pipe when tightened.

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Engineering Analysis

Risks & Mitigation

Improper installation causing leaks
Material incompatibility with fluid
Vibration-induced fatigue failure
Over-torquing leading to component damage

FMEA Triads

Trigger: Incorrect installation torque
Failure: Incomplete seal formation or tubing damage
Mitigation: Use calibrated torque wrenches and follow manufacturer specifications

Trigger: Material fatigue from cyclic loading
Failure: Crack propagation and sudden seal failure
Mitigation: Implement regular inspection schedules and use fatigue-resistant materials

Trigger: Corrosion from incompatible fluids
Failure: Gradual material degradation and leak development
Mitigation: Select appropriate material grades for specific fluid compatibility

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

±0.0005" on critical dimensions, concentricity within 0.002" TIR

Test Method

Helium leak test per ASTM E493, pressure cycling test per ISO 19879, vibration test per MIL-STD-810

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

Verify equipment lists, process limits, capacity, and representative production evidence.

Inspection readiness

Confirm test methods, calibrated equipment, sampling plans, and traceable reports.

Supplier transparency

Check the legal entity, factory address, ownership, certifications, and direct contacts.

CNFX does not score or rank suppliers. Buyers must verify all claims and documents with the legal manufacturer before ordering.

Manufacturers of Back Ferrule (if dual ferrule design)

Manufacturer profiles associated with Back Ferrule (if dual ferrule design).

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Compiled and source-reviewed by the CNFX editorial team. Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review

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Frequently Asked Questions

What is the difference between front and back ferrules?

The front ferrule creates the primary seal by biting into the tubing, while the back ferrule provides mechanical grip and prevents vibration loosening. Both work together for reliable connections.

Can back ferrules be reused?

No, back ferrules should not be reused. Once compressed during installation, they undergo permanent deformation. Reuse can compromise seal integrity and cause leaks.

How do I identify a worn back ferrule?

Look for excessive deformation, cracks, or galling on the contact surfaces. Also check for improper seating marks or changes in the compression ring profile.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification

This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

Back Ferrule (if dual ferrule design)