Stainless Steel Tube Fittings Supplier & Exporter in the UK — Precision Engineered Solutions by Mcneil Instruments

Introduction: Tube Fittings for Critical UK Industries

In the United Kingdom’s advanced industrial ecosystem — spanning oil and gas processing, offshore engineering, chemical and pharmaceutical production, power generation, water treatment, and manufacturing — precision components are vital to system performance. One such component is the tube fitting: a critical connector that ensures secure, leak-proof joins in fluid and gas systems.

Stainless steel tube fittings are specifically engineered to maintain integrity under high pressures, temperature variations, and corrosive conditions. They are widely used in instrumentation lines, process control systems, hydraulic circuits, offshore platforms, and industrial automation applications, where reliability and safety cannot be compromised.

As a trusted manufacturer, supplier, and exporter, Mcneil Instruments  delivers a comprehensive range of stainless steel tube fittings tailored to meet the exacting standards of the UK market, with compliance to international norms and full technical support for UK industrial projects.

What Are Stainless Steel Tube Fittings?

Tube fittings are mechanical connectors used to join tubing systems without welding. They feature precise manufacturing that allows:

  • Secure compression or ferrule sealing
  • High-pressure service
  • Repeated assembly and disassembly
  • Minimal leakage risk
  • Resistance to corrosion and temperature stress

In the UK, these fittings are commonly used for instrument tubing, sampling lines, pressure transmitters, process analyzers, and control systems. They also support stringent regulatory requirements in sectors such as chemical, pharmaceutical, and food processing.

Material Grades Supplied by Mcneil Instruments 

Mcneil Instruments  supplies stainless steel tube fittings in a broad selection of material grades to match the specific demands of UK industries:

Stainless Steel 304 Tube Fittings

  • General purpose grade
  • Excellent corrosion resistance in mild environments
  • Easy fabrication and formability

Stainless Steel 304L Tube Fittings

  • Low carbon variant of 304
  • Enhanced weldability and reduced sensitization
  • Ideal for fabricated assemblies

Stainless Steel 316 Tube Fittings

  • Contains molybdenum for improved chloride corrosion resistance
  • Widely used in chemical and marine applications

Stainless Steel 316L Tube Fittings

  • Low carbon variant optimized for welding and post-weld performance
  • Suitable for high-purity and hygienic installations

Stainless Steel 321 Tube Fittings

  • Stabilized with titanium
  • Enhanced resistance to intergranular corrosion
  • Ideal for high-temperature service

Stainless Steel 347 Tube Fittings

  • Stabilized with niobium
  • Excellent mechanical stability at elevated temperatures

Stainless Steel Duplex 2205 Tube Fittings

  • Mixed austenitic-ferritic structure
  • High strength and excellent chloride stress corrosion resistance
  • Ideal for offshore and harsh chemical applications

Stainless Steel Super Duplex 2507 Tube Fittings

  • Extremely high strength and corrosion resistance
  • Suitable for seawater, marine, and aggressive process environments

Stainless Steel 17-4PH Tube Fittings

  • Precipitation hardened grade
  • High strength and hardness, combined with corrosion resistance

Stainless Steel 15-5PH Tube Fittings

  • Another precipitation hardened grade
  • Offers improved toughness and strength in demanding service conditions

These materials are chosen based on service environment, corrosion exposure, pressure and temperature conditions, and regulatory compliance requirements within the UK.

Types of Tube Fittings Offered

Mcneil Instruments  provides a full suite of tube fitting types to support diverse UK industrial systems:

  • Compression Fittings
  • Ferrule Fittings
  • Union Fittings
  • Elbows (90°, 45°, 180°)
  • Tees & Crosses
  • Reducers
  • Adapters
  • Caps & Plugs
  • Specialty Machined Fittings

Each fitting is precision-machined and inspected to ensure consistent and reliable performance.


Specifications — Technical Details for UK Applications

Material Standards & Industry Compliance

StandardDescription
ASTM A312 / A269 / A213Stainless steel tubing standards
ISO 8434Metallic tube fittings for general industrial use
ASME B31.3Process piping compliance
BS EN StandardsEuropean and UK harmonized standards
API / ANSIApplicable where required (oil & gas and utilities)

Mcneil Instruments ’s fittings are manufactured in strict adherence to these recognized standards, ensuring compatibility and quality for UK project requirements.

Size & Connection Specifications

SpecificationDetails
Tube Outside Diameter (O.D.)1/8″ to 2″ (extended sizes on request)
Pressure RatingsUp to 6000 psi (depending on material and size)
Temperature RangeCryogenic to +982°C (depending on alloy)
Connection TypesCompression, Ferrule, Threaded
End FinishesPolypropylene caps, protective packaging

Mechanical Properties (Typical)

The table below provides representative mechanical properties of popular stainless steel tube fitting grades:

Material GradeTensile StrengthYield StrengthCorrosion Resistance
304≥ 515 MPa≥ 205 MPaGood
316≥ 515 MPa≥ 205 MPaVery High
Duplex 2205≥ 620 MPa≥ 450 MPaExcellent
Super Duplex 2507≥ 850 MPa≥ 620 MPaSuperior
17-4PH≥ 930 MPa≥ 720 MPaHigh
15-5PH≥ 860 MPa≥ 655 MPaHigh

Note: Exact values vary by grade and manufacturing tolerances; full Mill Test Certificates (MTCs) and detailed reports are supplied with each order.

Advantages of Stainless Steel Tube Fittings

Stainless steel tube fittings are preferred in UK projects for multiple reasons:

  • Excellent corrosion resistance, especially in marine, chemical, and offshore environments
  • High mechanical strength and durability
  • Reliable performance under high pressure and temperature conditions
  • Good weldability and fabrication adaptability
  • Reusability and ease of maintenance
  • Compatibility with instrumentation and process piping standards

These advantages make stainless steel fittings indispensable in industries requiring precision fluid control and process reliability.

Industrial Applications in the UK

Oil & Gas and Petrochemical Sector

Used in sampling lines, control instrumentation, and gas distribution networks where corrosion resistance and pressure performance are critical.

Power Generation

Supporting high-temperature and high-pressure loops such as steam probes, condensate return, and auxiliary systems.

Chemical and Process Plants

Used where aggressive media, acids, or chlorides are present.

Pharmaceutical and Food Processing

Hygienic and sterile systems depend on high-quality stainless steel tube fittings for contamination-free fluid delivery.

Marine and Offshore Engineering

Duplex and super duplex fittings are used in seawater cooling, platform process lines, and offshore support systems.

Quality Assurance, Testing & Certification

Mcneil Instruments ’s tube fittings undergo rigorous quality checks to ensure performance and compliance:

  • Material Test Certificates (EN 10204 3.1 / 3.2)
  • Positive Material Identification (PMI)
  • Hydrostatic and Leak Testing
  • Ultrasonic & Radiographic Non-Destructive Testing (NDT)
  • Dimensional and Visual Inspection
  • ISO 9001:2015 Certified Manufacturing

These certifications ensure reliability, traceability, and peace of mind for UK engineers, buyers, and project managers.

Why UK Buyers Choose Mcneil Instruments 

Global Manufacturer, Local Compliance

Mcneil Instruments  combines global production scale with full compliance to UK and European standards, ensuring products are suitable for UK infrastructure requirements.

Wide Material and Product Range

From standard stainless grades like 304 and 316 to premium alloys like duplex, super duplex, and precipitation-hardened grades, the range addresses diverse applications.

Custom Engineering Support

Technical assistance is available for designing custom fittings, selecting material grades, and aligning with project specifications.

Export Ready Supply

As a trusted exporter, Mcneil Instruments  handles documentation, logistics, and delivery to UK ports and job sites with reliability.

Quality and Traceability

Manufacturing transparency, certified quality control, and detailed test reports support project compliance and audit readiness.

Conclusion: High-Performance Tube Fittings for the UK Industrial Sector

Stainless steel tube fittings are more than connectors; they are essential components that support precision fluid delivery, safety, and reliability in critical industrial systems. Whether deployed in oil and gas, chemical processing, offshore engineering, power plants, or hygienic processing systems, these fittings must meet exacting standards.

By choosing Mcneil Instruments  as your manufacturer, supplier, and exporter of stainless steel tube fittings, UK businesses gain access to globally compliant, high-quality solutions engineered for performance, longevity, and safety.

Partner with Mcneil Instruments  for tube fittings that meet the demands of today’s industrial challenges and support the UK’s robust engineering landscape.

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Carbon Steel ASTM Tube Fittings: A Complete Guide to A105, A234 WPB, WP11, WP22 & WP91 Grades

Introduction — Critical Connectors for Industrial Piping Systems

In any industrial piping network, whether it’s transporting steam in power plants, chemical feeds in petrochemical plants, water in treatment facilities, or hydrocarbons in oil and gas refineries, tube fittings are essential. They join sections of pipe and tubing, adapt changes in direction or diameter, and provide secure, leak-proof connections in demanding environments.

Carbon steel ASTM tube fittings — manufactured under stringent industry standards — provide a robust and reliable solution for medium and high pressure, elevated temperature, and corrosive conditions. As a leading manufacturer, supplier, and exporter, Mcneil Instruments  offers a complete range of these fittings in different grades, each engineered to support specific industrial requirements.

This guide covers the most commonly used carbon steel tube fitting grades:

  • ASTM A105
  • ASTM A234 WPB
  • ASTM A234 WP11
  • ASTM A234 WP22
  • ASTM A234 WP91

We will explore their chemical and mechanical properties, applications, specifications, and differences — helping engineers and buyers make informed decisions.

Standard Overview — What Is ASTM Tube Fitting Material?

Carbon steel tube fittings covered in this guide adhere to recognized ASTM and ASME specifications. These standards define acceptable chemical compositions, mechanical properties, and performance criteria. The most relevant standards include:

  • ASTM A105 – Forged carbon steel for moderate and high-temperature service.
  • ASTM A234 WPB / WP11 / WP22 / WP91 – Carbon and alloy steel buttweld tube fittings designed for elevated temperature and pressure services.

These fittings are typically produced via forging and machining to achieve uniform strength and dimensional accuracy.

Types of Carbon Steel Tube Fittings

Before diving into grades, here are the common tube fittings typically offered by Mcneil Instruments :

  • Elbows (45°, 90°) – change direction of flow.
  • Tees & Crosses – branch flows or connect three/four lines.
  • Reducers (Concentric & Eccentric) – join two sizes of piping.
  • Caps & Plugs – close pipe ends.
  • Couplings & Adapters – join sections in different configurations.
  • Custom Machined Fittings – for special application requirements.

Each fitting type is produced to match the required grade, wall thickness, and dimensional tolerance.

Grade Profiles

1. ASTM A105 Tube Fittings

ASTM A105 is a forged carbon steel grade commonly used for moderate and high-temperature applications. These fittings offer good weldability and mechanical strength.

Chemical Composition (Typical)

ElementComposition (%)
Carbon (C)0.35 max
Manganese (Mn)0.60–1.05
Phosphorus (P)0.035 max
Sulfur (S)0.040 max
Silicon (Si)0.10–0.35

Applications:

  • Pressure and high-temperature services
  • Refining and petrochemical plants
  • Boiler systems

2. ASTM A234 WPB Tube Fittings

ASTM A234 WPB represents the most widely used grade of carbon steel buttweld fittings. These are suitable for moderate temperature and standard industrial applications.

Key Features:

  • Excellent weldability
  • Reliable performance in conventional process systems
  • Cost-effective for standard applications

Applications:

  • Pipeline connections in general plant services
  • Low/medium temperature fluid lines
  • HVAC systems

3. ASTM A234 WP11 Tube Fittings

ASTM A234 WP11 fittings are made from carbon steel alloyed with chromium and molybdenum, giving them better resistance in higher temperature environments compared to WPB.

Applications:

  • High temperature steam lines
  • Industrial boilers
  • Medium-pressure systems requiring oxidation resistance

4. ASTM A234 WP22 Tube Fittings

ASTM A234 WP22 is a higher alloy grade than WP11, with improved creep and oxidation resistance. These tube fittings perform better under sustained high temperatures and pressures.

Applications:

  • Superheaters and reheaters
  • High-pressure steam piping
  • Chemical processing lines

5. ASTM A234 WP91 Tube Fittings

ASTM A234 WP91 fittings represent one of the most advanced carbon steel grades. They are engineered for extreme conditions involving both high temperature and pressure.

Key Advantages:

  • Superior creep strength
  • High mechanical toughness
  • Reliability in prolonged elevated temperature service

Applications:

  • High-pressure boiler systems
  • Thermal power plant piping
  • Heavy industrial applications

Mechanical Properties Comparison

The following table summarizes typical mechanical properties for these carbon steel fitting grades:

PropertyA105A234 WPBA234 WP11A234 WP22A234 WP91
Tensile Strength (min)≥ 485 MPa≥ 415 MPa≥ 415 MPa≥ 520 MPa≥ 620 MPa
Yield Strength (min)≥ 240 MPa≥ 240 MPa≥ 205 MPa≥ 310 MPa≥ 415 MPa
Elongation (%)~20–25~22~22~22~20

Note: Actual mechanical values depend on manufacturing process, heat treatment, and test outcomes.

Chemical Composition Overview

Different grades are alloyed with varying levels of chromium, molybdenum and other elements to enhance high-temperature strength and corrosion resistance.

GradeKey Alloying Elements
A105Carbon, Manganese
WPBCarbon, Manganese
WP11Cr, Mo
WP22Higher Cr, Mo
WP91Cr, Mo with added elements for creep strength

Dimensions & Wall Thickness Standards

Carbon steel ASTM tube fittings are typically produced according to ASME B16.9 and/or ASME B16.11 dimensional standards. These define fitting geometry based on Nominal Pipe Size (NPS) and Schedule (SCH) designations.

Typical Size Range

  • 1/2″ NB to 48″ NB or larger (depending on product)
  • Wall thicknesses: SCH 10 to SCH XXS
  • Fittings manufactured for both buttweld and socket-weld connections

Certifications & Quality Assurance

Mcneil Instruments  ensures that all carbon steel ASTM tube fittings meet rigorous quality parameters. Each product undergoes:

  • Material Test Certificates (MTCs) (EN 10204 3.1 / 3.2)
  • Positive Material Identification (PMI)
  • Hydrostatic Pressure Testing
  • Dimensional Inspection
  • Weld Integrity & Hardness Tests

This makes them suitable for critical industrial services where safety and reliability are non-negotiable.

Applications Across Industries

Carbon steel ASTM tube fittings are used in:

  • Oil & Gas Production & Refining
    Fittings in crude handling, steam systems, gas lines
  • Power Plants & Boilers
    High temperature steam lines, superheated fluid circuits
  • Petrochemical & Chemical Processing
    Process piping with elevated temperature and pressure
  • Industrial Manufacturing
    Heavy equipment cooling lines, process fluid transportation
  • Water Treatment & Infrastructure
    Main lines, distribution systems, plant utilities

Each grade has its niche depending on operational temperature, pressure, and fluid characteristics.

Why Choose Mcneil Instruments  — Manufacturer, Supplier & Exporter

Mcneil Instruments  stands out due to:

  • Broad Product Range: Comprehensive offering covering all major ASTM carbon steel grades from A105 to WP91.
  • Global Standards Compliance: Manufacturing to ASTM, ASME, and international norms.
  • Quality Tracking & Documentation: Full traceability with certified test reports.
  • Custom Solutions: Machined fittings tailored to unique project needs.
  • Export Capability: Serving global markets with expertise in packaging, logistics, and export documentation.

This combination makes Mcneil Instruments  a reliable partner for global EPC contractors, industrial end-users, and procurement teams.

Conclusion — Fit for Purpose and Built to Last

Choosing the right carbon steel ASTM tube fitting is a key engineering decision. Each grade — from A105 through A234 WPB, WP11, WP22, and WP91 — is designed for specific use cases ranging from general service to high temperature and high pressure.

As industries in oil & gas, power, petrochemical, and manufacturing continue to evolve, having a supplier that delivers quality, consistency, and certified performance is essential. Mcneil Instruments  meets these expectations as a trusted manufacturer, supplier, and exporter, offering tube fittings designed for performance, longevity, and project success.

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