Metal Bellows Expansion Joint

The metal bellows expansion joint, also known as stainless steel bellows, pipe expansion joint, metal compensator, or corrugated metal connector, is a high-performance flexible element designed to absorb thermal expansion, vibration, and slight misalignment in pipeline systems.

Widely used in HVAC, power plants, petrochemical lines, and industrial piping, this product is made of multi-layer stainless steel (SS304/316L) and end flanges or welding ends. It provides excellent fatigue resistance, pressure containment, and temperature adaptability, making it ideal for both axial and lateral movement compensation.

Zhengda offers various types, including:

•Axial bellows expansion joint

•Universal type compensator

•Lateral and angular bellows

•Custom OEM designs for high-temperature and corrosive media.

Key Features

Key Features of Metal Bellows Expansion Joint

•Excellent performance in vibration absorption and noise reduction

•High flexibility, capable of compensating axial, lateral, and angular displacement

•High-pressure resistance with reinforced rubber or metal construction

•Available with standard flange connections: DIN, ANSI, JIS

•Suitable for HVAC systems, water supply, and chemical pipelines

•Custom rubber or metal materials available for different media and working conditions, such as EPDM, NBR, FKM, or stainless steel bellows

Technical Specifications

✅ Bellows Expansion Joint Specification Table (DN32–DN1000)

Nominal Diameter (DN)	Recommended Waves	Pressure Rating (MPa)	Effective Area (cm²)	Max OD (mm)	Length (mm)	Flange DZ/F (mm)	End DF/J (mm)
DN32	8	0.25 / 0.6 / 1.0 / 1.6 / 2.5	225	250	160	250	264
DN40	8	Same as above	244	259	164	259	269
DN50	8	Same as above	259	276	172	276	282
DN65	6	Same as above	270	294	215	294	300
DN80	6	Same as above	284	338	240	338	344
DN100	6	Same as above	304	317	235	317	323
DN125	6	Same as above	334	314	282	314	316
DN150	5	Same as above	364	389	282	389	338
DN200	4	Same as above	442	384	280	384	348
DN250	4	Same as above	507	379	315	379	415
DN300	4	Same as above	562	427	366	427	466
DN350	4	Same as above	622	452	397	452	497
DN400	4	Same as above	700	478	412	478	512
DN450	3	Same as above	760	498	503	498	503
DN500	3	Same as above	835	523	431	523	531
DN600	3	Same as above	980	548	478	548	578
DN700	3	Same as above	1110	590	490	590	590
DN800	3	Same as above	1265	602	502	602	602
DN900	3	Same as above	1186	689	689	689	689
DN1000	3	Same as above	1286	692	692	692	692

✅ Technical Parameters – Metal Bellows Expansion Joint

Parameter	Unit	Typical Value / Range
Nominal Diameter	mm (DN)	DN32 – DN1000
Design Pressure	MPa	0.25 / 0.6 / 1.0 / 1.6 / 2.5 (customizable up to 6.4 MPa)
Working Temperature	°C	-40°C ~ +550°C (depending on materials)
Applicable Media	–	Water, Steam, Oil, Gas, Air, Chemical Fluids, etc.
Material – Bellows	–	Stainless Steel SS304 / SS316L / 321
Material – Flange	–	Carbon Steel / Stainless Steel / Galvanized Steel
Connection Type	–	Fixed Flange, Loose Flange, Welded End
Movement Type	–	Axial, Lateral, Angular, Universal
Axial Compensation	mm	Typically 20–50 mm (varies by model and size)
Lateral Compensation	mm	Up to 30 mm (customizable)
Angular Deflection	degrees	Up to ±15°
Design Standard	–	GB/T 12777, EJ/T 1021, EN 14917, ASME B31.3

Material	Properties	Application Purpose

SS304

Good corrosion resistance, widely used

General pipeline systems, HVAC, clean water

SS316L

Excellent corrosion and acid resistance

Chemical, food, and pharmaceutical industries

SS321

Good high-temperature resistance

Heat exchangers, boilers

Carbon Steel

High strength, economical

Low-pressure or uncritical applications

Galvanized Steel

Rust prevention for outdoor use

General construction piping

✅ Maintenance Guide

• Inspect the joint regularly for deformation, leaks, or corrosion
• Check flange bolts for loosening and tighten if necessary
• Replace the joint if you find fatigue cracks or serious wear
• Clean dust or corrosive residue from the surface regularly
• Avoid long-term exposure to extreme heat or vibration
• Follow the manufacturer’s service life and replacement guidelines

1. Inspection Before Installation

•Check whether the rubber joint is damaged, aged, or defective.

•Confirm the model, pressure rating, and flange size match the system requirements.

2.Installation Environment

•Avoid installation under direct sunlight, ozone, or in environments with high temperature or strong corrosive chemicals.

•If outdoor installation is necessary, use UV-protective shields or covers.

3.Installation Instructions

•Align the rubber joint with the center of the pipe flanges. Avoid pulling or twisting during installation.

•Tighten bolts crosswise and evenly to avoid uneven force or deformation.

•Use proper washers and gaskets.

4.Precautions

•Ensure the pipeline is properly fixed; rubber joints are not designed to bear the full weight.

•Do not over-extend, over-compress, or apply excessive torsion to the joint.

•Allow for movement as specified (axial, lateral, angular) within rated limits.

•Install limit rods or anti-pull devices if the pipe system lacks sufficient fixation.

5.Working Pressure & Temperature

•Observe the rated pressure and temperature range during operation.

•Standard range: -15°C to +115°C (or as specified).

6.Routine Inspection & Maintenance

•Inspect every 6–12 months for signs of aging, damage, or leakage.

•Replace if any abnormalities are found.

✅ Why Choose Our Metal Bellows Expansion Joints

• Proven Durability
Crafted from high-grade stainless steel (SS304, SS316L), designed for high-temperature and high-pressure environments.

• Global Standards Compliance
Manufactured in accordance with international standards such as EJ/T, GB/T, DIN, and ASME.

• Versatile Applications
Ideal for thermal expansion, vibration absorption, and misalignment compensation in HVAC, chemical, power, and water systems.

• Flexible Customization
Available in various diameters, pressure ratings, lengths, and movement types (axial, lateral, angular).

• Factory Direct Supply
We provide competitive pricing and fast delivery from our own production base in China.

• Reliable Export Experience
Exported to over 30 countries with stable quality, complete certificates, and responsive customer support.

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Metal Bellows Expansion Joint