Push-in fittings are the standard connection for pneumatic tubing. Most are made from engineering plastics like PBT or POM. But when the environment is hot, wet, or physically demanding, plastic fittings crack, creep, and fail. Nickel-plated brass push-in fittings solve this. They keep the tool-free push-to-connect speed but add the strength, temperature range, and corrosion resistance of metal. This guide from Reayon Pneumatic covers the MP Series — our family of nickel-plated brass push-in fittings — including model types, specs, and when to choose metal over plastic.
What Are Nickel-Plated Brass Push-In Fittings?
Nickel-plated brass push-in fittings are metal-bodied pneumatic connectors. You push the tube into the fitting port — a stainless steel grip ring grabs the OD and an O-ring seals it. A release button or sleeve lets you pull the tube back out. No tools, no tape, no torque wrench.
The body is machined from brass (commonly DZ60 or similar leaded brass) and then electroplated with nickel. The nickel layer serves two purposes:
Corrosion resistance. Bare brass oxidizes and tarnishes, especially in humid or salty environments. Nickel plating seals the surface and keeps the fitting looking clean after years of service.
Surface hardness. The plated layer resists scratches and thread galling better than raw brass.
Inside, the functional parts match plastic push-in fittings: a stainless steel claw (grip ring), an O-ring (NBR or FKM), and a collet that holds the tube. The difference is all in the body.
Key Advantages of Metal Push-In Fittings
Higher pressure rating. Metal bodies handle more pressure than plastic equivalents. Typical working pressure is 1.0 to 1.6 MPa, compared with 1.0 MPa for plastic push-in fittings.
Wider temperature range. Brass fittings work from -20 °C to +120 °C (FKM seal), while plastic bodies are typically limited to -20 °C to +80 °C.
Mechanical strength. A metal body will not crack if a tool bumps it or if a heavy tube pulls sideways on the port. Plastic fittings shatter under the same load.
Corrosion resistance. Nickel plating resists humidity, salt spray, and many chemicals better than bare brass or plastic.
Professional appearance. The bright, uniform nickel finish looks clean on visible installations — instrumentation panels, lab equipment, and food-grade lines.
Thread durability. Nickel-plated brass threads resist galling and repeated assembly without damage — important for fittings that may be repositioned during maintenance.
MP Series Model Guide and Specifications
The MP Series includes several body styles for different routing needs. Each model is available in metric sizes (4 mm to 16 mm OD) and inch sizes (1/8" to 1/2" OD), with BSPP, BSPT, or NPT threads where applicable.
Model
Body style
Thread type
Use case
MPUC
Straight union
None (tube-to-tube)
Inline splicing of two tubes
MPUL
Elbow union (90°)
None (tube-to-tube)
Right-angle tube-to-tube connection
MPL
Male elbow swivel
BSPP / BSPT / NPT
90° turn from a threaded port
MPMF
Bulkhead female
BSPP / BSPT / NPT
Panel-mount straight connection
General specifications for MP Series nickel-plated brass push-in fittings:
Body material: Nickel-plated brass (DZ60)
Grip ring: Stainless steel (SUS304)
O-ring: NBR (standard) or FKM (high-temperature option)
Working pressure: 1.0 MPa (10 bar) at 20 °C
Temperature range: -20 °C to +80 °C (NBR); -20 °C to +120 °C (FKM)
Vacuum rating: Up to -100 kPa
Tube sizes: Metric 4, 6, 8, 10, 12, 14, 16 mm OD; Inch 5/32", 1/4", 5/16", 3/8", 1/2" OD
Thread sizes: R1/8" to R1/2" (BSPP), PT1/8" to PT1/2" (BSPT), NPT1/8" to NPT1/2"
Testing: 100% air-leak and pressure-maintaining test before delivery
Packaging: Plastic bag + white box + carton
Metal vs Plastic Push-In Fittings: When to Choose Brass
Most pneumatic systems use plastic push-in fittings — they are lighter, cheaper, and more than adequate for standard compressed air at room temperature. But several situations call for metal.
Factor
Plastic (PBT/POM)
Nickel-plated brass
Working pressure
Up to 1.0 MPa
Up to 1.0-1.6 MPa
Temperature
-20 to +80 °C
-20 to +120 °C (FKM)
Impact resistance
Brittle — cracks on impact
Durable — survives knocks
Chemical exposure
Limited by resin
Broader compatibility
Vibration resistance
Good
Excellent
Cost
Lower
Higher
Weight
Light
Heavier
Choose metal push-in fittings when:
Ambient temperature exceeds 80 °C near steam lines, ovens, or molding machines.
The fitting is exposed to splashing oils, solvents, or cleaning chemicals.
Equipment vibrates heavily — metal threads hold torque better.
The fitting is panel-mounted and must carry the weight of hanging tubes.
Appearance matters — food, medical, or lab equipment with visible fittings.
For standard automation at room temperature, plastic push-in fittings remain the right choice. Our guide to fittings for PU and nylon tubing explains the plastic fitting families in detail.
Where Nickel-Plated Brass Fittings Are Used
Food and beverage processing — washdown environments where plastic may degrade from cleaning chemicals.
Automotive manufacturing — engine bay and paint booth areas with elevated temperatures and oil exposure.
Pharmaceutical and lab equipment — clean, non-shedding metal surfaces for sanitary installations.
Marine and outdoor — salt-air environments where bare brass would corrode; nickel plating holds up.
Heavy machinery and robotics — high-vibration installations where metal threads resist loosening.
Panel and enclosure mounting — MPMF bulkhead fittings pass through panels and seal on both sides.
Why Choose Reayon Pneumatic for Metal Fittings
Reayon Pneumatic manufactures the full MP Series in-house. We machine, plate, assemble, and 100% leak-test every fitting before it ships. We are a factory — not a trading company — which means consistent material quality, direct technical support, and factory-direct pricing.
Full metric and inch sizes in stock — OD 4 mm to 16 mm, threads 1/8" to 1/2"
BSPP, BSPT, and NPT thread options on threaded models
NBR and FKM seal options for standard and high-temperature service
Custom sizes, special thread combinations, and OEM packaging on request
What is the difference between brass and nickel-plated brass push-in fittings?
Bare brass push-in fittings work mechanically but tarnish and oxidize over time, especially in humid or salty environments. Nickel plating adds a thin protective layer that prevents corrosion, resists scratches, and keeps the fitting looking clean. The pressure and temperature ratings are the same for both.
Can metal push-in fittings be used with PU and nylon tubing?
Yes. Metal push-in fittings use the same stainless steel grip ring and O-ring mechanism as plastic ones. They accept PU, PA (nylon), and PE tubing of matching OD. Always cut the tube square with a tube cutter and push it fully into the port to seat the O-ring.
What sizes are available in the MP Series?
Reayon Pneumatic MP Series fittings cover metric OD from 4 mm to 16 mm and inch OD from 5/32" to 1/2". Threaded models are available in BSPP, BSPT, and NPT from 1/8" to 1/2". Custom sizes are available on request.
Are nickel-plated brass fittings food-grade safe?
Nickel-plated brass is suitable for compressed air lines in food-processing equipment where the fitting is not in direct food contact. For direct-contact food or medical lines, specify stainless steel fittings instead. Always confirm material compliance with your local food-safety authority.
Does Reayon Pneumatic offer custom metal push-in fittings?
Yes. We manufacture the MP Series in our own factory and can produce custom thread combinations, non-standard tube sizes, and OEM-branded packaging. Contact us with your requirements and annual volume for a factory-direct quote.
Tell us your tube size, thread type, and annual volume. Reayon Pneumatic will quote factory-direct pricing with samples available for testing. Wholesale and OEM orders are welcome.
