Flexible Metal Hose Assemblies


Are all hose companies the same?

Its important to realize that all metal hose companies are NOT the same. There are lots of metal hose companies BUT the way they assemble their hose is what matters. Flexible metal hoses usually do not break in the middle, they break at the hose weld. This means that the method that is used to assemble and weld the hose is very important.

Most hose companies hack off the hose from the reel and weld a fitting or flange on to the end with no additional end fitting preparation. Unfortunately with this method you do not get a full penetration weld. The hose material is just a few thousandths thick and the fitting wall can be 5-10 times thicker. If you leave the thick wall and just weld it to the hose, what you are left with is a hinge point that over time with movement will fail. Hoses like this are not constructed for longevity, they are constructed for low price.

Why is Aero-Flex different?

Aero-Flex has developed our own way to “prep” and weld our hose ends that increases strength and durability compared to our competitors. Our hose core, wire braid and braidband are welded together first in what we call an “edge weld”. If done incorrectly you reduce the overall strength of your hose assembly. To attach your end fitting we remove the hinge point by ID tapering all of our end fittings so we achieve a full penetration weld. (See picture to the right) This also removes the “ledge” inside the ID of the hose which can affect flow of the medium inside the hose.

Now that you understand that all hose companies are NOT the same it’s now up to you to make a choice………

  1. Do you want a low quality, low price metal hose that will work as a temporary solution?


    2. Do you want a high quality, durable, long lasting metal hose that was constructed the right way?

If you chose 2 please see below for the information we need from you to quote your custom fabricated flexible metal hose assembly. This is the first step in ordering a flexible metal hose. Once you give us the S.T.A.M.P.E.D information we will have all of the information we need to get you a quote.

How To Order

To properly design a flexible metal hose assembly for a particular application, certain parameters must be determined first. To help remember them, we have arranged them to form the acronym “S.T.A.M.P.E.D.

S stands for SIZE; I.D., O.D. and length

T stands for TEMPERATURE of the material conveyed and environmental

A stands for the APPLICATION, the conditions of use

M stands for the MATERIAL being conveyed, type and concentration

P stands for the PRESSURE to which the assembly will be exposed

E stands for ENDS; style, type, orientation, attachment methods, etc.

D stands for DELIVERY; testing, quality, packaging, and delivery requirements

How to order a flexible metal hose
14" Flexible Metal Hose Assembly


Flexible metal hose and braid is manufactured in sizes from 1/4″ up to 12″ in diameter. Typically it comes with a single layer of braid or if you need a higher pressure rating you can add a second layer of braid. Typically the smaller the hose diameter the higher the pressure it can withstand. The exact opposite happens as you get larger in diameter. The larger the diameter the lower the maximum pressure rating is.
Cryogenic Flexible Metal Hose Assembly


The reason flexible metal hose assemblies are widely used in a variety of industries is because of the extreme temperature range they can perform well in. For example a cryogenic application like liquid hydrogen or oxygen transfer hoses where temperatures can get down to -320°F.

In contrast by using a flexible metal hose assembly you can reach much higher temperatures than a PTFE or rubber hose. This is because of the materials the hose is made from. For example power turbine’s and steel manufacturing use metal hoses because temperatures can reach up to 1500° F.

Pressure Test Hydrostatic Or Pneumatic


The diameter of the hose and number of layers of wire braid determines the maximum allowable working pressure of a flexible metal hose. The temperature of what’s going through the hose or the environment its in can also affect the MAWP of a flexible metal hose.

For example a 1/4″ ID flexible metal hose with 2 layers of braid can handle 6000 psi working pressure while a 12″ flexible metal hose with 2 layers of braid handles 325 psi working pressure. Furthermore, if the temperature goes up past 300°F we would need to downgrade the pressure rating based on the higher temperature.

Flexible Metal Hose, Braided Hose
Monel Braid, Alloy 400 Braid, Flexible Metal Hose Braid


Flexible metal core and braid comes in a variety of different alloys. Each alloy of core and braid is tailored to a specific application. Typically the core and braid comes in 321ss, 316ss, Alloy 400 (Monel) and Nickel 625. The standard braid alloy is 304 stainless steel, however this can also be substituted with 316ss, Alloy 400 and Nickel 625.

In general, 321 stainless steel is used for higher temperature applications while 316L stainless steel is used in corrosive environments. The low carbon content and the addition of molybdenum provides the protection from salt and other chemicals used in manufacturing.

Alloy 400 corrugated hose is made of Nickel-Copper alloy. This alloy has an excellent resistance to chlorine, sea water, salt and caustic solutions. As a matter of fact, in a chlorine environment, Alloy 400 hose operates superior as opposed to 316L when required.

As a low temperature corrosion resistant material, Nickel 625 has an excellent record in use in the chemical processing industry, in sea and brackish water and in power plant scrubber applications. Furthermore it resists chloride pitting and crevice corrosion as well as chloride stress-corrosion cracking.

Threaded Flexible Metal Hose Fittings
Flex Hose, Flexible Metal Hose Assembly

Threaded End Connections

There are several different standard off the shelf threaded end connections that can be used on a flexible metal hose. For the most part materials include carbon steel, 304 stainless steel and 316L stainless steel.  Below are a few of the threaded end connections we can provide.

  • Male NPT
  • Female NPT
  • Male JIC 37° Flare
  • Female JIC 37° Flare
  • ORFS – O-ring Face Seal

Aero-Flex can also machine a custom threaded end connector to the specific dimensions and alloys you require for your application. Ask us about custom threaded hose connectors and we would be happy to get you a quote.

ASME Flange Connection On Flexible Metal Hose
Flexible Metal Hose Assembly with custom flange.

Flange End Connections

Typically flange end connections are used on hoses larger than 2″ in diameter. Aero-Flex supplies off the shelf ANSI B16.5 flanges in 150#, 300#, 600#, 900# and 1500# classes. Some of the typical off the shelf ANSI flanges we can supply are…

  • Weld Neck Flange
  • Lap Joint Flange (Floating)
  • Slip On Flange
  • Blind Flange
  • Socket Weld Flange
  • Threaded Flange

ANSI B16.5 flanges come standard in alloys like carbon steel, 304 stainless steel, 316L stainless steel and 321 stainless steel. When required an Alloy 400 or Nickel 625 flange can also be supplied.

Aero-Flex can also machine custom flange connections upon request to your exact drawing specifications and specific alloys. Ask us about your next project that requires flexible metal hoses with custom flange connections and we would be happy to get you  a quote.

AN, MS or AS nuts and sleeves for tube or hose assembly.
Aerospace AS1895 V-Band Hose Fitting

Aerospace End Connections

Aero-Flex provides end connections used on hose and tube assemblies used in Aerospace applications. The aerospace end fittings are very similar to the JIC industrial end fittings especially since they are both 37° flares but they do have differences.

The most notable difference between these standards are in the threads. For instance, AN fittings use an increased root radius thread (“J” thread) and a tighter tolerance (Class 3) to achieve a 40% increase in fatigue strength and a 10% increase in shear strength. In fact, material requirements can differ greatly.  These two fittings function the same, they look the same but are slightly different. But, JIC fittings should not be used for Aerospace applications.

Some examples of Aerospace end connections would be…

  • AN Nuts & Sleeves
  • MS Nuts & Sleeves
  • AS Nuts & Sleeves
  • V-Band Flange

Aero-Flex can supply off the shelf aerospace fittings or we can custom machine your aerospace hose end connections from your drawing or a specific SAE fitting specification. Please ask us about custom aerospace hose end fittings that are required for your next project.

Silicone slip-on firesleeve for industrial or aerospace hoses.
Used as Armor Guard and as a flow straighter on a flexible metal hose.

Hose Protection

Aero-Flex can also supply different types of protection for your flexible metal hose assembly. Whether its for abrasion resistance or fire resistance, In any case, we can provide the right solution for your needs.

Interlocked Hose is sometimes used inside the flexible metal hose as a flow straightener when consistent pressure flow is required. More often you see interlocked hose used as an exterior abrasion guard. This helps protect the hose when its used in conditions where the hose and outer braid can be damaged by dragging around.

Fire sleeve is used on flexible metal hoses for heat and fire protection. This protects continuously to 500°F (260°C) and will withstand a molten splash at 2200°F (1200°C).   Made of either knitted or braided high quality fiberglass yarns, it is then coated with a high-grade, fully-cured silicone rubber. Resistant to hydraulic fluids, lubricating oils, and fuels, fire sleeve insulates against energy loss in piping and hosing. Additionally, it protects employees from burns and provides flame and molten splash resistant protection for wires, hoses, and cables.

We can offer other services once your flexible metal hose is complete . NDT, High Purity Cleaning and Pressure Testing to industry specifications or to your specific specifications are all available.

Click our services tab to learn more.

When Should You Use A Metal Hose

Flexible Metal Hose
Flexible Metal Hose - 37° Flare
FT4000 Custom Flexible Metal Hose
There’s a lot of different types of hoses on the market today and each of them have their own specific application. Aero-Flex specializes in the fabrication of custom flexible metal hose assemblies for applications where other types of hose materials won’t work. In other words, a high temperature application or high corrosion environment. Below are some examples when a metal hose is a perfect fit for your specific application.

  • Temperature Extremes
  • Chemical Compatibility
  • Permeation Concerns
  • Abrasion Concerns
  • Reduce High Vibration
  • Fire Safety
  • Full Vacuum Required

 We’ll choose an alloy that is compatible with your specific application. For example, using 316 Stainless Steel is great for minor corrosion or high purity environments. In instances where high corrosion is a factor, nickel or monel  is widely used in these applications. For most applications the standard 321ss core with 304ss braid will work fine.

Our Flexible Metal Hose Assemblies are extremely abrasion resistant and are widely used in industries where high vibration is a factor. Actually, reducing vibration in your machinery can have a lasting affect on the life span of your machinery.

What Industries Use Metal Hoses

Flexible Metal Hose
Aerospace Industry
Flexible Metal Hose
There are many different industries that require the use of flexible metal hose assemblies. As mentioned above, there are certain applications where a flexible metal hose assembly is the only option. Below are some examples of where flexible metal hoses are crucial in keeping that particular industry running smoothly.

Gas Power Turbine’s – Fuel, Lube Oil, Water, Detergent, High Pressure Lube Lines and Hot Air.

Aerospace/Aircraft – Fuel, Hydraulic Fluid & Exhaust Gas

Cryogenic Hoses – Manufacture of Cryogenic Liquids and Transfer Hoses

Chemical Transfer or MFG. – Loading / Unloading Tank Cars, Process Piping, Steam Lines, Dry Bulk Conveying, Chlorine Transfer.

Oil Refining- Gas Burner Connections, Lube Lines, Metering System Flex Lines, Oil Burner Connections, Stand Pipe on Cat Crackers, Steam Hoses, Dock Hoses

Steel Production- Blast Furnace, BOF Furnace, Boiler & Generation Units, Coke Oven, Cooling Water Hoses, High Temp. Lube Lines, Oxygen Lance Hose, Vacuum Degasser, Lime Injection

Pulp & Paper Production- Compressed Gas Lines, De-Inking Process, Lube Lines, Steam Connections, Tank Car Unloading, Connections for Liquor and dryer rolls.

Dry Bulk Transfer – Pneumatic Dry Bulk Conveying.

Water Treatment – Chlorine Transfer, Piping Systems

Petrochemical – Chemical Transfer, Loading / Unloading Tank Cars, Process Piping, Steam Lines, Dry Bulk Conveying, Dock Hose.