Frequently Asked Questions

A stainless steel corrugated hose is a flexible metallic conduit made from thin-walled stainless steel tubing that has been formed into a corrugated (bellows-like) profile. This corrugation allows the hose to flex, bend, and absorb vibration, thermal expansion, and misalignment while maintaining a leak-tight seal. It is widely used for conveying liquids, gases, and steam in industrial piping systems where rigidity, corrosion resistance, and high-temperature capability are essential.

We manufacture corrugated hoses using high-grade austenitic stainless steel, primarily:

• SS 304 / SS 304L - General-purpose grade offering excellent corrosion resistance for most applications. SS 304L is low-carbon for superior corrosion resistance in welded joints.
• SS 316L - Superior corrosion resistance, especially against chlorides, acids, and marine environments. Low-carbon grade for improved weldability.
• SS 321 - Titanium-stabilized grade recommended for continuous high-temperature service up to 700°C.

The outer braid is also made from stainless steel wire for added strength and pressure containment. The grade selection depends on the operating medium, temperature, and corrosion environment.

Operating Temperature Range: -270°C to +700°C (material dependent)

• Cryogenic: -270°C (liquid nitrogen, liquid helium applications)
• Low Temperature: -40°C to ambient (cold-service applications)
• Room Temperature: -40°C to +80°C (standard industrial)
• High Temperature: +80°C to +700°C (steam, hot gas applications; SS 321 above +425°C)

Material Grade Selection:

• SS 304 / 304L: -270°C to +425°C
• SS 316L: -270°C to +425°C (superior corrosion resistance)
• SS 321: -270°C to +700°C (recommended for continuous high-temperature service above 425°C)

Important: Working pressure ratings must be de-rated at elevated temperatures using the temperature correction factor provided in our technical datasheets. Consult with our technical team for applications above +600°C.

Pressure ratings depend on the corrugation series (11, 12, or 13), formation method (MF, HF), and nominal size. Our products offer these working pressure ranges:

• Series 11 & 12 — MF (6–50 mm bore): 1–12 bar unbraided, 27–120 bar single braid, 45–190 bar double braid
• Series 11 & 12 — HF (40–300 mm bore): 0.2–2 bar unbraided, 5–35 bar single braid, 8–55 bar double braid
• Series 13 (Extra Close Pitch) — MF, unbraided only: 0.5–10 bar (maximum flexibility, minimum pressure)

Formation Methods:

• MF (Mechanically Formed) - Standard corrugations formed by precision mechanical tooling. Suitable for general industrial applications.
• HF (Hydroformed) - Corrugations formed using hydraulic pressure for superior fatigue resistance and higher working pressures. Ideal for high-pressure and heavy-duty applications.
• EF (Elastomer Formed) - Corrugations formed using elastomer mandrel process for maximum flexibility and tight bend radius.

Burst pressure is typically 4 times the maximum working pressure. For detailed pressure ratings by nominal size, please refer to our product datasheets.

MF, HF, and EF refer to the manufacturing method used to form the corrugations. Each method offers distinct advantages:

• MF (Mechanically Formed) - Corrugations formed using precision mechanical rolling and tooling. Offers a balanced combination of flexibility and pressure rating. Available in series 11, 12 and 13. Ideal for general industrial applications, steam lines and standard process piping. Nominal bore: 1/4" to 2" (6–50 mm); series 11 and 12 take single or double SS wire braid, series 13 is unbraided.
• HF (Hydroformed) - Corrugations formed using controlled hydraulic pressure, producing a more robust profile with heavier wall sections. Delivers superior fatigue resistance and higher working pressures compared to MF. Better suited for vibration-prone installations and critical industrial systems. Nominal bore: 1½" to 12" (40–300 mm) — HF covers the larger bores, so its working pressures (up to 55 bar) are lower than small-bore braided MF, which reaches 190 bar.
• EF (Elastomer Formed) - Corrugations formed using an elastomer mandrel process, creating the finest pitch and maximum flexibility. Ideal for applications requiring frequent bending, tight routing in confined spaces, and tight bend radius requirements. Perfect for aerospace, demanding industrial, and specialty applications.

Selection Guide: Choose MF for standard applications, HF for high-pressure or demanding environments, and EF when maximum flexibility and tight routing are required.

We offer a comprehensive range of end connections to suit diverse piping configurations:

• BSP (British Standard Pipe) male and female threaded fittings
• NPT (National Pipe Thread) fittings
• Flanged ends (ANSI, DIN, JIS, and Table D/E standards)
• Tri-clamp (TC) sanitary fittings
• Cam-lock couplings
• Union connections
• Welding nipples

Custom end connections can also be manufactured to meet specific OEM or project requirements. All fittings are made from compatible stainless steel grades.

Our stainless steel corrugated hoses are used across a wide range of industries including:

• Petrochemical and Oil & Gas
• Pharmaceutical and Biotech
• Food and Beverage Processing
• Power Generation and Nuclear Plants
• HVAC and Refrigeration
• Steel and Cement Manufacturing
• Chemical Processing
• Shipbuilding and Marine
• Automotive and Railways
• Water Treatment Facilities

The hoses serve critical roles in steam lines, gas transfer, chemical dosing, thermal expansion absorption, and vibration isolation.

We are an ISO 9001:2015 certified company, ensuring consistent quality management across all manufacturing processes. Our products are manufactured in compliance with international standards and we can provide material test certificates, hydrostatic test reports, and dimensional inspection reports as per customer requirements. We continuously invest in quality assurance and testing infrastructure to meet the evolving needs of global clients.

We are flexible with order quantities and can accommodate both small and bulk orders. There is no strict minimum order quantity for standard products. For custom-manufactured hoses with special specifications, end fittings, or non-standard sizes, a minimum quantity may apply depending on the complexity. Please contact our sales team at sales@flexiblemetals.in or call +91 85958 70426 to discuss your specific requirements.

To select the right hose, you need to consider several parameters:

• The conveying medium (gas, liquid, steam, chemicals)
• Operating temperature and pressure
• Required nominal bore size (ID)
• Desired length and bend radius
• Type of movement to absorb (vibration, thermal expansion, misalignment)
• End connection type and standard
• External environment (corrosive atmosphere, outdoor exposure)

Our technical team can assist you in selecting the optimal hose series, material grade, and configuration. Contact us with your application details for a tailored recommendation.

Standard products in common sizes are typically available ex-stock or within 3 to 5 working days. Custom-manufactured hose assemblies, special lengths, or non-standard end connections generally require 7 to 15 working days depending on the complexity and quantity. For urgent requirements, we offer expedited manufacturing. Please contact our sales team to confirm delivery timelines for your specific order.

We stand behind the quality of our products. We offer a warranty against manufacturing defects in material and workmanship. The warranty is subject to the product being used within its specified operating parameters including pressure, temperature, media compatibility, and correct installation practices. Damage caused by improper installation, over-pressurization, external mechanical damage, or use beyond specified limits is not covered. Detailed warranty terms are provided with each order.

Yes, we export stainless steel corrugated hoses, PTFE hoses, bellows, and assemblies to clients worldwide. We have experience shipping to countries across the Middle East, Southeast Asia, Africa, Europe, and the Americas. Our products are carefully packed to withstand international transit, and we handle all export documentation including commercial invoices, packing lists, certificates of origin, and test certificates. Contact us to discuss your international procurement needs.

To request a custom specification, simply contact our engineering team via email at sales@flexiblemetals.in or call us at +91 85958 70426. Provide details such as:

• Application and operating conditions (temperature, pressure, media)
• Required dimensions (bore size, length, bend radius)
• Preferred end connection types and standards
• Any applicable industry standards or specifications
• Quantity required and desired delivery timeline

Our team will review your requirements and provide a technical proposal along with pricing and delivery timelines. We also welcome drawings and datasheets for reference.