L Fin Tube Alloy Steel Spiral Wound Seamless Fin Tube for Air Heat Exchanger

Material Description

This product is a tension-wound L-type spiral fin tube built on seamless Cr–Mo alloy steel boiler/heat-exchanger tube. The base tube is typically supplied in grades such as ASTM A213 T11/T22, EN 10216-2 13CrMo4-5, JIS G3462 STBA22, or GB 5310 12Cr1MoVG, all designed for elevated-temperature, pressure-bearing service in boilers and air-cooled heat exchangers.

Aluminum or copper fin strip is cold-formed into an “L” profile and helically wound under tension around the alloy steel tube so that the fin “foot” is pressed tightly against the tube surface, providing a continuous spiral fin with good thermal contact and partial protection of the tube wall from ambient corrosion.

Specifications

Base tube

• Material options (seamless, alloy steel):

  • ASTM / ASME: A213 / SA213 T11, T22

  • EN: 13CrMo4-5 to EN 10216-2

  • JIS: STBA22 to JIS G3462

  • GB: 12Cr1MoVG to GB/T 5310

• Outside diameter: approx. 16–50.8 mm (⅝"–2")

• Wall thickness: application-dependent, typically 2–8 mm for air coolers

Fin geometry (typical L-type wound fin)

• Fin type: L-foot, spiral wound

• Fin material: aluminium or copper strip

• Fin height: up to about 16.5 mm

• Fin thickness: ~0.4–0.6 mm (≈0.015–0.020")

• Fin pitch: from about 2.1 mm (≈12 FPI) upward, optimized per duty

Operating range

• Designed for air-side service where fin temperature is typically up to about 150–230 °C, depending on fin material and duty

• Base alloy tube grades support much higher metal temperatures on the fluid side, in line with their boiler/pressure-tube standards (typically 500–580 °C class for Cr–Mo steels in code use).

Key Features

1. High heat-transfer surface density

   • Continuous spiral fins dramatically increase outside surface area, enabling the same thermal duty with far fewer tubes and a smaller air cooler bundle compared with bare tubes.

2. Efficient fin-to-tube thermal contact

   • L-foot fin geometry and winding tension press the fin foot firmly against the tube surface, minimizing contact thermal resistance and promoting uniform heat transfer along the full tube length.

3. Alloy steel core for elevated-temperature, pressure service

   • Cr–Mo alloy tube grades such as T11, T22, 13CrMo4-5, STBA22 and 12Cr1MoVG provide high creep-rupture strength, good oxidation resistance and weldability for boiler and air-cooled heat-exchanger service.

Our Advantages

Below are several concerns buyers of air-cooled finned tubes commonly raise, and how this product is positioned to address them.

1. “Will the fins stay tight under temperature and start–stop cycling?”

• L-foot tension-wound fins use controlled winding tension so the fin foot is seated firmly on the tube surface, maintaining contact during normal temperature cycling.

• For alloy steel cores we match fin material and design temperature: L-type is used where fin wall temperatures are in the moderate range (roughly up to 150–230 °C) and thermal shocks are not severe. For harsher conditions we can advise on alternative fin types (LL/KL/embedded) based on the same Cr–Mo alloys.

2. “Is L-type the right balance of performance and cost for my air cooler?”

• L-type finned tubes are among the most cost-effective spiral fin solutions, frequently chosen where budget and surface area per cost are key and operating temperatures are in the typical air-cooler range rather than extreme furnace duty.

• By increasing outside area, a single finned tube can replace multiple bare tubes, reducing bundle size, fan power, structural steel and overall project CAPEX while maintaining required thermal duty.

3. “How do you handle corrosion and service life in outdoor air coolers?”

• The alloy steel core tube provides strong resistance to high-temperature oxidation and steam-side corrosion; on the air side, the L-foot fin partially shields the tube wall from direct atmospheric exposure.

• Fin materials (aluminium or copper) and optional metallized or coated surfaces can be selected to suit coastal, industrial or mildly corrosive atmospheres. Where wet air or aggressive atmospheres dominate, we can move to LL/KL finning or stainless-steel base tube/fin combinations for longer life.

4. “Will the tube material meet my code and traceability requirements?”

• We offer Cr–Mo alloy tube in standard boiler/heat-exchanger grades: ASTM A213 T11/T22, EN 10216-2 13CrMo4-5, JIS G3462 STBA22 and GB/T 5310 12Cr1MoVG, with mill test certificates per EN 10204 (typically 3.1) and full heat-number traceability.

• Non-destructive testing (eddy-current or ultrasonic), hydrostatic testing and dimensional inspection can be specified to match client quality plans for critical air-cooled heat-exchanger service.

Chemical Composition

Mechanical Properties

Applicable Standards

ASTM / ASME

• ASTM A213 / ASME SA213 – Seamless ferritic and austenitic alloy-steel boiler, superheater and heat-exchanger tubes (e.g. T11, T22).

EN (Europe)

• EN 10216-2 – Seamless steel tubes for pressure purposes, non-alloy and alloy steels with specified elevated-temperature properties (13CrMo4-5).

• EN 10028-2 / EN 10222-2 – Flat products and forgings with specified elevated-temperature properties, used for matching headers and manifolds.

JIS (Japan)

• JIS G3462 – Alloy steel tubes for boiler and heat exchanger (STBA22 and related grades).

GB (China)

• GB/T 5310 – Seamless steel tubes and pipes for high-pressure boiler (includes 12Cr1MoVG and related Cr–Mo grades).

GOST (Russia / CIS equivalents)

• GOST 5520 and related norms for alloy boiler steels such as 12KHM / 12Kh1MF, which are widely accepted equivalents to EN 13CrMo4-5 in high-temperature pressure service.

Application Fields

General application range
L-type alloy steel spiral fin tubes are used in air-cooled and gas-to-liquid heat exchangers where a hot process fluid inside the tube is cooled by ambient air or process gas on the finned side. They are especially common where water is scarce or expensive and air coolers are favored over shell-and-tube water coolers.

Typical industries and positions in the system

• Power generation (thermal, nuclear, geothermal)

  • Air-cooled condensers and finned tube bundles for steam condensing

  • Boiler air preheaters and economizer coils

  • Generator hydrogen coolers and lube-oil coolers (air side)

• Oil, gas and petrochemical plants

  • Air fin coolers for compressor discharge, gas dehydration and fractionation units

  • Overhead condensers and product coolers in refineries

  • Gas-to-air and liquid-to-air coolers on flare systems and utilities

• Chemical and fertilizer plants

  • Process-stream air coolers in ammonia, urea and nitric-acid units

  • Heat recovery coolers in oxidation and polymer plants

• HVAC, drying and general industry

  • Finned-tube coils in large air-handling units and industrial HVAC

  • Air heaters for spray dryers, kilns and process gas drying

  • Compact finned-tube exchangers in OEM equipment and packaged coolers

Q: Are you trading company or manufacturer ?

A: manufacturer,also can do trading.

Q: How long is your delivery time?

A: Generally speaking,it is 10-15 days if the goods are in stock,or it is 30-40 days if the goods are not in stock,

it is according to quantity.

Q: Do you provide samples? is it free or extra ?

A: Yes, we could offer the sample for free charge but need pay the cost of freight.

Q: What is your terms of payment ?

A: Payment<=2000USD, 100% in advance. Payment>=2000USD, 30% T/T in advance ,balance before shippment.

If you have another question, pls feel free to contact with me.