Materials

Base tube and fin material selection decides corrosion life, temperature capability and cost. This page lists what we stock and what we can source.

Base tube materials

Standard	Material	Typical use	Max temp.
ASTM A179	Seamless carbon steel	General air coolers	400 °C
ASTM A192	Seamless carbon steel, high pressure	Boiler and high-pressure service	450 °C
ASTM A213 T11 / T22	Chrome-moly alloy	Refinery and power plant	550–600 °C
ASTM A213 T5 / T9 / T91	Alloy steel	High-temperature service	600–650 °C
ASTM A312 TP304 / 316L	Austenitic stainless	Corrosive and hygienic	600 °C
ASTM A789 / A790	Duplex stainless	Chloride service	300 °C
ASTM B111	Copper-nickel 90/10, 70/30	Marine and cooling water	300 °C
ASTM B338	Titanium	Seawater and aggressive chemicals	300 °C

Fin materials

Material	Max temp.	Corrosion behaviour	Cost
Aluminium 1060 / 1100	250 °C	Good in clean air; poor in chlorides/alkalis	Low
Aluminium 3003	250 °C	Better than 1060 in mild atmospheres	Low
Copper	300 °C	Good, but incompatible with ammonia	Medium
Carbon steel	500 °C	Needs coating in wet atmospheres	Low
Stainless 304 / 316L	600 °C	Good general corrosion resistance	High
Alloy steel (T11, T22)	600 °C	High temperature, low corrosion	Medium-high

Galvanising and coatings

Hot-dip galvanising gives carbon steel fins a zinc barrier for onshore installations. Epoxy and phenolic coatings protect aluminium fins in coastal or mildly corrosive air; they reduce heat transfer by a small amount and must be specified before production.

Bi-metallic corrosion

Where the fin and tube are different metals, moisture at the joint can drive galvanic corrosion. Aluminium fins on copper tubes are acceptable in dry service but need coating in wet coastal air; aluminium on stainless is generally safe.