March 1998

Supersedes G-4A

Dated September 1984

SUBJECT : HEAT EXCHANGER MATERIALS

ALUMINIZED STEEL

Armco Type 1 Aluminizes Steel is cold-rolled steel with silicone-aluminum fused to both sides by a patented hot-dip process. Both the aluminum alloy bond are highly resistant to temperature and corrosion in normal service, making aluminized steel much superior to ordinary or ceramic-coated steel as a heat exchanger material.

409 STAINLESS STEEL

"409" is an improved Type 410 stainless now successfully used in automobile mufflers. It is low carbon steel containing about 12% chromium and a small amount of nickel for corrosion resistance. "409" also contains titanium, silicon, and molybdenum, which improve its mechanical characteristics.

Although its resistance to high temperature and corrosion is not as great as Type 321 stainless, "409" is much lower in price. It may, therefore be used where cost must be kept down, where strong corrosive elements are not expected, or where the longer guarantee of #321 stainless is not required.

321 STAINLESS STEEL

Type 321 is a titanium stabilized stainless containing 18% chromium and 10% nickel for extremely high resistance to temperature and corrosion. No commercially used metal can even approach it as a heat exchanger material.

HEAT EXCHANGER GUARANTEE

Applies to gas unit heaters, duct furnaces and indirect-fired heating systems.

* 1-Year warranty covering defects in material and workmanship only.

DIVISON OF ERIC INC.