Carbon steel is a steel alloy where the primary interstitial alloying component is carbon. A higher carbon content allows the steel to become harder and stronger during its heat treatment process. Due to its versatility and cost this is used in many components of heat transfer units.
Copper is an element known for high ductility, thermal conductivity, and corrosion resistance. This, combined with its soft and malleable properties, makes copper a great material to fabricate and manufacture various types of heat transfer equipment.
90/10 Cupro-Nickel is a copper alloy that contains nickel and other strengthening elements. It is a tough metal with high ductility. Traces of iron and manganese are used to enhance its corrosion resistance. It’s easy fabrication and welding properties make it ideal to work with in corrosive heat transfer applications.
80/20 Cupro-Nickel is a copper alloy that contains a higher amount of nickel than 90/10 cupro-nickel. This enhances the strength and corrosion resistance and is best used in heat transfer applications that require a more demanding corrosion tolerance.
70/30 Cupro-Nickel is a copper alloy that has the highest concentration of nickel. This alloy has improved corrosion resistance and more notably at higher velocities. This is best used with highly contaminated liquids and/or higher velocity heating/cooling applications.
Inconel® is an austenitic nickel-chromium based superalloy. This has a very high oxidation and corrosion resistance. It is acid resistant and easy to weld. This is typically used in heat transfer applications that call for extremely high temperatures. (Inconel® 600, Inconel® 625)
Incoloy® is typically a nickel-iron-chromium based superalloy. They are known for their resistance to oxidation and carbonization in high-temperature applications. Similar to Inconel®, Incoloy® is used in highly demanding applications that most other metals wouldn’t be able to stand up to the corrosion and/or temperature. (Incoloy® 800, Incoloy® 825)
Admiralty Brass is a copper alloy with approximately 30% zinc and 1% tin. This creates a strong corrosion resistance and malleability. The dezincification of this metal is great in heat transfer systems used with potable water.
304/L Stainless Steel
304/L Stainless Steel is the most common of the 300 series austenitic alloys. 304/L is a low carbon version of 304 which does not require post-weld annealing. This metal is used to prevent corrosive material from entering the liquid in heat transfer equipment.
316/L Stainless Steel
316/L Stainless Steel is the second most common austenitic stainless steel alloy. It is called the marine grade stainless due to its increased resistance to corrosion relative to 304/L stainless steel. This has good applications with chemical and other corrosive materials.
317/L Stainless Steel
317/L Stainless Steel is a molybdenum austenitic stainless steel. It has improved corrosion resistance over 304/L and 316/L stainless steel. It has higher levels of molybdenum, nickel, and chromium which improve chloride pitting resistance and corrosion. This has many heat transfer applications in the chemical and energy fields.
321/L Stainless Steel
321/L Stainless Steel is an austenitic 18/8 steel stabilized by either titanium or niobium. This has a high resistance to scaling, and resistance to aqueous corrosion especially at very high temperatures. This is good to be used to heat transfer units requiring strength up to 900ᵒC.
Duplex steels have a mixed microstructure of austenite and ferrite. They are characterized by high chromium and molybdenum with lower nickel contents. They are generally twice as strong as austenitic stainless steels, with improved resistance to localized corrosion, particularly pitting, crevice corrosion, and stress corrosion. (Duplex 2205, SuperDuplex 2207)
Alloy 20 is a nickel-chromium-molybdenum alloy initially created for applications involving sulfuric acid. It has a very high corrosion resistance. It is considered a “super” stainless steel because of its pitting and chloride ion corrosion resistance. Alloy 20 is widely used in chemical, food processing, pharmaceutical, and the plastic industries.
Monel® 400 is a nickel alloy, primarily composed of nickel and copper, with traces of iron and other elements. It has a very high strength and resistance to corrosion. Coupled with its thermal conductivity and ductility, Monel® 400 is a good material to use in heat transfer units that use sea water, hydrofluoric acid, sulfuric acid, and alkalies.
Hastelloy® B is a wrought nickel-molybdenum alloy. It offers superior protection against powerful chemical corrosion and has one of the best high-temperature strengths of any steel. It also has good stress corrosion cracking and pitting resistance. This “super-alloy” is excellent for high-temperature nuclear or chemical applications.
Hastelloy® C (Alloy C276) is a nickel-molybdenum-chromium “super-alloy” with an addition of tungsten. It has a superior corrosion resistance, as well as, resistance to pitting and crevice corrosion. It also has a strong resistance to oxidizing media. Hastelloy® C is excellent for many heat transfer applications including chemical procession, pollution control, pulp and paper, and many more.
Titanium alloys contain a mixture of titanium and other chemical elements. They are known for their toughness and high tensile strength, especially at extremely high temperatures. Most notably they have a very high corrosion resistance despite their very light weight. Due to the high cost, Titanium is used as required in heat transfer equipment in areas like aerospace, power generation, and chemical processing.
Aluminum alloys are known for having a high resistance to corrosion and highly malleable. It is very light relative to other metals, and has a good thermal conductivity. At high temperatures aluminum starts to lose its strength. However, at very low temperatures the strength increases while retaining its ductility making aluminum great for low-temperature heat transfer applications.
Nickel 200 is a wrought nickel, almost unalloyed containing typically less that 1% of other elements. It has a strong resistance to corrosion in alkalies and acids and is most useful under reducing conditions. Its high thermal conductivity, low gas content and vapor pressure makes nickel 200 particularly useful in heat transfer applications that need to maintain product purity such as food processing, synthetic fibers, and caustic alkalies.
AL-6XN is a superaustenitic stainless steel containing high nickel and molybdenum contents along with nitrogen and chromium. It is known for its resistance to chloride pitting, crevice corrosion, and stress corrosion cracking. Its nitrogen content gives it a higher tensile strength than common austenitic stainless steels. AL-6XN is a commonly used in heat transfer applications that call for higher temperatures and lower pH levels like food processing.