sheath material selection guide
Aluminum- MAX TEMPERATURE: 600 °C or (315°C). Commercially pure aluminum. Used in special applications requiring good thermal conductivity.
Incoloy 600: MAX TEMPERATURE: 2150 °F or (1175°C). Most Widely used thermocouple sheath material. Good high temperature strength, corrosion cracking and oxidation resistance to high temperatures. Do not use in sulfur bearing environments. Good in nitriding environments.
Incoloy 601: MAX TEMPERATURE: 2150°F or (1175°C) continuous; 2300°F (1260°C) intermittent. Similar to Alloy 600 with the addition of aluminum for outstanding oxidation resistance. Designed for high temperature corrosion resistance. This material is good in carburizing environments, and has good creep rupture strength. Do not use in vacuum furnaces! Suseptible to intergranular attack by prolonged heathing in 1000 to 1400°F (540 to 760°C) temperature range.
Incoloy 800: MAX TEMPERATURE: 2000 °F or (1095°C). Widely used as heater sheath material. Minimal use in Thermocouples. Superior to Alloy 600 in sulfur, cyanide salts and fused neutral salts. Susceptible to intergranular attack in some applications by exposure to the temperature range of 1000 to 1400°F (540 to 760°C).
Carbon Steel: MAX TEMPERATURE: 1000°F or (538°C) in nonoxidizing environments. Main areas of usage are galvanizing pots, tinning pots, molten babbitt metal, molten magnesium, molten zinc, petroleum refinery applications such as deqaxing and thermal cracking.
Alloy 20: MAX TEMPERATURE: 1800°F or (980°C). Generic version of Carpenter 20CB-3 developed specifically for resistance to sulfuric acid. Also used extensively in the manufacture of rubber, solvents, gasoline, plastics, organic chemicals and pharmaceuticals.
Copper: MAX OXIDIZING TEMPERATURE: 400°F or (205°C). Excellent thermal conductivity. Used in special applications for research and low temperature applications.
Hastelloy B: MAX OXIDIZING TEMPERATURE: 1000°F or (540°C) up to 2200°F or (1204°C) in a reducing or vacuum environment. This alloy offers excellent resistance to hydrochloric acid at all concentrations and temperatures. Also resistant to hydrogen chloride, sulfuric, acetic and phosphoric acids.
Hastelloy C-276: MAX TEMPERATURE: 2000°F (1095°C). Widely used in chemical applications. Excellent corrosion resistance, especially in chlorinated environments. Resistant to ferric and cupric chlorides, solvents, chlorine, formic acids, acetic acids, brine, wet chlorine gas and hypchlorite.
Hastelloy X: MAX TEMPERATURE: 2200°F or (1205°C). Widely used in aerospace applications. Resistant to oxidizing, reducing neutral atmospheric conditions. Excellent high temperature strength along with superior oxidation resistance. Resistance to stress corrosion crackin in petrochemical applications.
Molybdenum: MAX TEMPERATURE IN AIR: 750°F or (400°C). MELTING POINT: 4730°F or (2610°C). Refractory metal. Brittle, cannot be bent. Use only in inert, vacuum or reducing atmospheres. Most commpnly used with BeO insulation and tungsten rhenium conductors.
Monel 400: MAX TEMPERATURE: 1000°F or (540°C) in oxidizing conditions. Nickel-Copper alloy with good corrosion resistance. Excellent resistance to sea water, hydroflouric acid, sulfuric acid, hydrochloric acid and most alkalies.
Nickel 201: MAX TEMPERATURE: 2000°F or (1095°C). Comercially pure wrought nickel with low carbon. Used in molten salt bath furnaces. Offers good resistance to caustic alkalines and flourine.
Tantalum: MAX TEMPERATURE IN AIR: 900°F or (480°C). MELTING POINT: 5425°F or (2995°C). Refractory metal. Very ductile. Most commonly used with BeO and tungsten rhenium conductors. Do not use in environments containing nitrogen above 700°F or (370°C).
Titanium: MELTING POINT: 3135°F or (1725°C). Light weight, excellent strength in the 300°F to 800°F (150°C to 470°C) temperature range. Exellent resistance to oxidizing acids such as nitric or chromic. Resistant to inorganic chloride solutions, chlorinated organic compounds and moist chlorine gas. Resistant to salt water spray and sea water.
304 Stainless Steel: MAX TEMPERATURE: 1650°F or (900°C). Most widely used low temperature sheath material. Extensively used in food, beverage, chemical and other industries where corrosion resistance is required. Subject to damaging carbide precipitation in 900 to 1600 (480 to 870) range. Lowest cost corrosion resistant sheath material available.
304 L Stainless Steel: MAX TEMPERATURE: 1650°F or (900°C). Low carbon version of 304 SS. Low carbon content allows this material to be welded and heated in the 900 to 1600°F (480°C to 870°C) range without damage to corrosion resistance.
310 Stainless Steel: MAX TEMPERATURE: 2100°F or (1150°C). Mechanical or corrosion resistance, similar to but better than 304 SS. Very good heat resistance. This alloy contains 25% chromium, 20% nickel.
316 Stainless Steel: MAX TEMPERATURE: 1650°F or (900°C). Best corrosion resistance of the austenitic stainless steel grades. Widely used in the food and chemical industry. Subject to damaging carbide precipitation in 900°F to 1600°C (482°C to 870°C) range.
321 Stainless Steel: MAX TEMPERATURE: 1600°F or (870°C). Similar to 304 SS except titanium stabalized for intergranular corrosion. This alloy is designed to overcome susceptibility to carbon precipitation in the 900°F to 1600°F (480°C to 870°C) range. Used in aerospace and chemical applications.
446 Stainless Steel: MAX TEMPERATURE: 2100°F or (1150°C). Ferritic stainless steel which has good resistance to sulfurous atmospheres at high temperatures. Good corrosion resistance to nitric acid, sulfuric acid, and most alkalies. 27% chromium content gives this alloy the highest heat resistance of any ferretic stainless steel.