Selection of thermocouples for spent acid pyrolysis furnaces

It is recommended to use corundum tube material for protection; our company can provide a free trial.

This post was last edited by 1111111 on 2017-12-28 07:05. There are no better suggestions. 1300 degrees – it only gets damaged after a month, so it’s quite durable. . . Even if Sun Wukong burns it for a month, he’ll definitely manage to burn it down {:3_51:} 2018 is coming, and I wish you all that you’ll manage to burn more poles, work extra hours, and earn more work points. :P

For 1300°C, choose the K-type. For this selection, it’s better to abandon the design for now. . . If you want a longer lifespan, choose another type and another type of sleeve.

For this temperature, an S-type should be chosen, and a ceramic sleeve is suitable.

It is recommended to use corundum tube material for protection

It is recommended to use corundum tube material for protection

A thermocouple protection tube is a casing designed to maximize the service life of thermocouples. By selecting the appropriate material for the protection tube, the type of thermocouple, as well as the overall internal structure of the thermocouple based on the operating conditions, it is possible for the thermocouple to maintain long-term stability, high precision, good cost-effectiveness, and a prolonged service life in complex environments characterized by high temperatures, corrosion, and wear. Thermocouple protection tubes: yunrun.com.cn/tech/1548.html. Thermocouple protection sleeves are required to have properties such as material airtightness, mechanical strength, stability, high heat resistance, tolerance to high temperatures, thermal strength, corrosion resistance, as well as the ability to withstand sudden temperature changes. At present, no thermocouple protection tube that meets all these requirements exists; instead, different materials are used to create such tubes in order to meet the temperature measurement needs of specific applications. Thermocouple protection tubes are generally divided into metal and non-metal types. With the continuous advancement of material technology and manufacturing processes, there is an increasing variety of materials available for use in thermocouple protection tubes, offering more choices for manufacturers and end-users. Changhui Instrument Manufacturing Co., Ltd. shares information on the performance and applications of thermocouple protection tubes made from different materials, based on extensive field experience. I. Metal thermocouple protection tubes: 1Cr18Ni9Ti (1.4841) thermocouple protection tubes. 1Cr18Ni9Ti is the most commonly used type of thermocouple protection tube, suitable for use in oxidizing atmospheres, in environments with low corrosivity, and for long-term use at temperatures up to 871°C (1600°F) ； If the temperature exceeds 899°C, please select another material ； 1Cr18Ni9Ti has poor resistance to sulfur and reduction, making it unsuitable for use in such environments. Common K-type thermocouples use 1Cr18Ni9Ti material for their protective tubes. The temperature measurement range of the K-type thermocouple element is 0–1300°C. Some users have attempted to use ordinary assembled thermocouples for temperature measurements in the 900–1100°C range; as a result, the protective tubes of these thermocouples do not last long, and the lifespan of the thermocouples itself is very short. The service life of a thermocouple is determined by factors such as the properties of the thermocouple material, the diameter of the wire, the temperature resistance, corrosion resistance, and wear resistance of the thermocouple protection tube, as well as the overall design of the product. The total service life of the thermocouple is the result of these various factors combined together. 304 thermocouple protection tube; 304 refers to 0Cr19Ni10. The chemical composition of 304 differs slightly from that of 1Cr18Ni9Ti ； The hardness of 304 is lower than that of 1Cr18Ni9Ti ； The price of 304 is cheaper than that of 1Cr18Ni9Ti ； The low-temperature corrosion resistance of 304 is better than that of 1Cr18Ni9Ti ； 1Cr18Ni9Ti contains titanium, which resists intergranular corrosion; it is more widely used in the production of thermocouples. 0Cr25Ni20 (1.4841) thermocouple protection tube; 0Cr25Ni20 (German standard 1.4841) is used in oxidizing atmospheres, in conditions with low corrosivity, and for long-term use at temperatures up to 1038°C (1900°F) ； 0Cr25Ni20 has poor resistance to sulfur and reduction, making it unsuitable for use in such environments ； 0Cr25Ni20 is used to manufacture thermocouples for use in high-temperature oxidation environments. 316L (1.4404) thermocouple protection tube: 316L (German standard 1.4404) offers better corrosion resistance than 1Cr18Ni9Ti; it is suitable for use at temperatures up to 871°C (1600°F) in corrosive environments over extended periods of time. 316L thermocouple protection tubes are generally used in the production of thermocouples for applications in the food industry, as well as in environments involving phosphoric acid, sulfite solutions, sulfuric acid with a concentration of over 90%, chlorides, bromides, and similar substances. 316L is not used for thermocouple protection tubes in media containing nitric acid, chloride ions (Cl-), or fluoride ions (F-) for temperature measurement ； 316L is also suitable for H2S at various concentrations below 300°C, but such H2S can pose a risk of stress corrosion (hydrogen embrittlement) cracking in the protective tube of 316L thermocouples; therefore, Changhui Instruments does not recommend using 316L as the protective tube for thermocouples used in H2S temperature measurement. 1.4571 thermocouple protection tube: made of German-standard 1.4571 stainless steel resistant to intergranular corrosion; suitable for use at temperatures up to 850°C (1562°F). It is commonly used as a thermocouple protection tube in applications involving temperature measurement in sulfuric acid, phosphoric acid, formic acid, acetic acid, and titanium sponge production lines. Swiss 904L thermocouple protection tube. 904L is currently the steel grade with the best resistance to corrosion by sulfuric acid and dilute sulfuric acid, with a maximum operating temperature of ≤280°C. 2.4816 Thermocouple protection tubes: A nitridizing atmosphere is commonly found in high-temperature atmospheres such as nitrogen, nitrogen-hydrogen, and ammonia; in such environments, nitrogen can enter the metal to form metal nitrides (usually chromium nitrides), which reduces the toughness of the material or causes cracking along the grain boundaries. Nickel-based alloys are least sensitive to nitridation, and 2.4816 is the best material for thermocouple protection tubes in a nitriding atmosphere. 1.4591 thermocouple protection tubes are used in high-temperature environments with sulfidation conditions, and are often cooled to room temperature; they are also exposed to humid, sulfur-containing acidic environments. Changhui Instruments typically uses 1.4591 stainless steel for thermocouple protection tubes, as this material offers good resistance to sulfidation and acid corrosion. Thermocouple protection tubes made of high-chromium cast iron ZGGr28: High-chromium cast iron can be used at temperatures up to 1050°C for extended periods; it boasts resistance to wear, corrosion, and high temperatures. Changhui Instruments uses high-chromium cast iron tubes to manufacture thermocouples for measuring temperature in applications involving reducing sulfur-containing gases, sulfuric acid boiling furnaces, carbon calcination furnaces, and non-ferrous metal smelting furnaces. 2.4859 and 2.4610 thermocouple protection tubes: When metal materials are exposed to chlorine (Cl), hydrochloric acid (HCl), or other environments containing halogens, metal halides are formed, along with intergranular corrosion caused by Cl and F. ①In an oxygen-poor HCl atmosphere, chlorides of iron, nickel, and chromium may form. 2.4859 and 2.4610 maintain their corrosion resistance even at temperatures of 850°C in an atmosphere of 10% HCl/H2; therefore, Changhui Instruments selects 2.4859 and 2.4610 as thermocouple protection tubes resistant to chlorinated corrosion. ②In a stable atmosphere with low oxygen partial pressure, pure nickel (alloy 200) and Ni-Mo alloys (Nicrofer 6928-alloy B-2) can be used as thermocouple protection tubes. In oxygen-containing CL2/O2 atmospheres or during chloride precipitation, chloride-induced oxidation can often be observed in the thermocouple protection tubes of 2.4816 and 2.4889 types; this represents the main mode of corrosion for boiler pipes in waste incineration plants. Changhui Instruments uses 2.4816 and 2.4889 as thermocouple protection tubes for measuring the flue gas temperature in waste incinerators, offering excellent corrosion resistance. 2.4633 Thermocouple Protection Tube: 2.4633 can be used as a thermocouple protection tube in the oxidizing atmosphere of CL, but it is suitable for use in oxygen-poor HCl atmospheres. Iron-aluminum-ceramic thermocouple protection tubes: Changhui Instrument Manufacturing Co., Ltd. is a manufacturer of iron-aluminum-ceramic products; over the past decade or so, it has been supplying four types of TLC series iron-aluminum-ceramic protection tubes to various industries for use in manufacturing wear-resistant thermocouples for different operating conditions. ①TLC-type iron-aluminum ceramic is used as a thermocouple protection tube for temperature measurement in solutions resistant to hydrochloric acid, nitric acid, sulfuric acid, as well as sodium hydroxide and potassium hydroxide solutions. ②TLC1-type iron-aluminum ceramic is resistant to oxidation, sulfidation, and zinc vapor corrosion; it boasts high wear resistance as well as excellent heat and shock resistance, with a operating temperature of 1100°C. Based on actual use, the service life of the zinc concentrate boiler is 4 months, that of the pyrite boiler is 12 months, the service life of the boiler and the circulating fluidized bed furnace chamber is 6 months, and the service life of the ball mills and fan mills at their inlets and outlets is 6–8 months. ③TLC3 type iron-aluminum ceramic | The wear resistance of TLC3 type iron-aluminum ceramic is slightly lower than that of TLC1 type; it can operate at a temperature of 1300°C and belongs to the category of high-temperature wear-resistant thermocouple protection tubes. ④The wear resistance of TLC4-type ferroalumina ceramic is significantly higher than that of TLC3-type ferroalumina ceramic; under the same operating conditions, its service life can be increased by three times. The operating temperature is 1100°C. Based on practical applications by Changhui Instruments, thermocouples with TLC4 as the protective tube have achieved a service life of over 3 years when used for measuring temperatures at the inlet and outlet of ball mills. Inconel 600 thermocouple protection tubes: Inconel 600, a nickel-chromium-iron alloy, possesses excellent oxidation resistance at high temperatures; it can be used at temperatures up to 1000°C, and is employed for protecting high-temperature assembly thermocouples as well as armored thermocouples in oxidizing environments. Monel K500 thermocouple protection tube: The Monel K500 nickel-copper alloy can operate at temperatures up to 700°C; it possesses excellent resistance to intergranular corrosion, making it suitable as a thermocouple protection tube for use in environments with corrosive substances such as concentrated sulfuric acid. GH3030 thermocouple protection tube: made of GH3030 nickel-based superalloy steel, it boasts excellent oxidation and corrosion resistance. It can be used at temperatures ranging from 0 to 1100°C, and is employed as a protection tube for modular thermocouples and S-type armored thermocouples in high-temperature oxidative environments. GH3039 thermocouple protection tubes are made of GH3030 nickel-based superalloy steel, which boasts excellent oxidation and corrosion resistance. They can be used at temperatures ranging from 0 to 1300°C, and serve as protection tubes for modular thermocouples and Type B armored thermocouples in high-temperature oxidation environments. The table below can serve as a guide for selecting thermocouple sheath and jacket materials based on the process fluid. These include factors such as catalytic reactions, pollution, and electrolysis. However, in many cases, other factors must also be taken into consideration. It is recommended to submit reports on such special applications to Changhui Instruments to obtain relevant recommendations. These recommendations are merely guidance based on the principle of choosing the most cost-effective materials. If these recommendations do not meet the requirements of a specific application, Changhui Instruments shall bear no responsibility for this. Measuring medium state (concentration and temperature) Recommended materials Acetic acid solvent crude or purified Monel or nickel Acetic acid 10%-21˚C (70˚F) 304 stainless steel acetic acid 50%-21˚C (70˚F) 304 stainless steel acetic acid 50%-100˚C (212˚F) 316L stainless steel acetic acid 99%-21˚C (70˚F) 430 stainless steel acetic acid 99%-100˚C (212˚F) 430 stainless steel anhydrous acetic acid Monel acetate 100˚C (212˚F) 304 stainless steel acetylene 304, Monel, nickel ethanol 21˚C (70˚F) 304 stainless steel measuring medium state (concentration and temperature) recommended material ethanol 100˚C (212˚F) 304 Stainless Steel Methanol 21˚C (70˚F) 304 Stainless Steel Methanol 100˚C (212˚F) 304 Stainless Steel Aluminum Melted SiC Aluminum Acetate Saturated 304 Stainless Steel Aluminum Sulfate 10%-21˚C (70˚F) 304 Stainless Steel Aluminum Sulfate Saturated -21˚C (70˚F) 304 Stainless Steel Aluminum Sulfate 10%-100˚C (212˚F) 316 Stainless Steel Aluminum Sulfate Saturated 100˚C (212˚F) 316 Stainless Steel Ammonia Various Concentrations 21˚C (70˚F) 304 Stainless Steel Measures Medium State (Concentration and Temperature) Recommended Materials Ammonium Chloride Various Concentrations 100˚C (212˚F) 316 Stainless Steel * ao acid an Various concentrations 21˚C (70˚F) 304 stainless steel * ao acid an various concentrations 100˚C (212˚F) 304 stainless steel sulfuric acid an 5%-21˚C (70˚F) 304 stainless steel sulfuric acid an 10%-100˚C (212˚F) 316 stainless steel sulfuric acid an saturated 100˚C (212˚F) 316 stainless steel aniline various concentrations 21˚C (70˚F) 304 Stainless Steel Amyl Acetate Monel Asphalt Steel (C1018), Phosphor Bronze, Monel, Nickel Barium Carbonate 21˚C (70˚F) 304 Stainless Steel Barium Chloride 5%-21˚C (70˚F) Monel Measuring Medium State (Concentration and Temperature) Recommended Materials Barium Chloride Saturated 21˚C (70˚F) Monel Barium chloride water-hot 316 stainless steel barium hydroxide steel (C1018) Barium sulfate nickel-chromium alloy benzene 21˚C (70˚F) 304 stainless steel light gasoline steel (C1018), Monel, Inconel crude benzene hot 304 stainless steel boric acid 5% hot or cold 304 stainless steel bromine 21˚C (70˚F) Tantalum butadiene copper, 304 stainless steel measuring medium state (concentration and temperature) Recommended materials butane 21˚C (70˚F) 304 stainless steel isobutyl acetate Monel butyl copper butylene steel (C1018), phosphor bronze butyric acid 5%-21˚C (70˚F) 304 stainless steel butyric acid 5%-66˚C (150˚F) 304 stainless steel calcium bisulfite 21˚C (70˚F) 316 stainless steel calcium chlorate/diluted 21˚C (70˚F) 304 stainless steel calcium chlorate/diluted 66˚C (150˚F) 304 stainless steel calcium hydroxide 10%-100˚C (212˚F) 304 stainless steel measurement medium status (concentration and temperature) Recommended materials calcium hydroxide 20%-100˚C (212˚F) 304 stainless steel calcium hydroxide 50%-100˚C (212˚F) 317 stainless steel carbolic acid all 100˚C (212˚F) 316 stainless steel carbon dioxide dry steel (C1018), Monel carbon dioxide wet aluminum, Monel, nickel carbon tetrachloride 10%-70˚F Monel Caustic dichloroethyl ether 316 stainless steel, 317 stainless steel chlorine dry 21˚C (70˚F) 317 stainless steel chlorine wet 21˚C (70˚F) Hastelloy C chlorine wet 100˚C (212˚F) Hastelloy C Measurement medium status (concentration and temperature) Recommended material Chromic acid 5%-21˚C (70˚F) 304 stainless steel chromic acid 10%-100˚C (212˚F) 316 stainless steel chromic acid 50%-100˚C (212˚F) 316 stainless steel citric acid 15%-21˚C (70˚F) 304 stainless steel citric acid 15%-100˚C (212˚F) 316 stainless steel citric acid concentrated 100˚C (212˚F) 317 stainless steel coal tar hot state 304 stainless steel coke oven gas aluminum copper nitrate 304 stainless steel, 316 stainless steel copper sulfate 304 stainless steel, 316 stainless steel measurement medium state (concentration and temperature) Recommended Materials Core Oil 316 Stainless Steel Cottonseed Oil Steel (C1018), Monel, Nickel Methoxycresol 304 Stainless Steel Log Tar Steel (C1018), Monel, Nickel Cyanide Gas 304 Stainless Steel Dow Heat Transfer Steel (C1018) Epsom Salt and Cold 304 Stainless Steel Ethyl Acetate Monel Ethyl Chloride 21˚C (70˚F) 304 Stainless Steel Glycol Steel (C1018) Measure the medium state (concentration and temperature) Recommended materials Ethyl sulfate 21˚C (70˚F) Monel Ferric Chloride 1%-21˚C (70˚F) 316 Stainless Steel Ferric Chloride 5%-21˚C (70˚F) Tantalum ferric chloride 5% - boiling tantalum ferric sulfate 5% - 21˚C (70˚F) 304 stainless steel ferrous sulfate diluted 21˚C (70˚F) 304 stainless steel formaldehyde 304 stainless steel Freon steel (C1018) formic acid 5% - 21˚C (70˚F) 316 stainless steel formic acid 5% - 66˚C (150˚F) 316 stainless steel measuring medium state (concentration and temperature) Recommended materials Tannic acid 5%-21˚C (70˚F) Monel Tannic acid 5%-66˚C (150˚F) Monel Gasoline 21˚C (70˚F) 304 stainless steel glucose 21˚C (70˚F) 304 stainless steel glycerin 21˚C (70˚F) 304 stainless steel Glycerol 304 stainless steel heat treatment 446 stainless steel Hydrobromic acid 48%-100˚C (212˚F) Hastelloy B Hydrochloric acid 1%-21˚C (70˚F) Hastelloy C Hydrochloric acid 1%-100˚C (212˚F) Hastelloy B Measuring medium status (concentration and temperature) Recommended materials Hydrochloric acid 5%-21˚C(70˚F) Hastelloy C Hydrochloric acid 5%-100˚C(212˚F) Hastelloy B Hydrochloric acid 25%-21˚C(70˚F) Hastelloy B Hydrochloric acid 25%-100˚C(212˚F) Hastelloy B Hydrochloric acid 316 stainless steel Hydrofluoric acid Hastelloy C Hydrogen peroxide 21˚C (70˚F) 316 Stainless Steel Hydrogen Peroxide 100˚C (212˚F) 316 Stainless Steel Hydrogen Sulfide Dry and Wet 316 Stainless Steel Iodine 21˚C (70˚F) Tantalum Measurement Medium State (Concentration and Temperature) Recommended Materials Kerosene 21˚C (70˚F) 304 Stainless Steel Lactic Acid 5%-21˚C (70˚F) 304 Stainless Steel Lactic Acid 5%-66˚C (150˚F) 316 Stainless Steel Lactic Acid 10%-100˚C (212˚F) Tantalum Paint 21˚C (70˚F): 316 Stainless Steel Latex Steel (C1018) Lime Sulfur Steel (C1018), 304 Stainless Steel, Monel Linseed Oil 21˚C (70˚F) 304 Stainless Steel Magnesium Chloride 5%-21˚C (70˚F) Monel Magnesium Chloride 5%-100˚C (212˚F) Nickel Magnesium Sulfate Cold and Hot Monel Measuring medium state (concentration and temperature) Recommended materials Malic acid Cold and hot 316 Stainless Steel Mercury Steel (C1018), 304 Methane 21˚C (70˚F) Steel (1020) Milk 304, Nickel Mixed Acid (Sulfuric Acid and Nitric Acid) All Temperatures and % No. 20 Carpenter Molasses Steel (C1018), 304 Stainless Steel, Monel, Nickel Hydrochloric Acid 21˚C (70˚F) Tantalum Nap Reagent 21˚C (70˚F) 304 Stainless Steel Natural Gas 21˚C (70˚F) 304 Stainless Steel Neon 21˚C (70˚F) 304 Stainless Steel Measurement Medium State (Concentration and Temperature) Recommended Materials Nickel Chloride 21˚C (70˚F) 304 Stainless Steel Nickel Sulfate Cold and Hot 304 Stainless Steel Nitric Acid 5%-21˚C (70˚F) 304 Stainless Steel Nitric Acid 20%-21˚C (70˚F) 304 Stainless Steel Nitric Acid 50%-21˚C (70˚F) 304 Stainless Steel Nitric Acid 50%-100˚C(212˚F) 304 Stainless Steel Nitric Acid Concentrated-21˚C(70˚F) 304 Stainless Steel Nitric Acid Concentrated-100˚C(212˚F) Tantalum * * * 21˚C (70˚F) 304 Stainless Steel Nitrous Acid 304 Stainless Steel Measuring Medium State (Concentration and Temperature) Recommended Materials Oleic Acid 21˚C (70˚F) 316 Stainless Steel Oleum 21˚C (70˚F) 316 Stainless Steel Oxalic Acid 5% - Cold and Hot 304 Stainless Steel Oxalic Acid 10% - 100˚C (212˚F) Monel Oxygen 21˚C (70˚F) Steel (C1018) Oxygen 21˚C (70˚F) Steel (C1018) Oxygen Liquid 304 Stainless Steel Palmitic Acid 316 Stainless Steel Phenol 304 Stainless Steel Pentane 304 Stainless Steel Measurement Medium State (Concentration and Temperature) Recommended Materials Phosphoric Acid 1%-21˚C (70˚F) 304 Stainless Steel Phosphoric Acid 5%-21˚C(70˚F) 304 Stainless Steel Phosphoric Acid 10%-21˚C(70˚F) 316 Stainless Steel Phosphoric Acid 10%-100˚C(212˚F) Hastelloy C Phosphoric Acid 30%-21˚C(70˚F) Hastelloy B Picric Acid 21˚C(70˚F) 304 stainless steel potassium bromide 21˚C (70˚F) 316 stainless steel potassium carbonate 1%-21˚C (70˚F) 304 stainless steel potassium chlorate 21˚C (70˚F) 304 stainless steel potassium chloride 5%-21˚C (70˚F) 304 stainless steel measurement medium status (concentration and temperature) Recommended materials: potassium chloride 5%-100˚C(212˚F) 304 stainless steel potassium hydroxide 5%-21˚C(70˚F) 304 stainless steel potassium hydroxide 25%-100˚C(212˚F) 304 stainless steel potassium hydroxide 50%-100˚C(212˚F) 316 stainless steel potassium nitrate 5%-21˚C(70˚F) 304 stainless steel potassium nitrate 5%-100˚C(212˚F) 304 stainless steel potassium permanganate 5%-21˚C(70˚F) 304 stainless steel potassium sulfate 5%-21˚C(70˚F) 304 stainless steel potassium sulfate 5%-100˚C(212˚F) 304 Stainless Steel Potassium Sulfide 21˚C (70˚F) 304 Stainless Steel Propane 304 Stainless Steel Measuring Medium State (Concentration and Temperature) Recommended Materials Pyrogallol 304 Stainless Steel Quinine Bisulfate Dry 316 Stainless Steel Quinine Sulfate Dry 304 Stainless Steel Resin 304 Stainless Steel Rosin/Melting 304 Stainless Steel Seawater Monel Salommoniac Monel Salicylate Nickel Shellac 304 Stainless Steel Soap 21˚C (70˚F) 304 Stainless Steel Measuring Medium State (Concentration and Temperature) Recommended Materials Sodium Bicarbonate Various Concentrations 21˚C (70˚F) 304 Stainless Steel Sodium Bicarbonate 5%-66˚C (150˚F) 304 Stainless Steel Sodium Bisulfate Monel Sodium Carbonate 5%-21˚C (70˚F) 304 Stainless Steel Sodium Carbonate 5%-66˚C (150˚F) 304 Stainless Steel Sodium Chloride 5%-21˚C(70˚F) 316 Stainless Steel Sodium Chloride 5%-66˚C(150˚F) 316 Stainless Steel Sodium Chloride Saturated-21˚C(70˚F) 316 Stainless Steel Sodium Chloride Saturated-100˚C(212˚F) 316 Stainless Steel Sodium Fluoride 5%-21˚C(70˚F) Monel Measuring medium state (concentration and temperature) Recommended materials Sodium hydroxide 304 stainless steel sodium hypochlorite 5% distilled 316 stainless steel sodium nitrate/melting 317 stainless steel sodium peroxide 304 stainless steel sodium phosphate steel (C1018) sodium silicate steel (C1018) sodium sulfate 21˚C (70˚F) 304 stainless steel sodium sulfide 21˚C (70˚F) 316 Stainless Steel Sodium Sulfite 66˚C (150˚F) 304 Stainless Steel Steam 304 Stainless Steel Measuring Medium Condition (Concentration and Temperature) Recommended Materials Stearic Acid 304 Stainless Steel Sulfur Dioxide Moist Gas - 21˚C (70˚F) 316 Stainless Steel Gas - 300˚C (575˚F) 304 stainless steel sulfur dry-melted 304 stainless steel sulfur wet 316 stainless steel Sulfuric acid 5%-21˚C (70˚F) No. 20 Carp, Hastelloy B Sulfuric acid 5%-100˚C (212˚F) No. 20 Carp, Hastelloy B Sulfuric acid 10%-21˚C (70˚F) No. 20 Carp, Hastelloy B Sulfuric acid 10%-100˚C (212˚F) No. 20 Carp, Hastelloy B Sulfuric acid 50%-21˚C (70˚F) No. 20 Carp, Hastelloy B Sulfuric acid 50%-100˚C (212˚F) No. 20 Carp, Hastelloy B Sulfuric acid 90%-21˚C (70˚F) No. 20 Carp, Hastelloy B Sulfuric acid 90%-100˚C (212˚F) Hastelloy D Measure medium state (concentration and temperature) Recommended materials Tannic acid 70˚F 304 stainless steel Tar steel (C1018), 304, Monel, Nickel Tartaric acid 21˚C (70˚F) 304 stainless steel Tartaric acid 66˚C (150˚F) 316 Stainless Steel Tin Melted SiC Tolvene Aluminum, Phosphor, Copper, Monel Trichlorethylene Steel (C1018) Rosin 304 Stainless Steel Varnish 304 Stainless Steel Vegetable Oil Steel (C1018), 304, Monel Measuring medium state (concentration and temperature) Recommended materials Vinegar 304 Stainless Steel Water Fresh Water Copper, Steel (C1018) Brine Aluminum Whiskey, Liquor 304 Stainless Steel, Nickel 304 stainless steel Changhui Instruments is a manufacturer of temperature measurement standards, high-quality thermocouples and intelligent digital instruments. It has accumulated rich production and application experience in temperature measurement. This article introduces metal thermocouple protection tube materials and specific applications. "Thermocouple Protection Tube Materials and Usage Occasions (2)" will introduce relevant knowledge of non-metallic thermocouple protection tubes. Please continue to pay attention to Changhui Instruments' original technical articles!