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Steel excellent in resistance to sulfuric acid dew point corrosion and preheater for air

An air preheater and sulfuric acid-resistant technology, applied in the field of steel, can solve the problems of inability to exert corrosion resistance and incompatibility

Inactive Publication Date: 2003-11-12
NIPPON STEEL CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] However, the existing steel does not have the corrosion resistance under the above two corrosion conditions (the condition of 80-90% sulfuric acid at around 160°C, and the condition of 40-50% sulfuric acid at around 80°C).
Therefore, there is a problem that the desired corrosion resistance cannot be exhibited in equipment that is repeatedly started and stopped and is frequently exposed to high temperature to low temperature cycles.

Method used

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  • Steel excellent in resistance to sulfuric acid dew point corrosion and preheater for air
  • Steel excellent in resistance to sulfuric acid dew point corrosion and preheater for air
  • Steel excellent in resistance to sulfuric acid dew point corrosion and preheater for air

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Embodiment

[0042] Melt the steel with the chemical composition shown in Table 1 in a vacuum melting furnace, cast it into a 50kg ingot, and then hot roll it into a plate with a thickness of 12mm. Use rectangular test pieces of t3, 20, and 40mm in size to carry out sulfuric acid corrosion test . As the conditions representing the low-temperature region and high-temperature region under sulfuric acid dew point corrosion environment, in (a) 40% sulfuric acid, 60°C, (b) 50% sulfuric acid, 80°C, (c) 80% sulfuric acid, 140°C and (d) ) 90% sulfuric acid, and 160° C., four hours of immersion tests were carried out to obtain the corrosion rate.

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Abstract

A steel excellent in the resistance to sulfuric acid dew point corrosion, which has a chemical composition, in mass %: C: C22C 38 / 00 3 8 0 2002 / 2 / 1 1455822 2003 / 11 / 12 1195883 2005 / 4 / 6 2005 / 4 / 6 2005 / 4 / 6 Nippon Steel Corporation Japan Sakamoto Shunji Mishimura Satoshi Uzo Jiaki duan chengen liu jinhui 11247 Japan 2001 / 2 / 2 27455 / 01 2002 / 9 / 29 PCT / JP2002 / 000856 2002 / 2 / 1 WO2002 / 063056 2002 / 8 / 15 Japanese

Description

technical field [0001] The present invention relates to a steel material having excellent sulfuric acid dew point corrosion resistance for equipment such as flues, chimneys, and air preheaters of boilers exposed to exhaust gases produced by burning heavy oil, coal, garbage, etc. Background technique [0002] Combustion of fuel containing sulfur components produces SOx in the exhaust gas, which combines with moisture in the exhaust gas to form sulfuric acid. The temperature of the exhaust gas decreases, and once it reaches the dew point of sulfuric acid at about 160°C, the sulfuric acid gas condenses, and high-concentration sulfuric acid with a sulfuric acid concentration of about 80-90% adheres to the steel surface, causing corrosion. Furthermore, if the temperature drops to around 80°C, coupled with the condensation of water, sulfuric acid with a sulfuric acid concentration of about 40 to 50% is formed at a relatively low concentration, which accelerates corrosion. That is...

Claims

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Application Information

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IPC IPC(8): C22C38/00C22C38/02C22C38/04C22C38/06C22C38/16C22C38/60
CPCC22C38/02C22C38/06C22C38/004C22C38/04C22C38/16C22C38/60
Inventor 坂本俊治西村哲宇佐见明
Owner NIPPON STEEL CORP