結構用鋼在600℃抗高溫氧化性能研究

A Study of High Temperature Oxidation Resistant Characteristics of Structural Steels at 600℃

本文是研究五種結構用鋼在600℃空氣、純氧氣、模擬水泥廠窯殼氣氛（含CO2 12.5%、H2 13.3%、N2 62.2%、空氣12%）等三種氣氛中的抗高溫氧化性能。研究方法包括實驗室腐蝕失重試驗、熱重分析試驗、氧化銹皮金相觀察和X光繞射分析。結果顯示不論在何種氣氛中，SCR-TEN 2鋼比A 36、SB 42、A 242-2和SM 41 A都具較佳的抗氧化性。熱重分析氧化動力研究顯示在初期的24小時內各鋼材的氧化銹皮都具或多或少的保護性，雖然其氧化速率常數無法預測長期（18天或20天）的氧化量。在空氣中各鋼材的氧化銹皮均含一個外層銹皮Fe2O3（具有孔洞）和一個內層銹皮FE3O4（無孔洞），而造成氧化量不同的原因是有些鋼材的外層銹皮所佔之份量較多，保護性較差，腐蝕量也較大。在純氧中SCR-TEN 2和A 242-2之銹皮較不易破脆，反之，A 36、SB 42和SM 41 A之銹皮較易破脆，因此前二者腐蝕量比後三者低。在模擬窯殼氣氛中SCR-TEN 2和A 242-2之銹皮祇有FE3O4，A 36、SB 42和SM 41 A之銹皮除了FE3O4外，尚有保護性較差之FeO，因此前二者鋼材的腐蝕量亦比後三者低。

This paper is to investigate the high temperature oxidation resistant characteristics of five Structural steels at 600℃ in three atmospheres: air, pure oxygen, and simulated kiln atmosphere. Experimental methods include laboratory weight loss test, thermogravimetric analysis, as well as microstructural study and X-ray diffraction analysis of the corrosion products. The results indicate that Steel SCR-TEN 2 possesses better oxidation resistant characteristics than those of A36, SB42, A242-2, and SM41A. Kinetics study with thermogravimetric analysis reveals that the oxidation products in the initial 24 hours of all steels are more or less protective, although the rate constants can not predict the long term(18 days or 20 days) oxidation. In air, the scales on all steels are composed of outer porous Fe2O3 layer and inner compact Fe3O4 layer. The difference in oxidation rate comes from the fact that some steels possess more percentage of outer layer which is less protective and thus promotes the corrosion. In pure oxygen, the scales on A36, SB42, and SM41A, are susceptible to cracking, while those on SCR-TEN 2 and A242-2 are less susceptible and the latter two steels possess less corrosion rates. In kiln atmosphere, the scales on SCR-TEN 2 and A242-2 are composed of Fe3O4 only, while those on A36, SB42, and SM41A are composed of Fe3O4 and less protective FeO. Therefore, the former two possess less corrosion too.