不銹鋼及鎳基合金之塵化敏感性比較研究

Sensitivities to Metal Dusting of Stainless Steels and Nickel-base Alloy

本研究主要探討304、347及XM-19不銹鋼及鎳基690合金於具有高碳勢氣氛環境中之高溫塵化性質。在600℃之35CO-60H2-5H2O混合氣氛中暴露500小時後，以掃瞄式電子顯微鏡（SEM）觀察表面形貌變化，以能量散射光譜（EDS）分析反應產物，以探討不銹鋼及鎳基合金發生金屬塵化的敏感性。試驗結果發現，當發生金屬塵化反應時，304及347不銹鋼試片表面有嚴重積碳現象發生，且表面有明顯之蝕孔生成；若無金屬塵化反應發生，則試片表面積碳輕微且無蝕孔。XM-19合金及鎳基690合金經暴露試驗500小時後，試片表面無大量積碳及塵化反應發生。

The susceptibilities to high temperature metal dusting of AISI 304, 347 and XM-19 stainless steels and Ni-base alloy 690 exposed in 35CO-60H2-5H2O mixed gas at 600℃ for 500 hr were investigated. After exposure test, the specimen surface morphology was examined by a scanning electron microscope (SEM). Energy dispersive spectroscopy (EDS) was employed to analyze the chemical composition of the reaction product formed on the specimen surface. The experimental results showed that thick carbon deposits accompanied with pit formation were found on the surfaces of 304 and 347 SS if metal dusting took place. In the absence of metal dusting, however, only slight carbon deposition occurred and no pits were seen on the specimen surfaces of 304 and 347 SS. No serious carbon deposition and metal dusting reaction were found on the specimen surfaces of alloy XM-19 and Alloy 690 after exposure test for 500 h in the same environment.