冷卻對AISI 304不銹鋼銲件耐蝕性的影響

The effect of water quenching on the corrosion resistance of AISI304&304L stainless steel welds

不銹鋼因其耐腐蝕性極佳，在工業界通常被廣泛地被使用；但不銹鋼在銲接時，由於受熱的影響，使得溫度劇昇，因此易生敏化現象，造成晶粒間腐蝕，導致耐蝕性急遽下降，造成機件的損壞。本研究主要是在探討沃斯田鐵型不銹鋼銲接後，施以水冷對耐蝕性的影響，藉以改善不銹鋼銲件之防蝕效果。實驗過程採用電化學腐蝕法及ASTM262草酸腐蝕法，結果發現水冷卻對改善AISI304及304L不銹鋼銲件熱影響區之耐蝕性效果顯著。

Sensitization by carbide precipitation has great effect on the anodic polarization curves on AISI stainless steel welds. The sensitization temperature for 304 stainless steel is approximately 425-870℃. If the cooling rate is sufficient high, chromium carbide will not precipitate and the material will be super saturated with free carbon. This research aimed at examining the effect of water quenching on the welds of 304 stainless steel after gas tungsten arc welding (GTAW). In this investigation, the anodic polarization curves and ASTM262 oxalic acid etch test were employed to identify the corrosion resistance on air cooled and water quenched welds. The result showed that the water quenching process significantly improved the capability of corrosion resistance both on 304 and 304L stainless steel welds.