용융아연에 의한 철의 침식 현상에 관하여

Abstract

극연강재(極軟鋼材)를 440∼570℃ 범위의 여러가지 온도에서 용융아연 중에 침적(浸 漬)하여 그 침식량과 반응시간 및 온도와의 관계를 실험 조사 하였다. 495℃에서 침식량은 이상적(異常的)으로 증가하고 그 반응시간에 직선적인 비례 관계를 갖는다는 점을 확인 하였다. 또한 440∼475℃온도 범위에서는 거의 변화가 없고 520℃ 이상에서는 침식된 철분이 이보다는 많으나 급격한 증가는 없었으며 이러한 침식량들은 반응시간의 제곱근에 비례하였다. δ₁과 ξ상(相) 간의 peritectic reaction은 Schramm의 상태도에서는 530℃에서 일어남에 비하여 495℃에서 일어났었다.

이러한 결과로 부터 얻을 수 있는 결론은 도금가마(Galvanizing Kettle)의 수명을 연장하기 위해서는 Kettle Wall 외측온도가 530℃가 되지 않도록 Local over-heating을 피하여야 하며 488℃를 표준으로 도금로(鍍金爐)를 설계하지 않으면 안된다는 점이다.

The relation between the reaction time, temperature and the dissolved amount was experimentally investigated by dipping the extra mild steel in the molten zinc at different temperature within the range of 440-570℃.

It was found that the abnormal increase of dissolved amount took place at 495 ℃, and the relation of dissolved amount with respect to reaction time was lineary proportional. In the temperature region between 440-475℃, there were only the slight. changes and above 520℃, even though the amount of dissolved iron was larger, great increase could not be found and the dissolved amounts increased in proportion to the square root of the time. The peritectic reaction between δ₁and ξ phase took place at 495℃ in comparison to 530℃ in the Schramm's phase diagram. From these results, it was concluded that in order to lengthen the life of galvanizing kettle, it must be avoided for the outside temperature of kettle wall to reach 503℃ by local over-heating and the furnace for a kettle should be designed according to the standard temperature, 488℃.

The relation between the reaction time, temperature and the dissolved amount was experimentally investigated by dipping the extra mild steel in the molten zinc at different temperature within the range of 440-570℃.

It was found that the abnormal increase of dissolved amount took place at 495 ℃, and the relation of dissolved amount with respect to reaction time was lineary proportional. In the temperature region between 440-475℃, there were only the slight. changes and above 520℃, even though the amount of dissolved iron was larger, great increase could not be found and the dissolved amounts increased in proportion to the square root of the time. The peritectic reaction between δ₁and ξ phase took place at 495℃ in comparison to 530℃ in the Schramm's phase diagram. From these results, it was concluded that in order to lengthen the life of galvanizing kettle, it must be avoided for the outside temperature of kettle wall to reach 503℃ by local over-heating and the furnace for a kettle should be designed according to the standard temperature, 488℃.