這是中部一家規模很大的汽車零件外銷工廠 所做的檢驗報告. 請了一個半調子的金相檢驗工程師(德國人, 台灣女婿?)所做的錯誤報告. 去年發生過一次, 今年又發生了. 誰說遠來的和尚會唸經? 用英文寫的部份是要給他看的.去年與他會面時 他說他有在看我的 部落格.
浸蝕不均, 導致誤判. 建議使用浸浴式腐蝕(immersion eching). 腐蝕不要用滴的或刷的. 滴上幾滴浸蝕液再用棉花棒刷開, 常會有此不均勻的現象. 訓練/經驗不足時 就會誤判. 以下就是檢驗者的判讀原文:
在ZD0642我們看到"碳累積在一個永久變形區域"***(容易導致裂痕). 但這是在材料內部非表面,此批仍可允收.
***這句話是啥?外行的可真會被這種專業術語給唬倒. What on earth is this ! 這是啥米東東啊! Das ist nicht richtig.
Yellow arrows:黃箭頭所指黑線是front-line or border-line of etchant drops on the spcimen. After swabbing, you get a black line like this. This line got severe etching than elsewhere, so it reflects less light to our eyes. Red arrows: undissolved or retained carbide; aqua arrows: carbide particles precipitated during tempering. The more "sub-microscopic" carbide particles dispersion, the more ductile will the ballpin be. Ductile (Dimpled) fracture surface is resulted from the presence of these super-tiny carbide particles.
Below: Darker areas (red circles): under-Austenized areas. But if the impact test is O.K., then, this minor imperfection of the microstructure can be tolerated. Under-Austenization means workpiece is quenched while "solution" process is not fully completed and it shows a "rougher" area that reflect less light than elsewhere. 上面這調質金相組織, 做得非常好, 我給打95分. 下圖紅色圈圈內是"非M".---就是沒有成功變成Martensite的區域. 淬火得90%M 性能可過關. 但韌性在下限.
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