Powder Metal Parts Cleaning

Question:

I read Products Finishing, and I have come across a new opportunity for my heat treating company. We are being asked to carburize, oil quench, clean and temper a small part, 4.75 grams each. The part has a density of 7.0 ±0.05 grams/cu cm. The part is currently made and processed in Japan. While I am not aware of the environmental issues in Japan, I would think they are similar to our laws and the impact to cost of chlorinated solvents is what I am trying to avoid. Any advice on types of alternative cleaners or processes would be appreciated. I am not opposed to paying for consulting advice if you can refer someone who is knowledgeable. Thanks for the advice. P.H.

Answer:

Heat-treated steel that has been carburized and oil quenched would require significant cleaning to remove both oil and carbonaceous smut from the surface. A heavy-duty aqueous cleaner would probably be the first step required to remove the majority of oil from the quenching process. Tap water rinsing will be required after the cleaning step. An acid pickling will likely be required next in order to remove the carbon smut from the surface. Rinsing and possibly rust inhibiting steps will be necessary to complete the cleaning process. The physical impingement of ultrasonics may be beneficial in the cleaning and pickling steps for more efficient and complete removal of contaminants.