Surface treatment of light alloy casting

Abstract

Abstract PURPOSE:To prevent generation of dust from machine parts and to improve corrosion resistance by etching the precision machine parts by light alloy casting with a specifically composed acidic etching soln. then subjecting the parts to a chemical conversion treatment prior to machining. CONSTITUTION:The casting surfaces of die castings and lost wax castings of a light alloy such as an Al alloy, Mg alloy, etc. are etched >=10mum with an etching soln. consisting essentially of one or >=2 kinds among inorg. and org. acids such as the soln. contg., for example, 100cc/l phosphoric acid, 40cc/l ethyl alcohol and 120g/l citric acid or 100cc/l phosphoric acid, 200cc/l acetic acid and 40g/l NaNO3 prior to machining said parts to a shape having high dimensional accuracy. The etched parts are then rinsed and machined and thereafter the parts are subjected to a chemical conversion treatment with chromic acid and are then rinsed with water and hot water.

Inventors

• 👤 「よし」田　一郎
• 👤 Ichiro Yoshida

Bibliographic Details