METHOD FOR RESTORING INNER CYLINDRICAL SURFACES OF PARTS Russian patent published in 2006 - IPC B23P6/00 

FIELD: restoration of worn parts of ferrous and non-ferrous metals operating at friction condition without lubrication or at condition of boundary lubrication, for example restoration and strengthening of mounting openings of bearing units of shafts of reapers of harvesters.

SUBSTANCE: method comprises steps of preliminarily preparing part; making sleeve and strengthening its inner surface by micro-arc oxidizing; placing sleeve in part with use of adhesive; drying it and subjecting part with sleeve mounted in it to finish mechanical working till target size. Micro-arc oxidizing is realized in electrolyte containing 8 g/l of potassium hydroxide and 35 g/l of sodium liquid glass with module m = 3.6 - 3.7 for 70 min. Sleeve is mounted with use of adhesive BC-350. Part is dried at temperature 240 - 255°C for 1 h. After finish working, part heated to temperature 100 - 120°C is immersed in molybdenite suspension for 10 - 15 min in order to fill pores of strengthening coating. Invention provides increased by 45 - 65 % porosity of strengthening coating. It allows realize self-lubricating mode of coating. Invention also provides increased by 1.2 times thickness of coating layer, shortened by 1.5 times period of running-in for achieving optimal roughness degree, increased by 2.5 times useful life period of restored and strengthened part, decreased by 2 times interval for drying adhesive.

EFFECT: improved efficiency of method.

1 tbl