The field data and microscopic analysis of acupressure defects show that in the continuous annealing,the particle-like inclusions accumulated on the surface of the roller are the main factor caused the defect when there exists relative slide contact between the annealing furnace roller and the surface of stainless steel strip.

Base d on the f ormation mechanism of pinhole defect in ductile castings, the production process of the bump housing and impeller of the oil transfer pump, which had been rejected totally due to severe pinhole defect, was improved including:(a) reducing moisture content of the molding sand from 7% to 5%;(b) adding 7.

The extrusion defects of aluminium profiles most have relation with die structure,and recommending several methods of design dies and to overcome defects of aluminium profiles.