Abstract
Prestressed Concrete wire is used under high tensile stress in a wide variety of atomosphere, and stress corrosion will develop in this wire to some extent. We have studied on this problem using three methods: free loop bending and tensioning methods. The specimens were PC wires with a diameter of 2.9mm made of 0.7% and 0.8% carbon steel. They were cold drawn, cold drawn and stress relived and oil-tempered wires.
As corroding media, we applied some chrolides, nitrates and ammonium rhodanate. The results we obtained are summarized as follows:
(1) Oil-tempered wire is less stable to stress corrosion attack than cold drawn wire and cold drawn and stress relieved wire.
(2) The cracks and fractures of oil-tempered wire are trans-axial, but those of cold drawn wire are axial or semi-axial.
(3) As to the corroding media, rhodanate and nitrate are active, while chrolides are not so active.
(4) Of oil-tempered wires, the higher the tensile strength is, the more sensitive they are to stress corrosion.
(5) The amount of carbon content and stress relieving treatment have little influence on the resistivity to stress corrosion.
Anyway, we could conclude that cold drawn wire and cold drawn and stress relieved wire were rather stable to stress corrosion.
