TESTS PERFORMED ON NICKEL LAYERS ELECTRO-PLATED ON MOULD PLATES OF STEEL CONTINUOUS CASTING

摘要

This paper contains series of trials I conventional temperature conditions regarding the behaviour of the nickel coating on a copper support, in order to use them on the hardening of the mould plates surfaces from the continuous casting of steel. It presents the tests for a hetrtzian contact between a ball-shaped head and the samples made of copper and copper electrochemically coated with nickel in two different layers. This paper presents the first stage of a more comprehensive study, also including the tribological behaviour of various coatings on other support materials. The paper describes the test stand together with the methods which have been used and the experimental results obtained. These tests aimed to point out the moment of transition from the elastic range to the elasto-plastic range at the contact between the ball-shaped head and the sample. The experimental tests shown that, on the two nickel-coated samples, the coated layer presents almost the same tribological characteristics up to a value of Hertzian pressure sigma_k of about 2.200 Mpa. Above this value, on the sample with a nickel coated layer of 150 mu m in thickness, the plastic deformation process is intensifying.