On the effect of non-metallic inclusions in production of small diameter wires

Abstract

Invistigations are directed to detection of the metallurgical reasons of the breakage of alloy steels during production of the small diameter wire. Several batches of the coiled bar(s) of low carbon silicon-manganese steels of the Sv-08G2S and G3Si1 were taken as materials for invistigation. The main influence on the metal breakage during drawing is exerted by its structure and mechanical characteristics, it is known. The initial structure of the coiled bar(s) before drawing to small diameters from the differents smelting within one sort was not differ and represented globular pearlite for Sv-08G2S steel, ferrite and pearlite for G3Si1 steel. The influence of equipment and drawing technology on the wire breakage is minimal, as the processing is performed with the same conditnions. Special attention in the invistigations was paid to the contamination of steel with nonmetallic inclusions during the drawing. Analysis is showed in the wire of low carbon silicon-manganese steels the presence of the point oxides, non-deformable silicates and sulfides, and fragile inclusions, which are located along the rolling direction. The feature of the wire, which has observed the breakage during the production, is the presence of the large quantity of the line inclusions (3...5 points), which are located in some cases over the entire surface of the polished section of the Sv-08G2S steel. The structure of all investigated steels does not differ, the mechanical characteristics of the wire with breakage corresponded to the required standard values. It is shown that contamination of the original wire rod with (more than 2 points) of nonmetallic inclusions are significantly increases the chance of difficulties arising during production of the wire with a diameter of 1,2...0,8 mm and can lead to breaks. The high purity of steel in terms of nonmetallic inclusions guarantees the absence of breakage due to this defect during the production of wire, which contributes to increase of the performance and decrease in the cost of finished products.