Protrusions and indentations (rolling scars) on the surface of the wire rod

Wire surface protrusions and impressions (roll bumps) are inevitable when processing steel wires. These protrusions and indentations on the surface of the wire affect the technical performance and the product quality of the steel wire.

Surface protrusions deform significantly the original size of the wire, forming embedded polygonal bumps on the surface. The polygonal bump is a cavity formed during the process of wire drawing and cold heading due to the defect. The polygonal bump is like protrusions on the surface of the wire and is a kind of defect likely to cause failure during use. Generally speaking, the longest side of the polygonal bump should not be more than 2/3 of the original diameter of the wire. If the long side of the polygonal bump is longer than 2/3 of the diameter of the wire, it is not allowed.

Impressions (roll bumps) are caused by rolling processing technology. The bottom of the bumps is concave and the wall is curved. And the shape of the bumps is the shape of the rollers. Because of the poor lubrication, the rollers leave traces on the surface of the bars when pressed. The impression on the surface of the Rolled bars is usually shallow and narrow and it is also an important indicator of quality of the Rolled bars. The impression should not be larger than 1/3 of the wire diameter and the depth should not be more than 0.8mm.

In a word, protrusions and impressions on the surface of the wire do not meet the production requirements and need to be improved urgently. As for the present technical conditions, the prevention of surface protrusions and indentations is based on continuous improvement of the production technology and testing equipment, including reasonable design of wire drawing dies and their choice and matching in the process of cold heading. Thus, the conditions of wire drawing, lubrication and cold heading can be improved to ensure that the protrusions and indentations on the surface of the wire meet the corresponding technical standards.

The surface of the wire is the most important factor in determining the performance of the wire. The surface of the wire affects the overall performance of the wire and the life span of the wire. The texture of the wire, such as bumps and dents, leads to performance and durability of the wire.

Bumps and dents are commonly caused by cold rolling or hot rolling during the wire production process. When the wire is rolled, the material of the wire is pressed and some of the metal particles will be ground into tiny particles and scattered on the surface of the wire, resulting in bumps and dents.

The bumps and dents on the surface of the wire will weaken the mechanical and electrical performance of the wire. The roughness of the wire will cause the wire to have poor mechanical properties, and rapid oxidation of the surface of the wire will affect the electrical performance of the wire. The bumps and dents on the surface of the wire will also cause problems when winding, and if the winding is too tight, the bumps and dents will become more obvious.

To reduce the bumps and dents on the surface of the wire, it is necessary to control the pressure and rolling speed in the cold and hot rolling process, and use proper rolling method to ensure that the surface of the wire is smooth, reduce the number of bumps and dents, and ensure the performance and life of the wire.