Continuous casting of steel billets Mar19

Continuous casting of steel billets...

Continuous casting of steel billets Continuous casting of steel is a process in which liquid steel is continuously solidified into a strand of metal. Depending on the dimensions of the strand, these semi-finished products are called slabs, blooms or billets. Steel billet has a square cross section with one side normally 150 mm or less. It is a feed material for rolling of steel in light section mills, bar mills, and wire rod mills. Steel billets are also used in forging of certain products. The process of continuous casting was invented in the 1950s in an attempt to increase the productivity of steel production. Previously only ingot casting was available which still has its benefits and advantages but does not always meet the productivity demands. Since then, continuous casting has been developed further to improve on yield, quality and cost efficiency. Continuous casting of steel is now the method of choice by all steel producers replacing the old method of ingot casting. Distinguished by its many advantages, this process has gone through many improvements and was and still is the subject of wide range of studies both empirically and mathematically. Continuous casting of steel billets is one of the type of continuous casting adopted in steel industry, by which, steel billets are produced continuously and simultaneously. This type of process requires great control of operating parameters in order to produce sound and continuous billets. The process can be divided into a number of steps starting by pouring the hot liquid steel from the steelmaking furnace into the ladle, where the steel chemistry is being adjusted in secondary steelmaking, then pouring into the distributor (tundish), and from the distributor into the casting mould. Solidification of steel begins in the copper casting mould by indirect cooling,...

Billet Inspection and Conditioning Facilities Aug20

Billet Inspection and Conditioning Facilities...

 Billet Inspection and Conditioning Facilities A considerable percentage of steel bars and wire rods are used for the safety-related parts of automobiles after undergoing post-processing steps (secondary and ternary processing). Quality requirements for these steel bars and wire rods are becoming increasingly diversified in consideration of the workability at the stage of secondary and ternary processing and the use conditions of the machine parts into which they are made. In addition, the need for quality assurance throughout the entire length of the steel bars and wire rods has also increased, and the steel plants are required to apply very severe quality standards for meeting these requirements. Due to this reason, the importance of the reliability of inspection and conditioning of billets which is the starting material for the production of steel bars and wire rods has increased significantly. Depending on the application, billets require surface inspection and conditioning to minimize the surface imperfections. Standard inspection methods consist of visual inspection of the billet surface under white light conditions or wet magnetic particle inspection under black UV lighting. Normally steel plants shot-blast the surface of the billet to remove the mill scale and to improve the visibility of the surface, depending on the type of surface conditions they are trying to detect. The surface imperfections are normally marked as they are detected, and these locations are conditioned. Methods employed are usually machine- grinding and sometimes scarfing. The traditional inspection techniques (other than visual method), which have been aligned to the rolled billets, are all conditioned to the detection of defects which have a significant length component, i.e. seams, rolling laps, tonguing, etc. Continuously cast billets contain, on the other hand, a completely different type of defects such as pinholes, corner tearing, reciprocation marks, entrapped scum,...