Wire Rods and Wire Rod Mills Aug13

Wire Rods and Wire Rod Mills...

Wire Rods and Wire Rod Mills Steel wire rods are an all-round talent since they are the key product of steel industry with multiple uses. They are used as the material for fasteners, springs, bearings, wire ropes, chains, cables, wire meshes, wire fencings, tyre cord, reinforcement in railway sleepers, and many other uses. They are used for the components needed for the automotive industry, chemical industry, power stations and machine engineering. Unlike cold-rolled sheets, heavy plates, pipes, sections and other steel products, wire rods are seldom used as hot rolled for final products, but they are manufactured into machine parts after undergoing one or more stages of so called post-processing such as heat treatment, forging and wire drawing at specialist plants. Wire rods are generally drawn down to a specific diameter before being subjected to forging or other forming operations in secondary processing. In many cases, the size of the wire rods before being subjected to these forming operations is to be less than the minimum size of 5.5 mm that can be supplied as rolled. Generally each of the wire rod product is developed with due attention to its behaviour at the post-processing stages. What is required for a steel plant regarding wire rods is good processibility and fulfilment of the required properties after the processing. Furthermore, since the costs of the post-processing is sometimes several times the price of the wire rods, it is increasingly important to reduce the total integrated manufacturing cost from the steel material to the final product. Also thermo mechanically treated (TMT) reinforcement bars of 6 mm, 8mm and 10 mm basically required for the building construction are produced in the wire rod mills. The following generally characterizes the wire rod products. Product grades are widely varied from...

Productivity and Product Quality in Continuous Casting Machine Jun25

Productivity and Product Quality in Continuous Casting Machine...

Productivity and Product Quality in Continuous Casting Machine Continuous casting is the process by which liquid steel is solidified into a semifinished steel product (billet, bloom, or slab etc.) for subsequent rolling in the hot rolling mills. Continuous casting of liquid steel was introduced for commercial application in 1950s. In the relatively short time span since the introduction of continuous casting for the commercial application, the process has evolved with a wide variety of new process developments directed towards achieving improved productivity and superior product quality. These developments include new design concepts of continuous casting machines, metallurgical practices, and the application of process control and automation by computer systems. The main driving force behind these developments has been the recognition that substantial improvement in the yield and energy savings are possible which have a dramatic effect on operating cost. Through these developments, it has been possible to achieve major quality improvements of the continuous cast product.  Present day continuous casting machines produce cast steel products having quality which is fully equivalent to and exceeds that of products produced from ingot steel. Modern continuous casting machines efficiently produce essentially all grades of steels, including the highest qualities for critical applications. Productivity improvement The two methods to improve the productivity of the continuous casting process include improving the continuous casting machine throughput (tons/hour) and net-working ratio. The through put of the continuous casting machine is improved by increasing the casting speed as well as by increasing the cross sectional area, while the net- working ratio is improved by decreasing the casting machine down time. The casting speed of the continuous casting machine is limited by several different phenomena as given below. A high casting speed results in a significant increase in the flow velocity of the...

Defects in Continuous Cast Steels Dec11

Defects in Continuous Cast Steels...

Defects in Continuous Cast Steels Continuous casting (CC) is the process which converts liquid steel into a solid product mainly in the form of slab (either thick or thin), bloom or billets. It is one of progressive steel making technologies which produces a cast product of a desired cross section in indefinite length. The CC process requires strict observance of operating procedures,  technological norms, and advanced production and control techniques. Despite these measures, the occurrence of defects in the CC product cannot be fully ruled out. The formation and the type of defects depends on the status of CC machine equipment, the cast product shape and size, the steel grade, the technological conditions of casting such as casting temperature and speed, the mould oscillation and cooling, the quality and properties of the casting powder etc. A defect in a CC product can be defined as a deviation in the appearance, shape, dimension, macrostructure, and/or chemical properties when compared with the specifications given in the technical standards or any other normative documents in force. Defects are detected after casting in the CC product through visual inspection of their surface at the cooling beds, by checking the surface quality again by visual inspection on the inspection beds, or by checking the chemical analysis and the macrostructure of the test samples in the laboratories. The defects in CC products generated during the solidification and cooling process lead to loss or diversion of prime material for further processing or sale. To prevent these losses, it is necessary to analyze the causes of the occurrence of defects for taking preventive action by adopting preventive metallurgical technologies and constructive solutions. Also it is necessary to segregate and remove defective product from the prime material. A defect is not always the...