Steel and its types

Steel and its types Steel is basically an alloy of iron and carbon to which sometimes other elements are added to achieve certain properties for specific performance of the steel. It is the most common material which the people come into contact with every moment, all the day and every day. There is hardly any object that people use today which does not contain steel or which is not created with equipment made of steel. In fact, today it is hard to imagine a life without the use of steel in some shape or form.  One has to just think of what would be missing in everyday life if there is no steel. Mass production of steel started late in the nineteenth century. From that time onwards steel has become the material of choice in most of the applications which make the daily lives of the people possible. This position of steel is due to its versatility, strength, and recyclability. The versatility of steel is well known. It can be used in diverse applications which includes transportation, infrastructure, building structures etc. on one side and sewing needles, screws for laptops, mother board sheets for mobile phones, springs for wrist watches and many others such smaller applications. Ballpoint pens rely on a steel sphere less than 1 mm in diameter to dispense ink. Steel can also be used in a wide variety of atmospheres which include extremes of cold and hot climates as well as in both arid and wet climates. World today depends on the strength of steel. Steel makes it possible to build skyscrapers and long span bridges since it has strength, rigidity and durability. Tankers and bulk carriers which help in moving resources across the world are made of steel. Wind mills...

Product Quality and Manufacturing Technology Management...

Product Quality and Manufacturing Technology Management Manufacturing technology is defined as the act or process (or connected series of acts or processes) of actually and physically making a specified product from its material constituents. It is central to a production system which produces the specified product as required by the customer. Manufacturing process takes place when some input occurs in a production system and it appears as an output and provides result in the form of a product. On the other hand, manufacturing technology is that knowledge which is used in the production system during the process of manufacturing. Manufacturing technology is an interacting combination at any level of complexity, of people, materials, tools, machines, automation, software facilities, and procedures designed to work together for the common purpose of producing product of that quality which is needed by the customer. It provides the tools which enable production of the specified products.  These tools of the manufacturing technology magnify the efforts of individual workers and turn raw materials at the affordable cost into the quality products required by the customers The objectives of the manufacturing technology (Fig 1) are namely (i) low cost operation, (ii) high performance, (iii) consistent product quality, (iv) high productivity level, (v) high yield, and (vi) product customization. Fig 1 Objectives of manufacturing technologies There is a close link between the quality of the product and the manufacturing technology. An appropriate manufacturing technology is normally needed to produce product of quality since the technology is the principal quality determinant. In fact, manufacturing technology is to have capabilities to produce products of predictable quality at the productivity levels which keeps the product production cost under control. The technology needs not be unique, but it is to be mature and is to have innovative...

Sintering Technology for Iron ores and Optimization of Sinter Machine Design Oct19

Sintering Technology for Iron ores and Optimization of Sinter Machine Design...

Sintering Technology for Iron ores and Optimization of Sinter Machine Design  The technology of sintering in its most basic form is very simple and has been in use since early twentieth century. However, while the basic technology is simple, control of the process relies on a number of extremely complex interdependent process parameters and requires a thorough understanding of the effect of these parameters on production capacity and sinter quality. Basic sintering technology The sintering technology is basically an agglomeration process for the iron ore fines which is dependent on heat to melt the surface of the smaller particles together to form larger agglomerates. A typical sinter plant consists of a number of sequential operating units with the sinter machine at the heart of the plant. The simplified process sequence is as follows. Raw materials consisting of iron ore fines, coke breeze, slag modifiers such as lime stone, dolomite, manganese ore, lime, quartzite, and sand etc., and waste materials such as mill scale, screenings, dusts, sludges, and converter slags etc. are batched and conveyed to a blending system. The raw materials are blended in a rotating mixing drum after addition of sinter return fines and water to achieve a green feed for the a process. The mixing process is normally referred to as ‘nodulizing’. The nodulized green feed is charged to the strand of the sinter machine on top of a sized hearth layer to form the ‘sinter bed’. This bed passes through the ignition furnace (hood) to initiate the reaction. Burners in the hood ignite the carbon in the green feed charged in the form of coke breeze. The reaction is propagated by chemical reaction between the carbon and the air sucked through the sinter bed by the exhaust fans. The sinter burns...

Metallurgical Processes and Defects in Steel Products...

Metallurgical Processes and Defects in Steel Products Defects in steel products are defined as deviations in appearance, shape, dimension, macro-structure / micro-structure, and/or chemical properties when compared with the specifications given in the technical standards or any other normative documents in force. Defects are detected either through visual inspection or with the help of instruments and equipments. There are four main metallurgical processes for the manufacture of finished steel products where the steel products can pick up defects. The defects picked up during these processes are (i) casting defects, (ii) rolling defects, (iii) forging defects, and (iv) welding defects. (Fig 1).These defects are described below. Fig 1 Metallurgical processes and steel product defects Casting defects Casting is a forming process which converts liquid steel into a solid product. In foundries liquid steel is cast into complex shapes by pouring of liquid steel into a mould in which it sets to the required shape. In steel plants, liquid steel is normally continuously cast in the form of slab (either thick or thin), bloom or billets. Casting defects are defined as those characteristics which create a deficiency or imperfection exceeding quality limits imposed by design and service requirements. Defects in foundry cast steel products There are in general three broad categories of defects in the foundry cast steel products. These are (i) the major or most severe defects which result in scraping or rejection of castings, (ii) intermediate defects which permit salvaging of castings through necessary repairs, and (iii) minor defects which can be easily repaired. Common defects which generally occur in castings are given below. Porosity – It consists of the spherical holes of varying size, with bright walls, usually evenly distributed and formed due to the gases in the liquid steel. The larger holes...

Role of Inspection and Testing in maintaining Product Quality...

Role of Inspection and Testing in maintaining Product Quality It is important for an organization that the quality of the products is maintained when they are delivered to the customers since the product quality is the top most drivers for the success of the organization. However, in the organization, employees do make mistakes and machines and equipment do have breakdowns. These results into the production process getting destabilize which in turn cause production of the products which do not meet with the requirements specified in the standards and specifications. Hence, there is necessity of inspection and testing so as to ensure that the products delivered to the customer are complying with the specification as required by the customer. Inspection and testing measure and determine the quality level of the products. These are the activities or techniques used to verify the product quality as well to ensure that the results of the manufacturing process are the same as was expected. Inspection and testing activities are done to uncover the defects in the products and reporting to the production management who make the decision to allow or deny product release. Inspection and testing during the process of the manufacture of a product are the most common methods of attaining standardization, uniformity, and quality of workmanship. These are the process of controlling the product quality by comparing it with the established standards and specifications. It is one of the operational parts of the quality control. During the inspection and testing, If the product does not fall within the zone of acceptability then it gets rejected and corrective measures are required to be taken by the production management so as to ensure that the product manufactured further conform to specified standards and specifications. Inspection and testing are indispensable...