Bearings for Rolling mill Rolls...

Bearings for Rolling mill Rolls Rolling mills for rolling of steel differ in many aspects with each other. The rolling mills are of different sizes and capacities. The mills roll steel materials of different cross-sections, sizes and qualities and in material conditions which are either hot or cold. The mills have different configurations and speeds of rolling. The configurations of the mills can vary from cross country, reversing, semi continuous to continuous. The equipments of rolling mills can have manual operations, mechanical operations, electro-mechanical operations, pneumatic operations, hydraulic operations, or a combination of all of these. The controls provided in the mills can be manual controls, remote controls, instrumented controls, or fully automated controls. Further in many types of mills even heat treatment processes are integrated. In spite of the so many differences, all the rolling mills have in common some basic technologies and equipments. All the rolling mills have rolls for the rolling of materials which are fitted in roll stands. Rolls are either driven by electric power or friction driven and are to resist many forces for normal rolling. The roll stands can have two rolls, three rolls, four rolls, six rolls, or a set of multiple rolls mounted on them depending on the types of mills. During rolling, the load on the rolls gets transferred to the roll neck bearings and their assembly (chocks). Rolls for their smooth rotation as well as for resistance to different forces need ‘bearings’.  Roll bearings are to meet the basic need of the rolling mill which is the smooth rolling of the steel products. They are friction reducing devices which provide support to the rolls for effective rolling with minimum of energy loss. The bearings are designed to withstand high rolling loads, heavy shocks, varying...

Importance of Housekeeping and Cleanliness at Workplace...

Importance of Housekeeping and Cleanliness at Workplace Housekeeping and cleanliness at the workplace are closely linked to the industrial safety. The degree, to which these activities are effectively managed, is an indicator of the safety culture of the organization. Housekeeping and cleanliness not only make the organization a safer place to work in but also provide a big boost to the image of the organization. These activities also (i) improve efficiency and productivity, (ii) helps in maintaining good control over the processes, and (iii) assist in maintaining the quality of the product. These important aspects of housekeeping and cleanliness are shown in Fig 1. Fig1 Important aspects of housekeeping and cleanliness There are several signs which reflect poor housekeeping and cleanliness at the workplace in the organization. Some of these signs are (i) cluttered and poorly arranged work areas, (ii) untidy or dangerous storage of materials (such as materials stuffed in corners and overcrowded shelves etc.), (iii) dusty and dirty floors and work surfaces, (iv) items lying on the shop floor which are in excess or no longer needed, (v) blocked or cluttered aisles and exits, (vi) tools and equipment left in work areas instead of being returned to proper storage places, (vii) broken containers and damaged materials, (vii) overflowing waste bins and containers, and (viii) spills and leaks etc. Housekeeping and cleanliness refer to the processes which ensure facilities, equipment, work areas and access routes are kept in good condition. This condition is required for supporting safe and reliable operation and maintenance during normal plant operation. Additionally, during the emergency, housekeeping and cleanliness ensure that the plant operations are not inhibited. Further, the housekeeping and cleanliness both are interrelated. Reaching a good standard in one of them is difficult without reaching a good...

Ironmaking in Rotary Hearth Furnace May17

Ironmaking in Rotary Hearth Furnace...

Ironmaking in Rotary Hearth Furnace Ironmaking in the rotary hearth furnace (RHF) is a direct reduction process which utilizes non-coking coal for the reduction of iron ore. The RHF is the process reactor which consists of a flat, refractory hearth rotating inside a stationary, circular tunnel kiln. Inside the RHF, direct reduction of iron ore or iron-bearing waste materials occurs, using coal as the reductant. RHF is not a new technology. It has been used successfully in a range of industrial applications which includes heat treatment, calcination of petroleum coke, waste treatment, and non-ferrous high-temperature metal recovery. The history of ironmaking in RHF goes back to the mid-1960s with the development of the ‘Heat Fast’ process by Midrex. Since then several ironmaking processes based on RHF have been developed. These include ‘Fastmet’ process/‘Fastmelt’ process, and ITmk3 process which were brought into commercial operation. These processes have been described in separate articles having links    http://ispatguru.com/fastmet-and-fastmelt-processes-of-ironmaking/, and http://ispatguru.com/itmk-3-process-of-making-iron-nuggets/. Other RHF processes are ‘Redsmelt’ process, ‘Inmetco’ process, ‘Iron Dynamics’ process, ‘DRyIron’ process, ‘Comet’ and ‘SidComet’ processes and Hi-QIP process. Redsmelt process The Redsmelt process technology has been developed to meet the growing demand for a low cost environmental friendly ironmaking alternative to the traditional blast furnace route. The plant with this process can be designed for a production capacity of 0.3 million tons per year to 1.0 million tons per year of hot metal. The process can treat a wide range of iron ore fines and waste materials from the steel plant. The Redsmelt process is based upon a RHF which reduces green pellets made out of iron ore, reductant fines and binders to produce hot, metallized direct reduced iron (DRI) which is charged to a submerged arc furnace (SAF). The process operates at high temperature and...