Physical behaviour of material during reduction at High temperatures The behaviour of material from the time are charged on the stock line until their descent in to the bottom of the stock is of direct interest in assesiass the blast furnace operation. During this period the material may disintegrate by any one or more of the of the below reason : 1. Decrepitation 2. Low temperature breakdown under reducing condition. 3. Failure under overlying load at high temperature. 4. Swelling at high temperature under reducing condition. 5. Premature softening of materials. ● The permeability of the ..read more

Some laboratory tests have been devised to investigate, identify and quantify on a relative basis, an increasing number of burden properties to assess the extent of suitability of burden materials. These tests are empirical in nature and hence the results of two different investigation do not readily agree unless extensive standardisation is sought. ● The properties of burden material of interest are those properties which have bearing on its performance during handlings, until it is charge I'm the furnace, and subsequently on its behaviour inside the furnace. These properties are : 1. Roo ..read more

Firing machineThere are three types of pellet firing machines that in commercial use which have discuss below : 1. The shaft kiln 2. The grate machine 3. The grate kiln. The Shaft Kiln : ● It was developed in the 1950's. The green or dried pellets are fed vertically downwards in a central shaft of usually a rectangular cross section. Fuel is burned in two fire chambers, one on each long side of the shaft, and the hot gasses are allowed to enter the main shaft through multiple flues. ● It is in a way counter-current gas solid heater. The fired pellets are cooled in the lower portion and if a ..read more

Fatigue Test : Failure of a metal can take place at much lower stress as compared to tensile strength when it is subjected to repetitive or fluctuating load. Such failure is referred to as fatigue failure, which always result in brittle fracture. ● It takes place instantaneously without any warning. Many components such as crank shafts, gears, connecting rods, springs and blades of power driven machines, which are subjected to cyclic loading are prone to failure by fatigue. ● Such failure has been observed to be promoted mainly by application of sufficiently high tensile stresses, large flu ..read more

Impact Test Impact test measure the strength of a material under dynamic loading, where most of the structural components are subjected to dynamic loading. So tensile strength along will not be of sufficient use as a seeing parameter. ● In impact test the material is subjected to sudden load, a hammer is made to swing from a fixed height and strike the standard impact specimen. Impact strength of a material is defined as the capability of the material to absorb energy without failure under impact loading. Impact testing machine ● Depending on the nature of the standard impact specimen, there ..read more

Tensile Test Tensile test is one of the most widely performed tests. In this process we determined yield stress, upper and lower yield points, tensile strength, elongation and reduction in area. ● Universal tensile testing machine is frequently used for performing tensile test. The specimen is subjected to tensile load till fracture occurs. These results of tensile tests can be represented in the from of engineering or true stress-strain curve. Yield Stress :Stress strain curve The yield stress is defined as the stress at which plastic deformation of the tensile specimen takes place at a cons ..read more