Examine the tensile strength of three specimen of low, medium and high carbon steels is examined

The incur of this laboratory experiment is to examine the elastic strength of iii exemplification of low, medium and ut well-nigh one C stains is examined. The microstructure of the precedent is mark offd and calculations such as tensile strength, yield strength etc were clearly recorded. to a fault, the background conjecture was stated, the apparatus and procedure used to achieve the experiment was described. The briny part of this lab report is the word on the results and how close theyve been calculated to the original theoretical values by taking into consideration virtually external experimental errors. The last part of this report is the conclusion on the whole procedure.INTRODUCTIONThe main purpose of this lab report is by using a tensile testing machine (Hounsfield tensometer), to determine mechanical properties of cardinal variant bare(a) carbon steel materials (low carbon steel, medium carbon steel and noble carbon steel). excessively, their instill stru cture is to be examined using a Metallurgical microscope.BACKGROUNDThe three different materials are the low-carbon, medium-carbon and high carbon steels. Their tensile strength is examined which by definition is explained as the cadence of stress that a material can resist when a force pulls it along its length until a complete torture takes go in. A tractile material is a material that contains the properties of tractileity and tenacity and its competent to change its shape when a force acts on it and can keep that changed shape even afterward that force is removed. (Timings R. 2006)The tensile test is mainly used to specify the strength and ductility of a material. Also the tensile test involves1. Material showing a yield point which is the point that an point of reference takes identify without any increase in load2. Proof stress which is used to determine the amount of plastic deformation.3. Secant modulus which is used to determine the elasticity of the material. (Timi ngs R. 2006)Plain carbon steelsFerrous metals are basically a metallic material (iron) and it means that iron is combined with carbon. Iron and carbon, the simplest of the ferrous metals (Latin ferrum=iron), are the main elements of plain carbon steels.Low-carbon steels bring a carbon content 0,1-0,3% in addition to impurities. This kind of steels cannot be straight hardened by heat discussion, but they can be readily carburized and case hardened.The type of medium-carbon steels collapse a carbon content 0,3-0,5%. They can be toughened by heat treatment.All types of high carbon steels (carbon content 0,8-1,0%) are extremely strong and their response to heat treatment is better than the medium-carbon steels. However, because of the high carbon content they can be hardened to a high degree of hardness. (Timings R. 2006)The iron-carbon (Fe-C) diagram in encipher1 helps to study and learn much close to the microstructure of carbon steels as well as their heat treatment.Figure1. T he Fe-C physique diagram shows which phases are to be expected. (1)At the low-carbon end of the Fe-C phase diagram, we distinguish ferrite (alpha-iron), which can at about dissolve 0.028 wt. % C at 738 C, and austenite (gamma-iron), which can dissolve 2.08 wt. % C at 1154 C. (1)EXPERIMENTAL PROCEDUREIn order to complete this test, three tensile test specimens, each of different carbon content, are given. Also a tensometer machine is available in order to tense the specimens. The machine works as followsFirstly, the specimen is placed on the machine and a force pulls it along its length. This force is measured (in kN) on a digital force meter which is connected to the machine. On the top there is a cylinder with a graph paper around it in order to sketch a graph of force against the extension of the specimen. This is done by moving the pointer on the graph paper by 0,5kN respectively and pointing on the graph each time the study on the digital force meter increases by 0,5kN, for i nstance, if the reading reaches 1,0kN the pointer has to be pointing at 1,0kN and by the time that the reading is 1,0kN a point is sketched on the graph. (See figure 2 below)Figure 2.Furthermore, measurements of the length and cross-sectional area were taken before and after the test in order to determine the lucks of university extension and the reduction in area.The last part of the experiment is to examine the three micro-specimens given which is the exact same material and condition as the three materials used on the tensile machine and determine the percentage of the carbon content of their grain structure. This is done by using a Metallurgical Microscope.RESULTSThe results of the experiment were calculated and recorded on a table as shown below judge piecematerial% carbon contentYield strength(N/mm2)Ultimate tensile strength(N/mm2)% elongation% reduction in areaSpecimen ALow-carbon steel0,13154303766Specimen DMedium-carbon steel0,44756602862Specimen NHigh-carbon steel0,8932 9601330All the specimens had normalized treatment conditions. Graphs were plot for every specimen, which state clearly the points of force and extension. (See Tables below)The ultimate tension strength (uts) was calculated by the following formula (3)The yield strength (ys) was calculated by the following formula (4)The elongation percentage (elon.) was calculated by the following formulae (5)The reduction in cross-sectional area (red.csa) was calculated by the following formulax 100 (6)Microstructure resultsThe following specimens are the result of the experiment. The white region of each specimen is ferrite and the gray region is pearlite. The carbon content is determined using the iron-carbon (Fe-C) phase diagram.example ASPECIMEN DSPECIMEN NDISCUSSIONThe experiment is now completed and a discussion about the results is made. The values calculated in the experiment are going to meet the theoretical values of the three specimens used. In the table below all the results were record edCALCULATEDTHEORETICALLow carbon steelUTS (N/mm2)430162-3200YS (N/mm2)315140-2400ELONGATION (%)371-48 step-down A. (%)6613-99Medium carbon steelUTS (N/mm2)660450-2290YS (N/mm2)475245-1940ELONGATION (%)280.6-34.2REDUCTION A. (%)620.2-71.4High carbon steelUTS (N/mm2)960161-3200YS (N/mm2)932275-2750ELONGATION (%)131.9-30REDUCTION A. (%)3013.4-75.2The table supra show clearly that the calculated values are close to the theoretical values. This means that the experiment was prospered and the calculation were correct. Although, theres always a small percentage error in every experiment. The most viridity error in every experiment is the human error and this is the main type of error that whitethorn took place in this experiment. Also, differences in temperature and the purity of the material used is an important issue.Furthermore, from the examination of determining the grain structure of each material under the microscope the difference between them was very clear. For instance, the d ifferent amount of ferrite and pearlite could be identified, high-carbon steel had darker color than low and medium carbon steels which means that the amount of pearlite is almost 100%.Also, from the tables plotted on the tensometer machine the load that every specimen could withstand, the elongation percentage and the reduction in cross-sectional area were different. By considering these values, low-carbon steels have the least amount of load before complete deformation and the most percentage on both reduction in cross-sectional and elongation of the three specimens. This means that low-carbon steels have the least amount of carbon. In addition, low carbon steels can be defined as ductile materials. Medium-carbon and high-carbon steels are less ductile have les percentage of elongation. This means that they are harder and they are applied more load in order for deformation to take place.Finally, the last part of the discussion is about the different yield point of the three specim ens. If the graphs are considered, a sudden fall of the load appears to take place on the graphs of low and medium carbon steels during the procedure. This means that the two specimens faced a reduction in cross-sectional area (also known as necking). This doesnt seem to happen to the specimen of high-carbon steel which means that the deformation took place without having any noticeable reduction in cross-sectional area as the load was unplowed increasing.CONCLUSIONIn conclusion, the three specimens where tested and results were given. Since the calculated values meet the theoretical values, the experiment was successful. password about the ductility and the main structure of the given specimens was made and also the differences between them were stated.