Engineering - Steel - Lab Report Example

According to Degarmo and Black (2003, p.56), reinforced bars with high ductility and tensile strength are often preferred because they allow the materials to be rolled, drawn or made longer without breakage. Generally the tensile strength of reinforcing steel can be measured by dividing the cross sectional area of the steel tested by the stress exerted on the material. The amount of stretching force (N) needed to break the test material can then be measured and recorded. Experimental Procedure The tensile testing experiment involved calculating mechanical properties of three specimen samples of reinforcing steel bars which were designated as N12, R12 and RW11.9. Some of the main mechanical properties that were tested include yield stress, modulus of elasticity, elongation, tensile strength, ductility and reserve length.

Specimen N12 was a hot rolled deformed bar that was derived from a microalloy TEMCORE material. Generally such steel alloys are made by adding expensive alloys such as Silicon, Carbon, Manganese and Vanadium to the steel. As compared to the other steel samples that were used in the experiment, the surface of hot rolled deformed bar was rough and more imperfect. On the other hand, specimen R12 was a hot rolled plain round bar which was made from a mild steel material. Although the presence of carbon significantly lowered the ductility of the alloy, it was stronger and had more resistance to breakage (Pavlina and Tyne, 2008, p.216). Another important physical property of specimen R12 was that it was quite malleable and the surface was more polished.

Lastly, specimen RW11.9 was cold robbed riled wire which was also made from middle steel material. The surface was relatively smoother and malleable but the specimen was easier to bend than specimenR12. In terms of the geometry of the specimens, N12 had a diameter of 12mm, length of 500mm and a cross sectional area of 255mm2 . Specimen R12 was also 12mm in diameter, 500mm in length and had a cross sectional area of 113.1m2 . RW11.9 was 11.9mm in length, 12mm in diameter and the cross sectional area was 111.3mm2. The testing equipment that was used in the experiment included an Instron universal Machine and a clip on extensometer Epsilion model 3543 10 inch gauge length.

The model of Instron universal machine that was used300LX, SATEC Series, and the equipment had a large frame with a single test space which allows easy and safe loading and unloading of specimens for testing. Additionally the single print design of the Machine significantly reduced the floor space requirement and enhanced its use for testing high capacity tension, flex as well as shear of the specimens. Figure1. Instron Universal Machine model 300LX Designed by Epsilon technology, the Epsilion model 3543, 10 inch gauge length used in the experiment was uniquely designed to help in the testing of long samples such as wire materials, steel reinforcing bars and weld joints.

During the testing, the upper part of the extensometer is expected to pull out of the main body to deliver high accuracy and the equipment is only calibrated to measure displacement and loading using tension units only. Finally, the optional gauge length spacers of the extensomet