Mild steel is a type of carbon steel with a low amount of carbon. Various steel kinds have diverse tensile and production strengths. It mainly depends on the chemical composition.
Mild steel is generally subjected to a variety of tests. Out of those tests, the Tensile Test of Mild Steel test has received a lot of attention. So, in this article, we will go through the concept of the Tensile Test for Mild Steel.
What is The Tensile Test of Mild Steel?
The tensile test, also known as a tension test, is a technique for checking the strength of a piece of metal. It also determines Young’s modulus and the ratio of elasticity of mild steel. Thus, tensile tests analyze how strong a material is and how much it can elongate.
Why is The Tensile Test Important?
The tensile test records the load value at the yield point, flash point, and endpoint. This value gives the steel a grade.
The primary test properties from a tensile test of mild steel are as follows.
- Yield point- At this point, you need to apply maximum stress before it permanently begins to change form. It is a calculation of the elastic limit of a piece of steel.
- Elasticity modulus -It measures the rigidity of the metal. You can use it in various technical calculations like beam deflection. There is a connection between strain and stress, which is Young’s Modulus. The value of the elasticity modulus of mild steel is 200 GPa.
- Flexural strength– Relates to the tensile test elongation. You can calculate the elongation rate by the highest measuring length divided by the initial measuring length.
- Ultimate tensile strength (UTS)-This tells you the maximum stress before a failure occurs you may apply to the steel.
- Flashpoint– At this point, due to the stress, the steel piece begins to fracture.
There are several uses for the data derived in a tensile test which include:
- To assess the quality of the batch.
- To analyze manufacturing uniformity.
- Support the process of design.
- Reduce material costs and meet lean production objectives.
- Maintain international and industry compliance.
- Comparison of technical data for several material alternatives.
Equipment Necessary For Tensile Testing
The following pieces of equipment are essential for the tensile test of mild steel.
1) Universal Tester – It comprises mainly of two units.
a) Loading Unit -The loading unit is a UTM component meant to load specimens.
b) Control Panel -It facilitates and assists load release procedure.
2) Punching tool -It estimates tensile strength and total elongation of sheet metals.
3) Vernier Caliper – It measures the inner and outer width of the rods and also shows their thickness.
4) Extensometer -It is an accessory to a tensile strength tester. It measures the change in object dimension.
Tensile Test of Mild Steel
During this test, a flat or a round bar of steel is pulled within the testing machine. The experiment is being conducted until the steel bar breaks.
Before the steel bar is broken, two different points in it are marked. They will be the gauge points. These gauge points are usually at the center of the steel rod.
The distance that exists between these two points before the application of load is calculated as well. This distance will be named as the gauge length. The load is equivalent to the gauge length.
A specialized instrument named “extensometer” is used to measure the extensions.
The recorded strains, which correspond to the recorded extensions will be calculated. It is done by dividing the stain by the gauge length. In the meantime, the stresses are being calculated by dividing the load by the initial area of the cross-section.
After taking the measurements, you will be able to see that the actual value of the stress is higher when compared to the nominal stress. That’s because the load is increasing, while the specimen area is decreasing.
The Tensile Test of Mild Steel is a simple one and a person will be able to conduct it at the comfort of the home as well. You just need to hang material from a solid point, which is fixed, and hang weights to the other end of it.
Then you will need to keep on measuring the changes in length, as you go on adding weights. Along with time, mild steel would increase in its length. This will happen until it comes to a point, where it will break.
With the obtained measurements, you will be able to go ahead and plot a graph. For example, you can see how the amount of weight changes according to the displacement that you can see on the mild steel rod.
In addition, you need to keep in mind that the size of the material is in a position to create a strong impact on the weight added. Comparing the two materials will be a challenging experience for you.
However, you need to have a clear understanding of how to do an accurate comparison.
There are a few equations, that you will need to use after plotting the graph to get to know about the maximum withstandable stress. Therefore, you need to be extremely careful with the measurements that you take.
Even a simple mistake that you make with taking the measurements can plot an incorrect graph, which can make you end up with incorrect results. You need to make sure such a thing will not happen to you.
Therefore, you need to try out the best of your patience while conducting the Tensile Test of Mild Steel.
How Does The Tensile Test On Mild Steel Graphs Work?
If steel is bent, you must remember the ratio of the stress-strain curve for mild steel. A graph of stress gives a precise analysis of the features of steel.
It has an elongation when you exert a tensile force on a bar made of steel. The stress & strain percentage remain proportionate when the pressure is modest enough. You can observe a straight line between Point A and zero in the graph – also known as the proportionality limit.
When the strength is greater, the material plastically deforms. Yet the stress-strain ratio is not proportionate. It is the elastic boundary between points, A & B.
The mild steel will be subject to plastic deformation beyond the elastic limit. It begins with the yield point, i.e., point B or the highest point of yield.
There is no more direct connection between stress & strain. It bends from the lower yield point (C) to the maximum ultimate pressure (D) and finishes with the fracture stress (E). For a quick graphical calculation of the tensile test of mild steel, this explanation is adequate.
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