Charpy Impact Test

2.1 Overview

Charpy impact testing is used to determine certain mechanical properties of materials, it is mainly used for metals, but can be used on ceramics, composites and polymers as well, it is a cost-effective quality control test that is still used in industry to monitor the properties of manufactured materials.

2.2 Charpy Impact Testing

The Charpy impact test was invented by Georges Augustin Albert Charpy, a French scientist, in 1900.

Charpy impact testing consists of striking a notched test specimen with a controlled weight pendulum swung from a set height. The basic setup can be seen in figure 1. The usual Charpy V-notch is 55mm long, 10mm square and has a 2 mm deep notch with a tip radius of 0.25mm machined into one face [1].

It is more commonly used on metals but can also be applied to composites, ceramics and polymers [2].

FIGURE 1: CHARPY IMPACT TEST APPARATUS [1]. FIGURE 2: CHARPY V-NOTCH TEST SPECIMEN WITH DIMENSIONS [1].

2.3 Low Carbon Mild-Steel

Low carbon mild steel is considered the best steel for carburized parts and has excellent weldability. This steel offers a good balance of toughness, strength and ductility and when hot rolled this steel exhibits improved machining characteristics, Brinell hardness and better mechanical properties.

When specific manufacturing controls are used for this material they develop a high quality steel that is well suited for an array of fabrication processes, namely: welding, forging, drilling, machining, cold drawing and heat treating [3].

This material is used in the following processes:

• Bending, crimping and swaging processes.

• Carburized parts such as gears and tools.

• Fixtures, mounting plates and spacers.

• Used where high carbon, high strength steels are not needed.

• It is gives great surface hardness well still having a soft ductile core. Perfect for gears, shafts and tools.

• Used in the prevention of cracks in severe bends

as 100% machinability) 70 % 70 %

Shear Modulus (Typical for steel) 80.0 GPa 11600 ksi

2.4 Aluminium

This material was discovered in 1825 by Hans Oersted. It is a very versatile lightweight metal that is used extensively across many different sectors, some include cans, foils, kitchen utensils, window frames, beer kegs and aeroplane parts. This is due to its particular properties. It is a low density, non-toxic, corrosion resistant, easily castable, machined, formed and has a high thermal conductivity. It is also the second most malleable and sixth most ductile metal available. It is often used as an alloy as it not a particularly strong metal, but is often alloyed with other metals to improve its strength. Along with being very ductile, malleable and light weight it is a great electrical conductor and is often used in electrical transmission