The subject of our report is a security safe. The specific case we have chosen to look at is a personal domestic security safe with a storage space of. The purpose and main use of the security safe is to store valuable items from theft and break-ins. The security safe is to be fitted with a mechanically controlled and locking lock mechanism which is operated with a key pad. This report will focus solely on the material selection and manufacturing of the outer casing of the safe, which will be referred to as the safe walls. Safe walls must be able to sustain attacks from tools, machinery and dropping. This means that the walls must be made of materials which have the properties which can protect the safe from these attacks. The higher the weight of the safe the more desirable the product is as a heavier safe would in turn be harder to transport for a thief than a lighter one. Although the target storage space of the safe has been defined the external dimensions of the safe are not restriced in any way but are expected to be practical for transportation. As mentioned in the product description the security safe walls require material properties which prevent attacks from tools, machinery and dropping. The most essential material properties desired of the safe wall are:
Ultimate Tensile and Compressive Strength – The ability to be subjected to external loading without failure. The safe will perform better with a higher strength in order to withstand being crushed or impacted with steadily applied forces.Ductility – The ability to deform without brittle fracturing. Ductility has the opposite meaning of brittleness, and as brittleness would allow the safe to be broken into easily by dropping or impact. A material which fails in a ductile way must be used to produce the safe.Toughness – The amount of energy a material can absorb before failure. This is a property which relates to the shock, impact or vibration the material can be exposed to without failure. Toughness is one of the most essential material properties of the security safe is it is a direct measure of how well the material will withstand impact from attacks and dropping.Hardness – The materials ability to resist scratching, abrasion, indentation and penetration. This is an important material property for a safe as a break in could be performed by using tools or machinery which use indentation and drilling.Density – A material property relating the mass of the material to its volume. A material with a higher density will be more favourable for the purpose of a safe wall as it will make the safe more difficult to maneuverer in thefts.