Rachel - Table of materials

Below is a table that I have made to compare the young's modulus, yield stress and ultimate stress of different materials which would be considered for the crane.

Material	Specific gravity	Young's Modulus (E)	Proof/Yield Stress	Ultimate. Stress	Price
	kg/cu.m	GPa	x 106Pa	x 106Pa	USD/Kg
Steel C<=0.3%		203
Steel C=>0.3		202
Mild Steel	7850	210	200-400	300-500	0.55
Carbon-moly steels		201
Nickle Steels Ni 2%-9%		192
Cr-Mo steels Cr ½%-2%		205
Cr-Mo steels Cr2 1/4%-3%		210
Chromium Steels Cr 12%,17%,27%		201
Alum Alloy 7075	2810	72	145	276
Aluminium	2640	68.95	30-140	60-140	2.214
Carbon reinforced plastic (50/50 fibre/matrix, unidirectional, along grain)	1700-2000	125-150			Expensive

I have tried to find out prices where possible.

I believe that the crane will have to be made out of a steel of some sort or the more expensive aluminium alloy 7075. This aluminium alloy is normally used for aeroplanes, high performance bikes and mechanical switches but it might have a use within the crane.

It might be possible to have certain parts of the crane which will not be subjected to a high stress to be made out of another material such as aluminium to save on weight.

The table will be updated and reposted if more information becomes available.