Material & stock
Material data, stock weight, material costs, and bar and plate utilization.
In short: Material & stock
The material calculators determine stock size and weight, material cost, machining allowance and saw cuts, bar and plate utilisation as well as density, thermal expansion and hardness conversions. Densities and strengths are typical values per material. The mill certificate and the current supplier quote apply for costing and acceptance.
Frequently asked questions about Material & stock
How do you calculate the weight of a stock part?
Weight = volume × density. A steel round bar with 7.85 g/cm³, 50 mm diameter and 100 mm length has a volume of 196.3 cm³ and weighs about 1.54 kg. In aluminium with about 2.7 g/cm³ it would weigh about 0.53 kg.
How much allowance does a stock part need?
The allowance covers mill scale, form and position deviations of the semi-finished product and clamping. Typical values range from a few tenths of a millimetre to a few millimetres per side, depending on the stock, length and machining sequence. Drawing dimensions are finished dimensions; the allowance is added per side.
How exact are hardness conversions?
Conversions between Vickers, Rockwell, Brinell and tensile strength according to ISO 18265 are approximations that only apply to certain material groups and hardness ranges. For acceptance, the value measured with the specified test method always counts.
What drives the material cost per part?
Besides the price per kilogram, mainly the waste: saw kerf, clamping and bar remnants and the ratio of stock weight to finished weight. Good utilisation of bars and plates and a well-chosen stock size can lower the material cost per part considerably.