Density
Steel at 7.85 kg/dm3: a square metre of 1 mm plate weighs 7.85 kg. Aluminium at 2.70 kg/dm3. For stainless steel and other metals, enter the density from the standard or the certificate.
Reference tool — not a selection
Metal weight, before it goes in an RFQ.
Metal weight
Plate, bar, tube.
Pick the section and enter the dimensions in millimetres. The drawing and the RFQ line update with every change.
All 130 engineering tools
Plate for a hull repair, round bar for a shaft, tube for a pipe run: the mass decides the price, the freight and the lift. Pick the section, enter the dimensions and the quantity, and the calculator gives the mass per metre or per square metre, per piece and for the lot, draws the piece and writes the RFQ line.
The mass is calculated from the nominal dimensions. The weight of a delivered lot depends on rolling tolerances and is stated by the mill.
How it is worked out
Volume times density.
Sections
A round bar is pi times the diameter squared over four; a tube is the outer circle less the inner one; a hexagon bar is 0.866 times the square of the size across flats; a rectangular tube is the outer rectangle less the inner one, with sharp corners.
What it leaves out
Holes, cut-outs, the corner radii of rectangular tube and the rolling tolerances. For the order, the material grade matters most: for hull steel, the grade to the class society rules.
| Thickness, mm | Steel, kg/m2 | Aluminium, kg/m2 |
|---|---|---|
| 1 | 7.85 | 2.7 |
| 2 | 15.7 | 5.4 |
| 3 | 23.55 | 8.1 |
| 4 | 31.4 | 10.8 |
| 5 | 39.25 | 13.5 |
| 6 | 47.1 | 16.2 |
| 8 | 62.8 | 21.6 |
| 10 | 78.5 | 27 |
| 12 | 94.2 | 32.4 |
| 15 | 117.75 | 40.5 |
| 20 | 157 | 54 |
| 25 | 196.25 | 67.5 |
| 30 | 235.5 | 81 |
| 40 | 314 | 108 |
| 50 | 392.5 | 135 |
Steel at 7.85 kg/dm3, aluminium at 2.70 kg/dm3; aluminium alloys differ slightly.
Sources
Steel density 7.85 kg/dm3: steelorbis, Kloeckner Metals, epcland and the buildingclub plate calculator (they agree: a square metre of 1 mm plate weighs 7.85 kg); aluminium 2.70 kg/dm3 from the same sources. Stainless steel densities run from 7.93 to 8.03 kg/dm3 in the sources, so they are entered by hand. Sections are geometry; as a check, NPS 4 Sch 40 pipe (114.3 x 6.02 mm) comes to 16.1 kg/m, as in the ASME B36.10 tables.
Before you send the request
Questions about metal weight in an RFQ
How is the mass worked out?
Volume times density. Steel is taken at 7.85 kg/dm3, so a square metre of 1 mm plate weighs 7.85 kg and of 10 mm plate 78.5 kg; a 2 x 6 m plate of 10 mm comes to 942 kg.
Which density should I use for stainless steel?
Stainless grades differ, at about 7.9 to 8.0 kg/dm3; take the figure from the material standard or the mill certificate and enter it as a custom density.
Does it allow for holes, cut-outs or corner radii?
No. The plate is a full rectangle and the rectangular tube has sharp corners, so rolled tube with corner radii weighs a little less and cut-outs must be taken off separately.
What should the request include?
The material grade and its standard, the dimensions and quantity, the certificate needed, such as 3.1 to EN 10204, and whether the pieces are to be cut to size.
Weight clear?
Send the line with the material grade.
A calculation is an estimate, not a delivery note weight. Give the grade and the certificate, and Vessel Core checks them before an offer goes back.
Buyer tools
