Weld consumable calculator
Weld metal and consumable quantity for a single V butt weld and for a fillet weld, worked from joint geometry, weld length and the deposition efficiency of the process. Butt weld first, fillet weld second. Both update as you type, and both print the formula and the assumptions below so the number can be checked rather than trusted.
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Butt weld, single V preparation
Enter the preparation. Opening width (O) is calculated for you from the thickness, the included angle and the root, so you can check it against the drawing before you read the weight.
Fillet weld
Equal leg fillet. Fillet size (F) is the leg length, not the throat.
Formula and assumptions
Butt weld cross sectional area, single V
O = G + 2 x (T - R) x tan(A / 2)Root land area = G x RBevel area = (T - R)^2 x tan(A / 2)Cap area = (2 / 3) x O x CCross sectional area = root land + bevel + cap [mm^2]A is the total included angle, so each bevel face sits at A/2. Enter 60 for a 60 degree included V, not 30.
Fillet weld cross sectional area
Triangle area = F^2 / 2Convex cap area = (2 / 3) x (F x sqrt(2)) x CCross sectional area = triangle + convex cap [mm^2]F x sqrt(2) is the face width across an equal leg fillet, which is the base of the convexity. Design throat is F / sqrt(2).
From area to weight
Weld metal per metre = area (mm^2) x density (g/cm^3) / 1000 [kg/m]Total weld metal = weld metal per metre x weld length (m) [kg]Consumable usage = weld metal per metre / (efficiency / 100) [kg/m]Total consumable = total weld metal / (efficiency / 100) [kg]For carbon steel at 7.85 g/cm3 that first line reduces to the familiar area x 0.00785.
Assumptions
- Steel, unless you change the material. The default is carbon and low alloy steel at 7.85 g/cm3. The same joint in aluminium weighs roughly a third as much. The material dropdown carries austenitic stainless steel at 8.00 g/cm3 and aluminium at 2.70 g/cm3. Note that the deposition efficiency figures in the process list were compiled for steel consumables, so for aluminium and stainless treat the efficiency as a starting point and use the figure from your own consumable supplier.
- Single V, one side, symmetrical. A double V of the same total thickness has roughly half the bevel area for the same included angle, so run each side separately and add the two results. A U preparation, a J preparation and a compound bevel are not covered by this geometry.
- The cap is treated as a parabolic segment, area = (2/3) x base x height. That is the standard estimating approximation for a normally profiled cap and it applies to both the butt reinforcement and the fillet convexity.
- Root land area is taken as G x R. This is the convention the AWI calculator has always used, and it is kept so that a result can be checked against the previous version. Read it as a known simplification: it counts the root gap only over the height of the root face. The strict trapezoid form of the same preparation adds a further G x (T – R) mm2, because the gap continues up through the bevel region. On a 12 mm plate with a 3 mm gap and a 3 mm root face that is another 27 mm2, roughly 37 per cent. If your gap is wide and your plate is thick, add that term back by hand before you order.
- Deposition efficiency is deposited weld metal as a fraction of consumable purchased. Consumable required is weld metal divided by that fraction. The figures cover normal stub loss and spatter for each process. They do not cover a part used spool written off at the end of a job, consumable damaged by poor storage, or redrying losses.
- No allowance for anything other than the weld itself. Tack welds, run on and run off tabs, weld repairs, excess reinforcement ground back off and general wastage are all on top. Most estimators add 5 to 10 per cent.
- Non numeric or negative entries produce a dash, not a number. A blank root gap, root thickness or cap height counts as zero. Thickness, angle and length have to be entered before a total appears.
Worked examples
Check these by hand, or against the previous version of the calculator, before you rely on the tool.
Butt weld example
12 mm plate, 60 degree included V, 3 mm root gap, 3 mm root face, 2 mm cap, 10 m of weld, stick (MMAW) low hydrogen at 59 per cent, carbon steel.
tan(30 deg) = 0.577350O = 3 + 2 x 9 x 0.577350 = 13.39 mmroot land = 3 x 3 = 9.00 mm^2bevel = 9^2 x 0.577350 = 46.77 mm^2cap = (2/3) x 13.392 x 2 = 17.86 mm^2area = 9.00 + 46.77 + 17.86 = 73.62 mm^2weld metal = 73.62 x 7.85 / 1000 = 0.578 kg/mtotal metal = 0.578 x 10 = 5.78 kgconsumable = 0.578 / 0.59 = 0.980 kg/mtotal needed = 5.78 / 0.59 = 9.80 kg
Fillet weld example
8 mm equal leg fillet, 1 mm convexity, 20 m of weld, flux cored (FCAW) E71T-1 at 85 per cent, carbon steel.
triangle = 8^2 / 2 = 32.00 mm^2convex cap = (2/3) x (8 x 1.414214) x 1 = 7.54 mm^2area = 32.00 + 7.54 = 39.54 mm^2weld metal = 39.54 x 7.85 / 1000 = 0.310 kg/mtotal metal = 0.310 x 20 = 6.21 kgconsumable = 0.310 / 0.85 = 0.365 kg/mtotal needed = 6.21 / 0.85 = 7.30 kg
Where this sits against the standards
Consumable quantity is a commercial number, not a compliance number, so no standard sets it. Two connections are worth making anyway.
- The joint preparation you enter here has to be the preparation on the qualified welding procedure. Changing an included angle or a root gap to save consumable can move you outside the qualified range. ISO 15614 sets out the essential variables.
- Consumable control, including storage, redrying and traceability from batch to joint, is a quality system requirement. AS/NZS ISO 3834 covers what a fabricator has to be able to produce.
Disclaimer
AWI provides this calculator as a free resource to the welding industry. Validate the accuracy of any result before relying on it. AWI accepts no responsibility for consequent losses from the use of these resources.