Welding and fabrication calculators.Weld sizes, heat input, consumables, steel weights, sections, bending and cutting.

Heat input

Heat inputArc energy and heat input from travel speed (BS EN 1011-1)

E = \frac{60 U I}{1000 v}

Heat inputHeat input from run-out length and arc time (MMA)

v = \frac{60 L}{t}

Steel and preheat

Steel and preheatCarbon equivalent CE (IIW)

CE = C + \frac{Mn}{6} + \frac{Cr + Mo + V}{5} + \frac{Ni + Cu}{15}

Steel and preheatCarbon equivalent CET (BS EN 1011-2 method B)

CET = C + \frac{Mn + Mo}{10} + \frac{Cr + Cu}{20} + \frac{Ni}{40}

Steel and preheatMinimum preheat temperature, CET method (BS EN 1011-2 Annex C method B)

T_{p} = 697 CET + 160 \tanh \frac{d}{35} + 62 H_{D}^{0.35} + (53 CET - 32) Q - 328

Steel and preheatCooling time t8/5 from 800 °C to 500 °C (BS EN 1011-2 Annex D)

t_{3} = (6700 - 5 T_{0}) Q (\frac{1}{500 - T_{0}} - \frac{1}{800 - T_{0}}) F_{3}

Weld size and weld metal

Weld size and weld metalFillet weld throat thickness from leg lengths (BS EN ISO 2553)

a = \frac{z_{1} z_{2}}{\sqrt{z_{1}^{2} + z_{2}^{2}}}

Weld size and weld metalFillet weld leg length from throat thickness

z = \sqrt{2} a

Weld size and weld metalFillet weld cross-section and weld metal mass per metre

A = \frac{z^{2}}{2} + \frac{2}{3} \sqrt{2} z h

Weld size and weld metalSingle-V butt weld cross-section and weld metal mass

w = g + 2 (t - c) \tan \frac{α}{2}

Consumables, time and cost

Consumables, time and costFiller wire or electrode needed from deposited weld metal

m_{f} = \frac{m_{d}}{η / 100}

Consumables, time and costArc-on time and welder time from deposition rate

t_{a} = \frac{m_{d}}{D_{R}}

Consumables, time and costShielding gas usage and cylinders

V = \frac{60 Q_{g} t_{a} (1 + p_{a} / 100)}{1000}

Consumables, time and costWelding cost per metre (labour, wire, gas and power)

t_{a} = \frac{m_{L}}{D_{R}}

Weld strength (BS EN 1993-1-8)

Weld strength (BS EN 1993-1-8)Fillet weld design resistance, simplified method (BS EN 1993-1-8 4.5.3.3)

f_{v w, d} = \frac{f_{u} / \sqrt{3}}{β_{w} γ_{M 2}}

Weld strength (BS EN 1993-1-8)Fillet weld check, directional method (BS EN 1993-1-8 4.5.3.2)

σ_{⊥} = \frac{F_{E d} \sin φ}{a \sqrt{2}}

Steel weights

Steel weightsSteel plate or flat bar weight

V = \frac{L}{1000} \times \frac{W}{1000} \times \frac{t}{1000}

Steel weightsRound and square bar weight per metre

m_{r} = \frac{π d^{2}}{4} \frac{ρ}{10^{6}}

Steel weightsCircular hollow section (tube) weight per metre

A = π t (D - t)

Steel weightsSquare or rectangular hollow section (SHS/RHS) weight per metre

A = 2 t (B + H - 2 t) - (4 - π) (r_{o}^{2} - r_{i}^{2})

Section properties

Section propertiesSolid rectangle (flat bar or plate on edge): A, I, Z, r

A = \frac{b h}{100}

Section propertiesHollow rectangle (box section, square corners): A, I, Z, r

A = \frac{B H - (B - 2 t) (H - 2 t)}{100}

Section propertiesCircular hollow section (tube): A, I, Z, r

d = D - 2 t

Section propertiesI-section (UB, UC or welded plate girder): A, I, Z, r about the major axis

A = \frac{2 b T + (h - 2 T) t_{w} + (4 - π) r^{2}}{100}

Beams

BeamsSimply supported beam, uniformly distributed load: bending stress and deflection

M = \frac{w L^{2}}{8}

BeamsSimply supported beam, central point load: bending stress and deflection

M = \frac{P L}{4}

Bending and forming

Bending and formingBend allowance and bend deduction (K-factor method)

BA = \frac{θ π}{180} (R + K T)

Bending and formingFlat blank length for a bent part (equal bends)

BA = \frac{θ π}{180} (R + K T)

Bending and formingMinimum inside bend radius and outer fibre strain (cold bending)

ε = \frac{T}{2 R + T} \times 100

Cutting

CuttingCutting list: stock lengths needed (first-fit decreasing, with saw kerf)

L_{c} = n_{1} L_{1} + n_{2} L_{2} + n_{3} L_{3}

Bolting

BoltingBolt tensile stress area, tension and shear resistance, and preload (BS EN 1993-1-8)

A_{s} = \frac{π}{4} (d - 0.9382 p)^{2}

BoltingBolt hole diameter: normal and oversize holes (BS EN 1090-2 Table 11)

d_{0} = d + c

Coatings

CoatingsPaint or galvanising surface area per metre and per tonne

A_{m} = \frac{P}{1000}

Thermal movement

Thermal movementThermal expansion of steel

Δ L = α \times 10^{- 6} \times 1000 L Δ T

Handling

HandlingManual handling check for a fabricated part (HSE guideline weights)

G_{a} = G (1 - \frac{r_{t}}{100}) (1 - \frac{r_{f}}{100})

Running the business

Running the businessFabrication job price: steel by weight, labour, markup and VAT

C_{s} = \frac{M_{s} p_{s}}{1000}

Running the businessHMRC simplified mileage allowance (cars and vans)

M = \frac{r_{1}}{100} \min (B, B_{1}) + \frac{r_{2}}{100} \max (B - B_{1}, 0)

Welding and fabrication calculators.Weld sizes, heat input, consumables, steel weights, sections, bending and cutting.

Heat input

Steel and preheat

Weld size and weld metal

Consumables, time and cost

Weld strength (BS EN 1993-1-8)

Steel weights

Section properties

Beams

Bending and forming

Cutting

Bolting

Coatings

Thermal movement

Handling

Running the business

Welding and fabrication calculators

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