How to calculate and estimate Welding Cost?


Importance of Welding Cost Calculation

The cost elements of a welded part are those related to materials, labor, and overhead. Only welding materials such as filler metals, gases, and welder manhour rates are considered in this article. If you wish to include overhead cost or any additional cost then it needs to add separately in the total welding cost calculated here.

The reasons for costing welding are varied, but most often are to:

  1. Provide data needed for bidding on a job
  2. Compare the economics of welding with some other method of fabricating or manufacturing
  3. Establish information required in making a decision between alternate designs
  4. Evaluate proposed changes in procedures
  5. Compare the economic advantages of competing welding processes.

Steps for Welding Cost Calculation:

  1. Consider the joint geometry for every joint type.
  2. Break the weld into simple geometrical shapes. E.g., a groove weld is a made up of two insolence triangles and one rectangle. This is helpful for welding area & volume calculation.

Determine the total cross-section area for different welds:

At = A X (100 + X)/100

Where:

A = Theoretical weld cross-section area
X = Extra weld because of oversize and weld surface reinforcement (in %)
At = Total cross-section area of the deposited weld (includes excess weld)

Calculate volume of weld deposited:

V = At ×L

Where L = Weld Length (or total length of similar welds).

Calculate weight of weld (W):

W = V×M

Where,

V = Deposited weld metal volume, including the excess weld metal.
W = Weight of deposited weld metal for length ‘L’

Determine Welding arcing time in hours (To find shielding gas consumption & cost)

Tw = W/D

D = Weld metal deposition rate per hour.

Calculated Total Welding person-hours:

Tt = W/D x Dw

Where Dw = Welder/Operator work efficiency factor (arc time per hour expressed in decimal format)

Calculate electrode weight:

E= W/Dp

Where, Dp = Weld process deposition factor {(wt. of metal deposited) / (wt. of electrode used)}

Calculate gas consumption:

G = Tw x (cu volume/hour)*

Total Welding Cost:

With the above calculations, now we are having the:

  1. Total weight of weld
  2. Total manpower hours required for welding
  3. Shielding gas consumptions

we can find the cost of each item from 1 to 3 by multiplying with the cost of welding wire, cost of manpower, and cost of shielding gas. The total of these three factors will give the total cost of the welding.

References for Groove Weld & fillet weld weight

The below table provides the Weight of Steel Weld Metal for Fillet Joints. You can find out the weight of flat, convex, and concave fillet weld for sizes given here.

Just multiply the length of the weld with the weight given below. For example, 5 feet length of 1/8 inch flat fillet weld weight will be:

Total weight: 0.032 X 5= 0.16 Pounds

Similarly, the weight of groove welds are given in the below table:

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