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 than it need to added 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. Assume joint geometry for each type of joint.
  2. Make a weld take-off of the various types of welds. For example, a groove weld is a combination of two insolence triangles and one rectangle.

Calculate total cross-section area for the various welds:

At = A X (100 + X)/100

Where:

A = Theoretical cross-section area of weld size
X = Excess weld due to oversize and weld surface reinforcement (in %)
At = Total cross-section area of deposited weld (includes excess weld)

Calculate volume of weld deposited:

V = At ×L

Where, L = Length of weld (or total length of similar welds under consideration)

Calculate weight of weld (W):

W = V×M

Where,

V = Volume of deposited weld metal (includes excess weld)
W = Weight of deposited weld metal (total weight for length L)

Calculate Welding arcing hours (To calculate the shielding gas consumption)

Tw = W/D

Where, D = Weld metal deposition rate (weight 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 gives the total cost of the welding.

References for Groove Weld & fillet weld weight

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

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