welding cost estimation

Welding Cost Estimation and Calculation is an important step in all the welding processes. It determines the time of completion of fabricating welded structures and components. Welding cost estimation also plays a crucial role in welding shops run by independent welders. The requirement of cost calculation arises due the various factors like labor cost, time span, welder (machine) types, welding consumables (electrode), business trends, etc. Both manual ways and software programs can determine the calculation of welding cost. The estimation ways help to identify the cost of each weld and determine the feasibility of a particular weld. So, in this article, read all about the estimation and calculation of welding costs performed by various manufacturers, fabricators, and service providers.


Post Highlights:

  • What is Welding Cost Estimation?
  • Need of Welding Cost Calculation
  • Welding Cost Calculation Formulae
  • Welding Cost Estimation Steps
  • Welding Cost Estimation Computer Program
  • What is the Total Welding Cost?
  • Welding Cost Reducing Methods

What is Welding Cost Estimation?

Welding Cost Estimation is a process that determines the overall cost of performed welding work. There are many concepts that determine the cost of welding. They are deposition rate, deposition efficiency, the weight of weld metal, job time, arc time, operator factor, etc.

Deposition Rate – It is the weight of weld metal melted into the joint per unit of time (while the arc is struck)

Actual Deposition Rate:   

Deposition Efficiency – It is the proportion of the gross weight of filler material actually used (that is converted to useful weld metal)

Weld Metal Weight – It is calculated from the details of the joint according to welding drawings.

Job Time – It is the time of carrying out a particular welding job (both setting-up time and operation time)

Arc Time – It is the time for which the arc is actually burning. It can be arrived at in various ways.

Operator Factor – It reveals the relationship between the time for which the arc is struck and the total welding working time.

Need of Welding Cost Calculation

All the metal fabrication work requires a procedure for operation. The main reason for estimating welding cost is “how to reduce welding cost” along with keeping in mind higher productivity. Some more, all businesses work for profits. That’s why it becomes necessary for an operator to calculate and estimate all cost-deciding factors.

Also, the rampant business competition in the market forces us to think of welding costs. Working without not calculating welding costs can lead to a minor, major, or complete loss. Initially, the operator can decide the welding cost depending on the welding application. There are many calculation programs and apps available as well.

Welding Cost Calculation Formulae

The manufacturers and other fabricators can estimate welding costs either manually or using software programs. The following factors affect welding costs. They are labor cost, filler materials cost, machine cost, energy cost, etc.

Labor Cost – It consists of hourly direct wage costs, employers’ social insurance charges, holiday pay, etc.

Filler Materials Cost – It is the cost of consumables needed for welding.

Machine Cost – It includes the costs of welding equipment, mechanization equipment, special handling equipment, etc.

Energy Cost – It is the cost of arc time and power demand during welding.

Throat Thickness – It is a factor that decides the amount of filler material in fillet welds.

While welding expensive materials like stainless steel the cost of filler materials becomes more significant to calculate. Similarly, when automated and robot welding is employed, the machine costs become significant.

The cost of filler materials becomes more significant when welding expensive materials such as stainless steel. Machine costs become significant only when automated and robot welding comes into the picture.

The welding cost formulae are as follows-

Labor Cost-

Wage: 

Energy Cost-

Electricity:  Energy Consumption (kWh) × Energy Cost ($/kWh)

Machine Cost-

Equipment: 

Filler Materials Cost-

Gas: 

Wire:             

Welding Cost Estimation Steps

After determining many factors that affect welding cost, now we think of how to estimate welding cost using various steps and formulae.

1. Electrode Weight – To determine the weight of the electrode, the following equation is used.

E = W/Dp

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

2. Gas Consumption – To calculate welding gas consumption, the following is employed.

G = Tw x (cu volume/hour)

3. Weld Deposited Volume – The following equation calculates the volume of weld deposited.

V = At × L

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

4. Weld Weight – The following parameters determine the weight of the weld.

W = V × M

Where, V = Deposited weld metal volume (including the excess weld metal)

              W = Weight of deposited weld metal for length ‘L’

5. Total Welding Hours – To calculate the total welding person-hours, it is employed.

Tt = W/D x Dw

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

6. Cross-Section Area (Welds) – The following equation determines the total cross-section area for different welds.

At = AX (100 + X) / 100

Where,

At = Total cross-section area of the deposited weld (includes excess weld)

A = Theoretical weld cross-section area

X = Extra weld because of oversize and weld surface reinforcement (in %)

7. Welding Arcing Time (Hours) – To calculate the welding arcing time in hours or find shielding gas consumption/cost, the following parameters work.

Tw = W/D

D = Weld metal deposition rate per hour

Welding Cost Estimation Computer Program

There are various types of computer programs for calculating welding costs. Some of them are cheap but user-friendly. The simpler computer programs lack databases of filler materials and additional time.

But on the other hand, there is the Weldplan program (developed by the FORCE Institute, Denmark). It can handle the complete specification of the work, then forms the starting point for the cost calculations. It also produces an operations list and itemizes operations to produce a total manufacturing cost.

What is the Total Welding Cost?

The total cost of welding consists of factors like the total weight of the weld, total manpower hours required for welding, and shielding gas consumptions. Besides this, the cost of materials being welded plays a key role. For instance, welding aluminum is more expensive than steel. Some more, the welding joint types also affect the overall welding cost. For example, butt welds are more expensive than fillet welds. Also, the cost of labor determines the total welding cost. The hourly rate of welders’ wages varies as per their education level, skills, certification, experience, and geographic locations.

Welding Cost Reducing Methods

This is a big question before every manufacturer or fabricator that how to reduce welding cost vis-a-vis maintaining product quality. The following cost and time factors play a crucial role. The cost consists of stress relief, electrodes, shielding materials, electric power, preheating fuel gas, etc. The time consists of joint preparation, welding material preparing, assembly, joint preheating, tack-up, positioning, welding, slag removing, spatter removal, inspection, electrodes changing, welder (machine) movements, shifting welding machine settings, defective welds repairs, etc.

1. Use Modern Mechanization

The labor cost normally remains high in all types of manual welding. This is because the cost of labor ($/hr) is not the same at every place; it varies. The manufacturers can reduce labor costs by employing well-qualified employees. Because an experienced and certified welder can impart desired productivity than a non-certified one.

The introduction of mechanization, automation, and robot welding also reduces the labor cost. These new welding technologies reduce the overall consuming time for the project and impart accuracy, perfection, and risk-free job. Yet, these new techs are also handled by humans.

2. Choose the Proper Welding Process

For reducing total job time, manufacturers should select the appropriate welding process. Normally, a welding process with a higher deposition rate reduces the arc time significantly. Next, optimizing the welding parameters imparts fewer disturbances and less spatter. The high-reliability welding equipment also reduces downtime. Work planning is also important as only 30% of the total time is productive arc time.

3. Well-Planned Design Stage

The manufacturers should make a proper plan from the very design stage. It consists of the joint design and throat thickness of fillet welds. Make the joint design in such as way that minimizes the amount of weld metal required. Normally, too large a throat thickness leads to more weld metal. The joint preparation must be well planned i.e., by bringing together and holding the parts and welding. Also, the fillet weld penetration reduces the nominal throat thickness and decreases the quantity of weld metal.

4. Justified Filler Materials

The cost of filler materials or shielding gases can be justified in the same manner as that of reducing labor costs by efficient welding, reduction of preparation, and finishing work.

Conclusion

Thus, there are many factors that play a crucial role in calculating and estimating the welding cost. All these factors must work together in a well-planned way to obtain the desired welding production results. The above information is important for manufacturers, fabricators, welders, machinists, welding shop owners, etc.

Related: Other Welding Technology Topics

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