In some cases, welding may be a huge burden in terms of costs in metalworking projects. The scope of welding operations determines how much will the product, machine, or construction, cost. Why welding is a costly operation and what kind of measures can be taken to decrease the welding costs? In this extensive article, welding operations will be thoroughly explained and these questions will be answered.
What are the determining factors in welding costs?
Labor costs cover a major portion of total welding costs, contrary to robotic welding in which there are no labor costs, only maintenance costs incomparably negligible against labor prices. A welder is paid at an hourly rate and capable of processing a limited number of parts in one hour. Of course, this number can differ according to the experience and education of the welder. Within the given period of working time, a welder can only produce a limited number of welded material.
Two components mainly determine the amount of welding cost in various welding operations which are production time and hourly rate. Many factors influence production time and hourly rate. These factors may cause the cost of each product to differ from each others. Indirect costs like necessary space, equipment, manufacturing book preparation, and interim holding points are not included in the costs mentioned above.
Factors which affects hourly rate of operation:
- Costs of certification for welding
- Costs of research for welding
Factors which affects production time of operation:
- Size and shape of the material to be welded
- Welding point accessibility
- Material selection
1st Cost factor: Costs of certification for welding
One of the reasons for the increment in welding costs is due to necessary certifications for welding operations. There are standards regarding welding operations like EN 1090 and ISO 3834-2. These standards specify the requirements that should be followed in construction and welding operations. A welding company needs to organize its welding operations according to the requirements specified in these standards. These requirements include the following specifications:
- Execution of operation according to methods of welding descriptions (WPS) and methods of welding qualifications (LMK).
- Merit-based selection of the working labor.
- Assigning a supervisor to monitor and coordinate the whole of the welding operations.
- Inspection requirements for welding operations.
An increase in welding costs is caused by obtaining necessary certifications, documentation preparation and revising, hiring skillful laborers, etc. This natural increase in the welding costs is due to the fact that certain conditions must be met in welding works and hourly rates of laborers are increasing day by day.
How to reduce costs and save money regarding this issue?
Quality assurance and reliability are the two of the factors that are not easy to achieve and maintain in industrial sectors of high importance such as the energy sector, offshore equipment, and lifting equipment production sectors. The requirements for welding operations with certification have been skyrocketed by the European Standards. EN 1090 (Standards for Load-bearing steel production for steel constructions) is one of these European standards.
It is quite hard to reduce costs and save money in certificated welding operations. But, the creation of a comparatively higher price to quality ratio is possible because the quality of a product increases more rapidly than the asking price for that product.
2nd Cost factor: Costs of research for welding
Another factor that affects welding costs is establishing a commission for research operations for welding. Nearly all of the players in the market uses non-destructive testing methods (NDT). These methods consist of fluorescent penetrant inspection (FPI), magnetic particle inspection (MPI), ultrasonic and x-ray examinations.
There is a need for personnel with certifications for different types of non-destructive testing methods. When external parties of NDT are used, welding costs will continue to increase.
How to reduce costs and save money regarding this issue?
Cost-cutting measurements can be taken in various ways. For instance, there is no need to spend for researches more than necessary. First, decide whether a 100% check of weld seam or 20% is sufficient for your welding operation. Too much auditing works must be avoided to decrease welding costs. Each test costs you money and time.
Secondly, each type of NDT costs you differently. For instance, the x-ray examination method is much more expensive than magnetic particle inspection. It is also more exacting to perform an x-ray method due to the fact that the testing hall has to be evacuated during examination since radioactivity can harm workers. It is crucial to choose the right NDT method to decrease welding costs and save money.
3rd Cost factor: Size and shape of the material to be welded
The welding costs hugely depend on the type of product to be produced. The size and shape of the product to be welded are also decisive. That is to say, how much welding operations must be performed on a specific material and what are the geometry and dimensions?
The costs which depends on the product are:
- A-height
- Opening on front
- Tolerances
- Post-process
A-height
Costs increases as the a-height grow larger due to the existence of maximum precipitation. It is impossible to perform welding in one shot after the maximum precipitation limit is reached.
For instance: until the A height is 5, one go for welding is enough to melt down the weld seam. If the a-height is 7, melting the weld seam in one go is not possible and the material must be welded three times
Opening on front
If an opening (spacing between two pieces that must be connected) exists before welding, full penetration can be achieved. This situation improves the quality of the welding.
However, one disadvantage of this situation is that welder must fill the opening before the connection of these two pieces is done. As an undesired consequence, production time significantly increases.
Post-process
When wide tolerances are necessary for the product, for instance in terms of flatness, there emerges a need for further finishing operations that must be performed on the welded product. Even if it may not be considered as a welding cost factor, it is considered as a post-processing operation and cause production costs to increase.
Tolerances
The amount of tolerances also affects the costs. When high tolerances are required, the necessity of a welder to adjust and check the welding parameters will increase. Welding costs get higher as the need for accuracy in a welding operation increases.
How to reduce costs and save money regarding this issue?
How much saving can be done in terms of costs and money regarding this issue hugely varies with the compositions of welding. A-height in large dimensions or long welding lengths might be necessary to comply with the safety regulations of the project. But, over dimensioning might occur. When it happens, it is not that difficult to decrease the limit of a-height or to decrease the number of welding lengths.
In particular types, replacement of the weld seams by setting is possible. Setting the sheet metal helps to decrease the welding costs.
Finally, stripe welding can be done to replace the completed welds.
4th Cost factor: Welding point accessibility
Just like the size and shape of the material to be welded affects the costs of welding operations, the complexity and intricacy of the material to be welded also have an influence on the costs. Welding point accessibility is an important factor since a welder must determine in which positions the welding can be performed on a specific product before welding begins.
Some of these positions are not favorable for a rapid, safe, and sound welding operation. Since the material is tending to flow, the rate of deposition is lower. This especially occurs when overhead and vertical welding has to be done. For a higher rate of deposition, hand welding is more favorable.
Accessibility of the place to be welded on the product is another important factor regarding the costs. Time of welding operation increases as it gets harder for the welder to reach that place.
The cost of welding also depends on the dimensions and weight of the product. If the product is heavy and large, it is harder to relocate.
How to reduce costs and save money regarding this issue?
The complexity, size, and weight of the product are generally fixed. Sometimes in certain cases, the idea of modifying the product to make welding operation as convenient as possible can be an attractive idea to be realized. The rate of deposition gets higher and the necessary time for welding gets shorter even including the time spent for modifying the structure of the product.
5th Cost factor: Material selection
In some cases, wrong material selection can increase the costs for welding operations. Pre-heating treatment must be done in order to prevent brittleness and crack emergence on the material. According to the thickness and type, some steel types should definitely be treated with preheating treatment. This situation occurs when the product to be welded is made out of S690 steel. There requires so much time for preheating treatment. Furthermore, welding operations must be performed very carefully and rapid temperature drops must be prevented. The requirement for additional time in this process increases the labor costs indirectly.
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