If you don't know the weld volume and weight of a pipe welding job, you cannot price it accurately. Determining the cost of a job is crucial if a contractor is to make a profit and stay in business. Also, understanding the cost of different welding techniques and methods will help you reduce costs, which will further improve your company's profitability and competitiveness. The main factors that determine the cost of a weld job are the amount of welding consumables you need and the time you or your employees spend on each joint. Both of these factors are directly related to the weld volume and weld weight of a weld.
Determine the area of the weld; this will depend on the shape and size of the weld. For instance, if you choose to use a basic 45-degree fillet weld, which has the shape of an isosceles triangle, you must multiply the base of the weld by its height and divide by two. To illustrate, if you have a 2-inch by 2-inch fillet-weld, your weld area will be 2 square inches.
Multiply the area of your weld by its length. For example if you have 30-inch length of a 2-by-2-inch fillet weld, your weld volume will be 60 cubic inches.
Factor in the type of alloy you will use for the weld and its density. Alloys vary in density, which is directly related to the weld weight. For example, the density, in grams per cubic centimetre, of iron is 7.87, while for nickel it is 8.90.
Multiply the volume of the weld by the density of the alloy you are using. This will give you the total weight of the weld.
Multiply your weld volume and weight by your company's waste ratio. This ratio will depend on the size of the consumables you buy, the welding methods you use and the skill of your workers. Calculate this ratio by dividing the total amount of consumables used in previous projects by the amount of weld you estimated you would need. For instance, if your waste ratio is 20%, multiply your weld volume, for example 60 cubic inches, by 1.2, to get 72 cubic inches.