How to determine the weight of steel pipes: determination according to GOST, tables and calculation by formulas
Any metal rolling technology has one of the following main characteristics, as specific gravity. For a steel pipe with a length of one meter, the mass can be calculated regardless of the type of cross section according to the appropriate calculation formulas or tables.
What is the specific gravity of the pipe?
Such an indicator, as the specific weight of the steel pipe has the numerical value of the weight of one running meter of this product. This figure is very convenient, what, regardless of the volume of steel metal products, allows you to quickly calculate its total mass. To do this, simply measure or know in meters the length of the total number of expected or available batches of pipes. Data on the dimensions of steel pipes will also be required:
- lengths of the parties - for profile pipe rolling (rectangular, square);
- diameter of external section for round pipe products;
- steel grade (for a more accurate calculation);
- wall thickness of the product.
This information can be found in the accompanying documents for metal or measure with your own hands. Any specific size of the pipe corresponds to its specific specific weight. This value can be determined in one of the possible ways and after multiplying by the total length of the pipe get the required total weight of the pipe (one or the total number of these metal products).
Why you need to know the specific gravity?
The total mass of steel pipes is important and necessary quantitative information in any field, where this rental is used. At the plant, who makes pipes, you need to know, how much raw material is needed to fulfill an order to produce a batch of certain products. In this case, do not do without information about the total weight of the finished pipeline to the consumer. Financial and reporting, accounting, road transport, warehouse and other documents reflect the movement and accounting of metal products in kilograms and tons.
You need to know the weight of the pipe, to select the option of transporting it to the destination and select the desired mode of transport. This indicator is used during buying and selling, as well as in the financial calculation for pipe products. The weight of steel pipes is an integral part of strength calculations, reliability, scales are made of metal structures and are included in the relevant technical documentation. And in any case, it can be quickly identified, knowing the general dimensional data and the length of the rolling used, by means of the corresponding specific weight of one running meter of a pipe.
Methods of calculating the specific gravity
The weight of any pipe will depend on the specific gravity of the composition, from which the pipe is made, and its geometric indices:
- length;
- altitude, width or diameter;
- wall thickness.
Therefore, it is indicated as the mass of the volume (in m. Sq.) Profile or cylindrical shape, filled with homogeneous steel with the required density (in kg / m. Cube). The length of the pipe when determining its specific gravity is one meter. For steel pipe rolling, in any calculations, the density of the composition, of which it is made, constantly accepted for the value of 7850 kg / m. cube. To determine the weight of one meter of steel pipe (specific weight) choose one of these methods:
- according to calculation formulas;
- using tables, where the required data are specified for standard pipe sizes.
In any case, the data obtained are only a theoretical calculation. This is due to the following reasons:
- when calculating often have to round the calculated values;
- when calculating the shape of the pipe is geometrically correct, that is, inflows of metal on a welding joint are not considered, rounding in the corners (for profile hire), reduction or excess of the sizes concerning standard within admissible GOST;
- the density of different grades of steel differs from 7850 kg / m. cube. and for many alloys the difference is quite significant in determining the weight of a large number of pipe products.
With the help of special tables determine the most approximate theoretical indicator of the specific weight of the pipe, as in their compilation complex mathematical formulas were used, which took into account the technology of production and geometry of products. To use this calculation option, first, according to the available data on Pipe Rolling, its type is determined. After finding in the reference literature corresponds to this metal table or GOST for this range.
So, example, for steel pipes of square section it is necessary to use GOST 8639-82, and for round straight seams - GOST 10704-91. The next step in determining the specific gravity: according to the available indicators of the size of the pipeline to find the required value in the table. If the measured product dimensions or wall thickness do not correspond to any tabular value, then select the specific gravity for the closest to the value of the typical size.
The tabular version of the calculation is a good topic, that it does not require any calculations, which eliminates the possibility of mathematical error in the calculations. But this method implies the availability of special literature. The most universal option is to use mathematical formulas. This method can be used in any environment, even, so to speak "field", far from the possibilities and benefits of civilization.
Determination of the specific gravity of the pipe by formulas
As mentioned above, the calculation is based on determining the amount of raw materials, spent for the production of one meter of pipe. Then this value must be multiplied by the density of the composition (in the case of steel at 7850 kg / m3). The desired volume is determined as follows:
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Calculate the volume of the pipe one meter long according to its external dimensions. Why determine the cross-sectional area of the pipe, which is multiplied by the length, in our case on 1 meter.
- Calculate the volume of the hollow part of the pipe length 1 meter. Why first determine the size of the cavity (for a round product, the inner diameter is calculated, subtracting from the outer diameter twice the wall thickness, and for profile rolling - determine the height and width of the inner diameter, subtracting double the thickness from the external dimensions). After, based on the obtained results make a calculation, similar to that specified in the first paragraph.
- At the end of, subtract the second from the first result, this is the volume of the pipe.
All calculations are made only after the translation of the initial indicators in kilograms and meters. Determination of the volume of round and cylindrical sections of pipes is as follows:
V = RхRх3,14хL, where:
- V is the volume;
- R is the radius;
- L - length.
Another simple formula, but already for steel round pipes:
Weight = 3.14x (D — T) хTхLхP, where:
- D is the outer diameter;
- T is the wall thickness;
- L - length;
- P is the density of steel.
There are two more formulas, but for steel profile pipe. The original data must be translated into millimeters, the answer will be in kilograms. The formula is for a square pipe:
Specific weight = (A-T) хTх0.0316
For rectangular pipes:
Specific weight = (A + B-2xT) хTх0.0158
That is, special tables can be used to determine the exact weight of the material, where the specified mass of pipes, taking into account the cross section, diameter and other indicators. If you do not have this table at hand, then you can always use a special calculator, where to calculate the required values it is enough to enter the necessary data, such as wall thickness and type of section of the structure. How to determine the specific gravity everyone chooses.
