Profile pipe: dimensions, weight, wall thickness, specifications

Metal frames for a variety of structures are more convenient and reliable. With even a small inverter welding machine, assembling any design is not a problem. In recent years, more often they use not a round, but a square or rectangular pipe. It is called profile. The dimensions of the profile pipe are very different, so you can choose a product for any purpose – for poles, and for racks, and for lintels.

What is a profile pipe 

Profile pipes are pipes whose cross section differs from a circle. They can be oval, square and rectangular. Oval are rarely used. Most often, when they talk about a profile pipe, they mean either square or rectangular. It is also called profiled, professional pipe, metal / steel profile, metal profile, pipe profile. There are also names according to the section – square or rectangular. In general, there are many names, but they are all the same material.

When talking about the dimensions of a profile pipe, they mean its external dimensions. Also in the nomenclature is the wall thickness. Thus, the greater the wall thickness, the smaller the internal section will be. Sometimes this is important and worth taking into account.

Each type of section of a profile pipe is prescribed in a separate standard. The entire assortment is described there, indicating the dimensions of the section, wall thickness and weight per linear meter of the pipe.

• square section GOST 8639-82;
• rectangular 8645-68;
• oval 8642-68.

Why is a square or rectangular tube usually used, and not an oval one? Profile is more resistant to certain types of load than round. But because with a square it is easier to make a connection, whatever it may be – welded, bolted, rivet or fasteners. And also because due to the stiffening ribs, the corrugated pipe can withstand heavy loads. This is with the same radius, wall thickness and metal of the same brand.

The disadvantage of a profile pipe of square or rectangular cross section is that when the load is exceeded, it folds. Fast and sharp. And this usually leads to the destruction of the structure. A round pipe bends for a long time and breaks very slowly. There is time to take action – reduce the load or strengthen the structure.

What steel are they made from

Profile pipes of any shape and section are made of carbon and alloy steel. Their brands are registered in GOST 13663-86, which contains all the requirements for products. Including steel grades. You can find aluminum and alloys, but they are made according to DSTU, and not according to the standard. However, they also exist.

For normal use, carbon steel is suitable. The brand should be chosen specifically when calculating large structures (trusses). In home construction, it is unlikely that St1sp or St3sp makes a big difference. Completely unimportant. Usually they take what is in the nearest warehouse and what suits the price.

Dimensions of a square profile pipe and the weight of a running meter

The square pipe goes more often to the racks, a supporting frame is assembled from it, and the jumpers are made of a rectangular one. It is easier to attach materials (any) to such a frame. And yet, other things being equal, the bending strength of a square profile pipe is higher. It is comparable to that of an I-beam. But the resistance to torsional loads in a round pipe is much higher. So this must be taken into account.

But in order to avoid problems, it is necessary to maintain the recommended dimensions of the profile pipes. As already mentioned, all sizes (range) are prescribed in GOSTs. The possible wall thickness is also indicated there. For small pipes – from 10 to 35 mm in diameter – the thickness is from 0,8 mm to 5 mm. But for pipes with a side of 10 mm and 15 mm, the walls are not thicker than 1,5 mm. Then there is a gradual increase in the minimum size. For example, 40*40 mm has the thinnest wall 1,4 mm, 45*45 mm has no wall thinner than 3,0 mm. The same trend continues. The larger the size of the profile pipe, the thicker the walls.

The tables also indicate the weight per linear meter of the profile pipe of each size. It is needed not only in order to be able to calculate the load on transport. Using this data, the wall thickness can be controlled. You can weigh a piece of pipe, calculate the weight of a linear meter, and then compare it with the standard. If the data is close, everything is fine. If the actual weight turned out to be much less, the wall thickness is less than the declared one. True, the table shows the weight at a steel density of 7,85 g / cm². If the density of the steel pipe is less, this will need to be taken into account.

Dimensions of a rectangular profile pipe

Rectangular profile pipes have thicker walls. Even with the smallest section (15*10 mm), the wall thickness cannot be less than 1 mm. For private traders, the most common dimensions of a profile pipe are 20 * 10 mm or 20 * 15 mm, often 25 * 10 mm or 25 * 15 mm are used. Jumpers are made of them during the construction of gazebos, sheds, other buildings and small forms. Usually, lintels between support posts for fences made of corrugated board or other sheet material are also made from the same pipe.

The tables show standard dimensions with wall thicknesses for each section. The mass of one linear meter is also affixed. At retail metal depots, rolled products are sold in whips – segments that they have in stock. The minimum length of the whip depends on the method of manufacture. Seamless cold-formed and all electric welded ones can be from 1,5 meters to 11-14 meters. This is a range of their unmeasured length. Whips of measured length of the same manufacturing methods are not less than 4 meters. The same minimum length – 4 meters – (both measured and unmeasured) for seamless hot-deformed and furnace welding.

Wholesale bases sell a profile pipe in tons. If you have a serious amount of work ahead of you, why not save some money. But to know how much pipe will be in a ton, you need to divide it (ton) by the weight of one meter of pipe. Let’s say you want to buy a ton of metal profile pipe 35*20*2,5 mm. One meter of it weighs 1,88 kg (from the table). Now we divide a ton, and this is 1000 kg, by the weight of the pipe, we get 1000 / 1,88 = 531,9 m. This is almost 532 meters … You need such a footage – excellent. If not, then retail whips. Just remember that in the tables the weight is indicated for steel with a density of 7,85 g / cm². If the steel density of the pipe is higher, the footage will be proportionately smaller.

What load can the profile pipe withstand

The load that a profile pipe can withstand depends on its cross section, wall thickness and the characteristics of the steel from which it was made. The manufacturing method also has an effect. But all these factors are taken into account only when building frames, bridge spans, floor trusses, etc. are calculated. In less critical structures, it is usually limited to estimating the level of load that can affect the structure, and the pipe is taken with about a 20% margin of safety. It’s insurance “just in case”.

A few words about loads. A simple principle applies here: it’s better to play it safe and take a more “hardy” pipe than to redo it all over again. Therefore, the collection of loads is a very important step in choosing the section of a profile pipe. In private housing construction, a frame for a barn, gazebo, and a canopy is usually made from a steel profile. In such cases, it is necessary to take into account the mass of snow. It is he who usually causes destruction.

Arches or pergolas, frames for retaining systems, and fences are also welded from a profile pipe. You have to be careful with arches. They are usually made for plants. When calculating the mass of trunks / branches, add another snow load. And in the summer, it is worth considering the green mass and wind. In this combination, the load is also not weak.