The sizes of a metal corner - GOST

A metal corner is a product widely used in industry, in the construction of buildings and structures, as well as in other areas of the national economy. Due to the special design, this type of rolled metal has increased rigidity and can be used for assembling skeletons with a large margin of safety. It represents a corner of a long steel product, in the section resembling the letter "G". There are only two of its main types: equal and unequal. In the first case, the width of the "shelves" for products is the same, in the second - different. Dimensions of the metal corner, its weight and the type of material used for manufacturing regulates GOST.

Classification

Equal and unequal corners can be:

• Hot-rolled (produced according to the standards prescribed in GOST 8510-86 and GOST 8509-93);

• Bent (GOST 19771-93 and GOST 19772-93).

The first variety is characterized by increased strength. Such a corner is usually used for the erection of metal structures subjected to high loads. Curved corners are the most popular. They are used everywhere. They are made by the method of bending steel strips on special pressing equipment.

Also these metal products are classified into:

• Standard;

• High accuracy.

The first variety is marked with the letter "B", the second - "A".

Length of metal corner

According to this parameter, the products are classified into dimensional and immense. Also there is an angle of a multiple length and limited. Measured products can have lengths of 6, 7, 9, 10, 11 or 12 m. Their cost depends on the weight (that is, the consumer pays not for the unit of the product, but for the total weight of the purchase, or at least for the yardage). A non-magnetic corner can have any length. In this case, this indicator varies from 4 to 12 m. Most often, construction materials of this type are not too long, since they often simply represent trimming of dimensional products.

Sometimes in the manufacture of various kinds of frameworks, bearing structures, etc., it is required that the dimensions of the metal corner are non-standard. In this case, the customer has the opportunity to order products longer than 12 m.

Length Accuracy

Among other things, the GOST also regulates the maximum deviation of the angle in this parameter. The latter should not be more than:

• 30 mm for a 4 m length;

• 40 mm for products up to 6 m;

• 70 mm for a corner with a length of 6 to 12 m.

At the customer's request, these parameters can be changed in the direction of greater accuracy (40 mm for products of 4-7 m plus 5 mm for each meter of length over 7 m). GOSTs regulate not only the dimensions of the angle of the metal equal and unequal, their weight and limiting deviations, but also the degree of their curvature. After all, quality products must necessarily be even. The maximum value of the curvature of the angle in accordance with GOST shall not exceed 0.4% of the length. At the request of the customer enterprises engaged in the production of rolled metal, produce products with a curvature of no more than 0.2% of the length. Twisting the corner in the direction around the axis of GOST does not allow.

Shelf width and weight

What, in fact, can have a corner metal dimensions? GOST regulates primarily the ratio of the width of the shelves of these products, their thickness and weight. The first indicator varies from 20 to 200 mm. The thickness of the products can reach 16 mm. What exactly should be the ratio of the width of the shelves and the weight of 1 meter of the product, see the table below.

The above are the ratios of values for ravings. As you can see, with the same width of the shelves, their thickness can be different. Accordingly, the weight of the product also changes. Dimensions of the angle of the metal unequal, or rather, the width of its "shelves", can also vary within the range of 20-200 mm. The ratio of this parameter and the weight of products in this case is regulated by GOST and is indicated in special tables.

Steel grades

The strength of the metal corner depends not only on the method of its manufacture, the thickness and width of the shelves. The influence of this parameter is also influenced by what kind of material was used to make the product. Make a corner of the following types of steel:

• Carbon of normal quality;

• Low-alloyed increased strength.

In the first case, metal grades are used, the performance characteristics of which are regulated by GOST 380-88. The quality of low-alloy steels used for corner production is determined by GOST 19281-89.

The most popular sizes of metal corner

The most demanded products of this type are products bent from black metal of mark "B". This option is cheaper than an angle of stainless steel class "A". At the same time, such corners hold a sufficient margin of safety in order to be able to collect durable and reliable structures from them.

What are the most popular sizes of a metal corner? 40 x 40 mm, 50 x 50, 70 x 70 and 100 x 100 mm - this shelf width is the most popular. The first version of products, for example, can be used for the manufacture of awnings, arbors, benches, street tables, etc. For not very responsible structures, this corner has a sufficient margin of safety.

Products 50 x 50 mm can be used for the assembly of fences, gates, gratings, small children's swings, etc. They are used in engineering, as well as in the assembly of rail cars. Dimensions of the metal corner 50x50x5 mm or 50x50x6 mm allow you to collect all kinds of frames, experiencing small loads. In other cases, a less robust version of 50 x 50 x 3 or 50 x 50 x 4 mm can be used. This corner weighs more, and therefore costs less.

Galvanized steel corner

Very often metal rolling of this type is used to assemble metal structures, during operation, exposed to negative moisture. Since ordinary steel is susceptible to corrosion, in this case a special kind of metal corner is used - galvanized. This option is quite expensive, but even in the most difficult conditions can last for decades. The dimensions of the metal corner of this variety (the width and thickness of the shelves) are the same as those of the usual one.

The products of this variety are most often made of carbon steel. Zincing can be done in several ways. When a corner is simply immersed in a melt, products with a protective layer thickness of 150 μm are obtained. Sometimes galvanizing is also carried out in a rotating, sealed container at high temperatures. In this case, the zinc penetrates into the upper layer of the steel and, although the thickness of its layer is also 150 μm, is much better. Also coated with this metal, steel can be sprayed. In this case, it is possible to apply a much thicker layer of zinc - up to several millimeters.