Being in a high-rise building, on the deck of a ship, aboard a liner, few people assess the strength of the structure – comfort is important. But without a metal base in the form of a frame, sheets, channels, fittings, these structures simply would not exist. Not to do without products from the processed metal and in life: a roof, pipes of communications, a lattice, etc. The range of metal rolling is numerous and various. About how to choose products of the right size, and will be discussed in the article.
Definition of metal: that includes a range of metal
The word “assortment” is of French origin. True, the sound is somewhat distorted (French. – assortir), but the essence is identical: select, sort. Consequently, the assortment is a list of any selected products, combined by grade, type. Most often this concept is used in the metallurgical industry to refer to a set of rolled metal products. To understand how the assortment of hardware is formed, it is necessary to understand the question of what is metal rolling.
The metal passes through the rolls on a special device (mill) and acquires a certain size and shape. This process is called rolling. There are three rolling methods:
- hot;
- warm;
- cold.
They vary depending on the presence and degree of thermal effects on the metal. There are several types of rolling mills: pipe rolling, sheet, crimping, for special types of rolled products, billet.
Based on the above, it is possible to give a definition of the range of metal. The range of metal-roll is a list of rolled sections, which contains a description of their qualities and sizes. When forming the range takes into account three indicators:
- section shape (profile);
- dimensions;
- chemical and physical characteristics.
There are three main groups of the rolled product mix:
- rolled sheet;
- varietal and shaped prokaty;
- pipe products.
To summarize information about the types of products and their characteristics create directories of metal. It is in them that the consumer can get acquainted with the full list of products and their qualities, choose the necessary option.
Pipes – a fairly common category of rolled products. The main characteristics of these products:
- total length;
- wall thickness;
- inner and outer diameters;
- type of material;
- preparation method.
Most tubular products have a circular cross section, but square and flat pipes are also produced. There are several manufacturing methods:
- rolling;
- pressing;
- casting;
- welding.
Depending on the peculiarities of the manufacturing process, pipes are seamless and welded. Seamless used to transport gases and liquids under pressure above 1 MPa. Welded pipes are created by folding the strip (rolling strip), butt-and-overlaying and overlapping, and welding the seam. These products are used to move low-pressure gases and liquids through them. Requirements for tubular products are governed by the following documents:
- GOST 10705-80 – electric welded pipes;
- GOST 10704-91 – longitudinal products;
- GOST 8732-78 – seamless pipes;
- GOST 3262-75 (TU) – water and gas;
- GOST 8645-68 – profile rectangular;
- GOST 8639-82 – square profile.
Pipes are used in the gas and oil industry, in engineering, construction. They are used for laying various pipelines for the manufacture of industrial cylinders and vessels.
These products are made by rolling. Delivered as single sheets or in rolls. The edge of this product can be trimmed, and can retain the shape acquired after processing. The division of this product into types is based on the following characteristics:
- rolling method;
- rolling accuracy;
- surface quality;
- sheet thickness;
- Extensions
Sheets of steel are produced in cold-rolled and hot-rolled ways. The accuracy of the products is of two types – normal and high strength. The degree of traction is divided into deep and normal. Sheet thickness varies from 2 to 5 mm. The surface can be corrugated, grooved or smooth.
Regulating government documents:
- GOST 19903-74 – assortment of hot-rolled sheet metal;
- GOST 19904-90 – assortment of cold-rolled sheet;
- GOST 16523-97 – technical conditions.
Sheet metal is actively used in mechanical engineering, construction. It is used for welding structures, plating, making covers, sarcophagi. It can be used as blanks for other products (household appliances, appliances, etc.)
High-quality metal is standardized products. According to GOST 535-2005, the peculiarity of this type of product is that the diameter of the metal product has one of the geometrical shapes: square, hexagon, rectangle or circle. The characteristics that determine the range:
- profile form;
- its size;
- metal processing method.
Depending on the form, varietal products are divided into the following types:
- simple;
- shaped;
- special.
Simple forms include:
- Circle – hot-rolled steel with a round profile, which is used for the manufacture of fittings, wire, grids, decorative elements, monolithic structures. Regulated by the provisions of GOST 5751-82.
- Square – hot-rolled steel with a square profile. It can be small and large, it is used in various industrial sectors for welded structures. Available in accordance with GOST 2591-88.
- Hexagon. Used as blanks for the manufacture of other products, such as bolts.
- Strip – sheet of high strength, used for concrete products in mechanical engineering.
Products related to shaped products are channels and beams. Beams have the form of a bar. They are used in construction when it is necessary to make a strong frame. Channels – U-shaped products, characterized by rounded corners. Used to create floors.
Special forms of hire are wheels and round fittings. Wheels are used in mechanical engineering, fittings are used to reinforce structures.
One of the types of rolled metal products used for various industrial purposes is fittings. This is a metal rod of circular cross section with a ribbed surface. Produce this product in the form of segments of a certain length or coils. There is also a reinforcement with a smooth surface.
GOST for valves 5781-82 regulates the technical conditions. GOST 10884-94 created for reinforced reinforcement. The main scope of application – construction. This type of metal is used to reinforce concrete products and create frames. The full range of fittings is divided into VI classes. The most popular types of products (A400 and A500C) belong to class A III. The armature has a profile with two ribs and a transverse protrusion.
In many ways, the characteristics of the A400 and A500C valves are identical, which determines their belonging to the same class. But the differences in chemical composition, namely, a smaller amount of carbon and more – alloying additives, gives the A500C a greater degree of flexibility, which contributes to the formation of a stronger weld when using arc welding. The letter “C” denotes the possibility of using this type of welding.
- A careful study of the market for this product will allow you to identify a firm that is trusted. It is necessary to pay attention to the duration of the enterprise, the vastness of the regions of delivery, the range of products and reviews.
- The quality of the purchased products must be documented. If the characteristics are only voiced or there is only a descriptive option, the purchase of such goods should be abandoned.
- Visual inspection is required. The presence of rust, cracks, traces of welding indicates serious shortcomings that may be associated with a violation of the technology of metal rolling.
- An important point that characterizes the level of work of the enterprise is the packaging of goods and delivery. Negligence, lack of additional services should be alerted. Consequently, it is necessary to take a closer look at the trading company.
The acquisition of metal products is a responsible and rather troublesome process. In the chemical-technical criteria, you need to be confident, and quantitative indicators should be calculated in order to know how much to purchase and how to transport it.
