Armature - Hot-rolled steel for reinforcing concrete structures. To improve the mechanical properties of concrete structures to reinforce metal rods - steel reinforcement, to give the reinforced concrete structure with a strength several times greater than that without reinforcement. The process of manufacturing valves similar to manufacturing (rolling) of the usual round of metal. To obtain a ribbed surface on the fixture rollers (rollers), rolling machines are profiled by a profile fitting. By omitting the initial billet steel mill through a series of clips receive reinforcement corresponding profile. Reinforcing steel rod rolled to the specialized hot rolling mills. On the issue of reinforcing steel designed by several guests, most important of which is GOST 5781-82 - Hot-rolled steel for reinforcing concrete structures. " According to this GOST produced steel round smooth and round-periodic (ie, AC), a ribbed profile. Reinforcing steel periodic profile is a circular profile with two longitudinal ribs and transverse projections, reaching a helical line. Profile of the periodic rent, depending on its destination may be different. In addition, cross-tabs on the box office can be directed to one side of the ribs and in different directions. Characteristic of the steel reinforcement is its number (the nominal diameter of the rod). The range of numbers produced by the rods from 6 to 80 mm. Reinforcing steel ribbed by the letter "A" and a dash of Roman numeral from I to VI, indicating a different level of strength (the higher the number, the stronger), such as AI, AVI. With the reclassification of steel bars increased the strength properties, but reduces plastic. Therefore, the lower class, the valve is easier to bend, the more it is technologically, ie, is used where the installation requires bending, welding. Armature higher grade hard plastic, and sometimes it can not bend and are poorly susceptible to welding (cracking). Fittings made of carbon (eg St5sp, St5ps), and low-alloy steel (eg 20hgs2, 30hgs2). Steel grade is selected depending on the class of reinforcement and the diameter of the rod. Often the specified designations of three-or four-digit number indicating the yield strength. Reinforcing steel of class A-1 (A240) is made smooth. Reinforcing steel A-II (A300)-A-VI (A1000) is made with a periodic profile. Steel reinforcement AI and EA diameter of 12 mm and Class A-III with a diameter of 10 mm are manufactured in coils, large diameter - in the bars. Stem - straight reinforcement bars dimensional or random length. Skein (Bay) - reinforcing steel, rolled into the ring. Reinforcing steel grades A-IV-A-VI of all sizes available in the bars. Length of the rods from 6 to 12 m. The minimum length of W m. Notation example: 20A-II GOST 5781-82, ie steel with a diameter of 20 mm, class A-II. Reinforcing steel shipments, consisting of rods of one number and one of the class. The label affixed to each bundle, shall be designated by class fixtures. Mass of binder to 15 tons are allowed on 3 and 5 tons. GOST 10884-81 - Steel reinforcing rod thermally hardened periodic profile. In contrast to this GOST 5781-82 Steel is made only periodic profile and thermally toughened (tempered). Depending on the strength of steel is divided into classes of ATIII-ATVIII, where A - reinforcing steel, T - heat-hardened. The rods are made with a profile ranging from 10 to 40 mm in length from 5.3 to 13.5 m. rebar class AT-III with a diameter of 6-8 mm are supplied in coils, diameter 10 mm - in the bars. Steel the other classes available in the bars. The remaining requirements for reinforcing steel are the same in accordance with GOST 5781-82. For the manufacture of valves used different grades of steel. Choice of brand is defined by the scope of reinforcement. For valves in accordance with GOST 5781-82 are used as carbon steels of ordinary quality (StZkp, StZps, St5sp), so and medium-steel (35GS, 20-2G2SR, etc.). According to GOST 10884-81 are used mainly srednelegirovannye steels (ZOHS2, 20HGS2, etc.). Since the properties and quality fittings are determined GOST, no matter which plant it was made, its characteristics are the same.
No comments:
Post a Comment