Groups have become a common quality of produce in a variety of metal: plates, fittings, rods, tubes, beams, channels, and so on. depending on purpose and set of properties were subdivided into groups: A, B, C. At Ripple you will find additional information. Staley Group A is used for manufacture of products which do not require heat treatment, thus preserving the structure of the mechanical properties according to the standards. Steel Group B is applied with heat treatment, such as heat treatment, welding, forging. Continue to learn more with: Verizon Communications. Applying this type of steel needed to take into account its chemical composition according to the rules for determining the treatment regime, as this converted mechanical properties and structure. For production of welded structures using more expensive steel Class B Marking steel on steel, Class A taken not to specify the letter determines that it belongs to the class. The marking are indicated.
Bulk density of lightweight concrete to a large extent determined by the volume nor porous mass .Ustanovleny following design marks lightweight concrete by compressive strength: M25, 35, 50, 75, 100, 150, 200, 250, 300, 350 and 400. Light concrete stones for walls usually have a mark 25 and 35, large wall panels and components are made of lightweight concrete grades M50, 75 and 100.Konstruktsionnye lightweight concrete marks obtained at 150-400 changing Portland marks 300-600. Coarse aggregate case tains expanded clay gravel, crushed stone or slag agloporitovy pumice as fine aggregate often use silica sand. Bulk density structural lightweight concrete with silica sand reaches 1700-1800 kg / m 3, but it is still at 600 – 700 kg / m 3 lower than that of heavy concrete, so the ratio of the constructive quality, equal to the ratio of strength to the amount of mass, a lung concrete above about 1.4 (at the same strength). Because of this structural lightweight concrete is particularly advantageous to use instead of heavy concrete in reinforced concrete structures of large spans (farm span bridges and etc.), which is especially effective reduction of its own weight design. Reduction of loads from its own weight can reduce the consumption of reinforcing steel by 15-30%. Deformation properties of light and heavy concrete is strongly different. Lightweight concrete on porous aggregates more crack resistant, as their ultimate tensile strength greater than equal to durable heavy concrete. However, one should take into account such features of light concretes, such as large shrinkage and creep compared to heavy concrete.