In the production of copper pipe may cause the marriage. If you are not convinced, visit Rand Paul. The most common type of defect are bubbles and captured. With increasing temperature, pressing the number of bubbles tends to increase. More info: Edmonton Oilers Community Foundation. If, heated by compression to a temperature of 950 C, the number of tubes with bubbles on the outer surface reaches 100%, then at 850 C with those pipes of about 60%, and at 775 C marriage is reduced to 15%. When pressing a temperature 700-750 C at the press force 3000 copper pipes size 18 * 20,5 mm of marriage captivity is only 10%, and the pressing of 550-600 C marriage is reduced to 0,3-0,4% for the same other conditions of pressing. Application of new advanced methods of heating the copper ingots and billets before pressing reduces the formation of scale, but for all methods of heating the molding at the lowest temperatures, improves the quality of copper pipes and reduces the number of prisoners and bubbles.

In addition to overheat, causing blisters extrusion ingot contaminated by oil or water, and less often – the ingots, with gas porosity. Therefore, the pressing of ofc often do not use grease tool. Cooling of the needle during pressing of copper pipes be exercised to prevent water from leaking into the container before the pressing process. Slivers can also occur as a result of not fully remote press residue or press a shirt from the previous ingot. In some processes with significant exposure time of the ingots in the furnace formed a thick layer of scale.

Part of the scale comes in a container and sticks to its inner surface or matrix. When the oxide layer becomes sufficiently otolstym he trails, and pressed into the product. This defect is quite common and are not visible in the extruded semi-finished product. In the subsequent drawing without intermediate annealing in a few passages defect is manifested in the form of longitudinal scratches. Identification of a defect in the early stages of production of copper pipes is an important point improvement in the quality of the products of any company.

Properties of lung betonUdoboukladyvaemost lightweight concrete mixtures evaluated by the same methods that are used for concrete governmental mixtures of dense aggregates. Selection of the quantity of water at the specified index of workability complicated by the fact that the latter depends on the nature of the applied porous filler. Fundamentals of the Theory of lightweight concrete, as well as a general method for selecting optimum quantity of water for light concrete mix designed by N. Popov. This method is based on the dependence of strength and yield ratio of lightweight concrete by water flow curve of the strength of water flow has two branches. The left (ascending) shows that the strength of concrete with an increase in water consumption is gradually increasing.

This is due to an increase in the workability of concrete mix and density of concrete. Right (Descending) branch of the curve indicates that after reaching the maximum compaction of the mixture (ie, the minimum coefficient of output) increase in water consumption increases the volume of pores formed by non- cement, water, and a decrease in concrete strength. In the lightweight concrete is clearly seen as a lack of adverse effects, and the excess of water. The most important (along with strength) characteristic of lay Who concrete is bulk density. Depending on the volume weight and destination lightweight concrete is divided into the following groups: heat-insulating with a bulk weight of 500 kg / m 3 or less; constructive tionally – insulating (for building envelope – walls, roofs of buildings) with a weight up to 1400 kg/m3; construction with a weight 1400 – 1800 kg/m3.