One of the popular types of metalworking are milling and turning works, which are very similar to each other and can be used for work with both horizontal and vertical surfaces. The final stage of the process, as a rule, is abrasive metal processing , which is grinding or other methods of imparting the desired degree of roughness to the part. Depending on the strength of the material, different abrasive materials are used or the setting of the grinding machine.
Whenever working with a metal material there is a problem of its heating , which causes strong internal stress of the workpiece and the part, which can very quickly lead to deformation, which is unacceptable in the manufacture of high-strength products. Various methods are used to cool the treated parts, ranging from dousing with water or blowing and ending with the use of various pastes, oils, soap solutions. During milling and turning work, the coolant is supplied in the form of a gas-air mixture, which is sprayed in the working area or fed to the drill.
Carrying out milling and turning works is a chain of operations performed in a specific sequence, the purpose of which is to give the metal a given shape and qualities. Therefore, in most cases, these types of work are carried out in accordance with the standards established by GOST, TU and OST, describing the requirements for achieving quality.
Compliance with the established standards of requirements is important in the manufacture of high strength bolts, since they are used in environments of high aggression in chemical industries, in modes with high temperatures, they are used to fasten structures, mechanisms and structures and other objects that operate at very low temperatures ... For fasteners, such as high-strength bolts , increased requirements are imposed, since they must withstand large breaking forces, when increased dynamic and static loads.
High-strength bolts must have a ultimate strength of at least 800 MPa , and have a class of 8.8 - 10.9. To achieve the required strength characteristics, choose low-carbon or alloy steel (C <0.4%), marked with 20G2R, less often 35 and 40X. It is important to choose the right technology by which the product is manufactured. Usually they use the technology of hot and cold heading, thread rolling on special equipment. High-strength bolts are made in accordance with GOST 22356-70 /15150-69 /22356-77.
High strength bolts are marked with the letter "S" , if the hex head is enlarged, and with the letters "ХЛ", if their use is planned in harsh climatic conditions. The diameter takes values in the range of 16 mm 48 mm.
The article is provided by the company's website http://vpsmetall.com.ua/
