The ultimate strength of materials - what is it?
The mechanical properties of a metal or alloy, such as hardness, plasticity, resistance to deformation, tensile strength or wear resistance, are the main criteria for selecting a material.
Any metal (as well as wood or plastic),Being under the influence of any loads, is not able to endlessly test them. Deformations and disruptions occurring under the influence of all kinds of unfavorable environments and various operating conditions should be taken into account in each case individually. For example, adding an element to the chemical composition of an alloy, a method for processing a metal, the presence or absence of a hard chromium plating will allow differently to show itself to the same material in different operating modes.
Strength limit for each materialis determined both empirically, and with the help of complex mathematical analysis and tests in the laboratory. Using different methods allows you to achieve the most accurate results of research.
The data obtained are reduced to a single standarddocuments - GOSTs, OSTs and directories that are used in the calculation and selection of the necessary material. The resistance of metals and alloys to all possible deformations and fractures, determined by such a mechanical characteristic as the ultimate strength of steel or cast iron, composite, wood or plastic, affects the reliability and service life of the product.
The right choice of material and its rationalapplication in its essence is an economically justified guarantee of safety and durability of the structure. In the modern industry, any materials should be characterized by optimal characteristics. Strength, fatigue or yield strength, temporary resistance to bending or compression, twisting or stretching should not exceed permissible requirements and norms. In calculations only slight deformation is allowed.
If the load exceeded the permissibleultimate strength, the moment of destruction of a part, machine or structure comes. Thus, the wrong choice of material contributes not only to the additional costs of repair or replacement of machinery or parts, but also to the complete destruction of the entire structure.
From indicators of temporary mechanicalresistance depends on the reliability of the design in general, the duration of operation of parts, machines and equipment. For example, the tensile strength of 45 grade steel under tension or compression, torsion or bending has optimal parameters. It is this brand that is most often used for the production of parts and mechanisms that require increased strength characteristics.
Steel and cast iron used in construction, whiledid not find a worthy replacement. Thanks to new methods of obtaining these metals and their modern processing, the use of these materials is becoming ever wider. Reliability, durability and optimum ultimate strength are excellent performance indicators.