Release time：2020-01-16 18:44 Browse：
In industrial production and mechanical assembly, the extension screw is a key connector, and its quality is directly related to the safety and stability of the entire equipment or structure. Therefore, it is particularly important to strictly test the quality of the lengthening screws. In this paper, from the material selection, manufacturing process, mechanical properties testing, environmental adaptability assessment and appearance and packaging inspection, and other aspects, detailed description of how to comprehensively inspect the quality of lengthening screws.
1. Material selection inspection
The quality of the extension screw first depends on the choice of its material. High quality material is the basis to ensure the performance of screws. When testing, the following aspects should be paid attention to:
1. ** Chemical composition analysis ** : Through chemical analysis means, confirm whether the chemical composition of screw material meets the design requirements. For example, for stainless steel screws, it is necessary to test whether the content of nickel, chromium and other elements is up to standard to ensure its corrosion resistance.
2. ** Physical properties verification ** : including material hardness, toughness, tensile strength and other physical properties of the test. These properties directly affect the bearing capacity and durability of screws during use.
3. ** Material source review ** : Ensure that materials are sourced from reliable suppliers, and have the corresponding quality certification documents, such as certificate, material certificate, etc.
Second, manufacturing process inspection
The quality of manufacturing process directly affects the final quality of lengthening screws. In the inspection process, attention should be paid to the heat treatment and surface treatment of two key links:
1. ** Heat treatment test ** : Heat treatment such as quenching, tempering and other processes can improve the mechanical properties of materials, improve strength and toughness. During the inspection, it is necessary to ensure that the heat treatment temperature and time are controlled accurately to avoid performance degradation caused by overheating or undercooling. At the same time, by means of metallographic analysis, check whether the structure of the material after heat treatment meets the requirements.
2. ** Surface treatment inspection ** : Surface treatment such as galvanized, nickel plating, spraying, etc., can not only improve the corrosion resistance of screws, but also improve their appearance quality. It is necessary to check the uniformity, adhesion and corrosion resistance of the surface treatment layer. Specific methods include visual inspection, adhesion testing (such as scratch method, tensile test, etc.) and corrosion resistance testing (such as salt spray test).
3. Mechanical properties test
Mechanical performance test is an important means to evaluate the performance of lengthening screws, mainly including tensile strength test and torque test:
1. ** Tensile strength test ** : Through the tensile testing machine, determine the maximum tensile force that the screw can withstand before breaking. This index directly reflects the bearing capacity of the screw. During the test, you must strictly follow the relevant standards to ensure the accuracy and reliability of the test results.
2. ** Torque test ** : Through the torque wrench, determine the required torque value during installation. This helps to evaluate the mounting performance and fastening effect of the screws. In actual operations, pay attention to the recommended tightening torque range of screws of different specifications, and tighten the screws strictly according to the range.
4. Environmental adaptability assessment
Lengthening screws may encounter various complex environmental conditions during use, such as high temperature, low temperature, humidity, corrosion and so on. Therefore, it is essential to conduct an environmental adaptation assessment:
1. ** High temperature test ** : Test the mechanical properties of screws in a high temperature environment to evaluate their heat resistance. This helps ensure the stability and reliability of the screws under high temperature conditions.
2. ** Low temperature test ** : Similarly, test the brittle transition temperature and other performance indicators of the screw in a low temperature environment to evaluate its applicability under low temperature conditions.
3. ** Corrosion test ** : Test the corrosion resistance of screws by simulating the corrosive medium in the actual working environment (such as salt spray, acid and alkali solution, etc.). This helps to predict the service life of the screws in harsh environments.
5. Inspection of appearance and packaging
In addition to the inspection of the above key performance indicators, the appearance and packaging inspection is also a link that cannot be ignored:
1. ** Appearance inspection ** : Check the screw's color, surface finish and whether there are cracks, burrs and other defects. At the same time, confirm whether the screw specifications, models, marks, etc. meet the design requirements.
2. ** Packaging inspection ** : The outer packing box should be free from damage, deformation, moisture and other phenomena; The specified protective packaging materials should be used; The label of the outer packing case should be clear and complete, including the supplier name, production date, specification, model, quantity and other information.
Vi. Summary and outlook
To sum up, the comprehensive inspection of the quality of lengthening screws is a systematic project, which requires comprehensive consideration of material selection, manufacturing process, mechanical property testing, environmental adaptability assessment, appearance and packaging inspection and other aspects. Through the strict inspection process and methods, we can ensure that the quality of the extension screw meets the design requirements, and escort the safety and stability of the product. In the future, with the continuous progress of science and technology and the rapid development of the industry, the quality inspection standards and methods of lengthening screws will also be constantly updated and improved to better meet market demand and industry development.
# Lengthening screws # Lengthening bolts # Lengthening outer hex screws # Lengthening inner hex screws # fasteners
