Release time：2020-01-16 18:44 Browse：
In industrial production and daily maintenance, extension screws, as a special fastener, are favored because of their ability to achieve fastening function across large distances. However, ensuring that the performance of the extension screw meets the design requirements is not only related to the safety and stability of the product, but also directly affects the quality and life of the overall project. This paper will elaborate how to evaluate the performance of lengthening screws from five aspects: material selection, structural design, manufacturing process, mechanical property testing and environmental adaptability assessment.
First, material selection
The performance of extension screws depends first on their material. Commonly used materials include stainless steel, carbon steel, alloy steel, etc., each material has its own unique physical and chemical properties, suitable for different working environments and load requirements.
Stainless steel: Because of its excellent corrosion resistance, it is widely used in humid and corrosive environments. The evaluation should focus on its tensile strength, yield strength and corrosion resistance rating to ensure that it can maintain stable performance under harsh conditions. Carbon steel: relatively low cost, high strength, suitable for general mechanical connections. The evaluation should take into account the hardness, toughness and possible hydrogen embrittlement after heat treatment. Alloy steel: combined with the advantages of a variety of metal elements, with high strength, high wear resistance and other characteristics, suitable for high load, high stress occasions. The evaluation should pay special attention to the specific effect of the alloy composition on the properties.
Second, structural design
The structural design of the extension screw is directly related to its force distribution and service life. The following aspects should be addressed in the assessment:
Thread design: including thread shape, pitch, tooth Angle, etc., directly affect the fastening effect and anti-loosening ability. It is necessary to ensure that the thread design is reasonable and can meet the requirements of use through calculation analysis or experimental verification. Rod diameter and length: The diameter determines the bearing capacity of the screw, and the length affects its span and stability. Determine the rod size based on the actual application scenario to avoid over-design or under-design. Head design: Head shape, size and tool matching directly affect installation efficiency. Ease of installation, head strength and contact area with the workpiece should be considered in the evaluation.
3. Manufacturing process
The quality of manufacturing process directly affects the quality of lengthening screws. The evaluation should focus on the following aspects:
Heat treatment: through quenching, tempering and other processes to improve the mechanical properties of materials, improve strength and toughness. It is necessary to strictly control the heat treatment temperature and time to avoid overheating or undercooling resulting in performance degradation. Surface treatment: such as galvanized, nickel plating, spraying, etc., can improve the corrosion resistance and appearance quality of screws. The evaluation should check the uniformity, adhesion and corrosion resistance of the surface treatment layer. Machining accuracy: including thread accuracy, rod straightness, head shape tolerance, etc. High precision machining can ensure that screws are more smooth and stable in use.
4. Mechanical properties test
Mechanical property testing is an important means to evaluate the performance of lengthening screws. It mainly includes the following items:
Tensile strength test: Through the tensile testing machine, the maximum tension that the screw can withstand before breaking is determined to assess its load bearing capacity. Yield strength test: During the stretching process, the stress value at which the screw begins to produce significant plastic deformation is determined to assess its ability to resist deformation. Fatigue life test: Simulate the alternating load in actual use to determine the life of the screw under multiple cycle loading to assess its long-term reliability. Torque test: Through the torque wrench, determine the required torque value during installation to evaluate the installation performance and tightening effect of the screw.
5. Environmental adaptability assessment
In the process of use, the extension screw may encounter various complex environmental conditions, such as high temperature, low temperature, humidity, corrosion and so on. Therefore, it is very important to carry out environmental adaptation assessment.
High temperature test: Test the mechanical properties of screws in a high temperature environment to evaluate their heat resistance. Low temperature test: test the brittle transition temperature of the screw in a low temperature environment to evaluate its low temperature resistance. Corrosion test: Evaluate the corrosion resistance of screws by simulating a corrosive environment (such as salt spray test, acid and alkali soaking, etc.). Vibration test: Simulate the vibration environment of equipment operation, evaluate the stability and anti-loosening ability of screws under dynamic load.
To sum up, the performance evaluation of lengthening screws is a systematic engineering, which needs to consider many aspects such as material selection, structural design, manufacturing process, mechanical property testing and environmental adaptability assessment. Only a comprehensive and meticulous evaluation can ensure that the performance of the extension screw meets the design requirements and escorts the safety and stability of the product.
# Lengthening screw material # lengthening extra-long screw # Lengthening screw # Lengthening screw test # Fastener
