Release time：2020-01-16 18:44 Browse：
In the fastener industry, lengthening screws are a common connection element, and their tensile strength is one of the important indicators to measure their performance. Different materials and specifications of extension screws, the tensile strength is often significantly different. In this paper, the tensile strength range of lengthening screws will be discussed from the Angle of different materials and specifications.
1. Tensile strength of stainless steel extension screws
Stainless steel is widely used in the field of high-end equipment connection because of its excellent corrosion resistance and high mechanical properties. The tensile strength of stainless steel extension screws is closely related to its material grade.
#### 1.304 stainless steel (A2 series)
304 stainless steel, the A2 series, is one of the most widely used stainless steel materials. Its tensile strength increases with the increase of grade. For example, the A2-50 grade stainless steel screws have relatively low tensile strength and are suitable for occasions where the general requirements are not high. The A2-70 level represents a higher tensile strength, and its tensile strength per square millimeter can reach 700N (700MPa), which is suitable for occasions where the strength of the connection has certain requirements. It should be noted that 304 screws of small specifications (such as M4 and below) may not reach the A2-70 level, so there are lower grade products such as A2-50.
#### 2.316 stainless steel (A4 series)
316 stainless steel, that is, the A4 series, has better corrosion resistance than 304 stainless steel, so it is also commonly used in situations with higher environmental requirements. A4 series stainless steel screws are also available in multiple grades, such as A4-70 and A4-80. The screw tensile strength of the A4-70 grade is 700MPa, while the A4-80 is higher, reaching 800MPa. However, it should be noted that not all fasteners of 316 material can reach the A4-80 level, especially small fasteners such as thin nuts.
2. Tensile strength of carbon steel extension screws
Carbon steel, as a material with low cost and good processing performance, is widely used in general mechanical equipment and building structures. The tensile strength of carbon steel extension screws mainly depends on its material and heat treatment process.
#### 1. Ordinary carbon steel screws
Ordinary carbon steel screws without special heat treatment have relatively low tensile strength and are suitable for occasions where the connection strength is not required. This type of screw is low in cost, easy to purchase and install, and is one of the most widely used screws in daily life.
#### 2. High strength carbon steel screws
After heat treatment (such as quenching, tempering) of high-strength carbon steel screws, the tensile strength can be significantly improved. For example, the nominal tensile strength of 8.8 grade carbon steel screws reaches 800MPa, and the yield strength is 0.8 times the tensile strength, that is, 640MPa. This screw can withstand a large tensile force without breaking, while maintaining a certain elastic deformation ability, suitable for the connection strength has a certain requirement of the occasion.
Third, the tensile strength of other materials lengthening screws
In addition to stainless steel and carbon steel, there are a variety of other materials on the market, such as alloy steel, aluminum alloy and so on. The tensile strength of screws of these materials has its own characteristics.
#### 1. Alloy steel screws
Alloy steel screws improve their mechanical properties by adding alloying elements, and the tensile strength is usually higher than that of ordinary carbon steel screws. The addition amount and type of different alloying elements will significantly affect the tensile strength of screws, so the specific value needs to refer to the relevant standards or actual testing.
#### 2. Aluminum alloy screws
Aluminum alloy screws are used in specific fields because of their light weight and corrosion resistance. However, the tensile strength of aluminum alloy is relatively low, so aluminum alloy screws are mainly suitable for high requirements on weight and corrosion resistance, and the connection strength is not high.
Fourth, the tensile strength range of different specifications of extension screws
In addition to the material, the specification of the screw (such as diameter, length) will also have an impact on its tensile strength. Generally speaking, the larger the diameter of the screw, the higher the tensile strength. However, the specific value needs to be determined according to the specific material and heat treatment process. In addition, as the length of the screw increases, its tensile strength may be reduced due to factors such as stress concentration.
### Conclusion
In summary, the tensile strength of lengthening screws is a complex and variable parameter, which is affected by many factors such as material, specifications, heat treatment process and so on. In practical applications, the appropriate material and specifications of the extension screws should be selected according to the specific needs to ensure the reliability and safety of the connection. At the same time, for occasions with high strength requirements, the installation quality of the screw should also be strictly controlled to ensure that it achieves the desired fastening effect.
# Lengthening screws # Lengthening bolts # Lengthening outer hex screws # Lengthening inner hex screws # fasteners
