What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
T-bolt, the European standard is called hammer bolt, the material is carbon steel, the surface is galvanized or nickel-plated, the T-bolt can be directly put into the groove of the aluminum profile, and it can be automatically positioned and locked during the installation process. Used in conjunction with the blue nut, it is a standard matching connector when installing corner fittings. It can be selected and used according to the profile groove width and different series of profiles. When the T-bolts on the market are installed with the installation channel, the bolts need to be placed into the channel from the port of the channel, and then tightened when moving to the designated position. The bolts are easy to rotate during installation, and the connection is not tight. Therefore, it is necessary to propose a mounting structure that uses T-bolts and grooves.
1. For low strength (below 500 N/mm2 or below 60000 psi) bolts use general soft steel, generally use SAE 1008 or JIS SWRM 8 (or SWRCH 8). 2. Lower strength (600 N/mm2 or 74000 psi) ) bolts use general soft steel, but limited carbon content grade, generally use SAE 1010 - 1015 or JIS SWRM 10 - 15 (or SWRCH 10 - 15). .3. Higher strength ( 800 N/mm2 or 125000 psi ) bolts of medium carbon steel, low carbon boron steel plus quenching and tempering, generally use SAE 1035 - 1040 or SWRCH 35K - 40K. 4. High strength (900 N/mm2 or more or 150000 psi or more) bolts use medium carbon Alloy steel or low carbon boron steel, in terms of application, if the metric Class 10.9 uses low carbon boron steel, the imprint should be added under the series imprint to become 10.9, and the imprint of the inch 8.2 grade is also used with the general Grade 8 bolts The imprint is different for easy identification. High-strength bolts made of low carbon boron steel cannot be used in high temperature conditions. The design strength exceeds Class 12.9 or ASTM A574 ultra-high strength bolts are limited to medium carbon alloy steel plus quenching and tempering. The performance grades of bolts for steel structure connection are divided into more than 10 grades such as 3.6, 4.6, 4.8, 5.6, 6.8, 8.8, 9.8, 10.9, 12.9, etc. Among them, the bolts of grade 8.8 and above are made of low-carbon alloy steel or medium-carbon steel and are heat-treated (quenching, tempering), commonly known as high-strength bolts, the rest are commonly known as ordinary bolts. The bolt performance grade label consists of two parts of numbers, which represent the nominal tensile strength value and yield ratio of the bolt material respectively. For example, a bolt with a performance level of 4.6 means: 1. The nominal tensile strength of the bolt material is 400MPa; 2. The yield ratio of the bolt material is 0.6; 3. The nominal yield strength of the bolt material is 400×0.6=240Mpa . Performance level 10.9 high-strength bolts, after heat treatment, can achieve: 1. The nominal tensile strength of the bolt material is 1000MPa; 2. The yield ratio of the bolt material is 0.9; High-strength bolts, processing and manufacturing problems are compared Small, general fastener manufacturing companies can master the manufacturing process; but problems are prone to occur in material selection and heat treatment. Material selection is the primary link. Various alloying elements have a great influence on the properties of the material, and the material must be subjected to spectral composition analysis; secondly, the fracture problem and the choice of heat treatment process have a great influence and are very important. Dealers and traders must control the inspection and performance testing links; automotive fasteners have high requirements and must carefully control the quality.
Flat gaskets are usually thin pieces of various shapes used to reduce friction, prevent leakage, isolate, prevent loosening, or distribute pressure. There are such components in many materials and structures. The existing flat washer has a simple structure design. After long-term use, the phenomenon of thinning of the thickness is likely to occur, which in turn leads to poor wear resistance of the flat washer.
There are two ways to form the external knurling of the embedded copper nut. One is to use copper raw material to draw the knurl and then to produce it on the upper equipment. Generally, the pattern of this method is straight, and the other is to use The round copper material is directly embossed while tapping during the production process. This processing method can produce some non-standard size knurled copper nuts. The embossed shape of the embedded copper nut can be selected by the user, such as mesh, Character embossing, herringbone embossing and other knurling patterns. Aliases and usage
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