What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
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.
In real life, rivet nuts are used. With different specifications and different uses, many people are familiar with this tool but don't know how to use it properly. In fact, rivet nut tools have manual and transmission, and now are rarely used for manual. If you choose to use electric rivet nuts in order to improve production efficiency, which of the two is more widely used? The following describes the use of electric rivet nuts and manual nuts. How to use the manual rivet nut tool: Insert the rivet nut into the drilled installation hole with a rivet mother tool to fix the rivet nut. (1) Screw the rivet nut onto the rivet nut tool 2) Use the rivet nut tool to insert the rivet nut into the drilled mounting hole. (3) Tighten the nut, and press the handles on both sides of the rivet nut tool to the direction of the middle round rod. You can only press it hard. Therefore, this pressure must be in place. It is forbidden to repeatedly squeeze the handles on both sides to damage the nut. Fastening thread in the form of inside. (4) The rivet nut tool is separated from the rivet nut: just loosen the ball head in the picture, and the tool will be separated from the nut after completely loosening.
The traveling plate can be driven by the traveling cylinder to move from the lower end of the circlip sleeve rod to the lower ends of the two probes of the circlip tightening mechanism; after the two probes tighten the circlip, the traveling plate can be moved in the traveling cylinder. The tightening mechanism moves down under the drive of the lifting cylinder, the probe installs the tightened circlip in the workpiece, and then retracts the probe upward.
The lifting ring nut is a part that tightly connects the mechanical equipment. It can be connected together through the inner thread, the lifting ring nut and the screw of the same specification. Lifting ring nuts are often used in conjunction with externally threaded columns to lift various equipment, such as molds, chassis, motors, etc.
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