Service Hotline1. 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.
Installation method broadcast 1. One-time burying method: When pouring concrete, bury the anchor bolts. When the high tower is controlled by overturning, the anchor bolt should be buried once. 2. Reserved hole method: The equipment is in place, the holes are cleaned, the anchor bolts are placed in the holes, the equipment is positioned and aligned, and then poured with non-shrinkage fine stone concrete that is one level higher than the original foundation, and compacted and compacted. . The distance from the center of the anchor bolt once buried to the edge of the foundation should not be less than 2d (d is the diameter of the anchor bolt), and should not be less than 15mm (d≤20, it should not be less than 10mm), not less than half the width of the anchor plate Add 50mm, when the above requirements cannot be met, appropriate measures should be taken to strengthen it. The diameter of the anchor bolts used for the structure should not be less than 20mm. When subjected to earthquake action, double nuts should be used for fixing, or other measures to effectively prevent loosening should be adopted, but the anchorage length of anchor bolts should be increased by 5d compared with the anchorage length of non-seismic action. Installation planning of anchor bolts Treatment of anchor bolts loose in the foundation When the anchor bolts are tightened, the bolts may be pulled out. At this time, the bolts should be adjusted to their original positions, and the foundation around the bolts should be shoveled out enough. , and then weld two U-shaped steel bars vertically and horizontally on the bolts, and finally clean the pit with water and grouting, and then tighten the live anchor bolts after the concrete has solidified to the design strength. The treatment method of the live anchor bolt deviation is roughly the same as the dead ground. The method for the anchor bolts is the same, except that the anchor bolts can be pulled out for processing. If the bolt is too long, a section of the thread can be cut off on the machine tool; if the bolt is too short, it can be extended by hot forging; if the position is inconsistent, it can be corrected by bending. Application industry: suitable for various equipment fixing, steel structure foundation embedded parts, street lights, traffic signs, pump, boiler installation, heavy equipment embedded fixing, etc.
When using, after installing the nut and the bolt in place, insert the locking strip from the groove of the bolt, and make the V-shaped locking teeth of the locking strip snap into one of the V-shaped tooth grooves, and push the locking strip into the groove as a whole. The V-shaped locking teeth are stuck in the nut, and the locking strip body is stuck in the groove of the bolt, thereby restricting the relative rotation of the nut and the bolt, and there are threads between the nut and the bolt to restrict their relative sliding, so it can prevent the nut from loosening, even from The bolt falls off; when the nut needs to be disassembled, it is only necessary to pull out the locking strip from the groove, and the nut can be disassembled normally.
An asphalt pavement screw, the asphalt pavement screw includes a main rod, an outer jacket, a pressing piece and a nut, the main rod is a columnar rod, the lower end of the main rod is provided with a table for supporting the outer jacket, and the middle part of the main rod passes through the outer jacket The upper part of the main rod is provided with a threaded section, the pressing piece and the nut are set on the threaded section, and at least two deformation holes are provided on the outer sleeve, and the middle part of the deformation hole is larger than the upper and lower sides of the deformation hole, The part between the adjacent deformation holes is the deformation part, and the width of the middle part of the deformation part is smaller than the width of the upper and lower sides of the deformation part. After the asphalt pavement screw of Guangdong Yueluo Hardware Industry Co., Ltd. is assembled, it has strong bonding force with the asphalt road. Even if it is hit, it will not be separated from the asphalt road. Using this asphalt pavement screw to fix the road railing can strengthen the road railing. The firmness of the assembly.
Yueluo relates to a self-tapping screw according to the preamble of claim 1. A self-tapping screw is known from EP0623759B1, the ratio of the outer diameter to the smaller diameter of the self-tapping screw is about 1.25-1.5, the ratio of the outer diameter to the pitch lead is about 1.5-1.6 and the thread The flank angles of , are < 50° and ≥ 35°. EP0433484B1 proposes a self-tapping screw whose thread is provided with cutting teeth of approximately arcuate design, and the cutting edge and the thread crest are at the same horizontal position and are set in opposite directions. One purpose of Yueluo is to realize a general type of self-tapping screw so that it can be screwed particularly easily into holes drilled in concrete or other materials such as bricks and the like. According to Yueluo, this object is achieved by the features in the characterizing part of claim 1, and surprisingly, it has been found that the parallel arrangement of the flanks, ie with a flank angle of about 0°, will make screwing particularly easy when screwing in , especially if the diameter of the hole varies within an allowable tolerance. One reason may be due to the fact that there is no lateral pressure on the material screwed into the thread, even if threads of different depths are cut in concrete or other materials such as brick, chipped plywood, or hardwood. The thread cuts into the material over its entire width by cutting grooves. In particular according to the embodiment of claim 13 the material cut out when screwing in the screw can be discharged without any accumulation, the dependent claims reflecting many advantages of further embodiments.
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