Service HotlineThe traditional fixture shown in Figure 2 is composed of a hardened support cylinder and a hardened shear bar, and has a simple structure. The cylindrical pin is loaded into the hardened support cylinder, and the shear test is completed by applying an axial load to the hardened shear bar. Since the standard stipulates that the gap between the loading part and the supporting part does not exceed 0.15mm, in order to ensure the matching of the gap during the shear test of the cylindrical pin, the diameter of the cylindrical pin on the cylinder is generally equal to the theoretical cylindrical pin. In practical application, the cylindrical pin is irregular in size after heat treatment. To realize the shear test, the cylindrical pin must be inserted into the hole with the help of external force, which is difficult to install and clamp and takes a long time. If the double-sided shearing is performed, that is If the cylindrical pins need to be installed on both sides, the time is doubled, and the notch of the cylindrical pins cannot be guaranteed to face upwards.
When the rivet is riveted, it is often necessary to locate and fix the rivet. However, the common rivet positioning mechanism at present often has no way to effectively and quickly remove the restriction on the rivet after the rivet is fixed, which makes it difficult for the nailing mechanism to be inserted. Quickly drive the positioned rivets.
In specific implementation, the axial three-dimensional shape of the nut and the screw head is in the shape of a pentagonal frustum, the elastic surface of the screw is parallel to the center line of the bolt, and the upper contour line is arc-shaped; the screw can be full or partial thread; the top of the screw head The shape is round.
Ordinary open rivet is a kind of product in rivet. It is riveted to the workpiece by expanding the rivet body after the big end of the mandrel is pulled. After the traditional rivet is riveted, the operator will cut the mandrel short, the mandrel does not work, and the workpiece is riveted by the material strength of the rivet body itself. After the mandrel is pulled, the middle of the rivet body becomes a cavity, and the mandrel shears The distance of the segments is relatively random. The random shearing determines the length of the cavity of the riveting body, and the length of the cavity determines the tensile and shear strength of the riveting body. The volume of the cavity is large, the tensile and shear strength is low, and the cavity is small. , the tensile and shear strength is slightly improved, so the breaking point of the rivet can completely affect the use effect of the rivet.
The produced screws, due to unreasonable production aspects, are likely to cause quality problems in the screws. During production, many screw quality problems may be found upon delivery. Let's talk about the quality problems often encountered by screws and the reasons for the quality problems, and finally put forward some solutions. 1. The head of the screw is deformed and the head is crooked. The possible reasons are the poor installation of the first punch of the screw die and the improper adjustment of the machine. 2. The head of the screw is not round. The reason is that the selection of the first punch of the screw mold is improper or the first punch is not full enough. 3. The screw has burrs or burrs. The reason is the poor forming of one punch, mainly caused by too large gap between punch and die hole or too short punch. 4. The screw head is cracked and the screw head is cracked. The reason may be that there is a problem with the quality of the screw wire itself, so before the screw wire is headed, the quality department must check it and use the potion. Especially the stainless steel screw wire, it is necessary to check that it is stainless steel 201 and that is stainless steel 304. It is also possible that a die is used incorrectly (such as a die with a hexagonal washer head for a pan head), and the viscosity of the lubricating oil fails. For the problem of the screw head, you can read the article written by Manager Zhu above - high-strength screw fracture or head crack detection. In this article, some problems encountered by the screw head and how to detect the screw head problem are clearly introduced [4]. The common quality reasons for screws are of course more than the above, this is only part of it. There are other quality issues, then Manager Zhu will talk about it. The above screw quality reasons are for reference. If you encounter these problems, you can try the solutions proposed.
We have many years of experience in the production and sales of screws, nuts, flat washers, etc. The main products are: GB1339 hexagonal self-locking nuts, welded DIN outer wires, copper flower mother copper inlays, multi-axis aerial photography aircraft frame nuts and other products, we can provide you with Provide the right fastener solution for you.
