Service HotlineSubject content and scope of application This technical requirement specifies the technical requirements for the manufacture, installation and inspection of high-strength bolted joints of mobile machinery and equipment. Contents not specified in this technical requirement shall be implemented in accordance with relevant national standards. This technical requirement applies to mobile machinery steel structures that require high-strength bolted connections. This technical requirement applies to quality control and construction methods for in-plant and on-site installations. 2. Joint surface treatment 2.1 For friction type high-strength bolt connections, the joint surfaces at the joints are required to be in close contact with each other and have a sufficient friction coefficient. When the design drawing does not specify the treatment requirements for the joint surface, the treatment shall be carried out according to the following regulations: sandblasting or shot blasting the joint surface of high-strength bolts, remove impurities such as rust and oil stains on the surface, and reach the Sa2.5 standard , the roughness is 50 ~ 75μm, and the friction coefficient shall not be lower than 0.40. When there are regulations in the drawings, follow the regulations in the drawings. 2.2 The friction surface of the treated high-strength bolt connection should take protective measures to prevent contamination with dirt and oil. It is strictly forbidden to make any marks on the friction surface of the high-strength bolt connection. During storage in the factory, or during transportation, to the installation site, special precautions should be taken to prevent contamination of the connection surfaces. The installation unit should pay special attention to protecting the cleanliness and friction surface characteristics of the connecting plate of the high-strength bolt and the connecting surface of the parent body. It is not allowed to use a grinder to grind the connecting surface of the connecting plate and the connecting surface of the parent body. 3 Inspection of the anti-slip coefficient of the friction surface of high-strength bolts The inspection of the anti-slip coefficient should be based on the steel structure manufacturing batch, and each 2000t of a single project is regarded as a manufacturing batch, and those less than 2000t are regarded as a batch. When two or more surface treatment processes are selected, each surface treatment process needs to be inspected. Each batch of three groups of specimens. If the connection is diffused to an external enterprise, each corresponding enterprise shall conduct an anti-slip coefficient test. 3.1 The test piece used for the anti-slip coefficient test should be processed by the factory or the diffusion enterprise. The test piece and the representative steel structure member should be of the same material, produced in the same batch, using the same friction surface treatment process and have the same surface state. And use the same batch of high-strength bolt connection pairs of the same performance level and store them under the same environmental conditions. The anti-slip coefficient test is carried out according to the test method of GB50205 Code for Acceptance of Construction Quality of Steel Structure Engineering. 3.2 The minimum value of the anti-slip coefficient inspection must be equal to or greater than the design specified value. When the above specified values are not met, the friction surface of the component should be reprocessed. The friction surface of the treated component is re-inspected. 4. Connection and installation of friction type high-strength bolts for steel structures 4.1 Preparations before installation 4.2 Select qualified bolts, nuts and washers. The guarantee period for the torque coefficient of the connecting pair is six months from the date of delivery. 4.3 Bolts, nuts and washers in the following cases are unqualified products and are prohibited from being used. a. The source (manufacturer) is unknown; b. The mechanical properties are unknown; c. The torque coefficient k is unknown; d. Defective; e. No performance test report attached; f. Mixed with other batches of bolts; g. Bolts with insufficient length, that is, the bolt head does not show the end face of the nut after tightening. Generally, the length of the end face of the nut to be taken out is 2 to 3 threads. h. The torque coefficient of the connecting pair exceeds the warranty period. Special attention should be paid to waterproofing during transportation and storage. 4.4 Before the construction of the large hexagonal head high-strength bolts, the torque coefficient of the high-strength bolt connection pair should be re-inspected according to the factory approval. Each batch of 8 sets should be re-inspected. Less than or equal to 0.010. The re-inspection method of the torque coefficient shall be carried out in accordance with the provisions of GB50205 Code for Acceptance of Construction Quality of Steel Structure Engineering. The installation of high-strength bolts should be carried out within a short period of time after the test.
At present, there are two methods for removing rivets in the market, one is non-destructive manual removal, which has low work efficiency and high work intensity. The other is mechanical destructive dismantling, such as the electric drill dismantling method. This method has high work efficiency, but it is easy to cause damage to the riveted product, and it is easy to cause the rivet to splash, and the operation is dangerous.
Guangdong Yueluo Hardware Industry Co., Ltd. discloses a telescopic screw. The main point of its technical solution is that it includes an upper screw rod, one end of the upper screw rod is provided with a screw head, and the other side of the upper screw rod opposite to the screw head is provided with a lower screw rod, and the lower screw rod is provided on the other side. A fixing rod is provided, a limiting hole is set on the fixing rod, a sliding rod is set on the upper screw rod, a limiting block matching the limiting hole is set on the sliding rod, and a cover plate is slidably sleeved on the sliding rod. An inner thread is arranged on the plate, a thread matching the inner thread is arranged on the fixing rod, an elastic member is sleeved on the fixing rod, and both ends of the elastic member are respectively in conflict with the upper screw rod and the lower screw rod. Guangdong Yueluo Hardware Industry Co., Ltd. telescopic screw is provided with a telescopic mechanism between the upper screw and the lower screw. Therefore, the screw can be suitable for threaded installation holes with the same diameter and different lengths, avoiding the screw being limited by the length of the threaded hole and unable to be installed.
How to use, what is a rivet nut? Usually, rivet nuts used inside elevators are used to install some kind of screws when installing various parts on cars or individual boards on aviation. Commonly used places are very important connection parts, so the choice of rivet nut material is very important. How to use the rivet nut? Let's watch it together. Rivet nuts are used in the fixing fields of various metal plates, pipes and other manufacturing industries, and are widely used in the assembly of electromechanical and light industrial products such as automobiles, aviation, railways, refrigeration, elevators, switches, instruments, furniture, and decoration. It is designed to solve the shortcomings of sheet metal, thin-walled pipe welding nut, substrate welding deformation, internal thread taper, etc. It does not require internal thread, welding nut, rivet efficiency, and is easy to use.
When checking the finished blind rivet, check: the diameter of the rivet body, the length of the rivet body, the thickness of the rivet body cap, the diameter of the cap, the total length of the mandrel, the exposed size of the mandrel, the size of the nail cap, and the outer diameter after assembly can be considered. In the actual inspection, the weak links of the product can be measured, such as: tensile force, shear resistance, and core pull-out resistance. The key is to pay attention to the rivets, if the rivets are insufficient, whether they are riveted in place; or because the cap of the mandrel is too large, so that the mouth of the rivet body cannot be pulled down; and there are jump heads, that is, the mandrel is too low or broken. The size is too small etc. Length measurement of closed blind rivets
We have many years of experience in the production and sales of screws, nuts, flat washers, etc. The main products are: PM round head machine screw, high quality, single lug washer nuts, cross countersunk head screws and nuts and other products, we can provide you with suitable products for you fastener solutions.
