Service HotlineTwo combination screws are mostly used for the connection between thin metal plates, and play a connecting role. When connecting, first make a threaded bottom hole for the connected piece, and then screw the combination screw into the threaded bottom hole of the connected piece. Since the threaded surface of the combination screw has high hardness, the inner thread can be tapped in the threaded bottom hole of the connected piece to form a connection.
1. The expansion phenomenon of the spring washer is generally not the problem of the spring washer itself. 2. The spring washer with the expansion ring must be subjected to a radial external tension. The external tension is derived from the tightening axial force generated by the tightening torque. The chamfer creates a radial component of the axial clamping force, which expands the opening of the spring washer. The smaller the chamfer diameter, the greater the possibility of ring expansion. 4. Adding a flat washer between the nut and the spring washer helps to slow down or prevent the expansion of the ring, but the flat washer is too thin or too soft. Prevent ring expansion 5. The reason for the hydrogen embrittlement fracture of spring washers is generally due to unreasonable heat treatment process and the failure of hydrogen removal treatment after electro-galvanizing. A large number of tests and long-term practical experience have confirmed the above analysis.
flat washer, an annular groove is formed on the outer side of the upper surface of the flat washer, and a sealing ring is embedded in the annular groove, at least five circularly equidistantly arranged cylinders are fixed on the upper surface of the flat washer, and the The upper surface of the flat washer is provided with a circular hole that communicates with its bottom, a collar is arranged in the circular hole, an upper circular ring is fixed above the collar, a lower circular ring is fixed below the collar, and the upper circular The diameter of the ring is the same as the diameter of the lower ring, the diameter of the collar is smaller than the diameter of the upper ring, the diameter of the collar is consistent with the diameter of the circular hole, and there are at least three equally spaced holes in the middle of the outer wall of the flat washer. A circular groove, the outer wall of the flat washer is fixed with at least three reinforcing blocks staggered with the circular groove, and the reinforcing blocks and the flat washer are welded into one piece.
Subject 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.
The rubber ring and the metal ring are integrally bonded and vulcanized. It is a sealing ring used to seal the thread and flange connection. The ring includes a metal ring and a rubber gasket. The metal ring is rust-proof, and the rubber ring is generally made of oil-resistant nitrile rubber or fluororubber. Combination pads are available in metric and inch sizes, and the standard JB982-77 specifies the combination of metal pads and rubber. Combination sealing washer is used for threaded pipe joints and screw plug sealing. It is generally used with ferrule type pipe joints to block oil ports. It is mainly used for end face static sealing of threaded joints of hydraulic valve pipe joints. It is suitable for British and American standards. Inch thread and end face static seal at French and German standard metric thread connections, etc. The combined sealing gasket can be divided into A type and B type according to the structure; it can be divided into full package and half package according to the difference of rubber.
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