Service HotlineThe global economy continues to slump and overseas export trade is sluggish. Many fastener companies at home and abroad are facing severe tests. Accelerating economic transformation and structural upgrading is imminent, and developing overseas markets is undoubtedly an important way out for the development of the current fastener industry. From the fourth quarter of 2011 to the first half of 2012, affected by the objective environment, the development speed of the fastener industry may slow down, but from the third quarter of 2012, with the policy in place, the convening of the 18th National Congress of The upcoming series of development policies, etc., can promote the further development of the industry. And we must insist on innovation and adjustment and transformation, we must continue to rely closely on key industries such as automobiles, new energy, aerospace, shipbuilding, urban transportation, IT, electronic appliances, construction, etc., accelerate the optimization and upgrading of fastener products, and promote fasteners. The whole industry develops healthily and steadily. The global fastener market size exceeds 50 billion US dollars, and China's total fastener production in 2012 is also expected to reach about 6.8 million tons. However, compared with the manufacturing powerhouses such as the United States and Japan, there is still a big gap in my country's fastener industry.
When using screws, if you can understand the mechanical properties of screws first, then you can use screws better. Different types of screws have different mechanical properties, and the different mechanical properties lead to different occasions when screws are used. 1. Self-tapping screws: mechanical performance requirements 1. Heart hardness: standard value HRC28-38. When testing, take the section 1-2 times the diameter of the name from the tail. If the length of the name is too short, it can be embedded first, and then the hardness is measured. 2. Surface hardness: standard MIN HV450. 3. Carburized layer: standard 4#-6#: 0.05-0.18mm, 8#-12#: 0.10-0.23 mm, 14#: 0.13-0.28 mm. The main purpose of carburizing is to enhance the surface hardness and ensure the strength of the teeth. If the decarburization is too deep and the carburization is insufficient, the strength of the teeth will not meet the requirements, that is, the teeth will be damaged during the screw-in test. 4. Torque: standard specification 4#5#6#7#8#10#12#14#A tooth 14212835455696145AB tooth 142128354565102165. 5. Screw-in test: screw the self-tapping screw into a steel plate with a reserved test hole. The self-tapping screw should form a matching thread in the test plate, and the thread of the screw itself will not be deformed or damaged until the end. Tapered threads pass completely through the test plate. The screw-in test is only applicable to AB, B, BP and other types of self-tapping screws. It is stipulated in IFI that the test plate shall be prepared from semi-hard low-carbon cold-rolled steel, and the hardness of the steel plate is 70–85HRB in Rockwell. The standard specification of the steel plate, that is, the thickness, is shown in the table below. The test hole should be punched or drilled, and the tolerance is the specified nominal diameter (see the table below) ± 0.025mm. Specifications 6#7#8#10#12#1/4 Test plate thickness (mm) 1.85-1.953.12-3.234.68-4.84 Aperture (mm) ±0.0252.953.263.454.044.765.50.
When the mechanical components are installed on the concrete foundation, the J-shaped and L-shaped ends of the bolts are embedded in the concrete for use. The tensile capacity of the anchor bolt is the tensile capacity of the round steel itself. The size is equal to the cross-sectional area multiplied by the allowable stress value (Q235B: 140MPa, 16Mn or Q345: 170MPA), which is the allowable tensile capacity at the time of design. The anchor bolts are generally made of Q235 steel, which is smooth and round. Rebar (Q345) is strong, and the thread of the nut is not as easy to be round. For light round anchor bolts, the burial depth is generally 25 times its diameter, and then a 90-degree hook with a length of about 120mm is made. If the bolt diameter is large (such as 45mm) and the buried depth is too deep, a square plate can be welded at the end of the bolt, that is, a large head can be made (but there are certain requirements). The burial depth and hook are all to ensure the friction between the bolt and the foundation, so as not to cause the bolt to be pulled out and damaged.
1. Fixed anchor bolts, also known as short anchor bolts, are poured together with the foundation and used to fix equipment without strong vibration and impact. 2. The movable anchor bolt, also known as the long anchor bolt, is a detachable anchor bolt used for fixing heavy machinery and equipment with strong vibration and impact. 3. Expansion anchor bolts are often used to fix stationary simple equipment or auxiliary equipment. The installation of expansion anchor bolts should meet the following requirements: the distance from the center of the bolt to the edge of the foundation shall not be less than 7 times the diameter of the expansion anchor bolt; the foundation strength of the expansion anchor bolt shall not be less than 10MPa; there shall be no cracks in the drilling holes. The drill bit collides with the steel bars and buried pipes in the foundation; the diameter and depth of the drill hole should match the expansion anchor bolts. 4. The bonding anchor bolt is a kind of anchor bolt commonly used in recent years, and its method and requirements are the same as the expansion anchor anchor bolt. However, when bonding, pay attention to blowing out the debris in the hole, and do not get wet. [1]
Bolts with low hardness and strength. Generally, ordinary bolt materials are produced with ordinary screw wires. The hardness, strength, tensile strength and torsion force of ordinary bolt materials are not very high. High-strength bolts generally refer to high-strength bolts. Its own screw material, bolt material, and bolt material are relatively good, and the hardness is relatively high, and after the production is completed, the bolts will be hardened. Make the bolts meet the grade strength requirements of high-strength bolts.
We have many years of experience in the production and sales of screws, nuts, flat washers, etc. The main products are: cylindrical nuts, automotive lock bolts, internal stop washers, nylon bolts and screws and other products, we can provide you with suitable fastening products piece solution.
