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Carbon Steel Class 4.8 8.8 Black Oxide Cross Recessed Flat Black Drywall Screw
1,Description:
The performance grades of bolts used for steel structure connections are divided into more than ten grades, including 3.6, 4.6, 4.8, 5.6, 6.8, 8.8, 9.8, 10.9, 12.9, etc. Among them, bolts of grade 8.8 and above are made of low-carbon alloy steel or medium carbon steel and undergo heat treatment (quenching, tempering), and are generally called high-strength bolts. The rest are generally called ordinary bolts. The performance grade label of a bolt consists of two parts of numbers, representing the nominal tensile strength value and the yielding ratio of the bolt material respectively
Carbon steel grade 4.8 is the strength grade of bolts, which are usually made of 45 steel or Q235-A. Grade 8.8 bolts are made of 45 steel, and grade 4.8 bolts are made of Q235-A. The corresponding national standard standards are also different. For example, GB/T 819.1-2000: "Cross Groove countersunk screws - Part 1: Steel Grade 4.8". Grade 4.8 can be made of low-carbon steel materials such as A3, Q235, and Q195
| Applications | |||||
| car | In high-strength applications such as automotive engines, heavy-duty machinery, and bridge construction, they are preferred for their larger support area and better anti-loosening performance. | ||||
| mechanical | Mechanical, electronic, automotive, construction and other fields, used to connect various mechanical parts, circuit boards, engines, transmissions, building structures, etc | ||||
| energy | For the energy industry, brackets and fixtures used to connect power generation equipment and transmission lines | ||||
| architectural | In the field of construction engineering, shipbuilding, and petrochemical industry, it is used to connect building structures, improve the navigation safety and stability of ships, and ensure the safety and stability of petrochemical equipment | ||||
The main purpose is to make industrial products composed of a fixed body, in the use of teeth and teeth often can not be close, too hard to lock the screw head is broken, or poor dental lock is not tight and failed to meet the conditions of use, are precision problems. Screws are "quantity products", not hand-made artworks, in mass production, in order to achieve high precision and stable quality and popular price supply to consumers for the purpose. The accuracy of the screws is usually 6g (Class 2, the US specification "IFI" is 2A teeth), and the rough screws used in construction projects are 8g (Class 3, "IFI" is 1A teeth).
3,Specifications:
| material | |||||
| aluminium | Aluminum has excellent thermal and electrical conductivity. However, aluminum is naturally soft and may produce gelatinous buildup after processing. If not properly operated, it is difficult to cut during processing. | ||||
| titanium | Edm machining is well suited for titanium because the process can withstand the viscosity of this alloy and break down lengthy chips. However, deionized water is needed as a medium to help control the heat generated during processing. | ||||
| steel | Steel is a very strong metal, and many manufacturers tend to use wire cutting machines instead of CNC machines for machining complex steel features. However, this material generates a lot of heat, so necessary precautions need to be taken. | ||||
| brass | Brass has a high tensile strength and is easy to cut by machine. But the cutting speed should be slow because it is a soft metal. | ||||
4,Feature Advantage:
Performance grade 8.8 high-strength bolts, after heat treatment of the material, can achieve:
The nominal tensile strength of the bolt material reaches 640MPa grade.
The yield-to-tensile ratio of the bolt material is 0.8.
5,About us
6.FAQ
A: We are factory and OEM are available.
A: Generally it is 7-10 days if the goods are in stock. or it is 15-20 days if the goods are not in stock, it is according to quantity.
A: Yes, we could offer the sample for free charge but do not pay the cost of freight.
A: 30% T/T in advance ,balance before shippment or L/C.
If you have another question, pls feel free to contact us as below: