Different materials of bolt
Different materials are used according to the strength level of bolt BAI:
At present, du market standard parts mainly carbon steel, zhi rust steel DAO, copper three kinds of materials.
(1) Carbon steel.We classify low carbon steel, medium carbon steel, high carbon steel and alloy steel by their carbon content in carbon steel.
1. Low carbon steel C%≤0.25% is usually called A3 steel in China.Foreign countries are basically called 1008,1015,1018,1022, etc.Mainly used for grade 4.8 bolts, grade 4 nuts, small screws and other products without hardness requirements.(Note: The drilling tail nail is mainly made of 1022 materials.)
2. Medium carbon steel 0.25%& LT;C%≤0.45% is usually called no. 35 and no.45 steel in China, and basically called as 1035, CH38F, 1039,40 ACR in foreign countries.It is mainly used for class 8 nuts, class 8.8 bolts and class 8.8 hexagon socket products.
3. High carbon steel C%& GT;0.45%.It’s barely used in the market right now
4. Alloy steel: add alloying elements to common carbon steel to increase some special properties of steel, such as 35, 40 cr-Mo, SCM435, 10B38.Aromatic screw mainly USES SCM435 chromium molybdenum alloy steel, the main components are C, Si, Mn, P, S, Cr, Mo.
(2) Stainless steel.
Performance rating: 45,50,60,70,80
Austenite (18%Cr, 8%Ni) has good heat resistance, corrosion resistance and weldability.A1, A2, A4 martensite and 13%Cr have poor corrosion resistance, high strength and good wear resistance.C1, C2, C4 ferrite stainless steel.Cr 18% has better upsetting forging and corrosion resistance than Martensite.At present, the imported materials on the market are mainly Japanese products.
According to the level of SUS302, SUS304, SUS316.
(3) Copper.Common material is brass…Zinc copper alloy.H62, H65 and H68 copper are mainly used as standard parts in the market
Maintenance considerations
1. Do not start the machine until the screw reaches the preset temperature.
2. Prevent metal fragments and sundry things from falling into the hopper. If the recycled material is processed, a magnetic hopper shall be added to prevent iron filings from entering the barrel.
3, the use of anti-salivating to make sure that the plastic inside the barrel is completely fused, so as to avoid damage to the drive system parts when the screw back.
4, the use of new plastic, the screw should be cleaned.
5, when the molten plastic temperature is normal but constantly found that molten plastic appear black spots or discoloration, should check the glue screw.
6. During the processing, try to make the materials plasticized evenly, do not let metal foreign matter into the materials, and reduce the rotating torque force of the screw
According to the force mode of connection points: points common and hinged hole with.According to the shape of the head: hexagonal head, round head, square head, countersunk head, etc.The hexagonal head is the most commonly used.The countersunk head is usually used where connection is required.
The horse riding bolt is called U-bolt, which is non-standard and shaped like a U-shaped bolt. It is also called U-bolt with two threads that can be combined with a nut. It is mainly used to fix a pipe, such as a water pipe or a flake, such as the plate spring of an automobile.According to thread length, it is divided into full thread and non-full thread.
There are two types of teeth, coarse teeth and fine teeth, according to the thread. The coarse teeth are not shown in the bolt marks.Bolts are divided into eight grades according to their performance grades: 3.6, 4.8, 5.6, 5.8, 8.8, 9.8, 10.9 and 12.9. The bolts above grade 8.8 (including grade 8.8) are made of low carbon alloy steel or medium carbon steel and heat treated (quenching and tempering), which are generally referred to as high-strength bolts, and below grade 8.8 (excluding grade 8.8) are generally referred to as ordinary bolts.
Ordinary bolts can be divided into A, B and C grades according to the production accuracy, grade A and B are refined bolts and Grade C are rough bolts.For steel structure connection bolts, unless otherwise specified, are generally c-class bolts of ordinary rough design.Different processing methods are different, usually corresponding to the following processing methods:
The bolt rod of class A and B bolts is processed by lathe, with smooth surface and precise size. The material performance grade is 8.8, which is complicated to manufacture and install, high in price and rarely used;
(2) Class C bolts are made of raw round steel, the size is not accurate, the material performance grade is 4.6 or 4.8.Shear joint deformation is large, but easy to install, low production cost, used for tensile connection or installation of temporary fixation.