What material is used for hub screws?

Question 1: What is the aluminum alloy used for automobile tire bolts?

Question 2: What kind of steel is the fastener of automobile hub? The lead screw is steel with strength above 10.9, and the nut is 35CrMo alloy structural steel with high strength.

Question 3: What kind of steel is generally used to produce automobile hub nuts, low carbon steel can be used.

Question 4: What screws are used for automobile hub screws?

Question 5: What materials can be used for tire nuts? Carbon steel 8.8, high-strength alloy steels such as A3, 40Cr and 42CrMo, titanium alloy TC4 and iron A3 and 40Cr.

Question 6: What steel is used for tire screws? Is it forged or precision cast? What is the manufacturing process? What is the production process of bolts?

I. Materials and production technology of high-strength bolts

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Commonly used steel types for high-strength bolts are as follows:

35 steel, 45 steel and ML35 steel for grade 88 bolts.

35CrMo and 40Cr are used for 109 grade bolts.

35CrMo and 42CrMo for 129 grade bolts.

2. A production process for preparing persimmon.

The production process of high-strength bolts is as follows:

1 cold heading bolt: spheroidizing annealing → cold drawing → cold heading forming → thread processing → tempering → surface treatment.

2 Hot upsetting bolts: cold drawing → hot upsetting forming → hexagonal forming → thread processing → tempering → surface treatment.

2. Preheating treatment

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The original structure of cold heading bolt steel will directly affect the formability during cold heading. In the process of cold heading, the plastic deformation of local area can reach 60% ~ 80%, so the cold heading bolt steel must have good plasticity.

When the chemical composition of steel is certain, metallographic structure is the key to determine plasticity. Generally, coarse flaky spheres are not conducive to cold heading, while fine pearlite can significantly improve the plastic deformation ability of steel. Therefore, for medium carbon steel and medium carbon alloy steel with more pearlite content, spheroidizing treatment must be carried out before cold heading to obtain uniform and detailed spheroidized bodies.

Annealing process of double-head scale

When steel is spheroidized and annealed, the heating temperature is usually around the critical point Ac 1 of steel, and the spheroid is spheroidized after long-term heat preservation.

For medium carbon steel, the heating temperature should not be too high, and the ordinary spheroidizing annealing should be selected at 7 15 ~ 725℃ for 2 ~ 4 hours. The hardness should be controlled at 76 ~ 79 HRB, otherwise serious decarbonization will produce three cementite precipitates along the grain boundary, which will worsen the cold heading performance of steel and cause cold heading cracking.

For medium carbon alloy steel, the spheroidizing annealing temperature is selected below Ac 1, 10 ~ 30℃, about 760 ~ 770℃, the temperature is reduced to 690 ~ 7 10℃, spheroidizing isothermal annealing is carried out at 1 ~ 2 hours, and it is cooled to 550℃ with the furnace. The hardness is controlled at 8 1 ~ 84 HRB. When annealing at higher temperature, the decarburized layer will be too deep and too thick.

Through spheroidizing annealing, the metallographic structure of steel will change from coarse to fine, from flake to spherical, and the cracking rate of cold heading will be greatly reduced.

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The mechanical performance requirements of bolts are mainly manifested in the threaded end. Because the surface of the cold heading bolt is no longer processed after cold drawing and cold heading, the decarburized layer of steel will remain on the surface of the part all the time, and when the thread of the bolt is rolled, the decarburized layer will be squeezed to the top of the thread, which will lead to the decrease of thread strength and the phenomenon of tripping during use. Light will lead to early elongation and deformation, and heavy will lead to fatigue fracture. Therefore, the depth of decarburized layer must be strictly controlled during spheroidizing annealing.

Thirdly, final heat treatment.

High-strength bolts must be quenched and tempered at high temperature to obtain uniform tempered sorbite structure, so as to obtain high strength, sufficient toughness and good fatigue resistance.

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The quenching heating temperature of medium carbon steel can be determined by formula AC3+30℃ ~ 50℃. The chemical composition of 35 steel, 45 steel and ML35 steel is different in addition to carbon content, but it is important that Mn and Si elements are different, which directly reflects the difference of quenching performance caused by heat treatment process. But it must be pointed out that it is also restricted by the quenching medium and the size and shape of the parts. Therefore, the determination of quenching heating temperature varies with size factors and medium temperature. The principle is that the length-diameter ratio of bolts is less than 7, the lower limit is small ratio, and the upper limit is large ratio.

The Ac3 of 45 steel hot heading bolt is 780℃, which is very sensitive to quenching cracks. The forging stress of the external hexagon without annealing treatment is large, so the lower limit temperature is selected in principle.

For medium carbon steel 35 steel and ML35 steel, the mass percentage of carbon content is generally controlled below 0.35%, and the lower limit is mostly between 0.32% and 0.33%. Therefore, for large-size parts, the gradient distribution of hardness value after quenching is very steep, that is, > >

Question 7: To what extent do the hub screws need to be tightened? 15n.m

Question 8: What is the scientific name of the screw used for automobile tires? 1 scientific name: the long screw is called hexagon screw, and the port is called hub bolt.

Screw is a tool to gradually tighten the parts of an object by using the physical and mathematical principles of circular rotation and friction of the inclined plane of the object. Screws are called "screws" (screws) and "screws" (screws). In fact, screws are universal, and screws and screws are different. Screws are generally called wood screws; It's the kind with a pointed tip at the front end, with a large pitch, which is generally used to fasten wooden parts and plastic parts. Screw is a kind of machine screw (mechanical screw) with a flat head at the front end. It has a small and uniform pitch and is usually used to fasten metal and machine parts. ? Screws are called "screws" (screws) and "screws" (screws). In fact, screws are universal, and screws and screws are different. Screws are generally called wood screws; It's the kind with a pointed tip at the front end, with a large pitch, which is generally used to fasten wooden parts and plastic parts. Screw is a kind of machine screw (mechanical screw) with a flat head at the front end. It has a small and uniform pitch and is usually used to fasten metal and machine parts. ? screw

Question 9: How big are the screws on most car wheels? The screws on most car wheels are&; 12, the tooth profile is 1.25 and1.5-He Zhi's modification.

Question 10: How big are the car wheel screws? Yes 17. 19.5438+0.22, American cars are generally seventeen. There is something wrong with the car, find the car master. 4S shop professional technician, 10 minutes to solve.