Screws are tools that use the physics and mathematics principles of the oblique circular rotation and friction of objects to gradually tighten utensils and parts.

Screw is a general term for fasteners, a daily oral language. Screws are an indispensable industrial necessity in daily life:

Such as very small screws used in cameras, glasses, clocks, electronics, etc.; general screws in televisions, electrical products, musical instruments, furniture, etc.

As for engineering, construction, and bridges, large screws and nuts are used; transportation equipment, airplanes, trams, automobiles, etc. are used together.

Screws have important tasks in industry. As long as there is industry on the earth, the function of screws will always be important.

The screw is a common invention in people’s production and life for thousands of years. According to the application field, it is the first invention of mankind.

The screw production process is divided into 7 steps, which are annealing, pickling, wire drawing, forming, tooth grinding, and heat treatment level surface treatment.

Annealing process:

The processed products are put into the furnace and then closed with the furnace lid. One furnace can process 8.4 tons at the same time.

Then slowly increase the temperature to the specified temperature, this step takes 3-4 hours. Then slowly reduce the temperature to 550 degrees, which takes 3-4 hours, and let the product cool to room temperature naturally.

This process can adjust the crystal structure, reduce the hardness, and improve the wire workability at room temperature.

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Pickling process:

The purpose of the acid washing is to remove the oxide film of the wire. Now the entire disc is respectively immersed into three hydrochloric acid tanks with a concentration of 20-35 at room temperature for a few minutes.

Then use clean water to remove the hydrochloric acid corrosion products on the wire surface.

In order to make the film produced in the next process more compact, oxalic acid is used to increase the activity of the metal.

When the disc is penetrated into the phosphate, the surface of the steel is brought into contact with the chemical conversion treatment solution, and the treatment solution and the steel are dissolved to form a compound, which is attached to the surface of the screw to form a film.

Use clean water to get rid of the residue on the surface. Then use lubricating oil to increase its lubricity.

Drawing process:

Use the fine drawing and rough drawing for some products to cold draw the coil to the required wire diameter. This process is suitable for large screws, nuts, and threaded rods.

There are two kinds of forming of hexagon bolts:

one is four-die four-stroke or three-die three-stroke, but three-die three-stroke. The screw is a die with two punches.

Then hot beat, hot beat is divided into three steps, the first step is to put the product into the heating device to set the heating time and temperature according to the product specifications.

In the second step, after heating, the product is moved to the molding machine for molding. Then squeeze the rod with a rod machine to shrink the rod.

Teeth grinding process:

Through rolling or tapping, the semi-finished product that has been formed can reach the required thread.

Heat treatment process:

In order to improve the mechanical properties of materials, eliminate residual stress and improve the machinability of metals, it is necessary to heat the products.

According to the needs of the product, two methods can be selected: preliminary heat treatment and final treatment.

Surface treatment process:

Through electroplating, hot dip galvanizing, and mechanical galvanizing, a covering layer is formed on the surface of the product to make the surface of the product beautiful and anti-corrosive.