The production of screws is a complicated operation, and the processing methods and processing requirements of each screw are not the same;But in the eyes of opu people, these processes are not messy at all.

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Screw production (1)– annealing;

I. Purpose: to heat the wire to an appropriate temperature, keep it for a certain time, and then cool it slowly, so as to adjust the crystalline structure, reduce the hardness, and improve the normal temperature processing of the wire.

II. Operation process:

(1) Feeding: the products to be processed shall be hoisted into the furnace, and the furnace cover shall be tightly covered.Generally one batch can handle 7 rolls (about 1.2 tons/roll) at the same time.

(II) Heating up: the temperature in the furnace is slowly raised (about 3-4 hours) to the specified temperature.

(three), heat preservation: material 1018, 1022 wire at 680℃-715℃ for 4-6h, material 10B21, 1039, CH38F wire at 740℃-760℃ for 5.5-7.5h.

(4) Cooling: reduce the temperature in the furnace slowly (about 3-4 hours) to below 550℃, and then cool to normal temperature with the furnace.

Screw production (2)– pickling;

1. Purpose: to remove the oxide film on the surface of the wire rod, and form a layer of phosphate film on the metal surface, so as to reduce the abrasion of the mold in the process of wire drawing, cold pier or forming.

II. Operation process:

(a), pickling: the whole plate is immersed in three salt acid tanks at room temperature and concentration of 20 to 25 percent for several minutes, the purpose is to remove the oxide film on the surface of the wire rod.

(2) clean water: remove the hydrochloric acid corrosion products on the surface of the wire rod.

(three), oxalic acid: increase the activity of the metal, in order to make the next process generated by the film more dense.

(four), skin film treatment: the plate is immersed in phosphate, steel surface and into the treatment solution contact, iron and steel dissolved into insoluble compounds (such as Zn2Fe(PO4)2?4H2O), adheres to the steel surface to form a skin film.

(5) clean water: remove residual material on the surface of the skin membrane.

(six) lubricant: because the friction coefficient of phosphate film is not very low, it can not be given sufficient lubrication during processing, but it can react with metal soap (such as sodium soap) to form a hard metal soap layer, which can increase its lubrication performance.

Screw production (3)– drawing wire;

Purpose: to cold pull the dial element to the required wire diameter.Practically aiming at some products, it can be divided into two stages: rough pumping (shelling) and fine pumping.

Second, the operation process

After pickling, the coil is cold drawn to the required wire diameter by wire drawing machine.Suitable for wire used for big screws, nuts and teeth.

Screw production (IV)– molding;

Purpose: to achieve the shape and length (or thickness) of the semi-finished product by cold forging (or hot forging) of the wire.

II. Operation process:

1, hexagon bolt (four die four or three die three).

2. Hexagon bolt (three die and three stroke). 3, screw (general head type one mold two punch).