Fastener parts processing
- Purpose: Heat the wire to an appropriate temperature, maintain it for a certain time, and then slowly cool it to adjust the crystalline structure, reduce hardness, and improve the room temperature processability of the wire.
- Operation process:
(1) Feeding: Hang the products that need to be processed into the furnace, and pay attention to the furnace cover being tightly covered. Generally, one furnace can simultaneously process 7 rolls (approximately 1.2 tons per roll).
(2) Heating up: Slowly raise the temperature inside the furnace (about 3-4 hours) to the specified temperature.
(3) Insulation: Material 1018 and 1022 wires are maintained for 4-6 hours at 680 ℃ -715 ℃, material 10B211039, and CH38F wires are maintained for 5.5-7.5 hours at 740 ℃ -760 ℃.
(4) Cooling: Slowly reduce the temperature inside the furnace (about 3-4 hours) to below 550 ℃, and then cool down to room temperature with the furnace.
- quality control:
- Hardness: The material is 1018 and 1022 wire with a hardness of HV120-170 after annealing, and the material is medium carbon wire with a hardness of HV120-180 after annealing.
- Appearance: There should be no oxide film or decarburization on the surface.
2、 Acid washing
- Purpose: To remove the oxide film on the surface of the wire and form a layer of phosphate film on the metal surface to reduce scratches on the tool and mold during wire drawing, cold stamping, or forming processes.
- Operation process:
(1) Pickling: Immerse the entire disk element in three hydrochloric acid baths at room temperature with a concentration of 20-25% for several minutes, with the aim of removing the oxide film on the surface of the wire.
(2) Clear water: Remove hydrochloric acid corrosion products from the surface of the wire.
(3) Oxalic acid: increases the activity of metals to make the skin film generated in the next process more dense.
(4) Film treatment: Immerse the disc element in phosphate, and the surface of the steel comes into contact with the formation treatment solution. The steel dissolves to form insoluble compounds (such as Zn2Fe (Po4) 2-4H2O), which attach to the steel surface to form a film.
(5) Clear water: Remove any residue on the surface of the skin film.
(6) Lubricant: Due to the low friction coefficient of phosphate film, it cannot provide sufficient lubrication during processing. However, it reacts with metal soap (such as sodium soap) to form a hard metal soap layer, which can increase its lubrication performance
3、 Wire drawing
- Purpose: Cold pull the disc element to the required wire diameter. In practical terms, for some products, it can be divided into two stages: rough extraction (shell stripping) and fine extraction.
- Operation process: After the coil element is pickled, it is cold drawn to the required wire diameter through a wire drawing machine. Suitable for wires used for large screws, nuts, and teeth.
- Purpose: To achieve the shape and length (or thickness) of semi-finished products by cold forging (or hot forging) of the wire.
- Operation process:
(1) Hexagon bolt (four die four punch or the third mock examination three punch)
1) Cutting: By using movable scissors to move in one direction, the wire stuck in the cutting mold is cut into the desired blank.
2) One punch: The back punch presses the blank against the blank punch, forming the initial shape, and then the back punch pushes the blank out.
3) Second punch: The raw material enters the second punch, and the second punch is extruded. The raw material is in a flat circular shape, and then the later punch pushes the raw material out.
4) Three punches: The raw material enters the third punch and is cut through the hexagonal three punch core, forming the initial hexagonal head of the raw material. Afterwards, the later punch mold pushes the raw material into the third punch, and the cut material is cut from the hexagonal head, forming the hexagonal head.
(2) Hexagon bolt (the third mock examination and three punches)
(3) Screw (general head type the first mock examination and two punches)
1) Cutting: By moving the movable scissors in one direction, the wire stuck in the cutting mold is cut into the desired blank.
2) One punch: fixed by stamping, the first punch will preliminarily shape the product head, so that it can be fully formed in the next stroke. When the product is a straight cut groove, one punch is an inner concave or elliptical groove, and when the product is a cross groove, one punch is an inner concave square groove.
3) Second punching: After the first punching, the punching tool runs as a whole, and the second punching die moves directly in front of the mold, while the second punching die runs forward to finally shape the product. Afterwards, the embryonic material is pushed out by a recoil rod.
- Hot stamping
(1) Heating: Use the heating equipment to heat one end of the preform to a white hot state, and set the heating temperature and time according to the product specifications. Generally, heating for less than 3/4 for 7-10 seconds, and heating for 7/8-1 “for about 15 seconds.
(2) Forming: Quickly move the heated embryo material to the forming machine, fix it through the back seat, clamp the mold, and impact the embryo material with the head mold to form it. The distance of the backseat can be adjusted according to the length of the raw material. (3) Tie rod: Use extrusion on the tie rod machine to shrink the product. Hot beating is also known as red beating.
- Nut forming:
(1) Operation process:
1) Cutting: The wire is cut into the desired blank by the combination of an internal cutting die (410) and a cutting knife (301).
2) One punch: By combining the front punch die (111), stroke die (411), and rear punch rod (211), the deformed and uneven cut blank is shaped, and the blank is pushed out by the rear punch rod (211). 3) Second punch: The operating clamp (611) clamps the blank from the first punch to the second punch, which is coordinated by the front punch die (112), stroke die (412), and back punch rod (412) to further shape the blank and strengthen the flattening and saturation effects of the first punch. Afterwards, the back punch rod (212) pushes the blank out.
4) Three punches: The operating clamp (612) clamps the blank from two punches to three punches, and the blank is squeezed again by the front punch die (113), stroke die (413), and back punch rod (213) to fully form the lower punch. Afterwards, the blank is pushed out by the back punch rod (213).
5) Four punches: The operating clamp (613) clamps the blank from three punches to four punches, and the nut is fully formed by the combination of the front punch die (114), stroke die (414), and rear punch rod (214). The thickness of the nut is adjusted by controlling the thickness of the iron filings, and then the blank is pushed out by the rear punch rod (214).
6) Five punches: The operating clamp (614) clamps the blank from four punches to five punches, and the front punching die (119) and the stripping plate (507) cooperate to punch the fully formed blank, allowing the broken iron filings to enter the lower part of the punching die, ultimately completing the formation of the nut. The head marking of the nut is formed during this process.
5、 Rolling teeth
(1) Purpose: Roll or tap the formed semi-finished product to achieve the required thread. In practical terms, for bolts (screws), it is called rolling teeth, teeth are called rolling teeth, and nuts are called tapping teeth.
(2) Rolling teeth: Rolling teeth refers to fixing one tooth plate, while the other movable tooth plate drives the product to move, using extrusion to cause plastic deformation of the product and form the required thread.
(3) Tapping: Tapping is the process of tapping the formed nut to form the desired thread.
(4) Rolling teeth: Rolling teeth are two corresponding screw rollers that rotate in a positive direction and use extrusion to cause plastic deformation of the product, forming the required thread. Rolling teeth are usually used for tooth strips.