Views: 50 Author: Site Editor Publish Time: 2023-12-20 Origin: Panda fastener
Screw production process and technology
How is a screw made? Learn more about it below.
The production of screws can be divided into seven steps: annealing (pickling), wire drawing (molding), grinding teeth (level surface treatment), heat treatment and level surface treatment.
Annealing : First treated product placed in the furnace, then covered by the furnace lid. A single furnace can process 8.4 tons of material at once. This step will take 3-4 hours. After slowly raising the temperature to 550 degrees Celsius over 3-4 hours, the product will be allowed to naturally cool to room temperature. This process can improve wire processing, adjust the crystal organization, and reduce the hardness at room temperature.
Acid Washing Process :the purpose is to remove the oxide film from the wire. Now the entire disk was invaded by the acid at room temperature with a concentration of 20-35. Then, wash the hydrochloric corrosion off the wire's surface with water. To make the next step to produce a compact film and oxalic to increase the metal's activity. The discs will be infected with phosphate, and then the steel surface will come into contact with a chemical treatment solution. This solution and steel will dissolve and form a compound which attaches itself to the screw surface to form a thin film. Water is used to remove the residue from the surface. To increase the lubricity, lubricating oils are used.
Drawing Process: Wire is drawn cold to the desired wire diameter, using fine or coarse drawing for certain products. This process is used to draw wire for large screws and nuts, as well as bars.
The molding process is For hexagonal bolts, there are two types of molding: the first is four-mode-four-punch and the second is three mode-three-punch. The screw is a two-punch mold. Heat beating is then divided into three stages. The first stage will be placed into the heating equipment, according to the product specifications, set the heating temperature and time. After heating, the second step involves moving the product with a mould to the molding machine. It will then be shrinked by extruding with the bunching machines.
Milling Process: After the semi-finished part has been molded, it is milled to obtain the desired thread.
Heat Treatment Process: To improve the mechanical properties, eliminate residual stress and improve machinability, heat treatment is necessary. Depending on the requirements of the product, two methods of preheating and final treatment can be chosen.
Surface Treatment Process:Electroplating, Hot Invasion Galvanizing, Mechanical Galvanizing on the surface of the product to form a coating layer, so the product is beautiful and anti-corrosion.
Basic composition and shape of screws
Understanding screws and bolts requires that you know about their characteristics, types and functions.
A:Driving System
B:Head
C:Tooth type of part of the union
D: Introduction and tapping section
Functional dimensions
Needle part: Needleless due to the combination of head type and system drive
Head part: opposite side, wrench height (diagonal), receiving surface diameter
Tooth part (joint): Because strength = material stress * tensile area (according to ISO898-18.2) 3.1416/4*{(effective diameter of thread + small diameter of thread)/2}^2
Lead-in part: guide nut capacity chamfer is too small will cause customers to assemble difficulties.
Functional dimensions
Needle part: Needle type and needle depth Wrong needle type will cause the wrench can not be put in, the needle depth is not enough will cause the drive to slip.
Needle part: Too small R under the head will easily break the head.
Tooth part (joint): Self-tapping screws
Introducing part: guide nut capacity chamfer is too small will lead to customer assembly difficulties.
Functional dimensions
Needle part: Needle type and needle depth Wrong needle type will cause the wrench can not be put in, the needle depth is not enough will cause the drive to slip.
Needle part: Too small R under the head will easily break the head.
Tooth part (joint): Self-tapping screws
Introducing part: guide nut capacity chamfer is too small will lead to customer assembly difficulties.
OVAL ROUND HEXAGON HEXAGON PAN
Screw process
The rough flowchart is as follows:
Coil Process
The coil includes the following parameters, depending on the manufacturer of the raw material that purchased it: A, brand, B, name, C, specifications, D, material, E, furnace or batch number, F, quantity, or weight.
Carbon steel coils have the following chemical composition: C, Mn. P, Si. Cu. Al. The lower the Cu. Al content, the better.
Extraction of wire
To achieve the wire diameter we need (e.g. up to 3.5mm draw wire).
Cold Heading Process
By interacting with the molds you can shape it. First cut the wire off, then upsetting the screw blanks. Then form the head, cross-groove (or any other type of head), thread diameter, length, the head and rounded corners.
Description: Can be designed to meet customer requirements. Common head types include P head, B Head, F head and T head. The most common groove types are cross groove, one-groove, plum blossom, hexagonal, and so on.
Thread Rolling Process
The cold-headed blanks are rolled into threads and are then shaped through the interaction of the moving and fixed plates.
Changes before and after teeth rubbing
Heat Treatment Process
1. Purpose:
Cold heading is a process that increases the hardness and strength of screws.
2.Role:
Metal parts with improved mechanical properties, such as torsion and wear resistance, can be made to self-lock.
3.Classification:
A.Annealing (700x4hr) : positive polygonization - elongated organisation.
Cold Working Organization
Heat treatment B. Carburizing (adding carbon to metals to increase surface hardness for metals with low carbon content).
The Plating Process
The surface of the product will show the desired color and surface anti-oxidant plating effects after plating.
