This article introduces the related terminology, development history, processing method, basic configuration and process flow of screws. Do you have any thoughts after reading it?
The term for screws
1. The difference between screws, nuts, nuts, bolts, screws, studs: The standard statement is that there are no screws and nuts. Screws are commonly known, and those with external threads can be called "screws". The nut is usually hexagonal in shape and the inner hole is an internal thread, which is used to cooperate with the bolt and tighten the relevant part. Nuts are commonly known, and the standard should be called "nuts".
The head of the bolt is generally hexagonal, and the rod has an external thread. The screws are small, the head has a flat head, a cross head, etc., and the rod has an external thread. The stud should actually be called "double-ended stud", with an external thread at both ends, and the middle is generally a light rod. One end of the long thread is used to connect to the deep hole, and the short one is connected to the nut.
2. Common English expression: Screw / Bolt / Fastener (screw / screw) (bolt) (fastener)
3. Definition of thread: A thread is a shape that has a uniform spiral raised on the outer or inner surface of a solid.
Thread action
1. Fastening and joining function: suitable for most screw products at this stage.
2. Transmission effect (displacement effect): such as the micrometer used by QC to check the size. 3. Sealing effect: such as the connection of pipe sealing.
History of threads
Machine tooth thread
When assembling, drill holes in the assembly to attack the teeth, the attacked inner teeth are consistent with the specifications of the outer teeth of the screw, and the assembly is assembled with a small torque.
Self-tapping thread
When assembling, drill holes in the assembly first, no need to attack the inner teeth, and use a large torque assembly.
Self-drilling threads
Used directly on the assembly, the screw is drilled and tapped into the teeth in one shot.
How screws are processed
Turning
The material is removed to achieve its desired shape
Advantages: high machining accuracy, no mold restrictions
Disadvantages: high production costs, slow processing speed
Forging processing
The material is deformed by external force to achieve the desired shape
Advantages: fast production speed, low cost, suitable for mass production
Disadvantages: The molding is limited by the mold, and the mold cost of complex products is high
Heading
It is the process of using a mold to extrude and deform it with the help of external forces in the state of metal wire not heating, and the cold heading process is only a kind of forging process.
Introduction to the basic configuration of screws
To understand screw bolts, first know their type, characteristics, and function:
A: Drive system
B: Head
C: The joint of the tooth profile
D: Import and Attack Department
Mechanical tooth screws
Self-tapping dental screws
Triangular tooth screws
Screw head type
Screw tooth type
Screw process flow
Disc element process
Refers to the raw material manufacturer purchased the original wire, a disc mainly includes the following parameters: A, brand B, product name C, specification D, material E, furnace number or batch number F, quantity or weight. The main chemical components of carbon steel disc elements are: C, Mn, P, S, Si, Cu, Al, of which the lower the content of Cu and Al, the better.
The drawing process
In order to achieve the wire diameter we need (e.g. to 3.5mm drawn wire).
Cold heading (heading) process
Through the interaction between the molds, it is formed, the wire is first cut off, upset into a screw blank, forming a head, cross groove (or other head type) Thread blank diameter and rod length, rounded corners under the head, etc.
Description: Can be designed according to customer needs, the commonly used head type is P head, B head, F head, T head and other commonly used grooves have cross grooves, one-word grooves, plum troughs, hexagonal grooves and so on.
Teeth rubbing process
The cold-headed blank is threaded out of the thread, and the tooth pattern is formed by the interaction between the moving tooth plate and the fixed tooth plate.
↑↑Washboard (template)↑↑
↑↑Dental scrubbing machine↑↑
Heat treatment process
1. Purpose: In order to make the screws get higher hardness and strength after cold heading processing.
2. Function: Realize the self-attack and lock payment of the metal, improve the mechanical properties of the metal parts, such as anti-torsion, anti-tensile, wear-resistant.
3. Classification: A. Annealing: (700°C x 4hr): Elongated tissue – regular polygonalization.
Cold working tissue morphology
B. Carburizing heat treatment (adding carbon to metal parts to improve their surface hardness, for metal materials with low carbon content).
C. Quenching and tempering heat treatment (no element is added to the metal, and the internal structure of the metal is changed by the temperature change to obtain better mechanical properties).
Electroplating process
The surface of the electroplated product can present the desired color effect and the surface anti-oxidation coating effect.