Everyone shares the basic introduction and production process of screws
Terms related to screws
1. The difference between screws, nuts, nuts, bolts, screws, and studs: The standard statement is that there are no screws and nuts. Screws are commonly called "screws". The shape of the nut is usually hexagonal, and the inner hole is internal thread, which is used to cooperate with the bolt and tighten the related parts. The nut is commonly called, the standard should be called "nut".
The head of the bolt is generally hexagonal, and the shank has an external thread. The screw is small, the head has a flat head, a cross head, etc., and the rod has an external thread. The actual stud should be called "double-ended stud", both ends have external threads, and the middle is generally a polished rod. The long end of the thread is used to connect to the deep hole, and the short end is connected to the nut.
2. Common English representation: Screw / Bolt / Fastener (screw/screw) (bolt) (fastener)
3. The definition of thread: a thread is a shape with uniform helix protrusions on the outer or inner surface of a solid.
Thread effect
1. Fastening and connection: suitable for most screw products at this stage.
2. Transmission function (displacement function): such as a micrometer used for QC check size. 3. Sealing function: such as the connection and sealing of pipes.
The history of thread development
Machine thread: When assembling, drill holes and taps on the assembly first, and the inner teeth of the tapping are the same as the outer teeth of the screw, and the assembly is assembled with a smaller torque.
Self-tapping thread: When assembling, drill holes on the assembly first, without tapping the internal teeth, use a larger torque for assembly.
Self-drilling thread: directly used on the assembly, the screw is drilled and tapped once.
Screw processing method
1. Turning (Turning)
Make the material reach the expected shape by removing the material
Advantages: high processing accuracy, no mold restrictions
Disadvantages: high production cost, slow processing speed
2. Forging
Squeeze the material by external force to deform it to achieve the desired shape
Advantages: fast production speed, low cost, suitable for mass production
Disadvantages: molding is limited by molds, and mold costs for complex products are high
3. Cold heading
It is a process in which the metal wire is extruded and deformed with the help of an external force when the metal wire is not heated. The cold heading process is only one of the forging processes.
Introduction to the basic configuration of screws
To understand screws and bolts, you must first know their types, features and functions:
A: Drive system
B: head
C: dentition joint
D: Introduction and penetration department
Mechanical screw
Self-tapping screws
Triangular screw
Screw head type
Screw thread
Screw process
The general flow chart is as follows:
Inventory process
Refers to the original wire rod purchased by the raw material manufacturer. A disk element 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, and the lower the content of Cu and Al, the better.
Drawing process
In order to achieve the wire diameter we need (such as drawing the wire to 3.5mm).
Cold heading (heading) process
Through the interaction between the molds, it is formed. First, the wire is cut and upset into a screw blank to form a head, cross groove (or other head type), thread blank diameter and rod length, and rounded corners under the head.
Note: It can be designed according to the customer's needs. The commonly used head types are P head, B head, F head, T head, etc. The commonly used groove types include cross groove, flat groove, hexalobular groove, and hexagon socket.
Rubbing procedure
The cold-headed blank is twisted into threads, and the tooth pattern is formed through the interaction between the movable tooth plate and the fixed tooth plate.
Threading machine
Rubbing board (template)
Heat treatment process
1. Purpose: To make the screws get higher hardness and strength after cold heading.
2. Function: Realize the self-tapping and locking of metal and improve the mechanical properties of metal parts, such as torsion resistance, tensile resistance and wear resistance. 3. Classification: A. Annealing: (700°C x 4hr): Elongated structure-regular polygonalization.
Cold working structure B. Carburizing heat treatment (adding carbon element to metal parts to improve the 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 temperature changes to obtain better mechanical properties).
Electroplating process
The surface of the electroplated product can present the desired color effect and surface anti-oxidation coating effect.
The screw is rusty, can't unscrew the screw and helpless? These methods are solved in minutes
Because the screw is exposed to the air, it is easy to rust. Once rusted, it is difficult to screw, but you can easily solve this problem with the following tips, so hurry up and learn.
Ways to solve screw rust
1. Hit hard with a hammer
The screw is rusty. Never use a wrench to tighten the screw, otherwise it will be difficult to screw the screw. Use a wrench to tighten the screw, and then use a hammer to hit the handle of the wrench. The part is loose due to percussion.
If you screw it again, it will be easier, or you can tap the nut directly and tap around it several times, which will also loosen the nut and the screw, making it easier to unscrew.
2. Burn with fire
If the screw is corroded seriously, you can burn it with fire. Use gas welding and oxidation flame to fully grill the screw and nut, and then drop a drop of oil on the red screw. The principle is that the heat expands and contracts. The heating causes the screw to expand and let it Rapid cooling can increase the gap between the screw and the nut, and the screw can be easily removed.
3. Rust remover method
Spray the rust remover directly on the rusty screw, and wait until the rust remover penetrates into the screw, the screw can be easily unscrewed.
4. Coke method
Put the cola directly on the rusty screw. After a while, you will find that the screw is easy to unscrew, because the cola contains carbonic acid and the rust is composed of iron oxide. The chemical reaction between the two can remove the rust.
5. WD40 rust remover
You can spray this kind of rust remover on rusty screws, which can prevent rust, dehumidify, derust, lubricate, clean, conduct electricity, and is cost-effective.