Related terms for screws
1. The difference between screws, nuts, nuts, bolts, screws, and studs: The standard term is that there are no screws and nuts. Screw is a common name, and anything with external threads can be called "screws". The nut is usually hexagonal in shape, with an internal thread in the inner hole, used to cooperate with the bolt to tighten related parts. Nut is a common name, and the standard should be called "nut". The head of the bolt is generally hexagonal, and the rod has external threads. Screws are smaller, with flat heads, cross heads, etc., and the rod has external threads. Studs should actually be called "double-headed studs", with external threads on both ends, and the middle is generally a bare rod. The long end of the thread is used to connect with the deep hole, and the short end is connected with the nut. 2. Common English expressions: Screw / Bolt / Fastener (screw/screw) (bolt) (fastener) 3. Definition of thread: Thread is a shape with uniform spiral protrusions on the outer or inner surface of a solid. Screw functions
1. Fastening and connection: applicable to most screw products at this stage. 2. Transmission function (displacement function): such as the micrometer used by QC to check the size. 3. Sealing function: such as the connection seal of the pipeline. The development history of thread
Machine thread: When assembling, first drill and tap the assembly. The tapped inner teeth are consistent with the outer teeth of the screw. Use a smaller torque for assembly. Self-tapping thread: When assembling, first drill the assembly, no need to tap the inner teeth, use a larger torque for assembly. Self-drilling thread: Use directly on the assembly, the screw drilling and tapping are formed in one step.
Screw processing methods
1. Turning: Removing materials to achieve the desired shape. Advantages: High processing accuracy, no mold restrictions. Disadvantages: High production cost, slow processing speed.
2. Forging: Extruding materials by external force to deform them to achieve the desired shape. Advantages: Fast production speed, low cost, suitable for mass production. Disadvantages: Forming is limited by molds, and the mold cost of complex products is high.
3. Cold heading is the process of using molds to extrude and deform metal wires without heating them. Cold heading is just a type of forging process. Introduction to basic screw configuration
To understand screws and bolts, you must first know their types, characteristics and functions: A: Drive system B: Head C: Thread profile joint D: Lead-in and tapping section Mechanical thread screw
Self-tapping screw
Triangular thread screw
Screw head type
Screw thread profile
Screw process flow
The general flow chart is as follows:
Disc element process
Refers to the original wire rod purchased by the raw material manufacturer. A disc 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, among which the lower the content of Cu and Al, the better. Wire drawing process
In order to achieve the wire diameter we need (such as 3.5mm wire drawing), cold heading (heading) process
Through the interaction between the dies, it is formed. First, the wire is cut and headed into a screw blank to form the head, cross slot (or other head type), thread blank diameter and rod length, head bottom fillet, etc. Description: It can be designed according to customer needs. Common head types are P head, B head, F head, T head, etc. Common slot types are cross slot, slot, plum blossom slot, hexagonal slot, etc.
Thread rolling process
The cold-headed blank is threaded, and the tooth pattern is formed through the interaction between the movable tooth plate and the fixed tooth plate. Changes before and after thread rolling Thread rolling machine thread rolling plate (template)
Heat treatment process
1. Purpose: To make the screws have higher hardness and strength after cold heading. 2. Function: To achieve self-tapping locking of metals and improve the mechanical properties of metal parts, such as torsion resistance, tensile resistance, and wear resistance. 3. Classification: A. Annealing: (700℃ x 4hr): Elongated structure - regular polygonization. Cold processing structure morphology B. Carburizing heat treatment (adding carbon elements to metal parts to increase their surface hardness, for metal materials with low carbon content). C. Quenching and tempering heat treatment (not adding elements to the metal, changing the internal structure of the metal by temperature changes to obtain better mechanical properties).
Electroplating process
The surface of the electroplated product can present the required color effect and surface anti-oxidation coating effect.
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