Thread Content
Terms related to screws 1. Differences between screws, nuts, bolts, screws, studs: The standard terminology does not include the terms \"screw\" and \"nut\". \"Screw\" is a common term; anything with external threads can be called a \"screw\". The nut typically has a hexagonal shape, with an internal thread in its bore, which is used in conjunction with a bolt to tighten the connected components. Screw nut is a common term; the standard name is \"nut\". The head of a bolt is generally hexagonal, while the shank has external threads. The screws are small, with heads such as flat or cross-shaped, and the shank features external threads. A stud should actually be called a \"double-ended stud,\" as it has external threads on both ends, with a smooth shaft in between. The longer end of the thread is used to connect with the deep hole, while the shorter end connects with the nut. 2. Common English terms: Screw/Bolt/Fastener (screw/screw bolt) (bolt) (fastening element). 3. Definition of thread: A thread is a pattern of uniform spiral protrusions on the outer or inner surface of a solid. Functions of threads: 1. Fastening and joining: Applicable to most screw products at present. 2. Transmission function (displacement function): Such as the micrometer used for QC dimension inspection. 3. Sealing function: such as the sealing of pipe connections. History of thread development: Machine-threaded threads: During assembly, holes are drilled and tapped in the component; the internal threads created are matched to the external threads of the screw, allowing assembly to be carried out with a lower torque. Self-tapping thread: During assembly, a hole is drilled in the component first; there is no need to drill internal threads, and a higher torque is required for assembly. Self-drilling thread: Can be used directly on the assembly, with drilling and tapping of the screw being done in one step. Methods of screw processing: 1. Turning: The material is shaped to the desired form by removing material. Advantages: High precision in processing, no limitations imposed by molds. Disadvantages: High production costs, slow processing speed. 2. Forging: The material is deformed under external force to achieve the desired shape. Advantages: Fast production speed, low costs, suitable for mass production. Disadvantages: The shaping process is limited by molds, and the cost of molds for complex products is high. 3. Cold heading: This involves using molds to deform metal wire under external force without heating it; cold heading is simply a type of forging process. Introduction to the basic configuration of screws: To understand screws and bolts, it is first necessary to know their types, characteristics, and functions: A: Driving system; B: Head; C: Threaded portion and joint; D: Lead-in and threading portion. Mechanical-threaded screws, self-tapping screws, triangular-threaded screws. Screw head types, screw thread types, screw manufacturing process. The general flowchart is as follows: Coiled rod stage – This refers to the raw coiled rods purchased by manufacturers of raw materials. A coiled rod typically 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 discs are: C, Mn, P, S, Si, Cu, Al; among these, the lower the contents of Cu and Al, the better. Wire drawing process: To achieve the desired wire diameter (for example, drawing to 3.5mm). The cold heading process involves shaping the material through the interaction between molds. First, the wire is cut, then headed to form a screw blank, creating a head, a cross-slot (or other head shape), the diameter of the screw shaft and its length, as well as rounded corners under the head. Note: It can be designed according to the customer’s requirements. Common head types include P-head, B-head, F-head, T-head, etc. Common groove types include cross groove, straight groove, plum blossom groove, internal hexagon groove, etc. The thread rolling process involves rolling threads onto the cold-forged blanks; through the interaction between the movable thread die and the fixed thread die, the thread pattern is formed. Thread rolling process, changes before and after thread rolling, thread rolling machine, thread rolling die (template), heat treatment process. 1. Purpose: To achieve higher hardness and strength in screws after cold heading. 2. Function: To achieve self-tapping fastening of metals and improve their mechanical properties, such as torsional resistance, tensile strength, and wear resistance. 3. Classification: A. Annealing: (700℃ x 4hr): Elongated structure – regular polygonization. Cold working microstructure B. Carburizing heat treatment (adding carbon to metal parts in order to increase their surface hardness, for metal materials with low carbon content). C. Quenching and tempering heat treatment (no elements are added to the metal; the internal structure of the metal is altered through changes in temperature in order to achieve better mechanical properties). Plating process: The surface of the products after plating can achieve the desired color effect as well as an antioxidant coating layer.