Thread Content
Basic knowledge of screws – Terms related to screws 1. Differences between screws, nuts, bolts, screws, and 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\". Nuts typically have a hexagonal shape, with an internal thread in their bore, which is used in combination with bolts to tighten connected components. 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 screw is small, with a head that can be flat or cross-shaped, and its 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. * R: The function of I7 r7 threads is 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 screw threads: Countersunk thread: During assembly, holes are drilled and tapped in the component; the internal threads formed this way match the external threads of the screw, allowing assembly to be done with a lower torque. http://5b0988e595225.cdn.sohucs.com/images/20190613/eaf899e7279a4e0ab7e04b95b9fd7223.jpeg Self-tapping thread: A hole is drilled in the component first during assembly; there is no need to drill internal threads, and a higher torque is required for assembly. http://5b0988e595225.cdn.sohucs.com/images/20190613/207554b2148545e9b08e1f8f1e1474e9.jpeg Self-drilling threads: Can be used directly on the assembly, with drilling and tapping done in one step. http://5b0988e595225.cdn.sohucs.com/images/20190613/0bb45f61f4aa47fb9caa25d2cf5f6730.jpeg Methods of screw processing: 1. Turning: This involves removing material to give it the desired shape. Advantages: High precision in processing; no limitations imposed by molds. Disadvantages: High production costs and slow processing speed. 2. Forging: This involves using external forces to deform the material so that it takes on 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 is a process in which metal wire is deformed using molds under applied force, without heating. Cold heading is actually a type of forging process. Introduction to the basic configuration of screws: To understand screws and bolts, one must first be aware of their types, characteristics, and functions: A: Driving system; B: Head; C: Threaded portion; D: Lead-in and threading portion. http://5b0988e595225.cdn.sohucs.com/images/20190613/526736722530425ba9e25aff7b2b2123.jpeg Mechanical-threaded screws; http://5b0988e595225.cdn.sohucs.com/images/20190613/4e015a21d8ab4e2f9b3f44f4d029ee3e.jpeg Self-tapping screws; http://5b0988e595225.cdn.sohucs.com/images/20190613/8364f52564b7407b882fa5094281349d.jpeg Triangular-threaded screws; http://5b0988e595225.cdn.sohucs.com/images/20190613/d56de367e04d431ba3513cce20356642.jpeg Screw head types; http://5b0988e595225.cdn.sohucs.com/images/20190613/3dacd0e1537b474ca2eebbe09f3b7433.jpeg Screw thread types; http://5b0988e595225.cdn.sohucs.com/images/20190613/cdcaa4284c214c3b866d5fd24990abce.jpeg The general process flow for screw manufacturing is as follows: http://5b0988e595225.cdn.sohucs.com/images/20190613/afaea320b8ff4ff49395a5946cc63104.jpeg Coiled rod stage: This refers to the raw coiled rods purchased by the manufacturer from raw material suppliers. A coiled rod typically includes the following parameters: A. Brand; B. Product name; C. Specifications; 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. http://5b0988e595225.cdn.sohucs.com/images/20190613/65552af0442d4a8aafc619060ef9af62.jpeg The wire drawing process\" `5 b F- b# Z$ D2 O is used to achieve the desired diameter of the wire (for example, reducing it to 3.5mm through wire drawing). http://5b0988e595225.cdn.sohucs.com/images/20190613/9ff16be4af0d413ab6c07a7eddcb2883.jpeg The cold heading process involves shaping the material through the interaction between molds. First, the wire is cut, then headed to form the screw blank, creating the head, cross-slot (or other head shapes), the diameter of the screw blank and its shank length, as well as the radius of curvature at the bottom of the head. http://5b0988e595225.cdn.sohucs.com/images/20190613/bf242774410b4549b395be2259998ee1.jpeg http://5b0988e595225.cdn.sohucs.com/images/20190613/9dca71de882047b79ef54169b791b739.jpeg Note: The design can be adjusted 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, and hex key groove, among others. http://5b0988e595225.cdn.sohucs.com/images/20190613/d8c372988eb343078be9422e7fdcba35.jpeghttp://5b0988e595225.cdn.sohucs.com/images/20190613/43a858dabb744f45a7141dfe9a29a908.jpeg The thread-forming process: Threads are created on the cold-forged blanks by means of the interaction between a movable thread die and a fixed thread die, which enables the formation of the thread pattern. Teeth shaping process: http://5b0988e595225.cdn.sohucs.com/images/20190613/d72dbca1a60342e09f07a7947c3c9d7d.jpeg Changes before and after teeth shaping: http://5b0988e595225.cdn.sohucs.com/images/20190613/a3496019c9e44d84a41d0a88b63b7c01.jpeg Teeth shaping machine: http://5b0988e595225.cdn.sohucs.com/images/20190613/7414dc21b850408da2b7cbd3f6b0aba3.jpeg Teeth shaping template: http://5b0988e595225.cdn.sohucs.com/images/20190613/41d9d3cc74fc44aaa0a1b1df15076125.jpeg 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 polygonalization. http://5b0988e595225.cdn.sohucs.com/images/20190613/9cce52ac77ea473292c4104f50eaf10f.jpeg Microstructure of cold working. B. Carburizing treatment (adding carbon to metal parts in order to increase their surface hardness, applicable to metal materials with low carbon content). http://5b0988e595225.cdn.sohucs.com/images/20190613/e774d4b8b66d4c4b99c1c3851b1001f0.jpeg C. Quenching and tempering treatment (no elements are added to the metal; instead, changes in temperature are used to alter the internal structure of the metal in order to achieve better mechanical properties). http://5b0988e595225.cdn.sohucs.com/images/20190613/cddbc1fae5f7429ea53b7db65ebff68b.jpeg Plating process: The surface of the products after plating can achieve the desired color effect as well as an antioxidant coating on the surface. http://5b0988e595225.cdn.sohucs.com/images/20190613/65248e07829e4f0807881d772ebeaec.jpeghttp://5b0988e595225.cdn.sohucs.com/images/20190613/a6ee6c35e2af42f79745ef1e1228268d.jpeg’ n4 y2 a `. n: u( } ~- e: k Attachment: Table for looking up standard screw specifications. Screw size range: dl. Machine screws with slotted cylindrical heads: GB/T65-2000, M1.6–M10, 2–80. Slotted pan-head screws: GB/T67-2000, M1.6–M10, 2–80. Slotted countersunk screws: GB/T68-2000, M1.6–M10, 2.5–80. Slotted flat-countersunk screws: GB/T69-2000, M1.6–M10, 2.5–80. Cross-recessed pan-head screws: GB/T818-2000, M1.6–M10, 25–40. Cross-recessed countersunk screws: GB/T819.1-2000, M1.6–M10, 30–45. Cross-recessed flat-countersunk screws: GB/T820-2000, M1.6–M10, 30–45. Cross-recessed cylindrical-head screws: GB/T822-2000, M1.6–M10, 20–40. Cross-recessed small pan-head screws: GB/T823-2000, M1.6–M10, 20–50. Cross-recessed countersunk screws: GB/T819.2-2000, M2–M10, 3–60. Cross-recessed screws for precision machinery: GB/T13806.1-1992, M1.2–M3, 1.6–10. Slotted spherical cylindrical-head screws with holes: GB/T832-1988, M1.6–M10, 2.5–60. Slotted large cylindrical-head screws: GB/T833-1988, M1.6–M10, 2.5–20. Slotted spherical large cylindrical-head screws: GB/T947-1988, M1.6–M10, 2–20. Hex socket cylindrical-head screws: GB/T2671-2004, M6–M20, 10–120. Hex socket pan-head screws: GB/T2672-1986, M6–M20, 8–80. Hex socket countersunk screws: GB/T2673-1986, M6–M20, 8–80. Hex socket flat-countersunk screws: GB/T2674-1986, M6–M20, 8–80. Hex socket cylindrical-head screws: GB/T6190-1986, M6–M20, 8–80. Set screws: Slotted tapered-end set screws: GB/T71-1985, M1.6–M12, 2–60. Slotted flat-end set screws: GB/T73-1985, M1.6–M12, 2–60. Slotted recessed-end set screws: GB/T74-1985, M1.6–M12, 2–60. Slotted long cylindrical-end set screws: GB/T75-1985, M1.6–M12, 2.5–60. Hex socket flat-end set screws: GB/T77-2000, M1.6–M24, 2–60. Hex socket tapered-end set screws: GB/T78-2000, M1.6–M24, 2–60. Hex socket cylindrical-end set screws: GB/T79-2000, M1.6–M24, 2–60. Hex socket recessed-end set screws: GB/T80-2000, M1.6–M24, 2–60. Square-head long cylindrical spherical-end set screws: GB/T83-1988, M8–M20, 16–100. Square-head recessed-end set screws: GB/T84-1988, M5–M20, 10–100. Square-head long cylindrical-end set screws: GB/T85-1988, M5–M20, 12–100. Square-head short cylindrical tapered-end set screws: GB/T86-1988, M5–M20, 12–100. Square-head flat-end set screws: GB/T821-1988, M5–M20, 8–100. Hex socket cylindrical-head screws: GB/T70.1-2000, M1.6–M48, 2.5–300. Hex socket flat cylindrical-head screws: GB/T70.2-2000, M3–M16, 6–50. Hex socket countersunk screws: GB/T70.3-2000, M3–M20, 8–100. Hex socket cylindrical-head screws: GB/T6191-1986, M6–M20, 10–80. Positioning and shaft screws: Slotted tapered-end positioning screws: GB/T72-1988, M1.6–M12, 4–50. Slotted cylindrical-end positioning screws: GB/T829-1986, M1.6–M10, 1.5–20. Slotted pan-head positioning screws: GB/T828-1988, M1.6–M10, 1.5–20. Slotted cylindrical-head screws: GB/T830-1988, M1.6–M10, 1–20. Slotted headless shaft screws: GB/T831-1988, M1.6–M10, 1–20. Slotted spherical cylindrical-head shaft screws: GB/T946-1988, M1.6–M10, 2–20. Non-removable screws: Slotted pan-head non-removable screws: GB/T837-1988, M3–M10, 10–60. Slotted countersunk non-removable screws: GB/T948-1988, M3–M10, 10–60. Slotted flat-countersunk non-removable screws: GB/T949-1988, M3–M10, 10–60. Hex head non-removable screws: GB/T838-1988, M5–M16, 14–100. Knurled head non-removable screws: GB/T839-1988, M3–M10, 10–60. Special-purpose screws: Eyelet screws: GB/T825-1988, M8–M10, 0X66–140. Knurled high-head screws: GB/T834-1988, M1.6–M10, 2–35. Knurled flat-head screws: GB/T835-1988, M1.6–M10, 2–45. Knurled small-head screws: GB/T836-1988, M1.6–M6, 3–40. Plastic knurled screws: GB/T840-1988, M4–M16, 3–40. Self-tapping screws: Cross-recessed pan-head self-tapping screws: GB/T845-1985, ST2.2–ST9.5, 4.5–50. Cross-recessed countersunk self-tapping screws: GB/T846-1985, ST2.2–ST9.5, 4.5–50. Cross-recessed flat-countersunk self-tapping screws: GB/T847-1985, ST2.2–ST9.5, 4.5–50. Slotted pan-head self-tapping screws: GB/T5282-1985, ST2.2–ST9.5, 4.5–50. Slotted countersunk self-tapping screws: GB/T5283-1985, ST2.2–ST9.5, 4.5–50. Slotted flat-countersunk self-tapping screws: GB/T5284-1985, ST2.2–ST9.5, 4.5–50. Hex head self-tapping screws: GB/T5285-1985, ST2.2–ST9.5, 4.5–50. Cross-recessed recessed hex head self-tapping screws: GB/T9456-1988, ST2.9–ST8, 6.5–50. Cross-recessed self-tapping screws: GB/T13806.2-1992, ST1.5–ST8, 4.5–25. Self-tapping locking cross-recessed pan-head screws: GB/T6560-1986, M2–M6, 4–60. Cross-recessed countersunk self-tapping locking screws: GB/T6561-1986, M3–M6, 6–60. Cross-recessed flat-countersunk self-tapping locking screws: GB/T6562-1986, M3–M6, 6–60. Hex socket self-tapping locking screws: GB/T6563-1986, M5–M12, 10–80. Self-drilling self-tapping cross-recessed pan-head screws: GB/T5856.1-2002, ST2.9–ST6.3, 13–50. Cross-recessed countersunk self-drilling self-tapping screws: GB/T5856.2-2002, ST2.9–ST6.3, 13–50. Cross-recessed flat-countersunk self-drilling self-tapping screws: GB/T5856.3-2002, ST2.9–ST6.3, 13–50. Wood screws: Slotted round-head wood screws: GB/T99-1986, 1.6–10, 6–120. Slotted countersunk wood screws: GB/T100-1986, 1.6–10, 6–120. Slotted flat-countersunk wood screws: GB/T101-1986, 1.6–10, 6–120. Hex head wood screws: GB/T102-1986, 2–20, 35–120. Cross-recessed round-head wood screws: GB/T950-1986, 2–10, 6–120. Cross-recessed countersunk wood screws: GB/T951-1986, 2–10, 6–120. Cross-recessed flat-countersunk wood screws: GB/T952-1986, 2–10, 6–120