Hex nuts and bolts
are the most basic fasteners in mechanical connection. Their functions, applications, manufacturing processes and locking principles are as follows:
1. where the role:
1.1 Mechanical connection: two or more components are fastened together through a threaded fit to withstand static or dynamic loads.
1.2 Locking and sealing: The combination of nut and nylon can play a sealing or component positioning role.
2. Application field
2.1 General mechanical connections: mechanical assemblies and equipment, steel structures (such as Bridges, buildings).
2.2 Construction machinery/automobile: engine, chassis, gearbox.
2.3 Transportation track: high-strength anti-corrosion anti-tension firmware.
2.4 Electronic appliances: micro precision nuts.
2.5 Home furniture: DIY assembly, hardware connection.
3.thread standard
3.1. Metric Thread
Standard system: ISO (International), GB (China), DIN (Germany), JIS (Japan).
Code: M (such as M6, M8×1.25, 6 is the nominal diameter, 1.25 is the pitch).
Tooth Angle: 60°, coarse teeth (default) and fine teeth (high-precision, anti-loose scenario), specially marked on the drawing.
3.2. Imperial Thread
Standard system:
UNC (Unified Coarse Thread) : Coarse teeth, strong versatility (e.g. #10-24).
UNF (Unified Fine Thread) : Fine teeth, anti-vibration (e.g. 1/4″-28).
BSW (British Standard Whitworth) : British standard, 55° tooth Angle.
Code: in inches (e.g. 1/2″-13, indicating 1/2 inch diameter, 13 teeth/inch).
3.3. American Thread (ANSI/ASME)
Standards: ANSI B1.1 (unified thread), ANSI B1.20.1 (pipe thread NPT).
Features: Similar to the British system, but more segmented.
3.4. Pipe Thread
NPT (American taper pipe thread) : seal, tooth Angle 60°, taper 1:16.
G/BSP (inch straight/taper pipe thread) : 55° tooth type, divided into G (parallel) and R (conical).
Application: hydraulic pipeline, pneumatic system.
Specific drawings or technical parameters, with the tolerance zone, and with the corresponding stop-stop gauge measurement and inspection, because the screw is directly determined the tightness, and even the risk of oil leakage!
4.Manufacturing process
4.1 Bolt manufacturing:
4.11 Cold heading molding (mainstream process) : cold extrusion molding of wire with mold, high efficiency, low cost, suitable for large batch, standard parts production, because the mold cost is high;
4.12 Turning processing: for large size or non-standard bolts, or high-precision requirements, or not suitable for cold heading materials, because of the high cost of precision machining;
4.2 Nut manufacturing:
4.21 Cold heading or hot forging: the hexagonal shape is formed by the mold, and the internal thread is tapped or extruded;
4.22 Thread processing: thread rolling (high-speed rolling) and turning methods;
4.23 Pure machining method: nuts with small quantity or abnormity requirements;
4.24 Nylon nut: with high toughness and nylon (processed to a certain size),
5. Surface treatment process
5.1 Galvanizing: Ordinary galvanizing is the most common, low cost, but general rust prevention (need passivation treatment), and not environmentally friendly; Trivalent zinc is environmentally friendly, but the cost will be higher than ordinary galvanizing.
5.2 Hot dip galvanizing: thick zinc layer, there is a hidden danger of hydrogen embrittance, mainly used for outdoor steel structure, corrosion resistance is stronger than electric galvanizing.
5.3 Dacromet: no hydrogen embrittlement, high temperature corrosion resistance, resistance to high salinity seawater corrosion, so the application is mainly in the harsh sea, plateau, high humidity environment.
5.4 Oxidation black: beautiful, easy to flower and rust prevention ability is weak, often used in tool products.
5.5 Phosphating: chemical reaction, can improve wear resistance, often used with anti-rust oil.
6.the principle and significance of locking
6.1 Locking Mechanism
6.11 Friction locking:
Nylon Insert Lock Nut (Nylon Insert Lock Nut) : the nut is embedded in a nylon ring, which causes elastic deformation and increases friction when screwed in.
6.12 Butterfly self-locking washer: It is an elastic preload anti-loosening, the washer is compressed during installation, producing axial elastic recovery force, so that the bolt/nut is always subjected to additional compression force, when the connector is slightly loosened due to vibration, the elastic energy of the washer will compensate for the loss of preload and maintain the fastening state; In addition, the sawtooth structure at this time plays a more important role, so that the loosening tension is always less than the height of the sawtooth, to achieve the anti-loosening effect.
7, thread detection: through the gauge (GO/NO-GO), three-pin measurement method (precision thread).
Professional nylon nut locking scheme, butterfly self-locking washer samples and technical solutions, you can contact our team, free samples, welcome to technical exchange and learning.
