In the production of fuel tanks or water tanks, after the pipe joints are welded to the tank, the original threads on the pipe joints cannot be used normally due to welding deformation. In order to ensure quality, there must be a correction process. We use a circular die for correction. Most of the circular dies for threading are easy to buy, but some threads, taps are available on the market, but it is difficult to buy round dies. We used a modified tap to machine a circular die, which solved the problem better.
Plain washers, which spread a load, and prevent damage to the surface being fixed, or provide some sort of insulation such as electrical
Spring washers, which have axial flexibility and are used to prevent fastening or loosening due to vibrations
Locking washers, which prevent fastening or loosening by preventing unscrewing rotation of the fastening device; locking washers are usually also spring washers.
Materials
Washers can be fabricated from a variety of materials including, but not limited to:[23]
- Steel – Carbon steel, spring steel, A2 (304) stainless steel, and A4 (316/316L) stainless steel
- Non-ferrous metal – Copper, brass, aluminium, titanium, iron, bronze, and zinc
- Alloy – Silicon bronze, Inconel, Monel, and Hastelloy
- Plastic – Thermoplastics and thermosetting polymers such as polyethylene, PTFE (Teflon)[24]
- Nylon – Nylon 6, Nylon 66, Nylatron, and Tecamid MDS[25]
- Specialty – Fibers, ceramics, rubber, felt, leather, bimetals, and mica
- Phenolic – The material has good electrical insulation, is lightweight, tough, has low moisture absorption, is heat resistant, and is resistant to chemicals and corrosion. Phenolic washers are substitutes for flat metallic washers in cases where electrical insulation is required. Phenolic washers are stamped out of large sheets of the phenolic material. The term [phenolic washer" is sometimes used for stamped washers from laminated materials such as paper, canvas, and Mylar.
Plain washers Spring washers Locking washers
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