Stainless steel screws are classified into austenitic stainless steel, ferritic stainless steel, martensitic stainless steel, and precipitation hardening stainless steel. The selection of stainless steel screws is also based on principles. Where to start, let you choose the stainless steel screws you need. After comprehensive and comprehensive consideration of these five aspects, the grades, varieties, specifications and material standards of stainless steel screws are finally determined. Austenitic stainless steel: the most basic alloying elements of austenitic stainless steel are chromium and nickel. The grade is a chromium-nickel austenitic stainless steel with a chromium content of about 18% and a nickel content of about 8%, often called 18-8 stainless steel. The element ratio of chromium and nickel basically ensures that the structure of the steel is stable austenitic ferritic stainless steel: 430 type ordinary chromium steel, its corrosion resistance and heat resistance are better than 410 type, magnetic, but it It cannot be strengthened by heat treatment, and is suitable for stainless steel screws with slightly higher corrosion resistance and heat resistance and general strength requirements. Martensitic stainless steel: Type 410 and 416 can be strengthened by heat treatment, with a hardness of 35 to 45HRC, and good machinability. They are used for general-purpose heat-resistant and corrosion-resistant stainless steel screws. Type 416 has a slightly higher sulfur content and is a free-cutting stainless steel. Type 420, sulfur content? R0.15%, improved mechanical properties, can be strengthened by heat treatment, maximum hardness value of 53 ~ 58HRC, used for stainless steel screws requiring higher strength. Precipitation hardening stainless steel: 17-4PH, PH15-7Mo, they can get higher strength than the usual 18-8 type stainless steel, so they are used for high-strength, corrosion-resistant stainless steel stainless steel screws. A-286, a non-standard stainless steel, has higher corrosion resistance than commonly used Type 18-8 stainless steels, as well as good mechanical properties at elevated temperatures. Used as high-strength, heat-resistant, corrosion-resistant stainless steel screws, can be used to 650 ~ 700 ℃. Austenitic stainless steel: The commonly used models are 302, 303, 304, and 305, which are the so-called 18-8 austenitic stainless steels. Both corrosion resistance and mechanical properties are similar. The starting point of selection is the production process method of stainless steel screws, and the method depends on the size and shape of stainless steel screws, and also depends on the quantity of production. Type 302 is used for machined screws and self-tapping bolts. Type 303 In order to improve machinability, Type 303 stainless steel is added with a small amount of sulfur and is used to machine nuts from bar stock. Type 304 is suitable for hot heading stainless steel screws, such as longer gauge bolts, large diameter bolts, which may be beyond the scope of the cold heading process. Type 305 is suitable for cold heading processing of stainless steel screws, such as cold formed nuts, hex bolts. Type 309 and Type 310, their Cr content and Ni content are higher than 18-8 type stainless steel, suitable for stainless steel screws working at high temperature. Types 316 and 317, both of which contain the alloying element Mo, have higher high temperature strength and corrosion resistance than 18-8 type stainless steel. Type 321 and Type 347, Type 321 contains a relatively stable alloying element Ti, Type 347 contains Nb, which improves the intergranular corrosion resistance of the material. It is suitable for stainless steel standard parts that are not annealed after welding or serve at 420～1013℃.
Flat gaskets are usually thin pieces of various shapes used to reduce friction, prevent leakage, isolate, prevent loosening, or distribute pressure. There are such components in many materials and structures. The existing flat washer has a simple structure design. After long-term use, the phenomenon of thinning of the thickness is likely to occur, which in turn leads to poor wear resistance of the flat washer.
A medical self-locking screw, wherein the medical self-locking screw is composed of an outer screw and an inner screw, the outer screw includes a fixedly connected fitting body and the front part of the outer screw, and the front part of the outer screw includes a fixed connection The outer screw rod body and the outer screw head are provided with fixed external threads on the periphery of the outer screw rod body, and a backstop ring is provided on the periphery of the matching body;
The material of the rubber gasket is NBR nitrile rubber, which is the most commonly used and has the highest cost performance. The use of FFKM perfluoroelastomer gaskets is generally in the more advanced fields, such as the field of aerospace rockets. Because its price is quite expensive, but its performance is excellent and can exceed many metal materials. For specific material information, please refer to the following: Material Name Chemical Description English Abbreviation English Alias Nitrile Butadiene Rubber Acrylonitrile-Butadiene Rubber Ethylene-Propylene-Diene Rubber EPDM EP,EPT,EPR Neoprene Neoprene CR Neoprene Silicone Silicone Rubber WMQ PVMQ Fluorosilicone Fluorosilicone Rubber FVMQ FVMQ Acrylate Acrylate Rubber ACM ACM Ethylene Acrylate Vinyl -Acrylic Rubber AEM Vamac Styrene-Butadiene Styrene-Butadiene Rubber SBR SBR Polyurethane Polyester/Polyether Urethane AU/Eu AU/EU Natural Rubber Natural Rubber NR NR
The force condition of the screw is broadcasted: 1) Self-weight G; 2) Torque M required to overcome material resistance; 3) Axial force P generated by material pressure. Screw screw screw is generally scrapped due to long-term wear, the gap between the screw and the barrel is too large and cannot be extruded normally, but there are also examples of damage due to improper design or improper operation. Therefore, the screw should also meet certain strength requirements. 4) The dangerous section of the screw is generally at the smallest thread root diameter in the feeding section. According to material mechanics, for plastic materials, the composite stress is calculated by the third strength theory, and its strength conditions are:
We have many years of experience in the production and sales of screws, nuts, flat washers, etc. The main products are: stainless steel 304 cap nuts, Q411 standard, head square neck screws, hexagonal screws and other products, we can provide you with suitable fastener solutions for you Program.
The above content is uploaded by Yueluo or the Internet. If there is any copyright issue, please contact [email protected].