In order to use the management and description of the convenience, need to adopt a certain method of its classification. The standard parts are summarized in several commonly used fastener classification methods:
1. Classification according to the field of us
According to the different areas of use of fasteners, the international fasteners are divided into two categories: one is a general-purpose fasteners, the other is aerospace fasteners.General-purpose fasteners are commonly used ordinary fasteners. This type of fastener standards in the internationalization by the ISO/TC2 to develop and under the umbrella of national standards or standardization associations in various countries to appear. China’s national standards for fasteners are set by the National Technical Committee for Fastener Standardization (SAC/TC85). These fasteners use common threads and mechanical properties of the grade system, widely used in machinery, electronics, transportation, store, construction, chemical industry, shipping and other fields, but also for aerospace ground products and electronic products. Mechanical properties rating system can reflect the comprehensive mechanical properties of fasteners, but mainly reflect the load carrying capacity. The system is generally only limited to material categories and components, not limited to specific material grades. Standard parts for you
Aerospace fasteners are designed for aerospace vehicles fasteners, such fastener standards in the international ISO/TC20/SC4 to develop and attributed. China’s aerospace fastener standards by the fastener national military standards, aviation standards, aerospace standards together. The main features of aerospace fasteners are as follows: the standard parts are provided for you.
(1) The thread adopts MJ thread (metric system), UNJ thread (imperial system) or MR thread.
(2) Strength grading and temperature grading are adopted.
(3) High strength and light weight, the strength grade is generally above 900Mpa, up to 1800MPa or even higher.
(4) High precision, good anti-loosening performance and high reliability.
(5) Adaptable to complex environments.
(6) Strict requirements on the materials used. The standard parts for you
2. According to the traditional customary classification
According to China’s traditional habits, fasteners are divided into bolts, studs, nuts, screws, wood screws, self-tapping screws, washers, rivets, pins, retaining rings, connecting vice and fasteners – assemblies and other 13 categories. China’s national standards have been following this classification.
3. According to whether the development of standard classificationAccording to whether the development of standards, fasteners are divided into standard fasteners and non-standard fasteners. Standard fasteners are fasteners that have been standardized and formed a standard, such as national standard fasteners, national military standard fasteners, aviation standard fasteners, aerospace standard fasteners and enterprise standard fasteners. Non-standard fasteners are fasteners that have not yet formed a standard. With the broadening of the scope of application, the general trend of non-sandard fasteners will gradually form a standard, transformed into standard fasteners; there are also some non-standard fasteners, because of a variety of complex factors, can only have been applied as a special parts.
4.Classification according to whether the geometric structure contains threaded features or not
According to whether the geometric structure contains threaded features, fasteners are divided into threaded fasteners (such as bolts, nuts, etc.) and non-threaded fasteners (such as washers, retaining rings, pins, ordinary rivets, ring groove rivets, etc.).
Threaded fasteners are fasteners that make connections by means of threads. Threaded fasteners can be further subdivided.
According to the type of thread, threaded fasteners are divided into metric threaded fasteners, imperial uniform threaded fasteners, etc.
According to the characteristics of the formation of the parent body, threaded fasteners are divided into external threaded fasteners (such as bolts, studs), internal threaded fasteners (such as nuts, self-locking nuts, high locking nuts) and internal and external threaded fasteners (such as threaded bushings) 3 categories.
According to the positional characteristics of the threads on the fastener, external threaded fasteners are divided into screws, bolts and studs.
5. Classification by material
According to the use of different materials, fasteners are divided into carbon structural steel fasteners, alloy structural steel fasteners, stainless steel fasteners, high-temperature alloy fasteners, aluminum alloy fasteners, titanium alloy fasteners, titanium-niobium alloy fasteners and non-metallic fasteners.
6. According to the main molding process method classification
According to the different methods of forming process, the fasteners can be divided into upsetting fasteners (such as aluminum alloy rivets), cutting fasteners (such as hexagonal bar cutting and processing of screws and nuts) and cutting nodular fasteners (such as most screws, bolts and high lock bolts). Upsetting can be divided into cold upsetting and hot (warm).
7. Classification according to final surface treatment status
According to the difference of final surface treatment status, fasteners are categorized into non-treated fasteners and treated fasteners. Non-treated fasteners generally do not undergo any special treatment, and can be put into storage and shipped after necessary cleaning after passing the molding and heat treatment processes. Treatment of fasteners, the type of surface treatment is detailed in the fastener surface treatment chapter. After zinc-plated fasteners are called zinc-plated fasteners, after cadmium-plated fasteners are called cadmium-plated fasteners, after oxidation of the fasteners are called oxidation of the fasteners. And so on.
8. Classification according to strength
According to the different strength, fasteners are divided into low-strength fasteners, high-strength fasteners, high-strength fasteners and ultra-high-strength fasteners 4 categories. Fastener industry is accustomed to the mechanical properties of the grade below 8.8 or nominal tensile strength of less than 800MPa fasteners known as low-strength fasteners, mechanical properties of the grade between 8.8 and 12.9 or nominal tensile strength of between 800MPa-1200MPa fasteners known as high-strength fasteners, the nominal tensile strength of between 1200MPa-1500MPa between the fasteners known as high-strength fasteners, nominal tensile strength higher than 1500MPa fasteners known as ultra-high-strength fasteners.
9.Case the nature of the working load classification
According to the difference in the nature of the working load, fasteners are divided into two categories: tensile and shear type. Tensile fasteners are mainly subject to tensile load or pull-shear composite load; shear fasteners are mainly subject to shear load. Tensile fasteners and shear fasteners in the nominal rod diameter tolerance and threaded fasteners thread length, etc. There are some differences.
10. Classification according to the requirements of assembly operation
According to the differences in assembly operation requirements, fasteners are divided into single-sided connection fasteners (also known as blind connection fasteners) and double-sided connection fasteners. Single-sided connection fasteners only need to be connected to one side of the operation can be completed assembly.
11. Classification according to whether the assembly can be disassembled or not
According to whether the assembly can be disassembled or not, fasteners are divided into removable fasteners and non-removable fasteners. Removable fasteners are fasteners that need to be disassembled and can be disassembled in the process of use after assembly, such as bolts, screws, common nuts, washers and so on. Non-detachable fasteners refers to the assembly, in the use of the process and its fasteners are not disassembled; must be disassembled, this type of fasteners can also be disassembled, but often lead to fasteners or links to the system can not be reused because of damage to the fasteners, including a variety of rivets, high locking bolts, studs, high locking nuts, and so on.
12. Categorized by technical content
According to the different technical content, fasteners are categorized into 3 levels: low-end, mid-end and high-end. Fastener industry is accustomed to the highest marking accuracy is not higher than 7, strength less than 800MPa of general-purpose materials fasteners called low-end fasteners, such fasteners are less technically difficult, lower technological content and less value-added; will be the highest marking accuracy of 6 or 5, strength between 800MPa-1200MPa, the material has certain requirements of the fasteners known as the mid-range fasteners, which have a certain degree of technical difficulty, fasteners and other technical content. Fasteners have certain technical difficulty, certain technical content and added value; the highest marking accuracy of more than 5 levels, or strength of more than 1200MPa, or anti-fatigue requirements, or anti-temperature creep requirements, or special anticorrosion and lubrication requirements, such as special materials fasteners known as high-end fasteners, such fasteners are technically difficult, high technical content and added value.
There are many other ways to categorize fasteners, such as classification according to the head structure of fasteners, and so on, not to be listed. With the materials, equipment systems and process means and so on continue to innovate, people will be based on the need to put forward new fastener classification methods.
Post time: Sep-11-2024
