What is a bolt - everything about this Fasteners

Bolt in detail

there specific terminology, without which it would be difficult to understand when discussing the bolts.Therefore it is necessary to get acquainted with such definitions as thread, thread pitch, etc.

Thread - spiral cut into the surface of the shaft portion of the bolt along a helical path with a constant pitch.There is a great many types of threading, methods and guests.The most popular thread, which has a wide distribution and use - a metric thread.

Pitch - a height measured from a single turn in the thread to the other.The thread pitch of the thread is constant, enforced by state standards, measured in millimeters.

Revolution thread - a thread turn.

screwing length - the length of all the threads on the surface of the shaft portion of the bolt.

Application bolt

Bolts are classified by purpose, they can be: plowshare, engineering, travel and furniture.Depending on the application places different type of screws and the class of its strength.For example, it is impossible for the unit to the power unit of the machine screw bolt for furniture, if he still has a lower strength.And as a rule, screws for furniture made of less durable metal that is not adapted to work in extreme conditions.

This means that you need to clearly distinguish between the types of screws and their applications.Besides these four types there is one classification for use.

Classification bolts, depending on the application

• Black bolts.They are made by stamping.Typically, material for forming a high-carbon steel.These screws are used to connect a non-critical parts of the machine.This class is designed for rough assembly, only in those sites where there will be a large load, the long monotonous vibrations.Machining in the production of rough bolts is carried out only when threading.
• semifinished bolt.There occurs first stamping, and then machining the surfaces.Thus not all processed bolt, the bolt head is not processed, but the appearance and the mechanical properties should not affect it.The head must exactly match the requirements of GOST.Material for semifinished bolt - Medium Steel.It is used in most of such bolt connections, capable of withstanding prolonged monotonous oscillations not weak load.
• Net bolts.The material for the ready can be alloyed steels, non-ferrous metal alloys and low carbon steel.Processing performed in clean screw fully, and it means that all the machining pass of the bolt.Through the use of high strength metals and alloys, the bolt may be employed in important nodes.And thanks to the full treatment, they can be used in open areas where appearance is important.

to the listed should add some explanations.One of the properties on which there is metal quality classification, the amount of carbon in the steel.Accordingly, the smaller the carbon in the steel, the better the obtained steel itself.In steels with low carbon content significantly increases the level of wear resistance and toughness.

Note.To improve the quality of steel, to improve the structural strength of the doping is performed.This process involves an input of the alloying elements of steel, which may include: tungsten, vanadium, titanium, chromium, manganese, nickel and other metals and non-metals.

Classification by strength

have studs, bolts and screws there is a division on the strength of 11 classes: 3.6;4.6;4.8;5.6;5.8;6.6;6.8;8.8;9.8;10.9;12.9.The first point defines the number to the nominal tensile strength, measured in it, to find multiplied by 100. The second number, after the point is the ratio of yield strength to resist temporary percentage, as measured, for finding multiplied by 10. Accordingly, the above figures, the stronger will be the item.In Russia, according to GOST, is considered to be high-strength bolts are the ones that are in the range from 6.8 do12.9 strength.

Forms bolts

Due to the wide range of forms of choice, you can do different design complexity, to carry out various projects.Depending on the situation and the type of connection may be required to complete a non-standard bolt.However, finding a suitable type is not difficult enough to decide to start with the main form.The shape distinguish:

• screws with countersunk head
• Hexagon head
• eyebolts
• Anchor bolts
• bolts with flange
• bolts with round head
• Hinged bolts

This article will be considered in detailthe last option in the list of the bolts forms.

Bolt hinged

distinguished it its purpose and structure.As with all bolts are metal rod, on which a thread, but unlike the well-known hex bolt, here, instead of the head ring.The hole inside the ring can be used in fastening hooks.

folding head bolts is not only in the form of a ring, but also in the form of a hemisphere and forks.The design of the bolt with a fork designed specifically for articulated joints.The head of a hemisphere allows us to fairly tightly pressed when combined with flexible and elastic surfaces.Main application hinged bolts - rigging.

Basically, the material for forming this type of bolt is steel with high or medium-carbon and alloy steels, much less low-carbon steel.

particular advantage is hinged bolt strength and speed of construction of the connection.For example, bolts used in hinged connection nodes of furniture, in the field even when the machine need to quickly fix the platform or device.