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The Difference Between The High Strength Bolt Segment Bolt And Common Bolt
Nov 07, 2017

In tunnel construction, there is a kind of equipment is engaged in the originating and shield tunneling machine is machine, cutting soil excavation, conveying soil crusts, assembling tunnel lining, and other functions;

But when shield machine in the tunnel lining, based on a few segments for assembling, there is a kind of function connection fastening screws, form garden cylindrical pipe assembly, segment is cylindrical wall;

Excavation can effectively control the ground settlement, to reduce the influence of the ground buildings and underwater excavation shall not affect the water traffic characteristics of each segment together, form the pipeline, the design into a straight line or a curved tighten fittings, bolt is lining segments.

Segment bolt can be divided into circular and longitudinal.

Some design central to vertical and specifications.

Some design, central to the vertical and the two specifications, even two kinds of strength grade.

In general, the ring to the segment of the bolt length is longer than the vertical segment bolt.

Segment bolt type:

1 type, double head straight segment bolt

2, double arc segment bolt

3, hex head arc segment bolt

4 bolts, hex head arc thread lining segments

5 bolt, hex flange surface arc thread lining segments

Segments 6, non-standard bolts

High strength bolt is one of the most representative products, special bolt it compared with the ordinary bolt to high strength and long service life.

Normally, high strength bolt is by quenching and tempering treatment to enhance strength, its organization is tempered martensite.

Once the tempered martensite steel tensile strength of more than 1200 mpa, due to the effect of trace hydrogen, the original grain boundary embrittlement will happen, in use process happen delay fracture phenomena become apparent.

High strength bolt segment bolt and common bolt difference:

High strength bolt segment bolts made of high strength material.

High strength bolt screw, nut and washer are made of high strength steel, 45 # steel is commonly used, boron steel 40, 20 manganese titanium boron steel.

General bolt used Q235 steel production.

From the point of view of strength grade:

High strength bolts, the use is becoming more and more widely.

Commonly used 8.8 s and 10.9 s two strength grade, the majority in 10.9 on the Richter scale.

Generally lower bolt strength grade, generally with a magnitude of 4.4, 4.8, 5.6 and 8.8 magnitude.

From the point of force characteristic:

High strength bolt and by pre-tensioning force transfer outside force.

Generally by bolt rod bolt coupling shear and pressure on the hole wall to transfer shear, tighten the nut when the attack method is small, its influence can be neglected, and high strength bolts in addition to its high strength of materials, put great pretension bolt back, make the connection between components attack extrusion, which has a great resistance force perpendicular to the direction of the screw, and strong, resistance to sliding coefficient and steel varieties are directly affect the bearing capacity of high strength bolt.

According to pressure and resistance force characteristic points. The two calculation methods are different.

High strength bolt M12 minimum specification, commonly used M16 ~ (, large bolts specification function is not stable, planning should be used carefully.