Steel fasteners Engineering

Hainan Steel teach you: Steel fasteners Engineering

(A) material quality requirements
(1) connected by high-strength steel Hainan large hexagonal bolts connecting deputy, torsional shear bolts connecting deputy, steel grid with high strength bolts, common bolts, rivets, self-tapping screw, rivet, nail, bolt , anchor bolts and other fastening standard parts and nuts, washers and other standard accessories should have a quality certificate or certificate.
(2) high-strength large hexagonal bolts connecting deputy and torsional shear bolts connecting deputy factory inspection report shall follow me with a tightening torque coefficient and axial force (prestressing), and the site should be applied to a random sample t test torque coefficient and prestressed.
(Ii) quality control during construction
(1) Hainan Steel production and installation units should be required to the current national standard "Steel Construction Quality Acceptance" gb50205-2001 of high-strength bolts were connected to the anti-slip surface coefficient of friction test and retest; installation site processing friction surface treatment should be a separate anti-slip surface friction coefficient test results should meet the design requirements. When the high strength of the connection node by pressure or tension-type connector type connection strength design, do not carry out anti-friction surface test and retest slip coefficient.
(2) high strength bolts, the friction surface member must be processed. Anti-slip coefficient after treatment should meet the design requirements, methods are sandblasting, spray (throwing) pill, pickling, grinding wheel. When using manual grinding wheel, grinding direction should be perpendicular to the direction of the force member, and the range of not less than 4 times the grinding bolt aperture. Friction surface treated to take protective measures, the friction surface may not be marked. Anti-slip coefficient of friction surface reinspection by production units and installation of manufacturing units respectively send samples trial testimony batches units.
(3) common bolt connections are tight requirements:
① ordinary bolt should start in the middle, symmetrical on both sides to carry out large-scale joint should adopt complex twist.
② ordinary bolts as a permanent attachment bolts fastening bolt head and nut are placed side should be flat washers, bolts, washers cephalic place no more than two, nut-side washer placed more than one.
③ permanent ordinary bolts should be solid, reliable, not less than 2 exposed threaded buckle. To withstand dynamic loads or important parts of the bolt connection, the design of anti-loose requirements, should be taken with anti-loosening device of nuts or spring washers, spring washers on the nut side.
(4) should be free to penetrate the high-strength bolts bolt holes, not gas cutting reamer; reaming the maximum amount should not exceed 1.2d (d bolt diameter).
(5) The use of high strength bolts should be installed first punch mounting bolts and nails, can not serve as mounting bolts with high strength bolts.
(6) high strength bolts fastening requirements:
① high strength bolts should be installed after the component precision adjustments tightened.
② torsional shear type high strength bolts installed, the side of the nut with a round table with the side to be facing the washer chamfered.
High strength bolts with large hexagon head ③ When installed, the side washers under the bolt head bolt head should be chamfered side of the nut with a round table with the side to be facing the washer chamfered.
④ Tighten and test facilities with the torque wrench in the class should be corrected prior to calibration, checking after classes, Shi screwing torque wrench precision error should not exceed ± 5%; test with torque wrench precision error should not exceed ± 3%.
⑤ twist when applied, shall be applied torque on the nut.
⑥ high strength bolts fastening the bolt group should order all bolts evenly force, applied from the intermediate node to the edge twist, twist and final twist both early should certain order. The bolts should be installed on the same day the same day the final twist is completed, the exposed threaded should be 2 to 3 buckle.
⑦ torsional shear type high strength bolts, twist off the tail to head for the final twist Plum card ends.