when welding rebar, the scope of use and the number of inspections of various welding methods shall comply with the provisions of the table below.
1, engaged in rebar welding construction welders must hold the welder examination certificate, in order to be on-the-job operation. （1.0.3）
2, where welding of all kinds of steel bars, steel plates should have a quality certificate; welding rods, solder should have product certification. (3.0.5)
3, before the project is formally welded, the welder involved in the welding should carry out on-site conditions of the welding process test, and after passing the test, can be formally produced. the test results should meet the requirements of quality inspection and acceptance. (4.1.3)
(before the start of the project or the formal welding of each batch of rebar, welding process tests must be carried out under the same conditions as production, regardless of the welding process method used, in order to understand the welding performance of the rebar select the best welding parameters and master the technical level of the welder responsible for production. do at least 1 set of test pieces for each grade and rebar of each specification if the first time failed, the process should be improved, the adjustment parameters should be well documented for examination the results of the connector specimen test (stretch/bend/cut) should meet the requirements for quality inspection and acceptance .)
4, before the construction of rebar welding, should remove the steel bar, steel plate welding site and steel bar and electrode contact on the surface of rust spots, oil, impurities, etc. ; (4.1.3)
5, ribbed rebar for flash welding, arc welding, slag pressure welding and air pressure welding, it is advisable to vertical ribs to vertical ribs and welding. (4.1.4)
6, rebar welding joints should be in accordance with the inspection batch for quality inspection and acceptance, and divided into the main control project and general project two categories. quality inspection should include appearance inspection and mechanics performance inspection. (5.1.2)
7, longitudinally forced rebar welding joints, including flash welding head, arc welding head, electric slag pressure welding head, air pressure welding head connection method inspection and joint mechanics performance inspection provisions as the main control items. (5.1.3)
8, connector connection should meet the design requirements, and should be fully checked, inspection method for observation.
when the welding joint appearance inspection, the welder shall first self-inspect the welded head, then be inspected by the professional quality inspector of the construction unit, and the inspection record shall be carried out by the supervision (construction) unit.
when the longitudinal forced steel weld joints are inspected for appearance, 10% of the welding joints should be randomly selected in each inspection batch. the inspection results show that when the appearance quality of each sub-item is less than or equal to 10%of the number of spotchecks, then the appearance quality of the welded joint is rated as conforming.
when the number of non-conformities of a small item exceeds 10% of the number of spot checks, the batch of welding joints should be re-inspected one by one, and the non-conforming joints should be removed;
9, when the mechanics performance test, should be qualified after the connector appearance check randomly selected test pieces for testing.
1, the name of the project, sampling site;
2, lot number, batch;
3, rebar brand, specifications;
4, welding method;
5, welder’s name;
6, construction units;
7, the results of the hydraulic performance test. (5.1.6)
10, rebar flash to welding head, arc welding head, electric slag pressure welding head, air pressure welding head stretch test results. (5.1.7 strong bars.))
(1) Thetensile strength ofthe 3 hot-rolled rebar joint test pieces shall not be less than the tensile strength specified by the brand rebar;The tensile strength of theRRB400 rebar joint test piece shall not be less than 570N/mm;
(2) at least 2 specimens should be broken outside the weld and should be delayed. when the above 2 requirements are met, the batch of connectors should be assessed as tensile strength qualified. when the test results have 2 test pieces less tensile strength than the reinforcement specified by the rebar, or 3 test pieces are in the weld or thermal impact area of the brittle fracture, the batch of joints is judged to be non-conforming at one time. a retest should be carried out when the test results have 1 test piece with less tensile strength than the one specified by the rebar, or 2 test pieces with brittle fractures in the weld or thermally affected area, both of which are less than 1.10 times the tensile strength specified by the rebar. 6 more test pieces should be cut during the retest. retest results, when there are still 1 test piece of tensile strength less than the specified value, or 3 test pieces broken in the weld or thermal impact area, brittle fracture, its tensile strength is less than 1.10 times the required tensile strength of the rebar, the connector should be determined to be non-conforming.
(note: when the joint test piece is broken in the weld or thermal impact area, brittle fracture, but its tensile strength is greater than or equal to 1.10 times the pull strength specified by the rebar, can be broken outside the weld or thermal impact area, the same treatment of extended fracture.) ）
11, flash welding head, air pressure welding head bending test, should be pressurized surface of the metal burrs and rough bulge part of the partial elimination, and should be flush with the appearance of rebar. (5.1.8 strong bars.))
Bending test can be carried out on the universal test machine, manual hydraulic bending tester, welds should be at the center of the bend, bend diameter and bending angle should be in accordance with Table 5.1.8. (Note:HPB235,HRB335,HRB400,HRB500 bend diameters are 2d,respectively 4d, 5d,7d;
when the test results are bent to 90 degrees and there are 2 or 3 test pieces outside (including welds and thermal impact zones) that do not break, the batch of joint bending tests should be assessed as qualified. when all 3 specimens break, the batch connector is judged to be unqualified at a time. when 2 specimens have cracked, a retest should be performed. 6 more test pieces should be cut during the retest. as a result of the retest, when 3 test pieces break, the batch connector should be judged to be unqualified.
(note: when the outer transverse crack width of the specimen reaches 0.5mm, it should be considered cracked.) ）