The ends of the steel bars must not be bent, and should be straightened when bent. When cutting the steel bar, it is not allowed to use electric welding, gas welding and other heating methods or cutting with a steel bar cutting machine. It must be cut with a toothless saw to ensure that the end of the steel bar is straight and perpendicular to the axis of the steel bar, and there must be no horseshoe or bending.

Rebar wire head processing: The processing length of the wire head is 1/2 of the length of the standard coupler. The specifications of the steel bar should be adjusted to the thread rolling device. Consistently, the cumulative length of the bald teeth in the effective thread segment is less than the circumference of one thread. On the straight thread rolling machine, the straight thread head of the steel bar is rolled according to the designed pitch, feed length and other parameters, and the corresponding ring gauge is used. And the wire head clamp test is qualified. Refer to Table 1 for the reference processing size (mm) of the wire head.

Water-soluble cutting lubricating fluid shall be used for thread processing of steel bar rolling, oily cutting fluid shall not be used, and processing shall not be carried out without lubricating fluid.

After the steel wire head is processed, immediately put on a protective cap or screw on the connecting coupler to prevent damage to the wire head when loading and unloading the steel bar. It should be neatly stacked at the designated location as required, and the specifications of the steel bar should be clearly marked. The wrench will connect the steel bar to the straight thread coupler. Tighten it so that the two steel wire head joints are pressed against each other at the center of the sleeve. There should be two marking lines on the steel wire head. When the steel bars are connected, the length of the steel bar entering the coupler should be marked at the wire head to facilitate inspection and acceptance. .

Appearance and appearance quality: The thread of the rebar head should be full. Within the specified effective length of the thread, the cumulative length of the incomplete buckle with the major diameter of the thread lower than the pitch diameter of the thread should not exceed 2 thread circumferences. The skin can be removed with an iron brush.

Inspection of thread size: Use the go-stop gauge to inspect the thread size. It is required that after the end of the steel wire is inserted into the go-stop gauge, the end is within the upper and lower limits of the go-stop gauge to be qualified.

The processed steel wire ends should be self-inspected one by one with special testing tools.

The silk ends that pass the self-inspection shall be inspected by random sampling by the quality inspector. The silk ends processed in one work shift are regarded as one acceptance batch, and 10% of them shall be randomly inspected. When the pass rate is still less than 95%, all silk ends shall be inspected one by one.

When connecting steel bars, the specifications of the steel bars and the connecting couplers should be consistent, and the threads of the wire heads and connecting couplers should be clean and undamaged.

When constructing in sections, the exposed parts of the connecting coupler and the steel wire buckle should be tightly covered with a sealing cover.

The end faces of the two steel bars to be connected must be tight and in the middle of the coupler, and the deviation should not be greater than 1P (P is the pitch). No more than 1.5-2 threads are exposed outside the coupler.

Tightening torque of rolled straight threaded steel bar joints: steel bar diameter 18-22mm is 160/(N.m), 22-25mm is 260/(N.m), 28-32mm is 320/(N.m), 36-40mm is 350/(N.m)