1. The quality of electroslag pressure welded joints does not meet the requirements
The bending or migration of the axes at the joints is too large, the welding package is uneven, and there are some phenomena such as undercut, slag inclusion, non-fusion, etc. The reinforcing bar is burned at the clamping position.
(2) Cause analysis
1. The end of the reinforcing bar is not straight, clean or uneven; the installation of the reinforcing bar is not correct, the axis is offset, and the machine tool is damaged, resulting in the sway and displacement of the reinforcing bar; after welding, the joint has not been fully cooled;
2. Improper use of welding technology, inappropriate selection of welding parameters and poor operation technology;
3. Flux filling is uneven or damp.
(3) Measures for prevention and control
1. Before welding, the bending or distorted part of the end of the reinforcing bar should be corrected or removed, and the end of the reinforcing bar should be eradicated, and the end face of the reinforcing bar should be ground flat.
2. Reinforcement processing equipment should be carried out by licensed welders. When installing reinforcing bars, attention should be paid to whether the axes of reinforcing bars or fixtures are on the same straight line, whether the reinforcing bars are strong or not, and if the reinforcing bars are too long, an extension frame should be placed on the same horizontal plane. If the machine tool is damaged, especially the damage of welding fixture pads should be repaired or replaced in time, and quasi-welded
3. Reasonable selection of welding parameters and correct grasp of operation methods according to the Code for Welding and Inspection of Reinforcement Bars (JCJ18). After the welding is completed, the machine tool should be removed or moved after cooling for 1 to 2 minutes according to the condition, and when the joint has enough strength.
4. It is necessary for welders to hold a job certificate. Before welding, it is necessary to carry out trial welding according to construction conditions, and only after qualified can it be welded.
5. It is necessary to insist on self-inspection after welding. For joints with bending and migration exceeding the standard and incomplete penetration, the heat affected zone should be removed and then ab initio welding or reinforcing welding should be adopted; for joints with brittle fracture, the required re-inspection should be carried out, and for unqualified joints, the heat affected zone should be removed and ab initio welding should be adopted.
2. Machining Defects of Straight Thread Screw Bucks
Wire buckles are incomplete, the number is not good, and the end of the wire head is uneven (Fig. 1 and Fig. 2).
(2) Cause analysis:
1. Operators have not been trained, and the on-site information is unclear.
2. The process quality control is not strict and the maintenance of processing machinery is not in place.
3. The silk head was not maintained in time with David's cap after processing.
4. The end of reinforcing bar is cut by cutting machine directly.
(3) Measures for prevention and control:
1. It is necessary for the operator of steel bar joint thread processing to be trained, assessed and certified.
2. Inspection tools such as general rules and stop rules should be equipped on the spot, and regular inspection should be carried out on the processed silk heads.
3. Qualified silk heads should be equipped with maintenance caps in time.
4. The end of reinforcing bar should be cut with toothless saw to ensure that the end of reinforcing bar is flat.