The adjustment in the feeding process of used welded pipe machine can be divided into ① strip bite adjustment. ② Adjustment of forming 1 flat tube blank. ③ Adjustment of 2 (including 1 vertical) to 4 pipe blanks for forming. ④Adjustment of closed orifice section.

Strip bite adjustment

First, set the speed of the used welded pipe machine unit within the safe speed of 5~8m/min, and jog the test run at no-load. Then lift up the leveling roller, and pass the tube blank through it; at the same time, use the centering device to center the flat tube blank; for the tube blank with a thickness of less than 3mm, the head of the tube blank can be directly placed between the 1 flat rollers, point Biting in after moving; for biting thick-walled tubes, the first flat roll 1 should be lifted evenly and remember the number of turns, so that the head of the tube blank slightly exceeds the center line of the flat roll hole pattern, and then lower evenly. Press the corresponding number of turns to complete the bite.

Forming 1 Adjustment of flat tube blank

The deformation of the first forming tube blank plays a pivotal role in the entire tube blank forming, and has varying degrees of influence on subsequent welding, deburring, and dimensional finishing, and must be given sufficient attention. When the motor unit makes the deformed tube blank head advance between 1 level and 1 vertical, carefully observe the shape of the deformed tube blank before starting the adjustment, make a preliminary judgment, and then form the belly draft of the adjustment plan.

(1) Observe the shape of the deformed tube blank. Including shape, appearance and degree of deformation:

① The shape should be regular and symmetrical;

② The appearance of the tube blank has no local over-rolling marks and surface crushing defects;

③ The edge of the tube blank is fully deformed, the arc is rounded, and the transition is smooth.

(2) Check the roll gap. Irradiate the light source from below the discharge direction of the tube blank to the feeding direction, check whether there is light leakage, and carry out targeted rolling.

(3) Observe the height of the edge of the tube blank. Adjust the centering of the tube blank in the pass by reversely adjusting the centering roller in front of the leveling roller. It should be pointed out that the height of the edge of the tube blank after the flat roll is not equal, not all caused by the misalignment.

Adjustment of forming 2 (including 1 vertical) to 4 pipe blanks

(1) Adjustment of the first vertical roll of the forming. The function is not to form, but to focus on the control of the direction of the tube blank. The force applied by the roll pass should not be large, and it is only necessary to maintain the force that the roll can rotate; and the thinner the tube, the smaller the applied force. When the head of the forming tube blank has come out of the first stand and has not entered the second level, stop to observe the alignment of the forming tube blank and the second flat roll pass, and make corresponding adjustments.

(2) Adjustment of lanes 2 and 3. The second and third rollings are the same as the first, and are also the actual rolling of the full width of the tube blank by the pass, which is the most obvious stage of the transverse deformation of the tube blank. The adjustment method and precautions are roughly the same as the first step.

(3) Adjustment of the 4th to 5th flat rollers. Although the 4th to 5th flat roll passes are also real rolling, they only perform partial real rolling on the middle and bottom of the tube blank, and only 20% to 30% of the contact surface between the pass and the tube blank is left, and the contact part is very easy. is rolled thin. Therefore, except for the special needs of the forming process, most of the time, attention should be paid to preventing the forming tube blank from being partially rolled down unconsciously.

At the same time, the used welded pipe machine should pay special attention to the symmetry of the forming pipe blank and the upper roll to prevent the edge of the pipe blank from interfering with the upper roll.

(4) Adjustment of the vertical roller group. Some forming units have vertical roller sets between the rough forming section and the fine forming section. The vertical roller sets have 2, 3 and 4 roller types, as shown in the figure below. In terms of forming effect, the vertical roller group can not only completely replace the function of the 4th or 5th forming flat rolls, but also play a more significant role in controlling and stabilizing the edge of the tube blank when deforming the thin-walled tube. There are three key points for the adjustment of the vertical roller group:

①The degree of deformation of the tube blank should be obvious. The vertical roller group can be adjusted according to the trapezoidal rule of deforming the edge of the tube blank, and the vertical roller group can be arranged on the two sides of the "isosceles trapezoid" tube blank, so that the tube blank can be uniformly deformed in the vertical roller group.

②Control the forming "drum bag". In order to suppress the occurrence of "bulging", the upper part of the vertical roller pass can be fully used to directly control the edge of the tube blank, and the lateral force on the edge of the tube blank can drive other parts of the tube blank to deform.

③ Width control of deformed tube blank. The key is to adjust the width of the tube blank out of the vertical roller group, narrow it a little, or even a "♡" shape, so as to ensure that the tube blank enters the closed-hole flat roll smoothly.

Adjustment of closed-port section

The adjustment of the closed-hole section roll and the tube blank should be carried out around the four "controls" of controlling the edge of the tube blank, controlling the springback of the tube blank, controlling the allowance of the tube blank and controlling the shape of the tube blank.

(1) Control the shape of the tube blank. Before the formed tube blank enters the closed hole shape, the shape of the formed tube blank is very different due to the different forming methods. Only after the closed hole shape roll is rolled, the shape of the formed tube blank can be unified into a basic cylindrical shape, while a basic cylindrical shape The shape of the tube blank is the direction and phased goal of our efforts. The closed hole rollers should be adjusted track by track according to the following steps:

The first step is to confirm that the tube blank before entering the closed hole shape has no indentation and scratches, and the tube shape is basically regular.

In the second step, based on the theoretical roll gap, press the tube blank in the closed hole shape with a large reduction amount, and then start the motor unit, about 1/3 of the turn of the roll.

The third step, freehand along any side of the outer surface of the tube blank, first slide through the roll gap from top to bottom, and then slide through the roll gap from bottom to top along the original road, repeat this 1~2 times, and judge the hand feel: If you don't feel the hand when sliding through the roll gap from top to bottom, and when you slide from bottom to top to the vicinity of the roll gap, you will feel the hand; at the same time, repeat the above actions on the other side of the formed tube blank. If there is a feeling of slap in the roll gap, and there is no smack when sliding across the roll gap from bottom to top, it means that the upper roll gap is on the left side.

The fourth step is to raise the upper roll by about twice the roll gap, loosen the tightening nut on the right side of the upper roll. As for how much to loosen, it is mainly judged by experience, and the nut on the left side of the upper roll is tightened.

The fifth step is to re-press the closed-hole type upper roller to the original position, and repeat the second, third and fourth steps until the surface of the formed tube blank is smooth and smooth no matter which direction it slides from, indicating that the hole type has been Correction, the tube blank is also corrected to a basic cylindrical shape, so as to complete the adjustment of the forming roll and the forming of the tube blank.

(2) Control the springback of the tube blank. For some thick-walled pipes with high rigidity, as well as high-strength and high-hardness pipes, controlling the rebound after deformation to facilitate subsequent smooth welding has become a problem that needs to be solved for such pipes. There are three ways to control rebound:

① Appropriately increase the rolling force of the first and second flat rolls;

② Appropriately increase the reduction of the closed-hole flat roll;

③ Appropriately tighten the closed-hole vertical roller.

(3) Control the allowance of the tube blank. As far as the round-to-square tube is concerned, if the cutting width is fixed, if the production of a square tube with a larger r angle is required, then the reduction amount of the upper roller of the closed-hole type can be increased, and the closed-hole type can be passed through the closed-hole type. The roller consumes more allowance, that is, in addition to consuming the forming allowance of the duty, it can also consume some shaping allowance (assuming the welding allowance remains unchanged), the circumference of the circle changing to the square moment is relatively short, and when changing the square moment The material running to the corner of the pipe is less, and the r angle is relatively round (r is larger); on the contrary, if the pressure is light, the r angle will be sharper accordingly.

(4) Control the edge of the tube blank. It mainly refers to preventing the "bulging" of the edge of the formed tube blank and the parallel butt joint of the edge of the tube blank in the subsequent welding; moreover, this is also the ultimate goal of welded tube forming. Obviously, if there are defects such as forming bulge, welding seam dislocation, ∨ butt, ∧ butt, lap welding, etc., it is directly related to the force deformation and symmetry adjustment of the edge of the tube blank in the open hole and closed hole. and indirect relationships.

"Four controls" should have their own emphasis in the trial production of used welded pipe machine, and should be adjusted according to the actual situation of the welded pipe production site, grasping the main problems and main contradictions. For example, in the forming of high-strength thick-walled tubes, the first solution should be to effectively deform the tube blank, maintain and deform the results, prevent springback, and realize parallel butt welding of the welds; for thin-walled tube forming, the primary problem to be solved becomes how to effectively Controlling the edge of the tube blank to prevent edge instability and forming bulges; for tubes with extremely high requirements on the outer surface, keeping the surface absolutely free from scratches and indentations is a problem that requires special attention when forming. If these problems exist at the same time, it is necessary to prioritize which problems should be solved in a targeted manner, and which aspects should be postponed.