Analysis of the causes of the eight major defects that are easy to occur after hot-rolled boiler steel tubes are straightened and their treatment methods

First, the straightness of the hot-rolled boiler tube body after straightening does not meet the requirements.

1. Cause analysis: (1) The deflection value is too large or too small. 2) The reduction is too small.

2. Treatment method: (1) According to the specifications, materials, and curvature of the hot-rolled boiler tube, select the correct reduction and deflection value. 2) If the curvature of the boiler tube after straightening is greater than the curvature of the incoming material, it means that the deflection value is too large. If the curvature after straightening is less than the curvature of the incoming material (the straightness does not meet the standard), it means that the deflection value is too small.

Second, the curvature of the hot-rolled boiler tube head exceeds the standard after straightening, but the tube body does not exceed the standard.

1. Cause analysis: (1) The reduction is not enough. (2) The exit roller closes slowly.

2. Treatment method: (1) Adjust the appropriate reduction. (2) Adjust the delay of the exit roller closing to reduce the straightening blind area.

Third, hot-rolled boiler tube head flattening.

1. Cause analysis: (1) The straightening roller closes too early, causing damage to the tube head. (2) The amount of pressure is too large.

2. Treatment method: (1) Adjust the delay of the straightening roller closing. (2) Reduce the amount of pressure of the straightening roller.

Fourth, hot-rolled boiler tube tail damage

1. Cause analysis: (1) The deflection value is too large. (2) The angle of the entrance upper roller is too small. (3) Adjust the delay of the middle roller opening.

2. Treatment method: (1) Reduce the deflection value. If the incoming material is bent, appropriately increase the pressure of the exit roller and the middle roller. (2) Appropriately increase the angle of the entrance upper roller.

Fifth, hot-rolled boiler tube body correction

1. Cause analysis: (1) The angle of the straightening roller is too small or too large. (2) The straightening roller has no pressure.

2. Treatment method: (1) Appropriately adjust the angle of the straightening roller (find the straightening roller that produces the correction mark). (2) Appropriately adjust the amount of pressure of the straightening roller.

Sixth, the hot-rolled boiler tube body is scratched.

1. Cause analysis: (1) Sawdust remains in the entrance and exit tunnels. (2) The burrs on the tube end damage the lining plate in the tunnel, causing the tube body to be scratched.

2. Treatment method: (1) Clean the remaining sawdust in the tunnel and grind the scratched lining plate. (2) Replace the saw blade in time to reduce the burrs on the tube ends.

Seventh, the lining plate interface of the hot-rolled boiler tube outlet tunnel causes damage to the tube head.

1. Cause analysis: The lining plate interface is misaligned, and the hot-rolled boiler tube shakes in the exit tunnel, causing damage to the tube head.

2. Treatment method: (1) Grind and tidy up the lining plate in the exit tunnel. (2) Adjust the straightening parameters (such as increasing the deflection value, increasing the outlet pressure, etc.) to reduce the shaking of the boiler tube.

Eighth, the surface of the hot-rolled boiler tube body is crushed.

1. Cause analysis: After the side door of the outlet channel was opened, due to the problem of the L-shaped material hook and the sensor element, two steel pipes were placed on it. After the side door of the channel was closed, it pressed on the second boiler tube, causing the tube body to be crushed.

2. Treatment method: Adjust the position and sensitivity of the sensor element due to the L-shaped material hook.