When the mixer truck raceway is working, in addition to the bending moment generated by the self-weight of the cylinder and the weight of the concrete, it is also subject to the torque generated by the rotating motion, and the force of the concrete in the mixer truck raceway along the circumferential and axial directions. Under the action of cyclic alternating load, the initial micro-crack will be formed in the area of high stress, and then it will develop into a macro-crack, and then the macro-crack may continue to expand, leading to the fracture of the welding track or the base metal. So, let's take a look at the causes of welding cracks in the raceway of the mixer truck and the use of damage prevention measures.

1.Mixer truck racewayCause Analysis and Countermeasures of Welding Cracks

At work, in addition to the bending moment generated by the weight of the self-weight and the weight of the concrete, it is also subjectMixer truck racewayThe torque effect generated by the rotational movement, as well as the force acting on the inner concrete along the circumferential and axial direction, are complicated. Under the action of cyclic alternating load, the initial micro crack will be formed in the area of high stress, and then it will develop into macro crack, and then the macro crack may continue to expand, resulting in the fracture of the welding track or base metal.

ImpactMixer truck racewayThe main causes of the initial microcracks are as follows.

1. Stress concentration at welding part

Reason: When the rail and the cylinder are welded, the stress concentration often occurs at the weld. In addition, during use, due to the concentrated load at the track and the ring and the overall deformation of the track section, stress concentration will occur at the weld.

Countermeasures: Grind the stress concentration weld, re-implement welding, and drill holes to cut off the crack source for the weld or base metal with macro cracks, and re-weld.

2. Residual stress of welding part

Reason: There is a difference between the stiffness of the track and the cylinder. Generally, for a steel plate with a thickness of 6mm, the radial thickness of the track is about 60mm, and the thickness of the cylinder and the track is very different. During the welding process, the thermal expansion of the track is limited, and the shrinkage during the cooling process is also limited, but the degree of limitation is much smaller than that of the track, which affects the uneven size and distribution of welding stress, resulting in the generation of residual stress.

Countermeasures: adjust the welding sequence to reduce the primary heat intake. During the welding process, copper hammers are used to knock the components. The vibration aging method is adjusted, homogenized and residual stress is removed. In addition, the weld is partially polished to reduce welding defects.

3. Stiffness change of track and cylinder

Reason: The rigidity of the track and the cylinder decreases with the use of the vehicle, especially the large-capacity mixer. The decrease of the rigidity will accelerate the fatigue damage of the weld and lead to the crack of the weld or the base metal.

Countermeasures: in the track groove and the cylinder contact with the internal welding reinforcement plate, improve the overall stiffness of the region, improve the fatigue fracture resistance of the welded structure.

Preventive Measures for Damage of 2. Mixer Raceway

1. Pay attention to the rated load: do not overload the rotary drive;

2. Correct selection: Select the appropriate rotary drive according to the needs, purchase the time of the rotary drive, strictly calculate the parameters of the rotary drive, and select the turntable bearing suitable for the actual needs. How to choose the rotary drive improperly, the rotary drive track is easy to damage

3. Pay attention to maintenance: maintain regular maintenance, and regularly add lubricating oil in the rotating drive. Reasonable maintenance and maintenance make the rotary drive track not easy to be damaged and extend the service life of the rotary drive.

The above is the mixer raceway welding crack reasons and the use of damage prevention measures. If you need to know more, you can contact us at any time! Our company has many years of experience and looks forward to your joining at any time.