Cutting of hoist reels with welding and in shafts

Cutting of hoist reels with welding and in shafts

II. Method of dividing the reel

The shell of the winding hoist drum, which is subjected to pulsating cyclic loads, has high requirements for fatigue strength. Over the years, reels have often cracked and shortened during operation, so it is important to split reels and weld them in the harsh underground environment.

Preparation before cutting

To the reel cutting position to add two support ring, like the picture shows this, is to avoid the reel cut, due to the cylinder shell internal stress, resulting in the contraction of the steel plate to the inside or towards the outside of the open, as well as to prevent the transport of other conditions during the period. The support ring is made of ∠80×80×8 angle steel hot simmered into a semicircle, embedded in the inner wall of the drum to form a round shape, followed by the structural form shown in the figure, the uniform specification of the gasket iron clamped around the two support ring welded to the wall of the drum. And there are two additional support ring, one to prevent the axial to the cutting centre of the geometry of the gradual change; the second is in order to be able to adapt to the needs of the lifting distance of the more entangled steel rope to remove the wood lining. In addition, in the position of the radial counterparts of the reel, four stretchers are welded on, which are made of steel rails (24 kg / m). In this way, the alignment of the circumferential direction can play a fundamental role. And, it also prevents collision deformation during transport. At the same time, the strength of the reel is increased accordingly.

2. Cutting

After all the support ring and tie bar welding is completed, carefully check the two halves of the coil steel plate docking to become a round situation, after confirming that there is no error, half of the coil counterpart down on the platform placed in a smooth manner, to brake the big side as a benchmark, draw a good circumference cutting line, and then began to intercept the waist cutting. Cutting is best carried out by two welders from the middle of the same time to both sides of the implementation of the cut, the end of the cut can not use cool water for cooling. It should be cooled naturally and the cut should be made in the position as shown in the figure.

III. Welding of reels

1、Assembly to find the right

Before assembly, the four rail ties are cut off, then the reel sub plate and the hub are aligned and assembled in good condition, then the two middle rings are installed in the manner shown in the figure, after which the bolts are tightened and the spindle is mounted, then the reel is climbed and turned, and the out-of-roundness of the outer circle of the reel is measured as well as the straightness of the counterpoise is measured, and if there is no deformation, then it is possible to carry out the welding. During the installation of these four hoists, deformation of the shell was only found in the XKT hoist installed in 1973, as shown in the figure.

Thought from the deformation situation analysis, the deformation is in the cutting of four bars after gradual changes, and in the cylinder shell rolled into the process of forming the stress is not fully released, and in the external force under the welding moulding reason, and then lead to the drum in the cut after the removal of the bar when the deformation.

Handling of deformation

In dealing with the situation of inward contraction and deformation of the reel shell, the approach adopted is to use, more than one hydraulic jack to symmetrical support, presented is such a situation, as shown in the figure.

First let the jack produce the initial support force to tighten the shell, then in the outer surface heating, heating while increasing the support force, until the cylinder shell counterpart axis parallel to the AB line, you can stop heating, at this moment still allow to increase the support force, so that the deformation of the position of the surface of the cylinder shell than the other surfaces are higher than the other surface of the 5 to 7 mm, and then gradually reduce the support force, experience has shown that, in the temperature basically reaches room temperature, deformation of the position still Need to be higher than other surfaces 2 to 3 mm, so after welding, the outer surface of the cylinder shell unevenness in ± 1 mm or so, into a round effect is better. It should be noted that when heating the deformed position, the heated part should be 50 to 80 mm wider than the deformed trace line, and the whole heating line should follow the direction of the trace line, so as to form a heating band.

soldered

Reels for inclined shaft lifting are not only subjected to a wide range of stresses, but also have a high risk of deformation of the shell or cracks in the weld due to the quality of the weld and the process being unsuitable. Moreover, the welding requirements for the four halves of a circle are even more stringent. After 4 sets of hoist installation, there are the following experience:

(1) Welding materials

The material of the shell cylinder is 16Mn, according to the manual, for the junction 506 of x 108 Pa and the junction 507 of the welding material, we feel that the carbon content of the material itself is inclined to the upper limit, and the carbon content is also high, which determines the weldability of the base material itself, in addition to the tendency to weld cracks, in the objective aspect.