RU2027782C1 - Method to repair a workpiece - Google Patents

Abstract

FIELD: electric metallurgy, in particular, to produce multi-layered slabs by electroslag smelting, as well as to repair slabs, surfacing of which was interrupted. SUBSTANCE: carried out is oncoming surfacing on a slab, installed at an angle to horizon, with a section surfaced earlier by electroslag surfacing. Butt zone of surfaced layers is fused at immovable slag bath, with consumable electrodes oscillated between ends of oncoming surfaced layers with 8 - 20 frequency oscillation, 80 - 12- mm amplitude. EFFECT: workpiece repairing. 1 dwg

Description

 The invention relates to electrometallurgy, in particular, for producing multilayer slabs by the method of electroslag surfacing and can be used to repair slabs, the surfacing of which was interrupted.

 A known method closest to the proposed and taken as a prototype, according to which electroslag surfacing using melting electrodes of the horizontal surface of the workpiece is carried out with the oscillatory movement of the electrodes.

 The disadvantage of this method is that in the case of a forced termination of the surfacing process, it is impossible to resume the surfacing process at the place where it was stopped. At the junction of the end of the previous surfacing and the beginning of a new surfacing, non-fusion will take place, since it is impossible to warm enough the end zone of the previous surfacing. Thus, in the case when the surfacing is forced to interrupt, the slab remains unfinished and completely rejected.

 The purpose of the invention is to increase the yield due to surfacing of an unfinished billet.

 Figure 1 shows a diagram explaining the method at the beginning of the process; figure 2 is the same at the time of termination of the slag bath; figure 3 is a view of the workpiece with a deposited layer.

 The method is as follows.

 On a slab 1, installed at an angle to the horizon and having a section 2 previously deposited by the method of electroslag surfacing, a metal layer is deposited by electroslag surfacing by moving a liquid bath 3 on the slab surface, bounded on three sides by the walls of the mold, and below the surface of the slab. Consumable electrodes 4 are fed into the slag bath. Surfacing is started from the lower end of the slab, free from surfacing, towards the already existing surfacing. During the surfacing process, the volume of the slag bath remains relatively constant and the level of the slag bath relative to the upper edge of the mold takes a constant height. Therefore, upon reaching the slag bath of the area where the onset deposition begins, an increase in the level of the slag bath relative to the upper edge of the mold 5 is obvious due to the displacement of the slag bath with a layer of the overlay, which sinks into it as the slag bath moves. With further movement, the oncoming overlay layer 6 will displace the slag bath so much that it rises above the upper edge of the mold and will leak. Therefore, the process of moving the slag bath is stopped at the moment when the level of the slag bath rises above the upper edge of the oncoming surfacing end to a height of 15-20 mm, but does not reach the upper edge of the mold by the value A (see figure 2). After this, the process of remelting the electrodes is carried out until the gap is limited by the mold and the end face of the on-site surfacing.

· [V·Z] =

S₂= S_PNMO= S_{Δ NMP}+S_{Δ PMO}=

+

= 3δ $\genfrac{}{}{0ex}{}{\text{2}}{\text{Н}}$ tgα
где δ_н - толщина наплавки;
δ_к - толщина кристаллизатора;
α - угол наклона сляба.The remelting process can be carried out until the level of the slag bath rises to such a height that it reaches the upper edge of the mold, i.e., it does not rise relative to the mold by a distance A. Thus, the value of A is determined by the amount of space that needs to be melted. Since the length of the slag bath and the space filled with metal is the same, the equality S ₁ = S _{2 is} ensured (see Fig. ₂ ). From figure 2 it follows that
S ₁ = S _KLXV =

· [V · Z] =

S ₂ = S _PNMO = S _{Δ NMP} + S _{Δ PMO} =

+

= 3δ $\genfrac{}{}{0ex}{}{\text{2}}{\text{N}}$ tgα
where δ _n is the thickness of the surfacing;
δ _to - the thickness of the mold;
α is the slope angle of the slab.

= 3δ $\genfrac{}{}{0ex}{}{\text{2}}{\text{Н}}$ tgα
Величины δ_н, δ_к, α - величины, заданные конструктивно и технологически, т. е. величина А, являющаяся параметром, задающим момент прекращения перемещения шлаковой ванны, поддается определению, но практически величина А берется равной 25-10 мм при толщине наплавки 20-50 мм и высоте кристаллизатора 100-150 мм.Thus, it is obvious that

= 3δ $\genfrac{}{}{0ex}{}{\text{2}}{\text{N}}$ tgα
The values of δ _n , δ _to , α are the values given structurally and technologically, that is, the value of A, which is a parameter that determines the moment the cessation of the movement of the slag bath is stopped, can be determined, but practically the value of A is taken equal to 25-10 mm with a thickness of 20 -50 mm and a mold height of 100-150 mm.

 In the process of remelting the consumable electrodes and filling the joint zone of two layers of surfacing, the surface of the end face of the opposing surfacing will be heated less than the footboard of the base metal of the slab and the end face of the newly deposited layer. Therefore, in order to avoid non-fusion, it is proposed that the consumable electrodes oscillate from the end face of the newly deposited layer to the end face of the on-site surfacing during remelting to uniformly heat up the entire surface of the fused space. The amplitude of the oscillation should eliminate contact between the electrodes and the slab.

 PRI me R. The slab is installed on the installation for surfacing slabs in an inclined position by the method of electroslag surfacing, and the part of the slab, on which there is a section with a deposited layer, is at the top. The slab is set at the same angle at which the partial surfacing of the slab was carried out. They induce a slag bath, lower the consumable electrodes, and begin the normal surfacing process.

The surfacing process is carried out until the moment when the slag bath reaches the end of the onward surfacing. After that, the speed of movement of the slag bath is reduced to 0. In this case, the movement is stopped completely when the level of the slag bath occupies a level 10-20 mm from the upper edge of the mold. At the same time, the supply and remelting of the electrodes in the slag bath is continued. At the same time, oscillations of the consumable electrodes begin with an amplitude of 100 mm with a deposition thickness of 20-30 mm and an inclination angle of 20-40 ^o , but in such a way that the electrodes do not reach the ends at a distance of at least 50 mm.

 The oscillation frequency is set equal to 8-10 oscillations per minute.

 After that, an increase in the level of the slag bath is observed, and when the level of the slag bath reaches the upper edge of the mold, the process is stopped.

 At the end of the process, the deposited layer has the form shown in Fig.3. The influx is removed mechanically, after which the slab is sent for further redistribution.

Claims (1)

 METHOD OF PREPARATION REPAIR, including electroslag surfacing of the horizontal surface of the workpiece with a fixed upper mold using melting electrodes that oscillate, characterized in that, in order to increase the yield due to surfacing of the unfinished workpiece, they counter-weld on the lower side of the unfused surface of the workpiece installed at an angle to the horizon, at the end of which at the moment the slag bath touches the upper edge of the front wall of the mold at a height 10 mm away from its edge, the surfacing speed is reduced to zero and longitudinal vibrations of the melting electrodes are produced with a frequency of 8 to 20 vibrations per minute and an amplitude of 80 to 120 mm.

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