FR2703615A1 - Process for welding bells - Google Patents

Abstract

The invention relates to a process for welding a cracked, broken or damaged bell. The said bell is heated gently up to a temperature of approximately 600 DEG C, the latter is covered with a thermal blanket (heat mantle) allowing free access to the place to be welded, and then welding is carried out. Application in particular to bell repair.

Description

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  The present invention relates to a procedure for welding old bells which may have been broken, damaged or damaged.

which are simply worn out.

  Indeed, over time, a cioche wears out at the striking point of the leaf, which tends to dig This causes a change in the note and weakens the bell due to the lower sound obtained; of

  the more the metal around the striking point becomes hardened which has the effect of

  and to decrease the resonance time of the bell.

  One solution consists, to allow the bell to continue to be used, to ia turn a quarter turn so as to move the striking point, and to place inside a false bail for

  fix a leaf perpendicular to the first.

  This solution is neither satisfactory musically nor technically, because the bell remains fragile and can break De

  i 5 plus, this solution can only be temporary.

  If the wear is such that the bell breaks, it breaks or is

  damaged, for example that a hole is caused in the wall of ia

  bell, there are no other means than to break it and re-

melt to redo a new one.

  This operation is very dormaaeable for the patriioine in the case of an old bell presenting a historical or even sentimental value. There is currently a process for bringing in metal according to which we remove the work-hardened parts, we largely release the crack, we place a shape on the part to be brazed and we pour in the gap

molten metal.

  Attempts have also been made to repair broken or broken bells or

  damaged by welding, but the results are not always

  satisfactory because the heated bronzes crack locally notallim-

  those with a high tin content.

  it should be remembered that the bronzes used to make bells have a tin content of between 20 and 24 by weight relative to the total alloy: this is considered to be a very

high tin content.

  One of the aims of the present invention is therefore to provide a

  process for welding bells which allows them to make their sound

  originality without weakening them in any way.

  Another object of the invention is to provide such a method of supporting

  hard which allows to obtain a homozénêirté of the metai as perfect as possible. These goals and others that will emerge later are

  affected by a process to weld a broken or broken felium

  damaged which is, according to the present invention characterized in that one slowly heats this bell to a temperature of about 600 C, then covers the bell with a thermal mantle

  leaving free access to the place to be welded and welded.

  Advantageously, we weld with an arc system with the addition of metal i O in the form of a bronze wire whose constitution is also

  as close as possible to that of the bell alloy.

  Preferably, the temperature of the bell is continuously measured during the entire welding operation, the latter being stopped as soon as

this temperature reaches 450 OC.

  Advantageously, after completion of the welding, annealing by heating the bell to 600 ° C. and cooling it slowly for

  about 12 hours, up to room temperature.

  As has already been said, repairing a cracked or chipped bell

  broken or even perforated, or more generally having lost a substantial quantity of metal, is not easy and / or satisfactory according to the

currently known methods.

  Currently, only the recasting of a damaged bell allows

  to obtain a bell of homogeneous aspect having the desired sound.

  The present invention, to avoid recasting the bell.

  relates to a welding process in which a composite metal

  tion as close as possible to that of the bell is brought by welding. For this, the bell to be repaired is stripped beforehand by

  for example, by sandblasting and removing the damaged parts by

  Then, the bell is placed on a cradle to prevent it from deforming. The bell on a cradle is brought to a temperature of 60 ° C. by slow heating, in order to avoid the creation of internal tensions due in particular to large variations in thickness: this lasts approximately

6 hours.

  When the temperature of 600 C is obtained, the bell is covered with a thermal mantle co-posed, for example, with rock wool and asbestos, only releasing the end: it has to be welded.

  keep the bell at temperature and avoid a treiipe in the air ia-

  which would weaken the bell We weld quickly by MIG process

  under argon by bringing the metal in the form of bronze wire.

  The welding wire or the metal rod is a bronze, the tin content of which is as close as possible to that of the bronze.

the bell.

  The temperature of the bell is constantly monitored by a pyrometric probe, fixed on the bell and connected to a thermometer

  which permanently displays its temperature.

  I O When the minimum welding temperature, about 450 C is reached

  color, the welding operation is stopped and the bell reheated.

  When the welding is finished, we heat the bell again.

  calf at 600 C, then allowed to cool slowly in the oven to room temperature to anneal the metal and remove all internal tensions created by welding This operation

lasts about 12 hours.

Claims (5)

  1 Method for welding a broken or damaged felated bell characteristic   terrified by the fact that said bell is slowly heated to   a temperature of about 6000 C and then it is covered with a   heat shield leaving free access to the place to be welded and welded.   2 Method according to claim _ characterized by the fact that i'on welded with an arc system aiec addition of metal in the form of a bronze wire whose constitution is as close as that of the alloy of the bell.   3 Method according to claim l characterized in that the temperature of the bell is continuously measured throughout   the welding operation, this being stopped as soon as this temperature 1 D ture reached 4 O C.   4 Method according to any one of claims i to 3 characters   laughed at by the fact that after completion of the weld, annealing is carried out   heating the bell at 600 ° C. and cooling it slowly during   about 12 hours, up to room temperature.