Recuperacion de los rolos de Bucler de tren laminador

FILL AND REFILL OF ATRITED ROLLERS WITH HARD MATERIALS

ABSTRAC
ELEMENTS: Lopper roller,curls’s former (photo 1)
SITE: Curls´s former of train ACINDAR FENICSE PLANT
PROBLEM TO BE SOLVE: Attrition, of rollers caused by rubbing and rolling with hot bar on high
speed (photo2)
ACTION TAKEN: arch and mechanized welding with hard material.
DESCRIPTION: the element that we are talking about isa simple soport roller in 2 bearing mounted in
the end of the balance beam with a pneumatic system that makes the curls, that avoid stretching, therefore
the roller is in contact with the bar turning by the dragging of the bar.
Sometimes the bar slides over de roller because there wasn’t enough pressure on the bar to the roller, this
causes minor speed or the slide in the surface of theroller.
Such slide or draft causes in the roller some damage like channels, that makes the job difficult, because
the bar doesn’t move properly specially at the exit where the bar comes out in vertical position that is,
stands on his minor face.
Originally the roller is specified in SAE1045 treated to 34/38 HRC. The normal lasting of this piece is 3
to 5 shift of 9 hours that means 30 to 45 hoursof work. Then it is re-mechanized to eliminate the ruts
produced by the attired until his diameter descends. After this process we continue to refill which was
made with several types of electrodes of high hardness without any results.
To raise the yield to this element we proceed to the refill with CTS 660B. The test was made on a worn
roller which was filled once with a basic electrode(AWS 7015) without any previous treatment.
An electrode of 4mm of diameter was used to give it one layer and it was mechanized in wheel.
The yield of this piece went up to 51 shift of work.
PROCESS DESCRIPTION:
The roller after beeing used shows some stamps.Proceeds to refilled with CTS 660B with 4mm diameter electrode with a welder at 155/160-A.
The electrode must be used as shown in photo 3,trying not to finish the cord half of the table. With a
complete passage with an electrode of 4mm diameter is enough to do 3 passages as shown in photo 4 and
5, that means 3 successive cords, the thickness is approx. Of 4mm on the top which after the attrition
leaves a 1,5mm of thickness.
To shape it was used a wheel at 448RPM with insertion of negative edge of ceramic as shown.Before agrinder was used to eliminate differences in the filling because the ceramic is not resistance to
blows.When this process was finished we begging to do passages trying to cut deeper in the first passage.After all surface is clean we proceed to a passage of 0,3mm with a wheel at 980RMP to achieve the
finish.An important point is the finish because the piece will last longer if the piece is thinner.Successive refills have been made on roller already refilled with the same electrode without changing the
properties, obtaining average durability in 35shift.

RECUPERACION POR MEDIO DE RELLENADO CON APORTE
DURO CON ALEACIONES CTS DE LOS ROLOS DE LOOPER DE
FORMADOR DE BUCLE
ELEMENTO A RECUPERAR:
Rolo de looper de formador de bucle – Tren Continuo – Acindar Plta. Fenicsa - San NicolásFoto 1
El elemento en cuestión es un rolo de apoyo simple en 2 rodamientos con una configuración tipo muñeco,
montado en el extremo de un balancín con accionamiento neumático que al levantarse obliga a la barra en
proceso a generar el bucle o lazo necesario para evitar el estiramiento. El rolo por lo tanto está en
contacto directo con la barra, teóricamente girando por el arrastre de la barra,aunque en muchos casos no
se produce el giro sino el deslizamiento de la barra sobre el rolo estático, por la escasa fuerza ejercida por
la barra sobre el rolo, lo que no genera movimiento o genera un movimiento relativo pero de menor
velocidad con deslizamiento en la superficie del rolo.
Este deslizamiento o giro produce por desgaste en la tabla de trabajo del rolo, improntas generalmente...