Repair

 

 

Linings often require some form of repair to achieve its full potential.

Products

Most repair materials are relatively fine-grained chemically bonded products.

Area Product Name Product Description

Bond

Max service
temp.
/ °C

Plastics

Capram 60

Phosphate bonded high alumina zircon enriched plastic and repair mix Chemical

1600

Capram 70

Phosphate bonded high alumina plastic and repair mix Chemical

1700

Capram 90
High grade high alumina patching and topping material.
Chemical

1800

Repair materials

D10 Plaster

Alumino-silicate patching plaster. Chemical

1700

D10F

A finer version of D10 Plaster. Chemical

1700

D11

High grade high alumina patching material. Chemical

1800

Capram 90F
High grade high alumina patching and topping material.
Chemical

1800

Capram 90P
High grade high alumina patching material.
Chemical

1800


ProcedurePatching a Crack


The patching material should be smeared over any cracks, but should not be squeezed into cracks otherwise this can prevent the crack closing when the furnace is heated up (see digram right).

Short-former Repair

Lining lives can be extended by carrying out a short-former repair. This can be carried out on a lining that has worn by around half of its original thickness to leave a minimm of 30-50 mm of sidewall; this ensures that some protective unreacted powder is retained.

On the charge prior to the repair an alloy should be chosen to give minimum slag retention; it is also advisable to raise the metal temperature significantly(~50°C higher than normal) to remove as much residual slag as possible. The lining then needs throughly cleaning to remove metallic and slag impurities on the surface. It is usually advisable to remove the topping to gain better access to the lining.

A short-former is essentially a former without the base and typically 30-50 mm smaller in diameter. It does not need to be as thick as a full former: 3mm rather than 5 mm. It is located as vertically as possible and anchored in place. A ring of patching material is positioned at its base to seal it against the linng; this stops lining material from falling through to the bottom of the furnace.

The lining is then vibrated into place - typically by hand spiking because the former is not as robust and the seal will probably give way under strong vibration. The topping can then be applied as normal. We recommend that the lining should then be sintered by the liquid-sinter method with the usual pre-heat (30-60 mins) .