Wagstaff Table Top Refractory
- why Pyroform HP™?

There are many reasons why Pyroform HP™ is the only refractory material approved by Wagstaff for use on their billet tables. The following information explains why Pyroform HP™ has significant benefits when used in Metal Delivery Systems in addition to Wagstaff billet tables

Pyroform HP™ has significantly lower conductive heat losses compared to both fused silica and high density castable materials. Because Pyroform HP™ has an extremely low thermal mass, it also takes much less energy out of the metal at the start of the cast. Together, these properties can achieve the following:

IMPROVED METAL QUALITY

Less Hydrogen (H2) Absorption: As metal temperatures decrease, the volume of H2 taken into solution decreases dramatically. At typical aluminum casting temperatures, a 45ºF (25°C) temperature reduction can result in more than a 20% reduction in the metal's capacity to absorb H2.

Fewer Oxides Generated: Lower furnace temperatures result in a lower rate of oxide (Al2 O3) formation. This reduces both the likelihood of oxide inclusions in the cast product and the percent of melt loss.

Fewer Starting Defects: Many casting defects occur at the start of a cast. Defects associated with cast start include cracking, freeze-ups, hot tears, bleed outs, and cold lapping. All of these defects can result from poor temperature control. Pyroform HP™ minimizes the potential for these defects by providing very consistent starts. By eliminating the variables of launder preheating and "Super-heating", Pyroform HP™ provides a small, highly predictable and consistent temperature gradient from the furnace to the casting center, from the first mold position to the last. By reducing the temperature drop across the casting center, Pyroform HP™ gives the operator a larger "window of casting success." Temperature drops of less than 0.3ºF/foot (0.5°C/meter) of launder can be achieved with Rex Materials Metal Delivery Systems.

Near Zero Chance of Inclusions: The bulk density of Pyroform HP™ is significantly less than that of molten aluminum. If by chance a small piece of Pyroform HP™ is dislodged, it will float to the surface and remain in the skull.

ENERGY SAVINGS

Reduced Holding Furnace Temperature: You will be able to reduce your holding furnace temperature by as much as 45-90ºF (25-50°C) when compared to a launder system using other materials. The energy savings alone can provide a significant cost reduction. Lower furnace temperatures also provide the metallurgical benefits described above.

Eliminate Launder Preheating: Pyroform HP™ absorbs so little energy at the start that pre-heating of the launder can be eliminated except when drying is required. This may provide a reduction in process cycle time.

Reduce or Eliminate "Super-heating" for Starts: Plants are often required to "super-heat" their metal either on the surface of the holding furnace or in the degassing unit to compensate for heat losses at the start. Pyroform HP™ contributes to easier cast starts by reducing the chance of freeze-ups due to cold metal, while reducing or eliminating the need to "super-heat" the metal. This also avoids the possibility of casting delays while waiting for the metal to heat up.

LOWEST REFRACTORY COST PER TON OF METAL

Extremely long refractory life is achieved because of three factors: 1) the abrasion resistance and non-wetting properties of Pyroform HP™, 2) the stable steel shell provided by the Rex Materials design, and 3) the launder design which reduces the need to scrape the launder after the cast. Based on refractory cost per ton cast, Pyroform HP™ is a great value! At plants where the Rex Materials Metal Delivery Systems have been in heaviest use, over 500,000 tons of metal have been cast through these systems at operating costs of less than $.02 per metric ton.

IMPROVED SAFETY AND WORK ENVIRONMENT

Pyroform HP™ provides several desirable improvements to safety and ergonomics in the work place:

Reduced Steel Shell Temperature: Worker safety is improved by reducing the external steel shell temperature to a level where burns do not result from incidental contact. Covered Troughs: Launder covers, in addition to further reducing heat losses, also reduce the possibility of workers accidentally coming in contact with molten metal. Little or No Open Flame Preheating: Workers have less exposure to open flames.

Rapid Refractory Cool Down: A Pyroform HP™ equipped launder is better to work around after the cast because it cools much faster than fused silica or castable types due to its lower thermal mass. Light Weight of Sections: Fused silica weighs 60% more than Pyroform HP™. High alumina castable weighs more than twice as much. The potential for back injuries, pinched fingers and other injuries increases with the increase in weight. The installation process is also expedited by eliminating the need to use cranes or other lifting devices.

REDUCED DOWN TIME AND LABOR COST

Due to the modular design and light weight of Pyroform HP™ refractory sections, they are fast and easy to install and replace. The modular design also allows for the replacement of just one section rather than the whole launder. The need for costly and time-consuming bake-out or curing procedures is also eliminated.