Customer feedback from recent foundry installation projects featuring RFM ladles indicate superior performance and longer service life compared with traditional conventional steel or fibre laminate ladles in melting and casting operations.

Typical of successes reported include the case of one of Pyrotek’s leading die casting customers that had been experiencing short service lives of only two to six weeks with the fibre laminate ladles it had been using. Working closely with Pyrotek, new replacement AutoPour ladles using RFM technology were supplied, which now consistently achieve six months of service life and more than 150,000 shots. This customer has also reduced its oxide-induced scrap and improved cast repeatability from ladle to ladle.

Another die casting customer of Pyrotek wanted to reduce the process temperature in its dip well, and lower the holding temperature of the melt by a minimum of 25°F (13.8°C) from the previous level of 1420°F (770°C). Working closely with this company, the Pyrotek team proposed a process solution to incorporate a 30 kg RFM ladle which was accepted. The new ladle was installed in April 2008 and to date it is effectively reducing the metal holding temperature in line with this customer’s requirements. This brings process benefits of lower energy usage, reduced oxidation and hence less metal losses.

In general, customers have found that the non-wetting surface of Pyrotek’s ladles effectively prevents skull build-up. Metal build-up in the ladle can cause a short shot that leads to insufficient biscuit length. Since the robot removes the casting from the die by gripping the biscuit, inconsistent biscuit length can prevent proper robotic removal. This situation results in disruptive machine down time and the need for operator intervention.

Metal build-up in the ladle is also a prime cause of non-fill defects that result in scrap parts in the diecasting facility.
Skull build-up is avoided with the RFM ladles and the pouring volume remains the same, allowing a consistent biscuit length. Since their introduction, a range of foundry customers have recorded greater efficiency in robotic removal of castings.

RFM ladles are constructed from a low-density refractory composite material using a lamination process that results in tough products that are tolerant of mild mechanical abuse. The construction process allows the walls and base of the RFM ladle to be manufactured in complex shapes and with much thinner sections than usually associated with steel or cast refractory ladles, adapting better to the tight space constraints of the dip well and pouring envelope typical in many high-pressure diecasting facilities.

During manufacturing, RFM ladles are fabricated over a mould, and mounting hardware is placed and properly aligned with the aid of a fixture to ensure consistent location from ladle to ladle. The resulting consistent shape makes reprogramming unnecessary.

The shape of RFM ladles also contributes to their efficiency. When ladle shape is inconsistent, reprogramming of the ladle fill and pour parameters is required to maintain proper die fill.

With a high fracture resistance and a density of 1600 kg/m3 affording a good strength to density ratio, the RFM material is more durable in operation and offers superior insulating properties in comparison to many materials often used in this application.
Pyrotek’s RFM AutoPour ladles are supplied with a factory-applied finish of non-wetting ZYP Boron Nitride Lubricoat Blue to enhance ladle performance.

Process Advantages

    Light weight material
•    No pre-heating required
•    Low thermal heat sink
•    Excellent mechanical properties, including high fracture resistance
•    Excellent resistance to erosion
•    Excellent scull release
•    Non-wetted by molten aluminium
•    No iron contamination
•    Low maintenance
•    Reduced holding temperatures.

Examples of other products and systems exploiting the property advantages and process benefits that RFM delivers for aluminium melting and casting customers include: control pins; thermocouple protection tubes; melt skimmers; casting spouts, and the Pyrotek Metaullics Overflow Transfer System (OTS).