There’s an element of art in every casting, but what is often overlooked is that there is an impressive degree of technical proficiency at work in the numerous castings made in foundries.

Ingenuity and new technological advancements are transforming todays’ metalcasting industry which has become innovative, high-tech, challenging, clean, and safe. Multiple processes have been developed in the industry where each process is specific to the metal used and the results desired. Within each process there are several variables that impact the design of final product. Today, castings are used in a number of markets in a variety of applications that range from manufacturing to home decor.

The diverse range of casting alloys and their flexibility offers the selection of most economical materials to fulfill the prerequisites of a specific application. Every single alloy has particular physical and mechanical characteristics, as well as its own casting properties, machinability, weldability, corrosion resistance, heat treatment properties, and other characteristics.

The metalcasting process today has become integral to the manufacturing industry and can be used to create complex geometric parts with relative ease, irrespective of the size of the part. Cast metal products are found in 90% of manufactured goods and equipment including critical components for cars and aircraft to home appliances and surgical equipment. Also, the process is very economical and generates little waste, which can be reheated and used again.

However sometimes it is the creativity and skill of an experienced foundryman that is needed to make one appreciate the ingenuity of metalcasting.

Last year Viking Foundry was tasked to cast an impeller for APE Pumps, part of a centrifugal water pump that is in operation at a local power station. So what you might say – these are everyday castings! In this case though a number of foundries had tried to manufacture the casting and had not succeeded – reasons not given.

Impellers come in various sizes and are used in a variety of applications and generally in harsh conditions, so this has to be taken into account. The material used in this instance was stainless steel CA15. The dimensions and the order for two-off is what was critical though.

Gross weight of the casting was 3 250 kilograms with a final nett weight of 2 180 kilograms. The casting had a diameter of 1650 mm and a height of 1200 mm with a vain thickness of 50 mm, a heavy centre boss and outer wall thickness of 110 mm.

Viking Foundry also manufactured the back covers, which work in conjunction with the impeller.

Last year Viking Foundry was tasked to cast an impeller for APE Pumps, part of a centrifugal water pump that is in operation at a local power station. The large and difficult impeller was cast in stainless steel CA15. Gross weight of the casting was 3 250 kilograms with a final nett weight of 2 180 kilograms. The casting had a diameter of 1650 mm and a height of 1200 mm with a vain thickness of 50 mm, a heavy centre boss and outer wall thickness of 110 mm

“Making the first mould and core assembly took us over a week and kept the team scratching their heads,” said Greg Estman, Production Director at Viking Foundry.

“However it was the experience of the team that made it work. Consequently the second casting was complete cast from start to finish in four working days and as a result of the quality that we achieved we are now in line to receive more orders,” continued Estman.

“With casting capabilities of over six tons in iron it’s not Viking Foundry’s biggest casting or most complex one but it is our most expensive casting ever in terms of the value of the metal used in one melt.”

“Viking manufactures various impellers of different sizes and materials on a day to day basis so the concept was nothing new. But this one was special because of its size, even with all the years of experience that our staff have in the foundry industry. The size certainly gave the guys a challenge.”

“Starting at the pattern shop the Viking team, including the methods men, moulders, melting and fettling all put their best effort into ensuring a near perfect casting. From ceramic pipes to special sleeves there was no costs spared in producing the impellers.”

For further details contact Viking Foundry on TEL: 011 873 5093 or visit www.vikingfdy.co.za