Optimising investment casting at Ceracast

Postmasburg, Northern Cape might be a little out of the way and not a weekend getaway for most living in the main South African metropolises – the driving distance between Johannesburg and Postmasburg is 608kms and from Cape Town it is over 900kms – but it is in the heart of manganese and iron ore mining ‘country’ in South Africa. The Northern Cape province produces almost all of the manganese mined in South Africa. Tungsten, zinc, lead, asbestos and limestone are also extracted at other locations in the Northern Cape.

Casting taking place at Ceracast

There are some more familiar names associated with the area. These include Anglo American, Sishen, Khumani, Kolomela, Beeshoek and African Rainbow Minerals. A not so familiar name in the area but important in terms of manganese mining is Hotazel and not far to the north west is the Kalahari and the Kgalagadi Transfrontier Park. More recently a whole new town – Kathu – has sprung up around the mining activities spread across the area.

The Sishen Mine and the Kolomela Mine both have Anglo American Plc ownership and between them produced an estimated 37 MTPA of iron ore in 2020. The Sishen mine is owned by Kumba Iron Ore, which has a 73% interest in the Sishen Iron Ore Company Proprietary Limited (SIOC). Anglo American plc has a 64.3% stake in Kumba Iron Ore. Other stakeholders in the Sishen Iron Ore Company include Exxaro Resources Limited and ArcelorMittal SA (Amsa).

Rock drill bits – products made by Ceracast

Khumani Mine and the Beeshoek Iron Ore Mine, both owned by African Rainbow Minerals, produced somewhat small amounts in comparison – 16 MTPA. Mines will operate into the late 2030s and early 2040s. With reserves at over 2.5 billion South Africa does not even feature in the top 7 iron ore producing countries. Australia heads the list with approximately 48 billion tons of reserves.

Nonetheless mining is a very important and large contributor to the Northern Cape Province area and many are within a 50km radius of Postmasburg.

Of all the metals that make modern life possible, steel is the most widely used and iron ore is its main ingredient. Iron ore is needed for train tracks and other types of infrastructure, which is one reason for the great demand from emerging economies such as China and Brazil. It is used in the construction of buildings and bridges, and manufacturing of vehicles and many household appliances.

Stainless steel castings made by Ceracast

But it’s also used in medicine, cosmetics, engineering, paint and a whole range of products we need for modern life. Technology is demanding increasingly sophisticated forms of steel. Manganese is a vital component of stainless steel and many advanced alloys.

These minerals and the products form an integral part of the foundry industry weather it is input material or produced castings. Of course as many say in the foundry industry if it were not for all the different castings produced many products that surround you or are used on a daily basis by yourself would not be in existence.

These mines in the Northern Cape Province and the downstream industries are huge consumers of castings. Large equipment used in the rough and testing terrain and environment have many wear parts and components, big and small, that can reach a lifespan or have a mechanical breakdown.

Establishment of Ceracast
Ceracast was established in the Northern Cape Province town of Postmasburg in 1984 and ran as a family run business until 1995 when the family sold the company to Boart Longyear, a wholly owned subsidiary of Anglo American. However, after over 30 years of Anglo American’s ownership, Boart Longyear was considered a non-core asset for the Johannesburg-based mining company. In 2005, Boart Longyear was divested by Anglo American and acquired by the private equity firms Advent International, Bain Capital and several management investors.

A stage in the investment casting process

This offered the local management of Ceracast, which had only been in the Boart Longyear stable for 10 years, the opportunity of a management buyout and that same year Brian Richardson, Gerhard Claassens, Gerard Kloppers, Stephan Kloppers and Jean Kloppers acquired the company.

Up until then the bulk of Ceracast’s business had come from the local mining sector, to which it supplies hundreds of thousands of consumables every year – from coal borers and taper bit bodies to jackhammer components and conveyor belt scrapers.

Ceracast was one of the first foundry related companies to offer investment castings to the South African mining industry and has since captured a sizeable portion of the mining market by offering high-integrity castings, ready for use, or with a near net finish in conjunction with machining to exact dimensional tolerances and metallurgical specifications. The company now specialises in the manufacture and supply of high-volume ferrous castings weighing as little as three grams up to 9kgs.

Castings that have exited the furnace

“Although geographically far from the larger market places, Ceracast competes successfully for its market share throughout South Africa and especially in the Gauteng province. Product in stock can be delivered overnight to customers in Gauteng,” explained Gerhard Claassens, Managing Director of Ceracast.

“Often a mechanical breakdown is caused by one of the smallest components that make up mining related equipment and to order in these components from Johannesburg or further afield could delay mining and production operations unnecessarily. So locally in the Northern Province and surrounds we are well placed to service customers.”

“I was one of the original management buyout team and have been with the company since I left school in 1987 after matriculating at the Technical High School in Kimberley, which is about 200kms from Postmasburg and famous for its diamond mining, another product of mining that Anglo American, De Beers and the Oppenheimers have dominated.”

“My first job ever and still is was at Ceracast in the tool and die making department. I then went on to production development and was then appointed Foundry Manager before becoming Operations Director and then Managing Director.”

The wax room has six wax presses with PLC controls making die changes possible within minutes

“Most of my experience has come through on-the-job working. However, I did later on in life continue studying and in 2011 was awarded my BCom degree through Unisa.”

The truth about investment casting
“Although it is one of the world’s oldest metal casting technologies, investment casting (sometimes known as lost wax casting) has been subjected to a few misconceptions over the years. Ironically, these misconceptions probably have caused many people who could have benefited most from this process, to rule it out.”

“People seem to misunderstand some of the distinguishing points about investment casting that make it an ideal practice for making certain components. The truth behind the misconceived notions about the investment casting practice are saving our customers time and money.”

The dipping process at Ceracast

“Our customers enjoy cost savings when productivity increases by enabling them to eliminate machining and production time in the construction of parts that would be difficult to produce through any other casting practice.”

Not just for casting iron
“Possibly one of the most basic misunderstandings about investment casting is that it is used principally to cast iron parts. This is pretty incongruous when you think about it. Although you can use the process for iron, you can use it for just about every other metal but iron.”

“Investment casting is the precision casting of metal shapes using several steps, using a heat-disposable pattern by injecting wax into a metal die. When the assembly is heated, the wax escapes through openings in the outer mould, leaving a cavity into which the molten metal is poured.”

The autoclave at Ceracast

“These replicas, called patterns, are injection moulded in metal dies. A number of patterns are attached to a wax stem/runner bar to form a cluster/tree. After cleaning, the trees are immersed into a ceramic slurry and then covered with a fine fire-resistant stucco. After a couple of layers, the shell is allowed to dry. When the shell is completely dry, the wax is melted out in a high-pressure steam autoclave, leaving a hollow void within the mould, which exactly matches the shape of the assembly.”

“The shell is allowed to cool and the ceramic shell is broken off and the parts are cut off from the runner bar. The castings are shot blasted with high-pressure sand and water and then the castings are cleaned and in-gates removed by a grinding process. The castings then run past a rigorous quality check and are then stored for dispatch.”

“All of the above in short boils down to: A die which is the negative of the casting which produces a positive pattern. A ceramic mould which is formed around the wax pattern and when dewaxed leaves a cavity which creates the positive casting when cast.”

Offer more than a casting service
“We have also learned that it is no good just offering a casting service. You have to add value before and after casting.”

“For example, our tool and die making facility caters for manufacture and maintenance on tools and dies. We also have CNC die sinking, spark erosion, surface grinding and jig boring machines and these are used to manufacture the tools and dies to suit our manufacturing processes, as well as machining operations where they are required.”

The drying process

“Another example is our heat treatment plant that caters for customers that require annealed product for easy machining. We do specialised heat treatment in salt baths on products that are machined in house. These are mainly for hard rock mining tools. These rock drill bits are cast, heat treated, machined and fitted with tungsten carbide inserts in our CNC machining department.”

“The extensive knowledge gathered over the years of servicing the mining and quarrying industries has been used in the design and manufacture of our drill bit and borer range. Our Hardrock and Softrock customers are serviced nationally and internationally with our network of representatives and agents.”

“The foundry has a capacity of 14 000kgs per month and castings volumes of 90 000. The wax room has six wax presses with PLC controls making die changes possible within minutes. Two 380kg capacity furnaces are used in the foundry for low and medium carbon steels, 304SS, 3CR12, 310SS and 316SS.”

“Ceracast is growing it’s stainless steel market share. Currently 60% of the tonnage we produce monthly is stainless steel castings.”

The tool and die making facility caters for manufacture and maintenance on tools and dies. The department has CNC die sinking, spark erosion, surface grinding and jig boring machines

“We are confident of our product quality because we’ve managed the process in-house from the time the raw material enters our factory, to the time the end-product is dispatched to the customer. We also have a proud quality record and material certificates are available for every cast should the customer require batch material certificates.”

“Currently we employ 42 staff. For a private company in this part of the country this is an achievement, despite the boom in commodities and minerals. Mostly the mines would be serviced by multinationals but our service and quality record over the last 38 years speaks for itself.”

For further details contact Ceracast on TEL: 053 313 0667 or visit www.ceracast.co.za