There is a saying that roughly goes by the general wording: The whole is greater than the sum of its parts. The problem with this though is that without quality parts, the whole has no chance of being truly greater than the sum of those parts. If one poorly manufactured component fails, it won’t matter, because the whole becomes dysfunctional. This couldn’t be truer for heavy duty primary crushing equipment and the team that was assembled to conceptualise and create a colossal casting for export to Europe.
The gyratory crusher full ring spider cast by Sarco. It is the biggest steel (BS3100 A2) casting Sarco has made since entering into the general engineering castings sphere. The casting was made in the newly enlarged 7.8m x 7.8m pit, with a pouring weight of 55 tons using a tandem pour method
South African Roll Company (Sarco) has long been recognised as one of the leading international manufacturers of castings used in the steel and non-ferrous manufacturing industries and has been manufacturing castings since 1947. With a new focus on heavy engineering castings and a dedicated heavy engineering castings floor, Sarco was the foundry choice for a European client of SSS Group of companies, specialists in crushing equipment, seeking a gyratory crusher full ring spider.
“In 2016 Sarco expanded their casting capabilities to service the local and international heavy engineering sector. A combination of sophisticated equipment, the latest technology, together with skills and experience acquired through over half a century in the business, positioned Sarco amongst the world’s leading roll manufacturers currently available to the steel industry,” explains SP van der Walt, Sales and Marketing Manager at Sarco.
Machining of the gyratory crusher full ring spider
A gyratory crusher has a crushing chamber designed to accept feed material of a relatively large size in relation to the mantle diameter. Their primary use is for initial size reduction to convert large materials into smaller ones. Ore is typically transferred by haul trucks which discharge the material into a feed hopper at the upper level of the crusher moving vertically downward past the spider assembly which supports and houses the upper main shaft bearing. Material is then crushed and this ore is then discharged from the bottom shell assembly at a significantly reduced size, ready to be further refined.
The actual crushing action is produced by the oscillation of the gap between the moving mantle liner, mounted on the central vertical shaft, and the fixed concave liners mounted on the top shell of the crusher. It is the mantle and concaves from the working surfaces of the crusher that produce the force required to crush the ore.
“With a team dedicated to the heavy engineering castings side, we have employed a dedicated sales and marketing, and technical team that has taken control of the production side.”
Sarco have three furnaces with capacities of 22 tons each, one 5 ton, one 3 ton and one 12 ton unit giving the company a combined capacity of 20 000 tons in a year. The foundry has six coreless induction furnaces with a total capacity of 86 tons. The company can manufacture castings from 450 kilograms up to 85 tons.
The size of the casting is evident in this picture
“Initially when we introduced the concept of manufacturing heavy engineering castings into the foundry, all of these castings were done in the same pits and floor space as the mill rolls. Experience taught us that we had to separate the departments and now the general engineering castings department has its own pits, which have been upgraded, and floor space.”
“Additionally, we have ramped up the skills of the staff in this department with an emphasis on those that are on the foundry floor. They have advanced methoding courses and others on foundry practices.”
“Our predictive metal analytics software is also used in the casting process. The software determines the liquid metal solidification morphology and quality. Sarco is ISO 9001:2015, ISO 14001:2015 and OSHAS 18001:2007 accredited. The Quality Assurance department has strict procedures for planning, manufacturing, testing and document control.”
The team involved in the project included Sarel van den Heever (Project manager of Spares, Supplies & Services), Peter Pienaar (Director of Spares, Supplies & Services), Albie van der Walt (specialist consultant), SP van der Walt (Sales and Marketing Manager of Sarco) and Ettiene Boshoff (methods engineer at Sarco)
This expansion into heavy engineering castings has afforded Sarco, along with the help from a team comprising of Sarel van den Heever (Project manager of Spares, Supplies & Services), Peter Pienaar (Director of Spares, Supplies & Services), Albie van der Walt (specialist consultant of Ascast), SP van der Walt (Sales and Marketing Manager of Sarco) and Ettiene Boshoff (methods engineer at Sarco), the opportunity to produce the “gyratory crusher full ring spider”.
It is the biggest steel (BS3100 A2) casting Sarco has made since entering into the general engineering castings sphere. The casting was made in the newly enlarged 7.8m x 7.8m pit, with a pouring weight of 55 tons using a tandem pour method.
With the help of methods engineer Ettiene Boshoff and a specialist consultant, a solid casting with almost no upgrading required was achieved. The casting has an OD of 5.2m x 1.3m in height and will be exported to Europe.
Sarco MD, Harold Pretorius, said: “Strategically the decision was made to expand our general engineering casting division and this casting is an important step in the right direction.”
Spares, Supplies & Services
Amongst the parties involved in the project were the highly respected Spares, Supplies & Services
(SSS Group of Companies). SSS have been specialising in crushing equipment for more than 20 years and since inception, they have successfully repaired most major components on cone, gyratory and jaw crushers. As far as possible, all components are restored back to original and OEM specifications to ensure compatibility with spares available from OEMs. Welding, heat treatment, NDE testing and machining stages are monitored and documented to ensure sound and acceptable engineering practices. Mechanical repairs of components up to 20 ton capacity can be handled, but for larger components, such as the gyratory crusher full ring spider, outsourcing is necessary.
The final product loaded on a low-bed trailer ready for delivery
Everything is manufactured from approved drawings and material specifications as per the OEM specifications. Quality requirements as per the manufacturing processes are strictly adhered to and certification issued as required. SSS has also diversified over the years in terms of the products and components repaired or manufactured. SSS are not just limited to crushers and now have experience with a number of other heavy duty equipment.
SSS is now working with Sarco to produce castings with improved delivery times, reduced upgrading cycles and improved methods.
A comment from the customer: “This is one of the cleanest castings we have seen in the 20 years we have been specialising in crushing equipment. It is not every day that you get a casting of this complexity with such a small amount of upgrading.”
Ascast
Ascast, established in 2020, is a foundry and machine shop specific consulting company that brings together a combination of industry experts in order to be a complete foundry and engineering industry consultation group. Ascast specialises in casting materials, methods, refractories, patterns and processes for both foundry and engineering companies and is run by specialist consultant Albie van der Walt.
For further details contact Sarco on TEL: on 016 910 7000 or visit www.sarco.co.za
