Mechanical Technology January 2016

Mechanical Technology — January 2016

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Special report

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ounded in 1966 in the heart

of the chrome- and coal-rich

Mpumalanga province of South

Africa, Columbus Stainless is

Africa’s only producer of stainless steel

flat products and one of the few inland

stainless steel plants in the world not

connected to a major waterway. “This

site was built in close proximity to

chrome resources and low-cost power,”

begins Matthews. “While this disadvan-

tages us with respect to the logistics of

getting finished product out, we have

easy access to raw materials and we can

run on very low raw material stocks,”

he says.

Today, global stainless specialist,

Acerinox holds a 76% shareholding in

Columbus Stainless with the balance

(24%) being held by South Africa’s

Industrial Development Corporation

(IDC). “Our plant is a technologically

advanced, fully integrated, single-site

operation. This gives us flexibility to ad-

just quickly to changes in the market,”

Matthews points out.

At the starting point of the stainless

steelmaking process is stainless scrap.

“Stainless is the greenest of materi-

als, with 78% being recycled at

the end of a stainless product’s

life,” Matthews says. “In our

process, we melt scrap,

then add some chrome,

nickel and other metals,

according to the alloy recipe

being made. Eventually,

this is converted into sheets

and strips that are stamped,

pressed and welded to make

a host of different products:

for hygienic preparation surfaces

and storage systems; utensils and

containers for almost everything that we

eat or drink; stainless steel components

in critical areas of motor vehicles, such

as exhausts, airbag gas cylinders and

catalytic converters; and for decoration,

signage, shop fittings, architecture, fur-

niture, appliances and modern technolo-

gies such as hydrogen fuel cells.

“Goods manufactured in

stainless steel have a life

of 15 years or longer.

Then, after this time,

the steel comes back

into the plant for re-

processing into new

sheets – and there

is no limit to the

number of times

this can be done,”

he reveals, adding

that this is not just

hearsay: the lifecycle of

stainless steel has been

well documented through

studies at Yale University, for

example.

Stainless steel scrap is a high

value commodity for all stainless

MechTech

takes a tour of South Africa’s

Columbus Stainless plant in Middelburg

and talks to Lucien Matthews (right), the

company’s CEO.

At the heart of the 100 t electric arc furnace

(EAF) is a sophisticated in-house-developed

control system, which delivers composi-

tional control that is among the best in the

Acerinox Group.

Columbus Stainless: A plant tour

manufacturers and, while Columbus uses

as much as possible from local sources,

significant quantities of stainless steel

scrap is imported because there is not

enough in South Africa. “We also make

stainless steel by melting carbon steel

scrap – sourced from within SA – and

then blending that with chrome and

nickel as required,” Matthews adds.

Scrap and ferrochrome

Stainless and carbon steel scrap is accu-

rately sorted into grades in the stockyard,

where overhead cranes – connected to

the company’s in-house order manage-

ment and material flow software system

– weigh and load the required grades into

baskets for delivery to the 100 t electric

arc furnace (EAF).

At the same time, hot molten fer-

rochrome (charge chrome) is trans-

ferred from Samancor’s Middelburg

A basket of raw materials ready to be

loaded into the electric arc furnace

for melting.