liberty speciality steels accelerates production of ultra

Liberty Speciality Steels accelerates production of ultra-clean speciality steels with new vacuum induction melting furnace

Reprint from „MPT International“ (2017), issue-no. 4, page 48 – 53.

2

LIBERTY SPECIALITY STEELS

Liberty Speciality Steels, Stocksbridge, Sheffield, UKContact: www.libertyspecialitysteels.comE-mail: [email protected]

SMS group, Düsseldorf, GermanyContact: www.sms-group.comE-mail: [email protected]

3

At its Stocksbridge, Sheffield site (South Yorkshire, UK), newly formed Liberty Speciality Steels is improving its specialist alloy manufacturing facilities by increasing production levels at the VIM X-eed® vacuum induction melting furnace supplied by SMS Mevac. This new met-allurgical facility produces high-purity steels and spe-ciality alloys for extremely demanding applications like aerospace, motorsports and oil & gas. These facilities are coupled to a unique integrated mill, machined part and service centre offering, and are supplied globally as ingot, bar, cut piece or machined part.

Liberty Speciality Steels accelerates production of ultra-clean speciality steels with new vacuum induction melting furnace

Liberty Speciality Steels – the speciality steel business of Liberty Steel – has been successfully producing alloy and stainless steel grades for over sixty years for use in de-manding sectors such as aero space, oil & gas, industrial engineering and in the manufacture of bearings, bright bar, narrow strip and niche engineering applications for custom-ers around the world.

Their strength in speciality steels lies in the fully integrated production capability, which includes electric arc steelmak-ing, vacuum induction melting (VIM), mill processing capa-

The ingots produced will be refined further by processing through a vacuum arc remelting unit before being rolled or forged into products (Picture by courtesy of Liberty Steel).

4


bilities and dedicated service centres. Typical products in-clude ingots, blooms, billets, bars, slabs and narrow strip; in cast, rolled, drawn, peeled, heat-treated or re-melted condition, in exactly the quantities required by customers.

The production centres in Sheffield and the West Midlands area of the UK are backed by dedicated service centres in Bolton, UK, Nagpur, India and Suzhou and Xi’an in China. The service centres enable Liberty Speciality Steels to ser-vice their customers’ supply chains with bespoke combina-tions of added-value processing and just-in-time delivery.More than 100 component and equipment manufacturers, end users, third parties and national bodies have validated the quality management systems.

VIM plant enables Liberty Speciality Steels to deliver the highest purity steels

Liberty Speciality Steels has gained an excellent reputa-tion for supplying high-integrity steel to major commercialand military aerospace programmes around the world, using tailored supply chain solutions. Andrew Douglass, engineer-ing director at Liberty Speciality Steels, underlines: “We are a key supplier to some very significant aerospace players.” He continues: “It is definitely a growth sector in terms of aerospace production; Boeing forecasts a need for a record 41,000 new aeroplanes over the next twenty years. 38% of new planes will be for the Asian market, driven by China and India.” Some of the most demanding products – delivered as ingot, bar and cut pieces – are used in the production of engine components, landing gear, controls, aerostruc-ture, helicopter rotor components, etc. For the production

of such materials Liberty Speciality Steels has been oper-ating numerous remelting plants, i.e. two electro-slag re-melting plants (ESR) and nine vacuum arc remelting (VAR) plants at the Stocksbridge site, with feedstock mainly pro-vided by the nearby steelmaking operations. However, the business previously supplied small quantities of VIM-derived steel using ingots sourced from third parties.

Because of the enormous potential of the growing market, in 2013 the company decided to invest in creating its own VIM base. In late 2013 the company announced it would build together with SMS group a vacuum induction melting (VIM) furnace at its Stocksbridge site to enable the steel producer to tap into new market opportunities and develop on its own innovative new products for the aerospace and oil & gas industries. A challenging project had been launched. The company decided for a brownfield project. The furnace location was the site of a former continuous billet casting plant, in order to take advantage of existing buildings, over-head cranes and plant services. The final layout integrated the main furnace components with the raw materials prepa-ration area, the crucible relining and pre-heating area and the mould preparation and ingot stripping area.

VIM: vacuum induction melting process

The VIM facility produces ultra-clean ingots, i.e. remelt elec-trodes, that will be refined further by a remelting process, usually a vacuum arc remelting (VAR) unit before being rolled or forged and finally manufactured into products such as en-gine, transmission and structural components for the aero-space market.

Tapping and all other process sequences are remote controlled and monitored from the control room.

5

The VIM production route involves vacuum melting high-pu-rity steel and alloys in a crucible furnace, and then vacuum casting the purified liquid steel into ingot moulds – all with-in a low pressure vacuum chamber (vacuum level approx. 0.05 mbar or even less). The VIM technique comprises con-secutive process steps as follows:

The upper furnace and lower crucible are sealed togeth-er, evacuated and charged with raw material.

The raw material is melted by electrical induction heating. Induced current stirs the liquid metal; exposing it to the vacuum during hours of refining to remove gasses.

Alloying elements can be added under vacuum. Moulds are prepared and set. The moulds travel on rail car into the casting chamber.

Launder/tundish are prepared and set. Launder/tundish travel on rail to the casting chamber.

Casting chamber is sealed and evacuated and connect-ed to the melting chamber.

After setting the exact composition of the alloys and the casting temperature, the liquid metal is tapped under vac-uum. The furnace tilts forward to pour liquid metal via the launder/tundish into the mould during casting.

After casting: the filled mould exits the casting chamber on rail car to the stripping area.

After hours: the solidified ingots are stripped out and placed under insulated hoods to cool slowly. This pre-vents cracking of sensitive steel grades.

As the entire melting and casting operation is conducted in an oxygen-free atmosphere, the resulting steel is very clean and has very low gas content. The technology enables the achievement of very tight analytical tolerances. Alloying ad-ditions, also carried out under vacuum, allow for precise control of the steel’s chemical composition.

Melting in an oxygen-free atmosphere prevents the forma-tion of oxides and also the loss of elements with an affinityfor oxygen. Unwanted accompanying elements which have a high vapour pressure can be removed. The ingots pro-duced will be refined further by processing through a vac-uum arc remelting (VAR) unit before being rolled, or forged into products such as engine, transmission and structural components for the aerospace market.

Production of speciality alloys at the Stocksbridge works, using the new VIM X-eed® unit supplied by SMS group.

6


Technological concept and machine design

The concept of the VIM unit is based on a three-chamber system, in which casting, melting and exchange chambersare arranged adjacent to each other. The independent de-sign of the three chambers allows for individual evacua-tion of those.

The heart of the VIM X-eed® unit comprises an 8 t vacu-um induction melting crucible and the associated vacuum pumping, material charging and process control equipment.

All core components supplied by SMS Mevac have been de-signed to allow Liberty Speciality Steels to increase the melt size to 18 t at a later date.

The mechanical vacuum pump system consists of three skids that can be connected in parallel or alternately at three exhaust points (melting chamber, casting chamber and exchange chamber/charger). To protect the vacuum pumps against dust and metal particles, SMS group has developed special dry-type filters for this application. Sep-arate filter systems have been installed for each chamber.

Launder/tundish prepared and set for tapping under vacuum.

7

Liberty Speciality Steels

Liberty Speciality Steels is a division of Liberty Industries Group, part of the metals and industrials group Liberty House. It employs 1,700 people at its major steel melt-ing and processing sites in Rotherham, Stocksbridge and Brinsworth, South Yorkshire, service centres in Bolton, Lancashire and Wednesbury, West Midlands and two dis-tribution centres in China. The business produces a range of high-value steels made from recycled materials that are used in manufacturing components and finished goods for aerospace, automotive, oil & gas and industrial ma-chinery sectors.

Liberty House

The Liberty House Group is an international industrials and metals business specializing in commodities, metals recycling and the manufacture of steel, aluminium and en-gineering products. It operates from four hubs in London, Dubai, Singapore and Hong Kong and has presence in more than 30 countries. Its current turnover is over US$ 6.8 billion per annum. Liberty, along with its sister energy company SIMEC, is part of the worldwide GFG Alliance.

SIMEC

SIMEC is a resources group spanning five continents and encompassing major operations across shipping, infra-structure, mining, energy and commodities. The busi-ness is part of the GFG Alliance and was established over 50 years ago by Mr Parduman K. Gupta, who remains chairman. Latest SIMEC turnover exceeded US$ 2.7 bn, with net assets valued at US$ 796 m.

GFG Alliance

The GFG Alliance is an association between PK Gupta and Sanjeev Gupta’s business interests to forge a new agile, sustainable, non-cyclical, integrated, global busi-ness model. Its key focus is the creation of a resilient supply chain – from liquid metal produced from recycled scrap and renewable energy to highly-engineered prod-ucts, funded through a pioneering financial approach. The group encompasses: Liberty House Group – an in-tegrated international industrial and metals business; SIMEC Group – an international resources and infrastruc-ture group; Wyelands – a banking and financial services arm; GFG Estates – a division that manages the alliance’s property holdings; and GFG Foundation which is focused on the retention and creation of engineering skills.

Also ancillary equipment for crucible preheating and lining maintenance was included in the supply scope. The plant in-corporates vacuum pouring equipment for both top poured and bottom poured ingots, in single or multiple ingot con-figurations. All process sequences are remote controlled and monitored from the control room. The main process parameters and status indications as well as all important system functions are displayed on the HMI monitor and are additionally recorded to permanent files for full quality as-surance traceability within the Level 2 process control sys-tem. The condition of the heat and casting operations are visualized on separate video monitors using dedicated pro-cess monitoring cameras.

Conclusion

Liberty Speciality Steels takes pride in satisfying custom-er and OEM requirements from state-of-the-art specialist alloy manufacturing facilities which include vacuum induc-tion melting (VIM) alongside vacuum arc remelting (VAR)

and electro-slag remelting (ESR). These facilities are cou-pled to an integrated rolling mill and service centres, which allow the company to deliver its products around the world as ingot, bar, cut piece or machined part. Their highly qual-ified technical teams provide advice and help with day-to-day problem solving, and are available to assist with lon-ger-term developments.

Andrew Douglass, engineering director of Liberty Speciality Steels: “We are delighted to have the VIM in operation and producing aerospace grades for sale and customer accep-tance trials.” Jochen Schlüter, managing director of SMS Mevac: “We are very proud of having installed and success-fully commissioned the new VIM X-eed® facility in Stocks-bridge in close collaboration with Liberty Speciality Steels. As partners of Liberty Speciality Steels, we will continue to render our extensive metallurgical expertise to support our customer in developing and producing innovative high-end materials with the newly installed VIM X-eed® unit and responding successfully to the increasing requirements of this extremely exacting market.”

8


MPT International talked about the background of the VIM investment with Andrew Douglass, Engineering director, and Stephen Carey, manager Technology & Development, both Liberty Speciality Steels, Stocks-bridge, Sheffield, South Yorkshire (UK). The answers provide an insight into the company’s strategy in the respective market.

›› What is the total sum invested in the speciality steelmaking facilities at the Stocksbridgworks?

Andrew Douglass: There was recently significant invest-ment in the business here in Stocksbridge. We probably invested £ 20…30 million during a period of approximate-ly five years in various finishing and heat treatment activi-ties – not all new facilities, but also refurbishing of existing plants. We upgraded the peelers, invested in the rolling mill. Here we built a central control pulpit to take all the oper-ators away from the mill train. The new central pulpit has been interfaced with the old mill controls. Additionally, we bought two new VAR plants and the VIM plant.

›› What was the basis for the decision in favour of the VIM and why are you focusing on this technology?

Andrew Douglass: Certainly, the target is always around the high added value. We had growth plans around supplies to the aerospace industry which would involve additional vacuum capacity. That was one of the key points when we designed the new VIM capacity and went for the option of a bigger crucible. The move from the 8 t to an 18 t crucible is very much in line with the aerospace growth plans. Aero-space is definitely a growth sector. We can see the growth, so it is important for us to act, because we are a key sup-plier to some very significant aerospace players.

Stephen Carey: In addition to routine commercial produc-tion, the VIM furnace gives us the opportunity to develop new products and alloys. We can rapidly scale up from labo-

Background information aboutVIM investment project

ratory melts to heats of 4 to 8 tonnes made on the new VIM furnace. These are then processed and evaluated through our downstream processes.

›› How do you evaluate your footprint in the market for aerospace products?

Andrew Douglass: The aerospace sector is very much an international market. The supply chain will go through some of the key aerospace players – OEMs, who supply compo-nents to the aircraft companies. Our steel will be in the components, like engines or landing gears, that the OEMs supply to the aircraft companies. We are already part of the global supply chain where business is based on long-term supply contracts. We have established supply channels in various regions and countries to support that.

Andrew Douglass, Engineering director, says: “Aerospace is definitely a growth sector. That was one of the key points when we designed the new VIM capacity.”

9

›› What is your growth plan in terms of sales?

Andrew Douglass: We definitely have set ambitious tar-gets for strategic 5-year and 10-year growth plans for our aerospace segment. A lot depends on customer approvals. We want to broaden our range of steels to sell more. That’s one of the reasons for our investments in new technolo-gies, but also for future capacity increases.

There is a big pipeline of what we want to be able to offer in the future. Currently on the VIM we manufacture mainly 12 grades of alloy and stainless steels. We are increasing the value of what we are supplying, basically by adding higher alloys and more stainless grades to increase our portfolio.

It is important to note that we are already in the market with various of these grades. Now we are reaching out for ad-ditional customer approvals for grades that we are already producing. Also, with our new VIM plant we can add new grades that we never made before, which include certain alloyed steels and also super alloys.

The rational for our investment in the VIM was that previ-ously we had been buying VIM ingots from 3rd party sup-pliers to be remelted in our VAR shop. That gave us a foot in the market. Some of our key customers have expected us to seriously enter into VIM products supply by setting up our own VIM production facility. That was part of our growth plan. Now, as we have our own VIM manufacturing base, these customers consider us to be a more credible supplier of VIM products. Since application of VIM products is increasing, our market share for such product is increas-ing, too. Had we not invested, we would have less opportu-nities with these key customers. Now, as we invested, we are on a more level playing field with some of our compet-itors. It will ensure our competitiveness over a long term and with a wider product range.

›› Do you produce materials with customized characteristics?

Stephen Carey: Most of our products have to meet stan-dard specifications like AMS or European standards, or multiple classifications. These include products for very de-manding applications. The steels have to meet challenging combinations of metallurgical properties, for use in helicop-ter transmissions, formula-1 gears, etc. Most of these prod-ucts require production via the VIM-VAR route, to achieve the required levels of cleanliness, analysis control and me-chanical properties. We already have a number of existing approvals that we want to transfer to our new in-house production route.

As we now have the capability to produce larger quantities by the VIMVAR route, we can offer many more products for new applications in aerospace and other sectors.

Stephen Carey, manager Technology and Development: “The VIM furnace gives us the opportunity to develop new products and alloys.”

10


›› Why did you decide for VIM technology from SMS Mevac?

Stephen Carey: SMS group is highly regarded in terms of their engineering. We have had close relationships with the SMS group as our plant supplier in other parts of the company. As this was to be the first VIM plant built by SMS Mevac, there was a very good opportunity for us to work closely together with the engineers from SMS Mevac. This was a development project, where we could bring the op-erator’s perspective to the design. For us it was a brown-field project. We had to design the facilities to fit into our existing site footprint. However, we had the opportunity to start from a blank sheet and SMS Mevac were able to ac-commodate our requirements in their layout design. Final-ly, since this is a reference plant, it was designed to a very high specification, in terms of vacuum performance, pro-ductivity and metallurgical capability.

Andrew Douglass: We are a highly credible supplier of VIM steels to the aerospace industry. We are open for business. We develop steels. All our customers know that there are two main (plant) suppliers to the VIM industry, and we can underline that we opted for SMS Mevac because of the credibility and because we have got a really good plant. We both have a common interest, namely to make this proj-ect a success.

›› Do you intend to continue investing in VIM-VAR plants?

Andrew Douglass: Yes, absolutely. As explained before, the general backlog of orders for new aircrafts and the pros-pects of emerging nations like China and particularly India is the base for our growth plan. It is an area where we see positive market indicators.

Our VIM facility is now being operated with a 8 t crucible, but we intend to increase production using the originally de-signed 18 t capacity. This new facility will enhance our port-folio and increase our production of the respective prod-ucts. As all VIM production will go through the VAR – and our VAR capacity is full – we’ll have to think about addi-tional VAR plants if we increase our VIM production. Invest-ment in additional plants is the logical answer. This way we can increase the size of the aerospace order book, which is going to put some strain on other areas of our organi-sation. In parallel we have started to implement our plans to automate a part of our testing regime for the aerospace products, which because of their very nature are highly test intensive. Commissioning of some of the automated test preparation equipment is already underway. Very soon, we will go ahead with an investment in automated testing fa-cilities, which will also further enhance our on-time deliv-ery performance.

Yes, absolutely, we will continue investing in the VIM-VAR process route. It serves a growing market with good re-turns. It is one that we believe will acknowledge our exper-tise as product and service supplier and strongly underpin our commercial growth.

Thank you very much for the interview.

H5-2

24E

© S

MS

grou

p Gm

bH ·

Publ

ished

on

10.1

1.20

17 ·

Circ

ulat

ion

250

· Prin

ted

in G

erm

any

· Ky

SMS Mevac GmbH

Bamlerstrasse 3a 45141 Essen, GermanyPhone: +49 201 6323-0Telefax: +49 201 [email protected]

“The information provided in this brochure contains a general description of the performance characteristics of the products concerned. The actual products may not always have these characteristics as described and, in particular, these may change as a result of further developments of the products. The provision of this information is not intended to have and will not have legal effect. An obligation to deliver products having particular characteristics shall only exist if expressly agreed in the terms of the contract.”

liberty speciality steels accelerates production of ultra

Documents