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Innovation & Technologie Angebot

Semi solid metal casting process to reduce cost and energy consumption while improving quality of cast components.

Country of Origin: United Kingdom
Reference Number: TOUK20200416001
Publication Date: 16 April 2020

Summary

A UK SME has patented, developed and proven a versatile technology for the energy intensive metal casting sector. The device/process is applicable to all metal systems and provides energy saving to the process as well as a higher integrity casting with fewer defects. It is modular and can be easily fitted into current casting process streams. Industrial and research partners are sought for commercial agreement with technical assistance, license agreement or technical cooperation agreement.

Description

Conventional methods of casting can be labour intensive, produce dimensional inaccuracies, and defects are unavoidable which can result in structural weaknesses within components. One means of achieving structural refinement being tried out within the industry is by physically agitating metal as it solidifies.



Current methods being researched to exploit this theory have met with limited success as they are inherently not suitable to the application of this sort of metal processing. However, these technologies have run into several difficulties such as transport capability, air entrapment, contamination of melt while processing aluminium, inadequate shear, leakage, cavitation, process control and scaling up.



The UK SME’s new design can overcome these weaknesses to produce the required shear while maintaining transport capabilities. The machine is auxiliary and can be placed in the process route of current casting methods such as high pressure die casting, gravity die casting, sand casting, low pressure die casting etc. The process is also an effective means to produce metal matrix reinforced composites (MMRC’s).



Based on the axial compressor it consists of rotors and stators placed alternatively in a conical barrel. As it is a vertical machine the problem of melt traveling backwards to find its own level is eliminated as is the pocket of air behind the inlet i.e. the main cause for porosity in concepts based around screw extruders. Furthermore, being vertical the design is ergonomic and would occupy very floor space. Heaters can be attached along the sleeve into which the barrel halves sit in stages to produce a thermal gradient and control the temperature solid fraction and shear rate and therefore the evolution of the microstructure. The rotor stator mechanism ensures shear is provided without rubbing parts allowing for the design to be made from inert ceramics. Additionally, particles or gasses can be introduced into the melt and dispersed to produce metal matrix composites, metal foams with a refined microstructure or just aid with foundry applications such as degassing or transport of liquid metal.



The device can provide a high shear and dispersion rate to reduce agglomerations of reinforcement particles unlike most competing technologies in this sector which use a simple stirring mechanism. It has also been designed to specifically consider porosity arising from cavitation and air ingress from a swirling surface of melt. These factors currently hamper commercialisation of current additive manufacturing techniques.



The technology can be easily modified to be continuous or of batch nature and can also be used for one step liquid to extrusion/rolling essentially eliminating entire operations such as casting of billets or continuous casting. Typically, each of these processes is done in separate factories which might be miles apart. The device/process is applicable to all metal systems (Magnesium, Aluminium, Steel, Copper, etc.).



This is a proven energy saving technology capable of recycling and upcycling aluminium, for example, with patent protection across the major EU economies and the US. The company have achieved a 100C reduction in processing temperature and a 16% increase in strength of the material has been achieved, and this can provide significant advantages to recycling where it can be used to upcycle scrap aluminium into metal matrix composites.



The SME is currently affiliated with Universities around the world and have also secured investment for the technology. They are now looking for partner foundries who would be interested in developing this technology for their own specific applications under commercial agreement with technical assistance or license agreement. The company will also consider joint further development of the technology under a technical cooperation agreement, and are also open to other cooperation including R&D project bids under programmes such as EUREKA and Eurostars.

Advantages and Innovations

Semisolid metal (SSM) forming has several advantages over solid state forming. These include reduced forming force, unlimited formability and shortened manufacturing route. Compared to conventional die casting, semisolid technology has advantages of laminar flow during mould filling, reduced solidification shrinkage and lower operating costs. SSM processing offers a noted step change in technique with opportunities to reduce cost energy and resource more than any other novel forming process.



The new process/device represents an easy to manufacture technology that processes SSM to refine the cast structure. Research shows that turbulent mixing of an SSM can refine the structure of the solidified metal thereby increasing its mechanical properties leading to potential weight saving. Furthermore, turbulence can disperse particles within the molten metal. These particles can be non-metallic agents used to create high performance engineering materials known as metal matrix reinforced composites (MMRC’s) and mixing can refine the structure of the metal component in MMRCs. The concept is immensely scalable, offers good control over mixing parameters and therefore the structure of the processed material. The machinery can be built out of a variety of materials to become applicable to process all metals. The core technology can be easily adapted to several other metallurgical operations.



Better:

- Refined grain structure

- Less segregation 

- Less hot tearing

- Cutting edge technology



Faster:

- Shorter homogenisation time

- Reduced time for solidification

- Shorter heat treatment cycles



Cheaper:

- Lower operating temperatures

- Less waste from rejection

- Fewer run outs

- Longer life of tooling



In addition, the process can also be used to cut the cost of recycled material and provide it with more strength allowing for a higher amount of recycled material to be used in production. This is especially relevant in aluminium castings.

Stage Of Development

Prototype available for demonstration

Stage Of Development Comment

TRL5 - Prototype built and demonstrated the application of semisolid metal casting, and mechanically tested the aluminium ingots casted at a regional university.

Requested partner

The SME seeks foundries and manufacturers of castings who would be interested in developing this technology for their own specific applications under commercial agreement with technical assistance.



The company are also offering technical expertise and know-how to foundries on how to incorporate the technology into their own manufacturing process under license agreement, to make their process better, faster and cheaper.



The company will also consider joint further development of the technology under a technical cooperation agreement with such organisations or research centres.



They are also willing to cooperate over a wide range of formats including, for example, joint applications under EUREKA and Eurostars calls.