The CSIR has announced that it has secured approximately R50 million funding for the purchase of a hot isostatic press (HIP) through the Department of Science and Innovation (DSI) High-End Infrastructure Programme. Hot isostatic pressing is a critical step in several manufacturing processes being developed under the Advanced Materials Initiative (AMI), Advanced Manufacturing Technologies Strategy (AMTS) and processes being developed for the beneficiation of titanium under the TiCoC.

The Advanced Materials Initiative is an initiative of the Department of Science and Innovation, which was established in 2005 to facilitate minerals beneficiation. It is composed of four “legs”, The Ferrous Materials Development Network (FMDN) and Precious Materials Development Network (PMDN), hosted by MINTEK, Nuclear Materials Development Network (NMDN), hosted by NECSA, the Light Materials Development Network (LMDN) and Titanium Centre of Competence (TiCoC), hosted by CSIR.

The different networks in the AMI focus on upstream and downstream research and development with a specific aim of beneficiating the country’s natural resources or in the case of aluminium adding further value to imported natural resources, bauxite, being processed in the country.

CSIR has secured R50 million funding for the purchase of a hot isostatic press. The equipment, which is being supplied by Quintus Technologies of Sweden, will be housed at the CSIR Pretoria Campus

“Nearly all Ti components used in applications that require high structural integrity, including castings, metal injection moulding (MIM) and additive manufactured components have to be HIPed. There are currently no industrial HIP facilities in South Africa suitable for the processing of Ti products. All HIPing is done using an international service provider in Europe, which results in long lead times, and places locally developed IP at risk. HIPing is not solely used in the manufactured of Ti components. It is also used extensively for other metal products, where structural integrity is of critical importance. This may include nickel, aluminium, cobalt, and iron-based alloy components,” explained Sagren Govender, the leader of the Advanced Castings Technology research group at CSIR.

Hot isostatic pressing
Hot isostatic pressing is a process that is used to consolidate metal powder or to eliminate defects in solids such as pores, voids and internal cracks, thus densifying the material to 100% of the theoretical density. When loose metal powders are consolidated by HIP, or when previously densified parts having surface connected porosity need to be fully densified, the HIP cycle must be done in gas tight capsules made from sheet metal or glass. Previously densified parts not having surface connected porosity, such as products with a gas tight surface, can be HIPed without the need for encapsulation.

The process includes high temperature and a high isostatic gas pressure, meaning that the pressure acts on all surfaces of the component in all directions leading to densification. The mechanisms for densification during HIP are plastic deformation, creep and diffusion. Initially, plastic deformation is the dominant driving mechanism since the applied external pressure is higher than the yield strength of the material at the HIP temperature, thus making the voids in the material collapse. After the initial plastic deformation, creep and diffusion contributes to densification. These mechanisms not only collapse and close the pores, but totally eliminate them to create a material free of defects. The process has been successfully used for a number of decades to both manufacture and densify critical components for sectors such as aerospace, medical implants, power generation and oil and gas exploration. Hot isostatic pressing (HIPing) is a well-established method for healing internal porosity in titanium castings and has been widely used to significantly increase fatigue life in critical components.

In aerospace, gas turbines, and other critical areas, titanium-base alloys are used due to their low weight and high strength. These alloys have a high melting point and are difficult to machine. In consequence, hot isostatic pressing (HIPing) of titanium alloy powder is a preferred method for processing. The cost of HIPed parts can be reduced by minimising material waste and by reducing machining. To utilise near-net-shape powder metallurgy (PM) processing, it is important to determine the initial capsule dimensions. Methods for predicting the final dimensions of the HIPed product by simulation using numerical-solution techniques exist. Current computer technology enables finite element (FE) simulation for the HIPing of metal powders.

The two main industry sectors that will be supported are the additive manufacturing industry and the casting industry. Companies involved in aerospace, defence, medical (implants, tools, etc) and additive manufactured components for the high-end applications will benefit from using the facility, as will public organisations such as tertiary education institutions, science councils and SOEs

“This investment will establish a local industrial HIPing facility in South Africa with a chamber size of 300mm diameter by 850mm deep, a maximum workload weight of 350kg, a high quench capability, a maximum pressure of 207 bar and temperature capability of up to 1 500°C (2 000°C with a graphite furnace). This facility will be established at the CSIR and will be available for industry, science councils and TEIs for research, development, and industrial-level production.”

“The equipment, which is being supplied by Quintus Technologies of Sweden, will be housed at the CSIR Pretoria Campus. The equipment should arrive in late July/early August 2022. Installation commissioning is planned for August 2022 with hot commissioning by the end of August 2022. Based on the procurement and equipment manufacturing timeline provided by the supplier, it is anticipated that the HIP facility will be launched in September 2022. Thereafter there will be an official launch of the facility.”

“The facility will be run by the CSIR and it is anticipated that it will create employment opportunities directly and indirectly for engineers, technologists and technicians within the facility and other related technical platforms that will use this facility.”

“Initially the facility will be subsidised through the AMI and CSIR and commercial income. All users will need to pay for use of the equipment. The aim is that the HIP facility must be financially self-sustainable in three to five years. When the business grows sufficiently and there is room for expansion it is projected that it will become an independent business with expanded capabilities, additional equipment and personnel. It is also the intention for the facility to become a global service provider.”

“The two main industry sectors that will be supported are the additive manufacturing industry and the casting industry. Companies involved in aerospace, defence, medical (implants, tools, etc) and additive manufactured components for the high-end applications will benefit using the facility, as will public organisations such as tertiary education institutions, science councils and SOEs.”

“The services will obviously come at a cost because it is an expensive machine to operate but certain critical components will need to be HIPed in order to meet customer requirements. During the development of the Ti investment casting capability at the CSIR, cast components were sent to a service provider in Belgium at a significant cost and long lead times.”

“However, the intention is for the facility eventually to mainly service industry clients, local and international. It is not purely a research facility.”

“The LMDN, focusses on aluminium research and development across the value chain from value added products (alloy development, recycling, billet, slab and ingot casting) to final products. The main R&D focus has been in alloy modification and development and casting technologies while research on mill products, welding and fabrication was performed through postgraduate programmes at participating universities. The South African Aluminium Industry Roadmap was developed under this initiative in collaboration with AFSA and industry, published in 2017. The roadmap is under the custodianship of AFSA.”

“The TiCoC performed R&D on primary titanium production (upstream), downstream technologies and final products. The downstream Ti technologies included alloy development, powder metallurgical processes (press and sinter, metal injection moulding, etc), additive manufacturing and investment casting.”

“The LMDN and TiCoC provide services from fundamental to applied research, on both materials and process development, and mechanical engineering design, product development and testing. This has resulted in establishing technical capabilities to support a broad industry base.”

“Hot Isostatic Pressing was identified as one of the key technologies to completing the value chain to produce high integrity components via investment casting, additive manufacturing and powder metallurgy. Although it was identified under the titanium research activities, it can be used for other metal alloy systems but care must be taken to prevent contamination of the chamber.”

“During commissioning of the facility, we will need to have full workloads. It is an opportunity for potential users to send a sample to be included in the workload for commissioning.”

For further details contact the Light Materials Development Network (LMDN) and Titanium Centre of Competence (TiCoC), hosted by CSIR, on TEL: 012 841 2355.