Novel method for producing near-net shape metal components

For many thousands of years, humans have been making metallic parts for tools, for coinage, for jewellery, for weapons, for cookware, for home products, as well as for transport. Even during Egyptian times, 5000 years ago, metal workers were busy inventing and developing skills for manufacturing the parts they needed. In those early days of metallurgy, the main metals used and traded were the ones they could find in Nature. These included silver, gold, copper, tin, antimony and occasionally iron-nickel meteorites. With time and the invention of smelting and alloying, the range of useful metals expanded dramatically. In parallel to this, clever ways of making 3D objects were also developed. The two main methods for producing metallic parts include casting and forging. In the case of casting, a wax pattern and mould are first made to generate the desired 3D shape. Then the empty mould cavity is filled with molten metal, which is allowed to cool and solidify. Once the mould is broken, the final product inside is a net-shape metal component. In the case of forging, a block of metal is heated in a forge to soften the metal and then it is repeatedly hit with a blacksmith's hammer into the desired shape. The hot part could then be quenched in water to further strengthen it. While not as intricate as the shapes produced by casting, forgings have found many applications too. These ancient techniques, spanning many thousands of years, are still very much in industrial use today. Modern casting can produce anything from a ten-tonne ship propeller to a single crystal turbine blade for jet engines. Likewise, forging is used all round the world to make parts for nuclear reactors, oil and gas installations, aircraft and space satellites. In very recent times, additive manufacturing (AM) or 3D printing has emerged as a new method of making high-value metal parts, offering benefits to customers that traditional casting or forging cannot. HIPtec AS is a start-up company in Norway that has invented new AM processes that can deliver outstanding mechanical properties at affordable prices. The process involves high temperatures up to 1200°C, combined with very high pressures of 2000 atmospheres. That's the same pressure one would find at the bottom of the Mariana Trench in the Pacific Ocean. Perfected over 4 years, the HIPtec technique is being used for all kinds of alloys: carbon steels, stainless steels, nickel superalloys, stellites, bronzes, light alloys, as well as combinations of different metals and ceramics. HIPtec is currently making single-piece parts, where one half is steel, while the other half is nickel. Making multi-material parts like this is completely new and allows engineers to put materials and properties exactly where they want them. One of the main challenges at present is how to qualify such parts. The project team, with the help of DNV GL, is now working on non-destructive testing (NDT) methods. This kind of testing involves the use of ultrasonic inspection and allows HIPtec to qualify components for industrial service, without having to destroy the part during testing. At the beginning of 2021, Hiptec is able to produce 50-250 kg demonstrator parts in complex alloys. One of the aims of the project was to manufacture marine and oil&gas components. Hiptec has already made components which are about to enter the first stages of in-service testing. Hiptec is currently well underway to develop a pilot factory and will likely be ready to serve the energy, chemical, maritime, health and aerospace sectors in Norway (and abroad) within 2021. With the factory in place, HIPtec will scale-up the technology to even larger tonne-sized components.

The BIA project has allowed HIPtec to further develop and validate the novel AM+HIP process for making high-quality metal components in a variety of alloy systems. This research will further HIPtec's capabilities and help the company transition from R&D to qualified industrial supply. The impact is tremendous, since it will allow HIPtec to access markets, such as maritime, energy, oil&gas and renewables within the coming years. These markets all require high-value metallics with good reliability and precision, often with multi-material combinations. The impact for Norway will be factory creation, high-tech jobs and increased activity in the manufacturing sector.

HIPtec aims to enable production of high-quality complex metal components with minimal waste (near-net shape, i.e. with minimal need for post-process machining). HIPtec's process cost is estimated to become substantially lower than forging and current additive manufacturing techniques, with most of the advantages of high flexibility and short lead times associated with existing additive manufacturing routes, and even with additional novel features such as the capability to produce multi-material components. The unique aspects of this innovation include the combination of additive layer manufacturing, hot isostatic pressing and relatively low-cost commodity feedstock. HIPtec has already performed promising initial tests resulting in material quality comparable to standard forged specifications when it comes to ultimate tensile strength, yield strength and ductility, but there are remaining issues related to lack of 100% isotropy in the mechanical properties as well as insufficient ductility. Characterizations (SEM and EDS) of the initial samples have given some clues, but more structured analyses and modeling is needed to understand the underlying mechanisms, and thus provide a platform for targeted development. The technology is a "platform technology" applicable to a number of common metals used for industrial parts and a large range of component form factors with an enormous addressable market.