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The National High Magnetic Field Laboratory (NHMFL) has been funded to design and construct two series-connected hybrids (SCH), one each for the NHMFL in Tallahassee, FL and the Helmholtz Centre Berlin for Materials and Energy (HZB), Germany. The original designs for both hybrids contained three concentric coils comprising a Nb3 Sn superconducting cable-in-conduit (CIC) main-field outsert coil, a resistive main-field insert coil and a NbTi superconducting CIC shield coil. The fringe field requirements for both facilities were met by designing the NbT1 shield coil to match the 9.6 x 106 A-m2 dipole moment of the main field coils at an average radius of 1.16 m. Subsequent, alternate magnetic shielding concepts for both hybrids have been investigated with the objective of reducing the anticipated $700 k NbTi shield coil cost. The HZB fringe field requirements were targeted to a local area of concern at the adjacent Spin Echo facility, centered 15.65 m from the hybrid magnet center. An alternate, lower-cost shield concept comprised a set of four smaller shield coils positioned orthogonally around the HZB spin echo facility with a resultant total 85% to 90% reduction in required dipole moment compared to the original NbTi shield coil. The fringe field requirements at the NHMFL were not changed, but a lower-cost iron shielding option (not described here) located around the NHMFL hybrid was found to be a viable alternative. As a result, the NbTi CIC coil can be eliminated from the common superconducting magnet design for both the HZB and the NHMFL SCH's in favor of viable lower cost shielding options. [ABSTRACT FROM AUTHOR]

Recycling strategies for waste products from grinding processes have become an essential concern for the industrial sector, as up to 250,000 tons of grinding sludge is generated annually in Germany alone. In this paper, a suitable recycling strategy for the recovery of the metallic component of industrial sludge generated from cold work tool steel grinding is investigated and reported. Possible reuse of the recovered metallic material as a precursor for supersolidus liquid phase sintering (SLPS), a powder metallurgy process, is assessed for the first time. Using a novel technique, including washing, dry screening and magnetic separation, 50 wt% metallic swarf and 50 wt% abrasives can be recovered from dried, industrial grinding sludge. These metallic swarf are a mixture of discontinuous and continuous microchips with a particle size of up to 250 μm. The metallic swarf tend to agglomerate, resulting in larger accumulations and a correspondingly larger overall size with a particle size of over 1000 μm. Using SLPS, the densification of the metallic swarf was considered promising, as density increases with increasing sintering temperature. A maximum density of 76 vol% was achieved, owing to the morphology of the swarf. Occasionally, a few abrasives were observed in the microstructure. Hence, a new sustainable recycling strategy for the recovery of the metallic swarf in industrial grinding sludge has been proposed and the reuse of swarf as precursor for SLPS has demonstrated promising results. Further work is being undertaken to improve the densification of the metallic swarf by SLPS. • Characterization of grinding sludge. • Novel technique for recovery of metallic swarf from grinding sludge. • Reutilization of recovered high alloyed metallic swarf for supersolidus liquid phase sintering. • Particle shape and microstructural analysis and comparison of metallic swarf and gas atomized powders. [ABSTRACT FROM AUTHOR]