Experimental Study on Bead on Plate (BOP) Welding of 6 mm Thick 9% Nickel Steel by Fiber Laser Welding

Nine percent nickel steel has excellent properties in a cryogenic environment, so it has recently been used as a tank material for most LNG fuel-powered ships. However, 9% nickel steel causes arc deflection due to its tendency of magnetization during manual FCAW welding and the currently used filler metal is 10–25 times more expensive as a base metal compared to other materials, depending on manufacturers. Furthermore, the properties of its filler metal cause limitation in the welding position. To overcome these disadvantages, in this study, the tendency of penetration shape was analyzed through a fiber laser Bead on Plate (BOP) welding for 9% nickel steel with a thickness of 6 mm and a range of welding conditions for 1-pass laser butt welding of 6 mm thick 9% nickel steel with I-Groove were derived. Through this study, basic data capable of deriving optimal conditions for laser butt welding of 9% nickel steel with a thickness of 6 mm were obtained.

A Thermodynamic Analysis of the Selective Sulphidation of Nickel from a Nickeliferous Lateritic Ore

The production of a nickel sulphide concentrate through selective sulphidation of a nickeliferous lateritic ore at temperatures lower than current smelting temperatures, is being studied as a potential production method for upgrading lateritic ores. The ability to produce such a nickel sulphide concentrate at economically attractive grades, while achieving reasonable nickel recoveries, relies on the conversion of the maximum amount of nickel oxide to sulphide, while minimizing the amount of iron sulphide. This paper examines the thermodynamic basis for this selective sulphidation. The analysis includes both pure component equilibrium as well as various solid and liquid solution phases, which are anticipated to set limits on the maximum achievable grade/recovery combinations. Thermodynamic calculations show that, for high iron limonitic ores, grades of up to 20 to 25 mass percent nickel should be possible, while maintaining recoveries of greater than 80 percent.

0.4 μm Diameter Nickel-Filament Silicone-Matrix Resilient Composites for Electromagnetic Interference Shielding

Resilient silicone-matrix composites containing 7–13 volume percent nickel filaments (0.4 μm diameter) exhibited 74–93 dB electromagnetic interference (EMI) shielding effectiveness at 1–2 GHz and 1 × 10−1 – 2 × 10−2 Ω cm DC volume electrical resistivity. The high shielding effectiveness is due to the small diameter of the nickel filaments. The composites are useful for EMI shielding gaskets and cable jackets.