• Trautmann, Anton

Abstract

Hydrogen deteriorates the mechanical properties of metallic materials leading to component damage. During the research presented in this thesis, the low-alloy steels L80, 42CrMo4 and P110, the corrosion resistant alloys Super 13Cr, Duplex 2205, Sanicro 28 and A975, and the nickel-based alloy L718 were examined. The aim was to find out, how much hydrogen is absorbed by these materials under defined conditions and whether the existing hydrogen content affects the mechanical properties. In addition to immersion tests in hydrogen gas at elevated pressure, tests in hydrogen sulfide-saturated solution were conducted. None of the specimens under constant load immersed in hydrogen gas at elevated pressure failed, although increased hydrogen contents of up to 0.59 ppm were measured for the low-alloy steels and up to 14.21 ppm for the corrosion resistant alloys. The immersion in the hydrogen sulfide-saturated solution significantly increased the hydrogen absorption of the steels L80, 42CrMo4, P110 and Super 13Cr compared to that in hydrogen gas. Except for the former, the constantly loaded specimens cracked under these conditions due to hydrogen embrittlement. Since the L80 did not fail in spite of the significantly increased hydrogen content and a much lower hydrogen uptake was determined after charging in hydrogen gas at pressures of up to 150 bar, this material is suitable for application in the generation of renewable energies. A new mechanism is proposed for the hydrogen uptake of Duplex 2205, which was significantly increased by the presence of an electrolyte during charging in hydrogen gas.

Topics

• impedance spectroscopy
• nickel
• corrosion
• steel
• Hydrogen