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PM-HIP technique is used to produce very high quality super duplex stainless steels with, e.g., excellent stress corrosion cracking and corrosion fatigue resistance. The high standards of the base material impose strict quality requirements on the welding procedure. The conventional GTA welding can produce good quality welds, but has its weak point at small deposition rate and very low efficiency. The narrow gap GTA welding improves the quality and gives a much better economic efficiency. The narrow gap GTA welding offers a low number of beads, low total heat input, and results in a favourable residual stress profile in the HAZ.

The narrow gap GTA welding method was investigated for optimising the mechanical, corrosion and corrosion fatigue properties of thick wall HIPped P/M super duplex stainless steel welds. The effect of welding parameters, welding consumables, shielding gases and groove geometries were evaluated and the equipment was further developed. Microstructures of the welds were examined using light optical and scanning electron microscopy. Mechanical properties were examined using tensile, Charpy-V impact toughness and rotating bending fatigue tests. Corrosion properties were examined to evaluate CPT and CCT.

Additional information

Authors: KORHONEN M, Helsinki University of Technology, (FI);LUUKAS M, Helsinki University of Technology, (FI);HANNINEN H, VTT Manufacturing Technology (FI);LIIMATAINEN J, JRC-Institute Advanced Materials, Petten (NL)
Bibliographic Reference: Oral report given at: The 6th World Conference and Expo: Duplex 2000. Organized by: Associazione Italiane Mettallurgia. Held at: Venezia (IT), 17-20 October 2000
Record Number: 200013206 / Last updated on: 2001-03-23
Original language: en
Available languages: en
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