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Effect of nitrogen, titanium and strain ageing on the toughness of weld metals

Abstract

The effects of varying nitrogen and titanium contents on the as-desposited (AW) and artificially strain aged (SA) shielded metal arc weld metal (SMAW) properties have been investigated. The purpose of the study was to examine the Charpy-V and crack tip opening displacement (CTOD) fracture toughness behaviour of ferritic weld metals with respect to static strain ageing. The response of weld metals to strain ageing was established by clarifying the exact role of each element and interactions between these elements with respect to nine weld metal microstructure, strain ageing and fracture toughness properties. Systematic additions of titanium (in the range of 5 ppm to 450 ppm) and nitrogen (80 ppm to 260 ppm) were made to obtain various amounts of acicular ferrite and different microstructures which led to varying fracture behaviours and sensitivity to strain ageing. Artificially strain aged welds were obtained by two subsequent processes; (1) local compression (4%) of the weld region in the plate thickness direction at room temperature and (2) ageig at 250 C for 1/2h. An increasing nitrogen content in the weld metals leads to an increase in strenght and hardness and impairs the fracture toughness properties associated with an incrase of coarser microstructure and due  More>>
Authors:
Kocak, M; [1]  Petroviski, B; [1]  Evans, G [2] 
  1. GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Materialforschung
  2. OERLIKON Welding Ltd., Zurich (Switzerland)
Publication Date:
Dec 31, 1994
Product Type:
Conference
Report Number:
GKSS-94/E/57; CONF-9405291-1
Reference Number:
SCA: 360103; PA: DE-95:0G5520; EDB-95:051808; SN: 95001361323
Resource Relation:
Conference: 2. European conference on joining technology (Eurojoin-2),Florence (Italy),16-18 May 1994; Other Information: PBD: 1994
Subject:
36 MATERIALS SCIENCE; NITROGEN ADDITIONS; METALLURGICAL EFFECTS; TITANIUM ADDITIONS; FILLER METALS; SHIELDED METAL-ARC WELDING; WELDED JOINTS; MECHANICAL PROPERTIES; STRAIN AGING; IRON BASE ALLOYS; MICROSTRUCTURE; FERRITE; CHEMICAL COMPOSITION; DISLOCATION PINNING; DUCTILITY; 360103
OSTI ID:
10129146
Research Organizations:
GKSS-Forschungszentrum Geesthacht GmbH (Germany)
Country of Origin:
Germany
Language:
English
Other Identifying Numbers:
Journal ID: ISSN 0344-9629; Other: ON: DE95755992; TRN: DE95G5520
Availability:
OSTI; NTIS (US Sales Only); Reprinted from: EUROJOIN-2 proceedings, edited by Italian Institute of Welding, Genoa (Italy), 1994, p. 693-706
Submitting Site:
DE
Size:
16 p.
Announcement Date:
Apr 13, 1995

Citation Formats

Kocak, M, Petroviski, B, and Evans, G. Effect of nitrogen, titanium and strain ageing on the toughness of weld metals. Germany: N. p., 1994. Web.
Kocak, M, Petroviski, B, & Evans, G. Effect of nitrogen, titanium and strain ageing on the toughness of weld metals. Germany.
Kocak, M, Petroviski, B, and Evans, G. 1994. "Effect of nitrogen, titanium and strain ageing on the toughness of weld metals." Germany.
@misc{etde_10129146,
title = {Effect of nitrogen, titanium and strain ageing on the toughness of weld metals}
author = {Kocak, M, Petroviski, B, and Evans, G}
abstractNote = {The effects of varying nitrogen and titanium contents on the as-desposited (AW) and artificially strain aged (SA) shielded metal arc weld metal (SMAW) properties have been investigated. The purpose of the study was to examine the Charpy-V and crack tip opening displacement (CTOD) fracture toughness behaviour of ferritic weld metals with respect to static strain ageing. The response of weld metals to strain ageing was established by clarifying the exact role of each element and interactions between these elements with respect to nine weld metal microstructure, strain ageing and fracture toughness properties. Systematic additions of titanium (in the range of 5 ppm to 450 ppm) and nitrogen (80 ppm to 260 ppm) were made to obtain various amounts of acicular ferrite and different microstructures which led to varying fracture behaviours and sensitivity to strain ageing. Artificially strain aged welds were obtained by two subsequent processes; (1) local compression (4%) of the weld region in the plate thickness direction at room temperature and (2) ageig at 250 C for 1/2h. An increasing nitrogen content in the weld metals leads to an increase in strenght and hardness and impairs the fracture toughness properties associated with an incrase of coarser microstructure and due to the dislocation pinning effect of free nitrogen which hinders their movements. The combined effect of N and strain ageing increased the strength and hardness but decreased ductility and fracture toughness significantly. (orig.)}
place = {Germany}
year = {1994}
month = {Dec}
}