Effect of processing temperatures on the properties of a high-strength steel welded by FSW

Gonçalo Sorger, Teemu Sarikka, Pedro Vilaça, Telmo G. Santos

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

The need for weight reduction without compromising load-bearing capacity has driven the development of modern high-strength steels (HSS). The ability to take full advantage of these modern HSS is limited by their weldability. Friction stir welding (FSW) can join HSS at low peak temperatures, better preserving the properties of the base material. This work evaluates the influence of different FSW peak temperatures and cooling rates on the properties of a modern HSS. A HSS produced by a thermo-mechanically controlled process was welded by FSW with peak temperatures, measured within the processed zone, ranging from about 900 to 650 °C. Temperatures were measured using thermocouples positioned at the mid-thickness of the workpiece, at 5 to 10 mm from the joint line. The effect of the different peak temperatures was evaluated by mechanical testing, including bending, tensile testing with digital imaging correlation, Charpy impact test, and hardness measurements. Microscopic analyses, including optical microscopy and electron backscatter diffraction, were used to evaluate the microstructure. Results show that FSW enables welding HSS within the intercritical temperature domain. The impact toughness of the best weld condition overmatched the base material by over 37%, at both − 40 and − 60 °C. The yield strength efficiency was about 70%.

Original languageEnglish
Pages (from-to)1173-1185
Number of pages13
JournalWelding in the World
Volume62
Issue number6
DOIs
Publication statusPublished - 1 Nov 2018

Fingerprint

Friction stir welding
High strength steel
Processing
Temperature
Weldability
Mechanical testing
Tensile testing
Thermocouples
Bearing capacity
Electron diffraction
Optical microscopy
Yield stress
Fracture toughness
Loads (forces)
Welding
Welds
Hardness
Cooling
Imaging techniques
Microstructure

Keywords

  • Friction stir welding
  • High-strength steels
  • Mechanical properties
  • Microstructure
  • Temperature

Cite this

Sorger, Gonçalo ; Sarikka, Teemu ; Vilaça, Pedro ; Santos, Telmo G. / Effect of processing temperatures on the properties of a high-strength steel welded by FSW. In: Welding in the World. 2018 ; Vol. 62, No. 6. pp. 1173-1185.
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Effect of processing temperatures on the properties of a high-strength steel welded by FSW. / Sorger, Gonçalo; Sarikka, Teemu; Vilaça, Pedro; Santos, Telmo G.

In: Welding in the World, Vol. 62, No. 6, 01.11.2018, p. 1173-1185.

Research output: Contribution to journalArticle

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