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Leif Karlsson

Professor

Staff member at Division of Welding Technology.

Conducts research in engineering and technology, production technology.


Research area/research interest

The focus of the research is welding technology and specifically welding metallurgy. The aim is to understand, predict and control the relations between on the one hand weld metal compositions, the welding process and procedure and on the other hand weld metal microstructure and properties.

Teaching/supervision

Leif supervises PhD students working with fatigue of welded components, welding of super duplex stainless steels, welding of new alloys for automotive applications and heat treatment of tool steels. He also teaches in the course "Welding Technology" at University West.

Keyword

Welding technology, high strength steels, super duplex stainless steels, tool steels.


Publications


A New Approach to the Study of Multi-Pass Welds–Microstructure and Properties of Welded 20-mm-Thick Superduplex Stainless Steel

Published

A New Approach to the Study of Multi-Pass Welds–Microstructure and Properties of Welded 20-mm-Thick Superduplex Stainless Steel

Type 2507 superduplex stainless steel 20 mm in thickness was multi-pass-welded with Gas Metal Arc Welding (GMAW) and Flux-Cored Arc Welding (FCAW)...

A new EBSD based methodology for the quantitative characterisation of microstructures formed by displacive fcc–bcc transformations

Published

A new EBSD based methodology for the quantitative characterisation of microstructures formed by displacive fcc–bcc transformations

This work is concerned with a new methodology that can be used to quantify the degree to which grains in the microstructure are aligned in the form...

A novel arc heat treatment technique for producing graded microstructures through controlled temperature gradients

Published

A novel arc heat treatment technique for producing graded microstructures through controlled temperature gradients

This paper introduces a novel arc heat treatment technique to produce samples with graded microstructures through the application of controlled...

Applicability of Low Transformation Temperature welding consumables to increase fatigue strength of welded high strength steels

Published

Applicability of Low Transformation Temperature welding consumables to increase fatigue strength of welded high strength steels

Application of Low Transformation Temperature (LTT) consumables in welding is a recent approach to increase the fatigue strength of welds. In this...

Cold laps - micro-lack of fusion defects in steel arc welds : a review

Published

Cold laps - micro-lack of fusion defects in steel arc welds : a review

Correction to : Time-temperature-precipitation and property diagrams for super duplex stainless steel weld metals (Welding in the World, (2018), 62, 3, (517-533), 10.1007/s40194-018-0548-z)

Published

Correction to : Time-temperature-precipitation and property diagrams for super duplex stainless steel weld metals (Welding in the World, (2018), 62, 3, (517-533), 10.1007/s40194-018-0548-z)

Unfortunately due to typesetting mistakes, Tables 4-€“6 have been displayed erroneously in the article. © 2018, International Institute of Welding.

Correlation between laser welding sequence and distortions for thin sheet structures

Published

Correlation between laser welding sequence and distortions for thin sheet structures

Thin ultra-high strength steel shaped as 700 mm long U-beams have been laser welded in overlap configuration to study the influence of welding...

Distortion Analysis in Laser Welding of Ultra High Strength Steel

Published

Distortion Analysis in Laser Welding of Ultra High Strength Steel

Due to increased demands on reduced weight in automotive industries, the use of ultra high strength steels (UHSS) has increased. When laser welding...

Editorial: Work-Integrated Learning in Scandinavia

Published

Editorial: Work-Integrated Learning in Scandinavia

Effect of Austenitization and Tempering on the Microstructure and Mechanical Properties of a 5 wt% Cr Cold Work Tool Steel

Published

Effect of Austenitization and Tempering on the Microstructure and Mechanical Properties of a 5 wt% Cr Cold Work Tool Steel

The effects of austenitization and tempering temperatures for a 5 wt% Cr cold work tool steel are studied with an aim of understanding the influenc...

Effect of HFMI treatment procedure on weld toe geometry and fatigue properties of high strength steel welds

Published

Effect of HFMI treatment procedure on weld toe geometry and fatigue properties of high strength steel welds

The effects of high frequency mechanical impact (HFMI) treatment procedure on the weld toe geometry and fatigue strength in 1300 MPa yield strength...

Effect of high frequency mechanical impact treatment on fatigue strength of welded 1300 MPa yield strength steel

Published

Effect of high frequency mechanical impact treatment on fatigue strength of welded 1300 MPa yield strength steel

High frequency mechanical impact (HFMI) is a recent post weld treatment method which can be employed to increase the fatigue strength of welded...

Effect of interpass temperature on residual stresses in multipass welds produced using low transformation temperature filler alloy

Published

Effect of interpass temperature on residual stresses in multipass welds produced using low transformation temperature filler alloy

Weld filler alloys that exploit transformation plasticity through low austenite to martensite transformation temperatures offer an effective method...

Effect of Laser Welding Parameters on Porosity of Weldsin Cast Magnesium Alloy AM50

Published

Effect of Laser Welding Parameters on Porosity of Weldsin Cast Magnesium Alloy AM50

Pores in the weld metal lower the mechanical properties of the weld. It is therefore important to understand the pore formation mechanisms and find...

Effect of multipass TIG welding on the corrosion resistance and microstructure of a super duplex stainless steel

Published

Effect of multipass TIG welding on the corrosion resistance and microstructure of a super duplex stainless steel

This is a study of the effect of repetitive TIG (tungsten inert gas) welding passes, melting and remelting the same material volume on microstructu...

Effect of shielding gas on welding performance and properties of duplex and superduplex stainless steel welds

Published

Effect of shielding gas on welding performance and properties of duplex and superduplex stainless steel welds

The influence of shielding gases on welding performanceand on properties of duplex and superduplex stainlesssteel welds was studied. Using argon as...

Effect of sigma phase morphology on the degradation of properties in a super duplex stainless steel

Published

Effect of sigma phase morphology on the degradation of properties in a super duplex stainless steel

Sigma phase is commonly considered to be the most deleterious secondary phase precipitating in duplex stainless steels, as it results in an extreme...

Effect of welding position on properties of duplex and superduplex stainless steel circumferential welds

Published

Effect of welding position on properties of duplex and superduplex stainless steel circumferential welds

The influence of welding position on properties ofduplex and superduplex stainless steel welds was studied. Circumferential pipe welds were produce...

Effects of Austenitisation Temperature and Multiple Tempering on the Microstructure and Impact Toughness of a 5 wt. % Cr Cold Work Tool Steel

Published

Effects of Austenitisation Temperature and Multiple Tempering on the Microstructure and Impact Toughness of a 5 wt. % Cr Cold Work Tool Steel

The microstructure and properties of a 5 wt.% Cr cold work tool steel were studied after austenitisation at 1020°C, 1050°C or 1075°C followed by...

Effects of dilution and baseplate strength on stress distributions in multipass welds deposited using low transformation temperature filler alloys

Published

Effects of dilution and baseplate strength on stress distributions in multipass welds deposited using low transformation temperature filler alloys

Transformation plasticity can be utilised to control residual stresses in steel welds. This requires special filler alloys that transform at a...

Efficient welding of high strength steel

Published

Efficient welding of high strength steel

 Producing welds with properties matching those of the steel is a challenge at high strength levels. The present study investigated how cooling rat...

Ferrite content measurement in super duplex stainless steel welds

Published

Ferrite content measurement in super duplex stainless steel welds

Approaches to determining ferrite fraction (%) and ferrite number (FN) were examined for super duplex stainless steel (SDSS) welds. A reference...

Going global!

Published

Going global!

Identification of Weld Residual Stresses Using Diffraction Methods andtheir Effect on Fatigue Strength of High Strength Steels Welds

Published

Identification of Weld Residual Stresses Using Diffraction Methods andtheir Effect on Fatigue Strength of High Strength Steels Welds

It is well known that fatigue strength of welded joints does not depend on steel strength. Better fatigue strength of welded joints, e.g. longer li...

Improving fatigue strength of welded 1300 MPa yield strength steel using HFMI treatment or LTT fillers

Published

Improving fatigue strength of welded 1300 MPa yield strength steel using HFMI treatment or LTT fillers

Fatigue improvement techniques are widely used to increase fatigue strength of welded high strength steels. In this paper high frequency mechanical...

Increasing fatigue life using Low Transformation Temperature (LTT) welding consumables,

Published

Increasing fatigue life using Low Transformation Temperature (LTT) welding consumables,

Influence of dilution on properties of high strength steel weld metals

Published

Influence of dilution on properties of high strength steel weld metals

Influence of low energy laser welding on solidification and microstructure of austenitic stainless steel welds

Published

Influence of low energy laser welding on solidification and microstructure of austenitic stainless steel welds

Primary austenitic solidification is related to increased hot cracking susceptibility in welding of austenitic stainless steels. It is also...

Influence of multiple thermal cycles on microstructure of heat-affected zone in TIG-welded super duplex stainless steel

Published

Influence of multiple thermal cycles on microstructure of heat-affected zone in TIG-welded super duplex stainless steel

The influence of heat input and multiple welding cycles on the microstructure of the heat-affected zone in autogenously TIG-welded 6 mm 2507 type...

Influenza del gas di protezione sul comportamento e le proprietà  di giunti sa dati di acciai duplex e superduplex : Effect of shielding gas on welding performance and properties of duplex and superduplex stainless steel welds

Published

Influenza del gas di protezione sul comportamento e le proprietà  di giunti sa dati di acciai duplex e superduplex : Effect of shielding gas on welding performance and properties of duplex and superduplex stainless steel welds

The influence of shielding gases on welding performance and on properties of duplex and superduplex stainless steel welds was studied. Using argon ...

Low Porosity in Cast Magnesium Welds by Advanced Laser Twin-Spot Welding

Published

Low Porosity in Cast Magnesium Welds by Advanced Laser Twin-Spot Welding

Porosity is reported to be a major issue when welding cast magnesium. Therefore, it is important to understand the pore formation mechanisms and fi...

Metallurgical effects and distortions in laser welding of thin sheet steels with variations in strength

Published

Metallurgical effects and distortions in laser welding of thin sheet steels with variations in strength

Geometrical distortions occur while welding, but the understanding of how and why they occur and how to control them is limited. The relation betwe...

Microstructure and functionality of a uniquely graded super duplex stainless steel designed by a novel arc heat treatment method

Published

Microstructure and functionality of a uniquely graded super duplex stainless steel designed by a novel arc heat treatment method

A novel arc heat treatment technique was applied to design a uniquely graded super duplex stainless steel (SDSS), by subjecting a single sample to ...

Monitoring Thermal Cycles in Multi-pass Welding

Published

Monitoring Thermal Cycles in Multi-pass Welding

Differently from any previous investigation in welding, this research work presents a novel development that allows temperature to be measured and...

Multipass Autogenous TIG Welding of Super Duplex Stainless

Published

Multipass Autogenous TIG Welding of Super Duplex Stainless

Multipass welding of super duplex stainless steels (SDSS) needs further characterization due to their growing applications inpetrochemical and...

Mäthjul Volvo Personvagnar : utvärdering inför inköp

Published

Mäthjul Volvo Personvagnar : utvärdering inför inköp

Neutron Diffraction Evaluation of Near Surface Residual Stresses at Welds in 1300 MPa Yield Strength Steel

Published

Neutron Diffraction Evaluation of Near Surface Residual Stresses at Welds in 1300 MPa Yield Strength Steel

Evaluation of residual stress in the weld toe region is of critical importance. In this paper, the residual stress distribution both near the surfa...

Neutron Diffraction Studies of Residual Stress Distribution in the Vicinity of the Single Pass Fillet Steel Welds

Published

Neutron Diffraction Studies of Residual Stress Distribution in the Vicinity of the Single Pass Fillet Steel Welds

In this contribution the results of residual strain/stress measurements performed on several single pass fillet steel welds, which were carried out...

Nitrogen loss and effects on microstructure in multipass TIG welding of a super duplex stainless steel

Published

Nitrogen loss and effects on microstructure in multipass TIG welding of a super duplex stainless steel

Nitrogen loss is an important phenomenon in welding of super duplex stainless steels. In this study, a super duplex stainless steel was autogenousl...

Non-destructive measurement of weld toe radius using Weld Impression Analysis, Laser Scanning Profiling and Structured Light Projection methods

Published

Non-destructive measurement of weld toe radius using Weld Impression Analysis, Laser Scanning Profiling and Structured Light Projection methods

Optimising Quality and Productivity in Welding of Duplex and Superduplex Stainless Steels

Published

Optimising Quality and Productivity in Welding of Duplex and Superduplex Stainless Steels

The aim of this work was to study the influence of shielding gases and welding positions on properties of duplex and superduplex stainless steel...

Orientation relationships of intragranular austenite in duplex stainless steel weld metals

Published

Orientation relationships of intragranular austenite in duplex stainless steel weld metals

Formation and characteristics of fine intragranular austenite were studied for low energy input duplex stainless steel welds. Microstructures were...

Physical and kinetic simulation of nitrogen loss in high temperature heat affected zone of duplex stainless steels

Published

Physical and kinetic simulation of nitrogen loss in high temperature heat affected zone of duplex stainless steels

High temperature heat affected zone (HTHAZ) of duplex stainless steels is prone to local corrosion attack due to a high ferrite fraction and nitrid...

Productivity Aspects in Submerged Arc Welding of Thick High-Strength Steels

Published

Productivity Aspects in Submerged Arc Welding of Thick High-Strength Steels

A series of welding tests were made on 35 mm thick F500W high strength steel. This specific steel grade is developed for use in arctic conditions,...

Residual stress distribution measurement by neutron diffraction of the single pass fillet steel welds

Published

Residual stress distribution measurement by neutron diffraction of the single pass fillet steel welds

In this contribution the results of residual strain/stress measurements performed on several single pass fillet steel welds which were carried out ...

Residual stress distributions at high strength steel welds prepared by low transformation temperature (LTT) and conventional welding consumables

Published

Residual stress distributions at high strength steel welds prepared by low transformation temperature (LTT) and conventional welding consumables

Residual stress distributions in fillet welds in 8 mm 900 MPa steel have been mapped perpendicular and parallel to the weld line and also through t...

Retained Austenite Transformation during Heat Treatment of a 5 Wt Pct Cr Cold Work Tool Steel

Published

Retained Austenite Transformation during Heat Treatment of a 5 Wt Pct Cr Cold Work Tool Steel

Retained austenite transformation was studied for a 5 wt pct Cr cold work tool steel tempered at 798 K and 873 K (525 degrees C and 600 degrees C)...

Retained austenite transformation during heat treatment of a 5wt.% Cr cold work tool steel

Published

Retained austenite transformation during heat treatment of a 5wt.% Cr cold work tool steel

Role of inclusions in formation of high strength steel weld metal microstructures

Published

Role of inclusions in formation of high strength steel weld metal microstructures

A series of high strength weld metals with varying Al content are studied. The inclusions are characterised using energy dispersive X-ray analysis...

Spinodal Decomposition in Functionally Graded Super Duplex Stainless Steel and Weld Metal

Published

Spinodal Decomposition in Functionally Graded Super Duplex Stainless Steel and Weld Metal

Low-temperature phase separations (T < 500 °C), resulting in changes in mechanical and corrosion properties, of super duplex stainless steel (SDSS)...

Research projects