Study of microstructure and mechanical properties of friction stir welded ferrite-martensite DP700 steel

Mahdi Mahmoudiniya1, 2*, Leo A.I. Kestens2, 3, Shahram Kheirandish1, Amir Hossein Kokabi4

1School of Metallurgy and Materials Engineering, Iran University of Science and Technology (IUST), Tehran, 16846-13114, Iran​​​

2Department of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, Delft, 2628 CD, the Netherlands​

3Metals Science and Technology Group, Ghent University, Ghent, Technologiepark 903 B-9052 Zwijnaarde, Belgium

4Department of Materials Science and Engineering, Sharif University of Technology, Tehran, 11365-11155, Iran

DOI: 10.5185/amlett.2019.2211

Publication Date (Web): Jan 10, 2019



In the present study, a 2 mm thick ferrite-martensite dual phase steel was subjected to friction stir welding. The welding was conducted by a tungsten carbide tool at a constant rotational speed of 800 rpm and various feed rates of 50, 100 and 150 mm/min. The microstructural features of friction stir welded joints were characterized by field emission - scanning electron microscopy as well as by transmission electron microscopy. The relationship between microstructure and tensile properties of the joints was investigated. Results showed that the stir zone of the welds consisted of bainite packets, exhibiting a different morphology compared to the ferrite phase and to the martensite phase. Microstructural examination of the heat affected zone showed that there is a softened region in the heat affected zone in all joints, irrespective of the welding speed. Decomposition of the martensite phase during tempering of the initial martensite of the base material was responsible for the observed hardness reduction. The decrease of the hardness in the softened zone was 28 ± 3, 21 ± 2.5 and 15 ± 3.2 HV for welding speeds of 50, 100 and 150 mm/min, respectively; whereby the base material exhibited a hardness of 275 ± 3 HV. The lower softening corresponded to the higher welding speed, i.e., under conditions whereby heat input to the weld was minimum. The tensile test results showed that the ultimate tensile strength of all welded joints is lower than the base metal and failure takes place in the softened region of the joints. The increment of welding speed increased the strength of the joint so that the weld conducted at the highest welding speed (150 mm/min) showed the highest tensile strength of 687 MPa, i.e. 95% of the strength of the base metal (723 MPa).


Friction stir welding, ferrite-martensite dual phase steel, mechanical properties, microstructure.

Current Issue

Artificial intelligence and machine learning empowering the mass medicine

Piezo-therapy in cancer: Current research and perspectives

Magnetic microwires for sensor applications

A fundamental study on the mechanistic impact of repeated de- and rehydration of Ca(OH)2 on thermochemical cycling in technical scale

Fabrication and characterization of nano-bridge Josephson junction based on Fe0.94Te0.45Se0.55 thin film

Riboflavin-UVA gelatin crosslinking: Design of a biocompatible and thermo-responsive biomaterial with enhanced mechanical properties for tissue engineering

Broadband and fast photodetectors based on multilayer p-MoTe2/n-WS2 heterojunction with graphene electrodes

Ionic liquid [BMIM][Cl] immobilized on cellulose fibers from pineapple leaves for desulphurization of fuels

Synthesis and role of co-dopants (alkaline earth divalents and halides) on the photoluminescence of Eu2+ doped BaAl2O4 phosphor

Metal oxide (V2O5) incorporated fly ash based geopolymer for better sustainable engineering composites

Highly efficient storage of solar gains using aluminum foam heat exchangers  

Green fabrication of zinc oxide nanospheres by aspidopterys cordata for effective antioxidant and antibacterial activity

Effect of diamantane on the thermal stability of cryomilled aluminum alloy

Previous issues

Tech-footprints for virtual medicine

Advances in corrosion inhibition materials and technologies: A review

Ring models of atoms, molecules and nanomaterials

(FeCo/Ppy@C): Pt-free FeCo-Polypyrrole Nanocomposites Supported on Porous Carbon for Electrochemical Application

Physical and mechanical properties of microwave absorber material containing micro and nano barium ferrite  

Formation of nano-dispersed Cu particles during aging of a Fe-Cu alloy and dislocation effect

Preparation of novel tragacanth gum-entrapped lecithin nanogels 

Modulation of optical properties with multilayer thickness in antimonene and indiene   

Bi-doped CH3NH3PbI3 effective masses and electronic properties research: A theoretical study using VASP

Novel synthesis of Pd nanosheets used as highly sensitive SERS substrate for trace fluorescent dye detection 

Silver nanoparticles mediated by extract of Guar plant (Cyamopsis tetragonoloba), and evaluation of their photocatalytic and antibacterial properties

Study of TiO2 nanofibers prepared by electrospinning technique

Determination of leachate pollution content in soil using in-situ dielectric measurement  

Upcoming Congress

Knowledge Experience at Sea TM