In this research, the 600 MPa acid resistant steel was used as flash butt welding base material, to study effect of different upset allowance on microstructure and mechanical properties joints. The results can be obtained follows: with increase allowance, it has a significant elongation, ferrite content in heat affected zone increases, joint strength first increases then slowly decreases. When ...

Abstract In the present work different approaches to improve mechanical properties of a resistance spot welded 1200 MPa transformation induced plasticity-aided bainitic ferrite steel are evaluated. An extension welding time results in coarsening microstructure outer fusion zone and maximum force derived by cross tension strength test did not significantly. A temper pulse after long cooling lead...

The paper demonstrates the capability of developed phase transformation model to design cooling conditions in Stelmor process allowing for obtaining different types microstructures wire rod 32CrB4 steel. based on modified JMAK equation was using results tests conducted a DIL 805 A/D/T dilatometer. is composed sub-models ferritic, pearlitic, bainitic and martensitic transformations. Its predicti...

The current study reports in situ TEM observations of the growth bainitic ferrite an Fe-0.3C-3Mn-1.5Si-0.15Mo steel held isothermally at 300 °C with a higher spatio-temporal resolution than previous studies. Significant variations were found lengthening rate, highest being excess 30,000 nm.s−1 while more common rates 10–1000 provided quality observations. Both sheaves visible sub units and indi...

Experimental results and explanations for the transition temperature from upper to lower bainites in carbon steels containing from 0.20 to 1.80 wt%C were presented metallographically and kinematically. The experimental results are summarized as follows: I) Lower bainite is not formed in steels with less than 0.35 wt%C and no transition from upper to lower bainite occurs. 2) The transition tempe...

There are two well-known phenomena associated with the bainite reaction, both of which have been exploited here to enhance the mechanical behaviour of steel. Firstly, the bainite plate size decreases as the transformation temperature is reduced. Secondly, it is bad to have large regions of untransformed austenite in the microstructure; this is because they can transform, under the influence of ...

The microstructural evolution and properties for varied austempering routes are investigated in a cold-rolled bainitic steel. Special attention is given to the effect of retained austenite (RA) terms its fraction, carbon concentration, morphology resulting from different on mechanical stretch flangeability. Bimodal sized laths provided, concentration RA maintains highest value through two-step ...

the influence of aluminium on the microstructure of austempered ductile cast iron (adi) has been studied. the presence of well distributed graphite in the matrix, and a relatively high volume fraction of retained austenite are responsible for the good mechanical properties of the aluminium alloyed austempered ductile irons including excellent wear resistance, higher resistance to thermal shock,...

The boron-free S700MC steel is usually produced by exploiting the properties of a ferrite-bainite mixed microstructure formed coiling strips at temperature about 450?C, i.e.below bainite starting temperature. With aim further enhancing mechanical 6 to 10 mm thick strips, industrial tests were carried out 600?C promote formation structure ferrite and carbides, which also acceptable for this type...