• Energy Research

The paper presents results of impact energy effects on real welded specimens of fine- grained high-strength S960QL steel, and elaborates the dependence of real welded specimen hardness on heat input. Results are obtained through measuring of hardness HV 10 and by experimental Charpy V-notch test. V- notch on test tubes was moved for 0, 5mm from the fusion line in the heat affected zone.

This paper presents the results of weldability investigation on welded joints made of fine - grained high-strength S1100QL steel. The investigations are performed on two welded plates by HV 10 hardness measuring and by Charpy V notch testing at different test temperatures. Mechanical properties of welded joints are overviewed, along with welded parameters, all of which enable obtaining of high-quality welded joints.

In this paper the influence of silicon content of 3,1 to 5,4 wt. % on the tensile properties, hardness and impact energy of ferritic ductile iron was analysed. It was found that silicon strengthens the ferrite, resulting in an increase in yield strength and tensile strength with increasing silicon content up to 4,22 wt. %. Elongation and impact energy decreases and the hardness increases with increasing silicon content. Since ferritic ductile irons alloyed and strengthened by silicon have a higher Rp0,2/Rm ratio and a higher elongation than conventional ferritic, ferritic/pearlitic and pearlitic ductile irons at the same level of tensile strength, we can expect an increased demand for these materials in applications where high resistance to impact load and low temperature impact properties are not required.

The research objective was to test the parameters of real welding of the high-strength micro-alloyed S1100QL steel against the hardness and impact energy. The samples were welded at different welding parameters. Results of measuring the HV10 hardness and of experimental Charpy V-notch test performed at different temperatures are presented in tables and diagrams. This paper presents also the welding parameters, which provides a high quality welded joint without cold cracks.

Abstract Hot rolled plate steel is heat treatable steel made in Indonesia for commercially developed to Quenched and Tempered Steel. This steels made by PT. Krakatau Steel (Persero) Cilegon, Banten, Indonesia. The aim of this study to improve the hardness and energy impact through heat treatment of double quench + temper. The method used is heating up to 900°C (maintained for 30 minutes and cooled by water) for fives specimen hot rolled plate steel and produce the quenched 900 steel (Q900 Steel). Four Q900 steel specimens were heated at 750°C, 800°C, 850°C, and 900°C (maintained for 30 minutes) each. Then five specimens (include Q900 Steel) are tempered at 150°C (maintained for 30 minutes) and produced Q900 & T Steel, Q900+750 & T Steel, Q900+800 & T Steel, Q900+850 & T Steel, Q900+900 & T Steel. Results of the study were changes in microstructure, hardness and impact energy. Hardness and impact energy absorbed of Q900+750&T Steel higher than Q900 &T Steel.