Welding wires for un and low alloyed steels

Steel is available in many grades, usually the yield strength must be respected when choosing the suitable filler metal. The most common type is S355 that indicates that the yield strength is at least 355 N/mm2, usually this type of steel requires no special instructions for preheat or interpass temperature or the thickness have to be very thick. The last years more and more higher strength steels are applied such as: S460, S690, S890, X70, X80, HY 100 etc. in order to make thinner constructions and save weight and welding cost. How higher the yield strength how tighter the restrictions are, think about heat input, interpass and preheat temperature to achieve the right cooling speed (T8/5) to obtain the required mechanical properties.