Influence of phosphorus, aluminium and boron on the property profile of hot-work tool steel X38CrMoV5-1.

The influence of the tramp elements phosphorus (<0.005 to 0.110%), aluminium (0.006 to 0.096%) and boron (<0.0001 to 0.0500%) on the properties of hot-work tool steel X38CrMoV5-1 was determined by Investigating fifteen heats containing different percentages of these elements. Besides certain mechanical properties such as hardness, toughness and fatigue strength - the workability and working properties of this steel were the main objects of research. Phosphorus was found to be responsible for a decrease in toughness as determined In impact bending tests and notched bar impact bending tests. Its embrittling effects also became clear in the investigation of - continuous castability. Finally, phosphorus was causing a slight deterioration in creep rupture strength and resistance to thermal shocks. Increasing amounts of boron brought about a change in solidification behaviour which resulted in a distinct deterioration in continuous castability and hot forming properties. At the same time, toughness was slightly impaired. Percentages of aluminium of up to 0.096% had no influence on the properties of the hot-work tool steel investigated except for a small decrease in toughness.