Bulletproof Welding Procedures for Q&T Steels

The applications for high hardness quenched and tempered (Q&T) steel plate has greatly increased in recent years. Q&T steels used in the hard rock mining industry have allowed miners to greatly increase productivity of equipment exposed to the most gruelling of environments, while similar alloys manufactured to military standards are used to provide additional protection from high velocity projectiles in ballistic applications. As the use of these heat treated alloys has increased so has the demand for cost effective fabrication and joining methods. Traditional welding procedures when applied to Q&T steel often result in significantly reduced performance and in the worst case, premature weldment failures. This presentation will review the fundamentals of welding Q&T steels, the practices and pitfalls, common to these alloys and the details of successful welding procedures both with and without the need for preheat.