Hardening is a broad topic and Flame hardening and Shot peening are just a form/type of hardening.
Don't be too concerned that you cannot find it in any Eng St textbooks. Questions in the HSC do not ask specifically "What is Flame Hardening?" but rather "Name two methods of hardening and why you would use these methods?" So they are very open ended to see what knowledge you have on the topic.
Short answer to your question, no Flame hardening and shot peening are not in syllabus specifically, but hardening and heat treatment is. (Confused?)
In other words, the more you know about everything, the better you will be in the exams. The freedom Eng St gives you on what you NEED to know is scary and liberating.
