101) What is the temperature that change of structure to austenite starts at 723? in heat treatment process?

102) What is the process if hot steel is cooled slowly the old structure is retained and it will have fine grains that makes it easily machined?

103) What is the name if hot steel cooled rapidly to form a new structure ?

104) What is the process to add cutting ability and wear resistance on steel?

105) What is the heat treatment process to remove extreme brittleness and induce toughness and shock resistance in steel?