40) For annealing hypoeutectoid steel according to the carbon content, it should be heated to

30 Degree Centigrade to 50 Degree Centigrade above the lower critical point

30 Degree Centigrade to 50 Degree Centigrade above the upper critical point

600 Degree Centigrade to 630 Degree Centigrade

1000 Degree Centigrade to 1030 Degree Centigrade

Answer is:

30 Degree Centigrade to 50 Degree Centigrade above the upper critical point

Sodium carbonate

Sodium sulphate

Sodium cyanide

Barium chloride

Answer is:

slowly in the furnace itself by switching the heat supply off

by removing the piece from the furnace and allowing it to cool in open air

by removing the piece from the furnace and placing it under a blast of air

by removing the piece from the furnace and dipping it in a tank containing water

Answer is: