Presentation on theme: "Annealing Annealing is done to improve ductility (the ability to be drawn and extruded) and reduce brittleness. Annealing consists of softening the."— Presentation transcript:
Annealing Annealing is done to improve ductility (the ability to be drawn and extruded) and reduce brittleness. Annealing consists of softening the metal by heating it between 30 & 50 degrees C above it upper critical point and allowing it to cool slowly. This can be done in either hot sand, ashes of a fire or by leaving the metal in an oven or furnace until cooled.
Tempering Tempering is done to remove some of the brittleness and hardness of steel after hardening. Suitable temperatures for tempering vary considerably Tempering by colour still provides an accurate and reliable method of dealing with plain carbon steels Hacksaws blades 220.C Pen knifes 250.C Light brown
Normalising The main purpose of normalising is to obtain a structure that is uniform throughout the work piece and is free from any ‘locked up’ stresses. Similar to annealing, but the cooling rate is accelerated by taking the work piece from the furnace and allowing it to cool in free air. This more rapid cooling results in a finer grain structure which in turn leads to improved physical properties and improved finishes when machining.
Hardening Hardening of steels is done to increase the strength and wear properties. Carbon steel is heated 30 & 50 degrees C above the upper critical point and then quenched quickly The quicker the steel is cooled the harder it will be.
Assignment- Heat Treatment and work hardening of metals Aim: The aim of this experiment is to test the effects of hardening then tempering a piece of medium carbon steel to a level required for a punch Hypothesis: I predict that after hardening…….. Method: Hardening……. Results/ Testing….After filing and hammering Conclusion: After the results