Lesson 5: Materials Properties and Treatment - PDF

Lesson 5: Materials Properties and Treatment What is Treatment? Heat treating is an application of hot or cold applied to metal material that alters its metallurgical properties. Over the past dozen years, Jones Metal has developed a state of the art in-house heat treating department,...

Lesson 5: Materials Properties and Treatment What is Treatment? Heat treating is an application of hot or cold applied to metal material that alters its metallurgical properties. Over the past dozen years, Jones Metal has developed a state of the art in-house heat treating department, refining processes to harden, soften or relieve stress on metal parts. Cold and hot treatments can improve machining, advance formability and help restore metal ductility. The 4 Types of Heat Treatment Steel Undergoes Heat TreatmentSteel: Annealing. Heat TreatmentSteel: Normalizing. Heat TreatmentSteel: Hardening. Heat TreatmentSteel: Tempering.  Annealing is a heat treatment process which alters the microstructure of a Annealing material to change its mechanical or electrical properties. Typically,in steels, annealing is used to reduce hardness, increase ductility and help eliminate internal stresses.  The three stages of the annealing process that proceed as the temperature of the material is increased are: Recovery Recrystallization Annealing and grain growth. Stress Relieving is the treatment of a metal or alloy by heating to a predetermined temperature below its lower transformation temperature followed by cooling in air. Normalizing Normalizing is a heat treatment process that is used to make a metal more ductile and tough after it has been subjected to thermal or mechanical hardening processes.... This heating and slow cooling alters the microstructure of the metal which in turn reduces its hardness and increases its ductility A heat treatment process consisting of austenitizing at temperatures of 30–80˚C above the AC3 transformation temperature followed by slow cooling (usually in air) Hardening The hardening process consists of heating the components above the critical (normalizing) temperature, holding at this temperature for one hour per inch of thickness cooling at a rate fast enough to allow the material to transform to a much harder, stronger structure, and then tempering. Other Heat Treatment process related to Hardening Quenching or Rapid Cooling - is a form of Hardening whereby the metal is heated to a temperature above the critical point then quickly immersing it into a cold water or other cooling medium. Cyaniding - is case of Hardening with powdered potassium cyanide or potassium ferrocyanide mixed with potassium bicarbonate substituted for the carbon Nitriding - is a Surface Hardening accomplished by heating certain steel alloys immersed in ammonia fumes Tempering also known as Drawing , in metallurgy, process of improving the characteristics of a metal, especially steel, by heating it to a high temperature, though below the melting point, then cooling it, usually in air. The process has the effect of toughening by lessening brittleness and reducing internal stresses. Purposes of Heat Treatment Remove Strains after cold working Remove internal stresses such as those produced by drawing, bending or welding Increase the hardness of the material Improve machinability Improve the cutting properties of the tools Increase wear-resistance properties Soften the material as annealing Improve or change the physical properties of the material such as: Corrosion Resistance, heat resistance and magnetic properties or other are required