Forging Heat Treatment Process – Tempering for Open and Closed Die Forgings
Here we will know a little bit more about Tempering In Heat Treatment for Open and Closed Die Forging
A process in which part has to heat steel not more than its lower critical temperature and cool at specified temperature calls tempering. Tempering is the last heat treatment operation. Steel gains required mechanical properties by tempering operation. Tempering removes or decreases internal stresses. Stress generated in parts due to processes relieves during maintenance of same temperature for 15 to 30 minutes. Maintaining parts at specified temperature for 1 hour and 30 minutes and stress comes to its most possible lowest value. Rate of cooling after tempering also performs important role in stress relieving. Low cooling rate means less stresses.
Temperature of tempering also controls mechanical properties of a material. If tempering done on low temperature of 150 0C to 250 0C then strength and toughness of part increases. Friction resistance increases during this process. We get hardness till 58 to 64 Rockwell through this process. Cutting and measuring tools are tempers on low temperature.
Tempering temperature in the range of 350 0C to 500 0C calls medium tempering temperature. We can gain highest possible elasticity and increase toughness by this process. We get hardness till 40 to 50 Rockwell through this process.
Tempering temperature in the range of 500 0C to 680 0C calls high temperature tempering. This process can remove total internal stresses of steel parts. Material’s impact strength increases. Found decrease in strength and hardness but it still has better values then values after annealing. Increases yield point, endurance limit and impact strength. Because of reduction in hardness friction resistance property doesn’t found well. Ductility and toughness increases due to tempering.
we will see Hardening Forging Heat Treatment Process in next article. This article publish by Forging Company India.
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