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Liquid state quenchs defect of medium general character
From;    Author:Stand originally
In research tap water serves as quench in the article of the two big drawback of medium, accessary the drawback that posed liquid state to quench medium has two general character. One of defect are: A kind of any certain liquid state quench medium, have quite limited suitable scope only, use at the requirement the workpiece of higher cooling rate, temper by dipping in water not hard; Use at the requirement the workpiece of lower cooling rate, meet again temper by dipping in water is cracked. Of defect is: When should quenching workpiece comes down from the characteristic temperature refrigeration of prep above medium, often produce cooling rate mutation in the local district of workpiece, because this causes very great internal stress, cause out of tolerance possibly thereby quench be out of shape. The article quenchs comprehensive discussion liquid state medium the defect of these two general character, is all sorts of measure that the introduction overcomes the first kind of weakness mainly.
One about the first defect
Of tap water and N32# engine oil cold fast curve is comparative
Certain work " oily temper by dipping in water is not hard, water temper by dipping in water should be cracked " once was a difficult problem that puzzles heat treatment production. Investigate its reason, common engine oil and tap water have limited suitable scope only. From cooling rate distributinging circumstance looks, there is a quite wide blank region between tap water and common engine oil, if pursue,1 is shown. With fill this one blank is a target, carry work of a few years, research was developed a variety of oily with medium of ability in swimming, basically fill the blank between water and common engine oil. To now, quench commonly usedly medium, by cooling rate by arrive slow fast order arranges: The isotherm with use higher temperature classifications quenching oil (hot oil) , the isotherm with common engine oil, use inferior temperature classifications quenching oil (half heat is oily) , in fast quenching oil, fast quenching oil, it is PAG of tall pH indicator quenchs subsequently fluid, medium pH indicator PAG quenchs PAG of fluid, low pH indicator quenchs fluid, salt of tap water, low density (alkaline perhaps) water. They have respective actor defect and respective suitable scope. A kind of quenching oil is a kind quench certainly medium. Quenching medium of akin ability in swimming, match different chroma, quench differently namely medium. The blank between fill tap water and common engine oil, need so much is planted quench differently medium! This is the decision of place of the first defect of general character of liquid state medium. Current high tension enrages temper by dipping in water, make choice of a kind of proper gas, through changing atmospheric pressure, can obtain Cong Jing to stop air is cold the different and cooling effect to medium fast quenching oil. Under photograph comparing, this defect of liquid state medium is honest also too serious.
The 2 measure that overcome weakness of the first kind of general character
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