The Jominy end-quench test is used to measure the hardenability of a steel, which is a measure of the capacity of the steel to harden in depth. Jominy Test and Hardness Depth. Thanks to Walter Jominy (the Chief Metallurgist of Chrysler Corporation sometime before the war), there is a simple but. The Jominy end quench test is used to measure the hardenability of a steel, which is a measure of the capacity of the steel to harden in depth under a given set.
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The Jominy End Quench Test
General Remarks to Literature and Sources. Overview of Major Steels.
Alloying Elements in Detail. Jominy Test and Hardness Depth.
Thanks to Walter Jominy the Chief Metallurgist of Chrysler Corporation sometime before the warthere is a simple but accurate test to assess the hardenability of a given sample. Just take a jomijy size sample The cooling rate will be different from one end to the other of the sample, and all you do after it has cooled down completely, is to measure the hardness along its twst. What you might find is shown to the right of the test set-up.
Plain carbon steel with sufficient carbon e.
Hardenability – Wikipedia
Now add some CrV jominu, MnNior Mo or some other suitable elementsand if you do everything right, you may obtain the blue curves – steels with good hardenability and a much larger hardening depth.
The hardening depth is around 10 mm for the carbon iron the exact number depends on how you define it in this example.
For the alloy steel it is larger, they are hard for at least 25 mm. However, the high-carbon steel etst the hardest for the first few millimeters.
jmoiny You can also use the Jominy test for checking the efficiency of your cooling fluid. The next picture tells it all:. Adopted from a ” Key to Metals ” article. Assume that a steel bar with a certain diameter is cooled completely in a medium as shown.
What is shown is the relation of the hardness values you get throughout the material relative to the hardness you get at a certain distance from cooling only the end in the same medium is what is shown For example, if you can live with the hardness you get 2 cm from the end of a bar in a Jominy test red lineyour bar can gave a diameter of about 10 cm blue line and will have that hardness everywhere if you cool with maximal cooling rate liquid nitrogen, for example.
Cooling in some well circulated oil is less efficient, the bar diameter goes down to about 6 cm violet line. We now could assess the efficiency of all that disgusting stuff the ancient smiths used for quenching their steel: You do the experiments.