What is hardenability curve?

Hardenability curves are constructed from the results of Jominy Tests. Examples of a few steel alloy curves are shown in Figure 4. With a diminishing cooling rate (steeper drop in hardness over a short distance), more time is allowed for carbon diffusion and the formation of a greater proportion of softer pearlite.

What is hardenability explain the hardenability test shortly?

The hardenability is defined as the ability of the steel to partially transform from austenite to martensite at a given depth below the end surface, when cooled under a given condition.

What is hardenability and explain the Jominy end quench test?

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 of conditions.

What are the factors that influence the hardenability curve?

The major factors affecting hardenability and the rate of austenite transformation are carbon content, grain size, and alloying elements.

How is hardenability measured?

The hardenability of a ferrous alloy is measured by a Jominy test: a round metal bar of standard size (indicated in the top image) is transformed to 100% austenite through heat treatment, and is then quenched on one end with room-temperature water.

What do you understand by hardenability of steel?

What is hardenability explain in sufficient detail how does it differ from hardness?

Recap. To recap: hardness is how hard the actual steel is based on the resistance of penetration. Hardenability is the potential the steel has to be hardened by thermal treatment. Each of these has tests associated to come up with a measurement that is quantifiable.

What is a Jominy curve?

Jominy curves provide an excellent indicator of relative steel hardenability. Figure 29.10. Jominy curve comparison of the hardenability of one unalloyed and a number of other different alloy steels. The Jominy test provides valid data for steels having an ideal diameter from about 25 to 150 mm (1 to 6 in.).

What is hardenability of material?

The hardenability is defined as the ability of the steel to partially transform from austenite to martensite at a given depth below the end surface, when cooled under a given condition. From: Comprehensive Materials Processing, 2014.

Why is knowing hardenability important?

To select a steel for a component that will be heat treated, it is important to know its hardenability. Both alloying and microstructure affect the hardenability, allowing the correct steel and quenching rate to be selected. Prior processing of the steel also affects the microstructure and should be considered.

How is hardenability determined?

Hardenability is usually determined by the Jominy end-quench test. The method involves machining a piece of steel to specific dimensions, heating the steel to its appropriate austenitizing temperature followed by spraying a volume of water onto the end face of the bar.

What is hardenability describe a test that is used for determination of hardenability of steel?

Hardenability describes the capacity of the steel to harden in depth under a given set of conditions. For example, a steel of a high hardenability can transform to a high fraction of martensite to depths of several millimeters under relatively slow cooling, such as an oil quench.