How do you calculate Jominy distance?

The resulting curve is called ‘Jominy hardenability curve’ and the distance from the quenched-end is known as Jominy distance-J. (1/16″ = one Jominy distance = J1). Fig. 4.18 illustrates typical Jominy curves of some low alloy steels.

What is Jominy value?

Hardenability is a measure of the capacity of a steel to be hardened in depth when quenched from its austenitizing temperature. This cools the specimen from one end, simulating the effect of quenching a larger steel component in water.

Which ASTM standard governs the Jominy end quench test?

The Jominy End Quench Test ASTM A 255 measures Hardenability of steels. Hardenability is a measure of the capacity of a steel to be hardened in depth when quenched from its austenitizing temperature. Hardenability of a steel should not be confused with the hardness of a steel.

How is hardenability calculated?

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 is Jominy sample?

The test sample is a cylinder with a length of 102 mm (4 inches) and a diameter of 25.4 mm (1 inch). Jominy test specimen. The steel sample is normalised to eliminate differences in microstructure due to previous forging, and then austenitised. This is usually at a temperature of 800 to 900°C.

What is the Jominy test used for?

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.

Which steel has highest hardenability?

4340 has a less extreme rate of coolness relative to 4140 and thus has the highest hardenability of the trio. Hardenability curves are dependent on carbon content. A greater percentage of carbon present in steel will increase its hardness.

What is difference between hardness and hardenability?

Hardness vs Hardenability Hardness is a material property that signifies an alloy’s resistance to penetration. Hardenability signifies how deep the alloy can be hardened upon quenching after its exposure to heat treatment.

Why does 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. This describes the ability of the steel to be hardened in depth by quenching.

What increases hardenability?

Hardenability curves are dependent on carbon content. A greater percentage of carbon present in steel will increase its hardness. Most metallic alloying elements slow down the formation of pearlite, ferrite and bainite, therefore they increase a steel’s hardenability.

What is jominy sample?

How do you perform a Jominy test?

The Jominy Test involves heating a test piece from the steel (25mm diameter and 100mm long) to an austenitising temperature and quenching from one end with a controlled and standardised jet of water. Take a sample from the furnace and place it on the Jominy test fixtures and observe the cooling pattern.

What is the purpose of 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. This article considers the basic concepts of hardenability and the Jominy test.

How is hardenability measured in The Jominy test?

Hardenability is measured by means of a standardized procedure named Jominy Test or Jominy End Quench Test [1]. In this test an almost cylindrical sample (about 100 mm long with a diameter of about 24.5 mm) is firstly heated then quenched by cooling in water or oil. Hardenability is an important property of steel,…

How are hardness of round bars related to Jominy end quench?

In these charts, the hardness of round bars of different thickness is correlated to the Jominy end quench data (Figure 5).

Is the Jominy curve useful for air hardening?

Deep hardening steels are normally air-hardening steels, and thus, the Jominy curve for such a steel in relatively Hat (steel 3140 in Fig. 4.18) and no useful information can be obtained from such a curve. 5. Use of Jominy Curves: