How do I use this quench test data in Jominy end?
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 key objective 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.
What do Jominy curves measure?
The Jominy test provides a measure of the ability of a steel to harden by transforming into martensite under set conditions, i.e., a measure of the hardenability of the steel.
Which ASTM standard governs the Jominy end-quench test?
12.02. 6.2 Jominy Curves. Jominy bar end-quench test is the most familiar and commonly used procedure for measuring steel hardenability. This test has been standardized and is described in ASTM A 255, SAE J406, DIN 50191, and ISO 642.
What do you know about quenching?
Quenching is the soaking of a metal at a high temperature, above the recrystallization phase, followed by a rapid cooling process to obtain certain desirable material properties. Quenching also increases toughness of both alloys and plastics. Quenching may also be known as quenched or quench hardening.
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 the ideal critical diameter and can it be determined with a Jominy test?
The ideal size, or ideal diameter, of a steel can be defined as the size of bar hardened to 50% martensite in a “perfect” quench medium. In such a quenchant, the surface of the bar is assumed to cool instantaneously to the temperature of the quenching medium.
What is quenching in analysis?
Abstract. Fluorescence quenching refers to any process that decreases the fluorescence intensity of a sample. A variety of molecular interactions can result in quenching. These include excited-state reactions, molecular rearrangements, energy transfer, ground-state complex formation, and colli-sional quenching.
What is meant by the term Jominy distance?
The Jominy distance is defined as the distance from the end to the portion in which the martensite fraction is 50%, which conventionally corresponds to the inflection point of the curve.
How can you tell Jominy distance?
Why the specimen has to be cleaned after quenching?
The object is heated in an oil bath, immediately after quenching, to prevent related cracking, to relieve internal stress and to decompose austenite without much softening.
What kind of test is Jominy end quench used for?
However, the latter steel is alloyed with Cr, Mo, and V and shows a higher hardenability by exhibiting higher hardness values along the length of the specimen. The Jominy end-quench test is used mostly for low-alloy steels for carburizing (core hardenability) and for structural steels, which are typically through-hardened in oils and tempered.
What are the results of end quench hardenability test?
Figure 4 shows the results of an end-quench hardenability test performed by nine laboratories on a single heat of SAE 4068 steel. Generally, quite good reproducibility was achieved, although the maximum difference may be 8–12 HRC up to a distance of 10 mm from the quenched end depending on the slope of the curve.
What is the distance from the quenched end of a Jominy curve?
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 = J 1 ). Fig. 4.18 illustrates typical Jominy curves of some low alloy steels.
What kind of test for hardening of Jominy?
For shallow-hardening steels (D I < 1 inch), as the quenched end of Jominy piece is not hardened fully, Grange proposed a hot-brine (H – B) test.