Understanding the Jominy end quench test

2011

Hardenability of steel is defined as the susceptibility of the steel to hardening when quenched, and is related to the depth and distribution of hardness across a cross section. There are various factors which effect hardenability of steels such as austenite grain size, carbon content and alloying elements percentage. Hardenability property is so important that a simple test is essential to measure it. There are various methods to measure hardenability of steel such as Grossman critical diameter method, Jominy end quench test, estimation of hardenability from chemical composition and Fracture test .The Jominy end-quench test, though inelegant from a scientific standpoint, fills this need. In this paper we discussed about the significance of hardenability and role of Jominy test in measurement of hardenability.

The purpose of this work is to analyze the hardenability of various steels using Jominy End Quench Test. The basic idea is study of martensite generation in different grades of steels, by taking them to their austenization temperature and quenching. A particular hardness for steel is required for many applications. Hence we have tried to analyze the martnesite formation in EN353, 20MnCr5, EN24, EN8, EN19, EN31 and M. S. (Mild Steel).In this project effort has been taken to analyze for the selection of proper combination of steels for a specific application as per the hardness required.

The Jominy End-Quench Hardenability Test was used in this experiment to characterize the hardenability property of an AISI 1020 steel sample which was initially austenitized at 868ᵒC on a muffle furnace for 1 hour and transferred to a Jominy apparatus to cool for 20 minutes with water jet. Following the standard procedures of the test, two parallel surfaces were ground on the opposite side of the specimen after which indentions for hardness readings and photomicrographs were taken from one of the sides with specified spacing between the indentions considered according to the standards settings. The Hardenability Curve indicated a gradual decrease in hardness values while the microstructures varied from martensite to non-martensitic (pearlite, bainite, ferrite) as the distance moved away from the quenched end. The first derivative plot suggested a high rate of hardness drop with a maximum of 12 HRC per inch at close distances from the quenched end.

Materials Science Forum, 2007

The modified Jominy-test was designed for prediction of hardenability of high-hardenability tool steels and possibility of application of modified Jominy-test in computer simulation of quenching of high-hardenability tool steels has been investigated. Because of high hardenability there are limits in application of original Jominy-specimen in simulation of quenching of steels. The performance of investigated modified Jominy-test in simulation of quenching of high-hardenability tool steels was estimated by comparison of cooling curves of modified Jominy-specimen (JM®-specimen) and cylindrical specimen. The influence of dimension of JM®-specimen on cooling curves has been investigated. The time of cooling, t8/5 relevant for results of quenching was predicted. Modified Jominy-test can be applied in simulation of quenching of steel with higher hardenability rather than original Jominy-test.

Materials Science Forum - MATER SCI FORUM, 2007

The modified Jominy-test was designed for prediction of hardenability of high-hardenability tool steels and possibility of application of modified Jominy-test in computer simulation of quenching of high-hardenability tool steels has been investigated. Because of high hardenability there are limits in application of original Jominy-specimen in simulation of quenching of steels. The performance of investigated modified Jominy-test in simulation of quenching of high-hardenability tool steels was estimated by comparison of cooling curves of modified Jominy-specimen (JM ®-specimen) and cylindrical specimen. The influence of dimension of JM ®-specimen on cooling curves has been investigated. The time of cooling, t 8/5 relevant for results of quenching was predicted. Modified Jominy-test can be applied in simulation of quenching of steel with higher hardenability rather than original Jominy-test.

Metals

Studying the effect of quench and tempering heat treatments on steel, more specifically screening the effect of the austenitizing, quenching, and tempering conditions on mechanical properties, can be extremely material- and time-consuming when standard tensile testing specimens are employed. Jominy bar end quench testing has been used as a standard method to reduce the resources that are required for this type of screening. Jominy bar testing by itself shows, though, the limitation of yielding only hardness and microstructure as a result. In the last few years, the small punch test (SPT) standard has been developed. This technique can obtain an estimation of tensile mechanical properties with miniaturized specimens, which can be dissected from Jominy bars. The paper proposes a new testing methodology for screening the outcome of heat treatment conditions by combining the Jominy bar testing and SPT. Quench and tempering of API 5L X65Q pipe steel is used as a case study to describe th...

International Journal of Microstructure and Materials Properties, 2007

The possibility of application of modified Jominy-test in computer simulation of quenching of cold work tool steels has been investigated. Because of high hardenability of cold work tool steels there are limits in application of original Jominy-specimen in simulation of quenching of steels. The modified Jominy-test was designed for prediction of hardenability of cold work tool steels. The characteristic cooling time, relevant for results of quenching, was predicted by computer simulation of quenching of both of JM ® -specimen and of cylindrical specimen. Modified Jominy-test can be applied in simulation of quenching of high hardenability steel more successfully than by original Jominy-test.

2005

The possibility of application of modified Jominy-test in computer simulation of quenching of cold work tool steels has been investigated. Because of high hardenability of cold work tool steels there are limits in application of original Jominy-specimen in simulation of quenching of steels. The modified Jominy-test was designed for prediction of hardenability of cold work tool steels. The performance of investigated modified Jominy-test in simulation of quenching of dies was estimated by comparison of cooling curves of modified Jominy-specimen (JM ®-specimen) and cylindrical specimen. The characteristic time, relevant for results of quenching was predicted. Modified Jominy-test can be applied in simulation of quenching of steel with higher hardenability rather than original Jominy-test.

2014

Received in a revised form 16.02.2008; published 15.02.2009 Purpose: The performance and possibilities of application of modified Jominy-test (JMC®-test) in computer simulation of high-hardenability steel quenching were investigated. JMC®-specimen and cylindrical specimen has similar cooling curves if the cylindrical specimen has been quenched in oil or cooled in air. Design/methodology/approach: The performances of investigated JMC®-test have been estimated by comparison of cooling curves of JMC®-specimen and cylindrical one cooled in different quenchants. Findings: Based on the sufficiency of both, time of cooling and similarity of cooling curves of investigated workpieces and JMC®-specimen it can be concluded that JMC®-test can be accepted as very useful test for estimation of the hardness of quenched workpieces made of high-hardenability steels. Research limitations/implications: The cooling curves of JMC®-specimen and the cooling curves of cylindrical specimens have been given ...

2009

Purpose: The performance and possibilities of application of modified Jominy-test (JMC®-test) in computer simulation of high-hardenability steel quenching were investigated. JMC®-specimen and cylindrical specimen has similar cooling curves if the cylindrical specimen has been quenched in oil or cooled in air. Design/methodology/approach: The performances of investigated JMC®-test have been estimated by comparison of cooling curves of JMC®-specimen and cylindrical one cooled in different quenchants. Findings: Based on the sufficiency of both, time of cooling and similarity of cooling curves of investigated workpieces and JMC®-specimen it can be concluded that JMC®-test can be accepted as very useful test for estimation of the hardness of quenched workpieces made of high-hardenability steels. Research limitations/implications: The cooling curves of JMC®-specimen and the cooling curves of cylindrical specimens have been given by computer simulation and more experimental researches are ...