Fabrication of End Quenched Machine: Hardenabilty Evaluation

Journal of Minerals and Materials Characterization and Engineering, 2014

The Jominy end quench machine was designed, manufactured and tested. The manganese steel was developed. The as-cast manganese steels were quenched in water at different austenising temperatures and hardenability test was carried out on the samples cut at different distances from the quenched surface with the use of the manufactured Jominy end quench machine. The optical microscope was used to investigate the microstructure of the cut samples. Results revealed that the Jominy end quench machine worked effectively with short cycle time and improved water management system. The extremely rapid cooling prevents the decomposition of the chromium carbides. However, the hardness values of the samples decreased with increase in the distance from the quenched surface and the size of the chromium carbides increased with austentic temperatures which is responsible for reduction in the hardness values of the quenched samples at higher austentinic temperature. The manufactured Jominy end quench machine has advantages of improved water management system and short processing time over the existing ones.

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.

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.

International Journal of Engineering and Management Sciences, 2019

The X153CrMoV12 ledeburitic chromium steel characteristically has high abrasive wear resistance, due to their high carbon and high chromium contents with a large volume of carbides in the microstructure. This steel quality has high compression strength, excellent deep hardenability and toughness properties, dimensional stability during heat treatment, high resistance to softening at elevated temperatures. The higher hardness of cryogenic treated samples in comparison with conventional quenched samples mean lower quantity of retained austenite as at samples quenched to room temperature and tempered in similar condition. In the microstructure of samples were observed that the primary carbide did not dissolve at 1070°C and their net structure have not been changed during to heat treatment. During to tempering at high temperature the primary carbides have become more and more rounded. After low tempering temperature in martensite were observed some small rounded carbides also, increasin...

Materials Science and Engineering: A

With the aim of improving the strength and impact toughness combination of two ultrahigh-strength quenched and tempered steels, the effect of high-temperature austenitization and quenching prior to conventional austenitization, quenching and tempering at 200°C has been investigated. The CrNiMoWMnV steels concerned had carbon contents of 0.18 and 0.32 wt% C and tensile strengths 1370 and 1840 MPa. Microstructures were characterized using laser scanning confocal microscopy, field emission scanning electron microscopy combined with electron back scattering diffraction and X-ray diffraction. Carbide characteristics were studied using transmission electron microscopy on carbon extraction replicas. Mechanical properties were characterized in terms of hardness, tensile and Charpy-V impact testing. The microstructure of the investigated steels after all treatments consisted of tempered martensite with small fractions of precipitates and retained austenite. The volume fraction of retained austenite was increased through the use of the double austenitization and quenching plus tempering route as compared to the conventional quenching and tempering route. Three main precipitate types were observed in all the investigated steels: complex carbides M x C y , aluminium nitride AlN, titaniumvanadium carbonitride (TiV)(CN) and complex AlN precipitates with a core of (TiV)(CN). The size of the largest precipitates was reduced as a result of the double austenitization treatment. In both investigated steels, the energy absorbed and the percentage ductile fracture in the CVN impact test were improved as a result of the extra austenitization and quenching: in the case of the 0.18C steel this was achieved without a loss of hardness or tensile properties, but with the 0.32C steel there was a slight decrease in the hardness and tensile properties.

2014

In recent years, the intensive research work have been carried out on the development of heat treatment which allowed obtaining a carbide-free microstructures with retained austenite. These include the quenching with isothermal annealing (austempering) leading to obtain a nanocrystalline bainite [1, 2] and Quenching&Partitioning (Q&P) [3] leading to obtain a microstructure composed of carbon-depleted martensitic matrix and carbon-enriched retained austenite. These processes are suitable for steels containing alloying additions of Silicon and Aluminum, that suppress formation of iron carbides [3]. In the case of Q&P process the quenching is performed at temperature (TQ) below MS in order to obtain an incomplete martensitic transformation. The stability of retained austenite is obtained by carbon partitioning from martensite to thin interlath films of untransformed austenite. Carbon partitioning process occurs during isothermal holding at partitioning temperature (TP) directly after c...

Thermochimica Acta, 2008

The thermal properties, the Rockwell hardness (HRC) and the microstructure of three end-quench bar (Jominy bar) steels (C48, 42CrMo4 and 35NiCrMo16) have been investigated. The thermal properties are determined using photothermal deflection (PTD) technique and the hardness is measured by the Rockwell durometer. In this paper we have tried to relate the thermal properties to the hardness for each steel illustrated by an empiric mathematical equation.

2021

Medium carbon steel always used in most parts of the oil and gas industry, due to their cheap, simple manufacturing and easy deformation. However, as-rolled medium carbon steel usually does not meet the demands for many petroleum applications where high hardness and strength are needed; mainly because of their limitations in some mechanical features. Hence, many methods of thermal treatment techniques were adopted with a view to manipulate its structure and thus extend its scope of applications.This study focus on using a proper heat treatment to enhance medium carbon steel properties. Quenching and tempering treatments are usually the end of any manufacturing process to production of a machine component. However, the internal and residual stresses which generate during the heat treatments due to the non-uniform the quenched layer depth lead to distortion or cracked the machine component result in deteriorate the properties. Thus, the selection of optimum parameters of the quenching...

In this research work the mechanical properties of medium carbon steel has been studied. the Steel AISI 1039 quenched in different quenching media. These quenching media were cold water, water , oil and hot water. Hardness , tensile , impact and wear tests have been carried out for specimens after quenching in different media. It was found that the tensile strength and hardness increased with increasing the heating temperature values of heat treatment process. Also quenching in cold water has a great effect on tensile strength and hardness values. where the heights value for tensile strength was (998.6N/mm²) and the hardness was (360.4 Hv) for steel which quenching in cold water. The percentage of elongation decreased with increasing the temperature of heat treatment process. also the lowest values of elongation was after quenching process in cold water. However, the impact toughness and wear rate values were high for alloy after stress relief and lower after quenching in different media. But the lowest values were recorded after quenching in cold water. It was found that the absorbed energy and the wear rate for the alloy quenched in cold water were (23.6) J and (2x10¯⁷gm/cm) respectively. While, for steels treated with the stress relief process were (62.02) J and (7x10¯⁷gm/cm) respectively.