scholarly journals Influence of modes of thermal hardening and the subsequent cryogenic processing on structure and properties of steel 38Ni3CrMoV

2021 ◽  
Vol 98 (2) ◽  
pp. 14-22
Author(s):  
S.V. Bobyr ◽  
◽  
P.V. Krot ◽  
G.V. Levchenko ◽  
O.Ye. Baranovska ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Retained Austenite ◽  
Thermal Stresses ◽  
Cryogenic Treatment ◽  
Steel Structure ◽  
Residual Austenite ◽  
Machine Building ◽  
Isothermal Quenching ◽  
Complex Alloy ◽  
Alloy Steels

For the production of various machine-building products - rolling rolls, parts of power equipment, piercing mandrels - complex alloy steels containing chromium and a significant number of other deficient alloying elements (nickel, vanadium, molybdenum) type 38Ni3CrMoV are used. The paper presents the results of research on the influence of modes of hardening and subsequent cryogenic treatment on the parameters of the structure, hardness and wear resistance of this steel. Visible changes in the microstructure of thermally improved steel samples during cryogenic treatment were not found, which can be explained by the high thermodynamic stability of the sorbitol structure and the practical absence of residual austenite due to its decomposition during high tempering. It is shown that cryogenic treatment of thermally improved 38Ni3CrMoV steel contributes to an increase in the hardness, toughness and wear resistance this steel (~3.8 %). In this case, there is a slight increase in the parameter and magnitude of microstresses of the crystal lattice, an increase in the density of dislocations due to the removal of thermal stresses. To obtain a multiphase structure of 38Ni3CrMoV steel with retained austenite, isothermal quenching from the γ - α region has been proposed. The use of cryogenic treatment for the experimental mode of hardening of 38Ni3CrMoV steel samples promotes the transformation of retained austenite in the final structure of the samples into martensite with a significant increase in the microhardness of its structural components at the 22.3 %. The experimental hardening mode + cryogenic treatment provides a significant increase in the hardness and wear resistance of 38Ni3CrMoV steel at the 21.6 % while ensuring a certain level of its impact toughness (more than 4 J/cm2) and can be recommended for the implementation of the technology of differentiated hardening of large-sized products made of 38Ni3CrMoV steel. Keywords: steel, structure, hardness, wear resistance, isothermal hardening, cryogenic treatment.

scholarly journals Examination of Heat Treatment on the Microstructure and Wear of Tool Steels

2019 ◽  
Vol 2 (2) ◽  
pp. 87-92
Author(s):  
Enikő Réka Fábián ◽  
László Tóth ◽  
Csenge Huszák
Keyword(s):  
Wear Resistance ◽  
Retained Austenite ◽  
Cryogenic Treatment ◽  
Residual Austenite ◽  
Tool Steels ◽  
Austenite Content ◽  
The Matrix ◽  
Primary Carbides ◽  
Matrix Hardness ◽  
Multiple Tempering

Abstract The microstructure of the investigated X153CrMoV12 grade tool steel in delivered condition consisted of spheroidal matrix and primary carbides. The primary carbides were not dissolved under austenitisation time on either 1030°C or 1070°C. The microstructure and abrasion resistance of the steel changed due to quenching from different austenitisation temperatures. After conventional quenching from the higher austenitising temperature, there is more residual austenite in the steel than at quenching from the lower austenitisation temperature, which decreased the wear resistance. As a result of quenching from 1070°C followed by a multiple tempering process around 500 to 540°C, the retained austenite content is reduced and finely dispersed carbides are precipitated in the matrix, resulting in a higher matrix hardness and an increased wear resistance. After cryogenic treatment, the residual austenite content decreases compared to the conventional process, which leads to an increase in hardness and wear resistance.

Effects of Cryogenic Treatment on the Microstructure and Mechanical Properties of High-alloyed Tool Steels

2020 ◽  
Vol 75 (5) ◽  
pp. 73-93
Author(s):  
Alwin Schulz ◽  
Chengsong Cui ◽  
Matthias Steinbacher ◽  
Tuncer Ümit ◽  
Martin Wunde ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Retained Austenite ◽  
Cryogenic Treatment ◽  
Homogeneous Distribution ◽  
Tool Steels ◽  
Positive Effects ◽  
Heat Treated ◽  
Primary Carbides ◽  
Complete Transformation

Abstract In this work, the influence of a cryogenic treatment on the microstructure, mechanical properties and wear resistance of the high-alloyed tool steels X38CrMoV5-3, X153CrMoV12 and ~X190CrVMo20-4 were investigated. Based on tempering curves of the steels, the heat treatment parameters were determined for the mechanical and wear specimens so that the conventionally heat-treated steels and the cryogenically treated steels featured similar hardness. The investigations showed that an almost complete transformation of retained austenite and a more homogeneous distribution of secondary carbides in the microstructure could be achieved by incorporating a cryogenic treatment. However, the cryogenic treatment does not show significantly positive effects on the investigated mechanical properties and wear resistance of the tool steels. The wear resistance of the samples was dominated by primary carbides. The cryogenic treatment would have a positive effect on large tool components with large wall thicknesses in terms of uniform and complete transformation of retained austenite throughout the entire components.

A Study on Austenite Catalytic Cryogenic Treatment of Cr-W-Mo-V High Alloy Medium-Upper Carbon Steel

2014 ◽  
Vol 936 ◽  
pp. 1173-1178
Author(s):  
Yong Qing Ma ◽  
Xiao Jing Zhang ◽  
Yu Fen Liang ◽  
Guo Fang Liu
Keyword(s):  
Carbon Steel ◽  
Retained Austenite ◽  
Precipitation Hardening ◽  
Cryogenic Treatment ◽  
Residual Austenite ◽  
Carbon Steels ◽  
High Alloy ◽  
Austenite Transformation ◽  
Quenching And Tempering ◽  
Better Than

The processing of austenite catalytic cryogenic treatment of two components of Cr-W-Mo-V high alloy medium-upper carbon steels and the effect on the retained austenite transformation and tempering hardness were studied in this paper. The results show that, the effect of austenite catalytic cryogenic treatment of Cr-W-Mo-V high alloy medium-upper carbon steel is better than that of direct cryogenic treatment after quenching, and the content of residual austenite reduced to below 5%, and the hardness improved by 1.5HRC than that of conventional quenching and tempering. The retained austenite catalytic temperature of Cr-W-Mo-V high alloy medium-upper carbon steel merely is higher than 10°C~20°C of the temperature for the highest tempering hardness. Catalytic temperature Tc can be determined by experimental method of conventional quenching and tempering of the steel, in which the microstructure feature is precipitation of M3C carbide particle of 0.01μm~0.03μm in martensite matrix, and the content of retained austenite decreases evidently. By cryogenic treatment after the austenite catalyzed the retained austenite of quenching are transformed into more martensite, and in the subsequent tempering processing the original quenching martensite and the martensite from retained austenite transformation almost will form synchronous precipitation hardening. Thus the tempering hardness improves evidently as well.

Effect of Deep Cryogenic Treatment on Carbide Precipitation and Mechanical Properties of Tool Steel

2006 ◽  
Vol 118 ◽  
pp. 9-14 ◽  
Author(s):  
Young Mok Rhyim ◽  
Sang Ho Han ◽  
Young Sang Na ◽  
Jong Hoon Lee
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Tool Steel ◽  
Retained Austenite ◽  
Cryogenic Treatment ◽  
Carbide Precipitation ◽  
Deep Cryogenic Treatment ◽  
Tempering Temperature ◽  
Fine Carbide ◽  
Forming Temperature

It is well known that the durability of tool steel could be improved by deep cryogenic treatment. It has been assumed that the increase of service life of tool steel caused by decrease of retained austenite and/or by formation of nano-scale fine η-carbide. But the principles of deep cryogenic treatment remain unclear yet. In this research, to manifest the effect of deep cryogenic treatment on wear resistance, the specimen was emerged in liquid nitrogen for 20 hours for deep cryogenic treatment after austenitizing and the following tempering temperature was varied. The microstructure of specimens was observed using TEM and the mechanical properties and wear resistance were examined. As the tempering temperature increased, the carbides became larger and fine carbides were formed above certain temperature. In the case of deep cryogenic treated specimen, the number of carbides increased while the carbides size was decreased, furthermore, the fine carbide forming temperature was lowered also. It was considered that the deep cryogenic treatment increased the driving force for the nucleation of carbides. As tempering temperature increased, hardness decreased while wear resistance and impact energy increased. The deep cryogenic treated specimens showed this tendency more clearly. It was considered that the wear resistance is affected not only to the hardness but also to the precipitation of fine carbides, and this carbide evolution can be optimized through the deep cryogenic treatment.

scholarly journals Effect of Cryogenic Treatment on Microstructure, Mechanical Properties and Distortion of Carburized Gear Steels

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1940
Author(s):  
Yongming Yan ◽  
Ke Liu ◽  
Zixiang Luo ◽  
Maoqiu Wang ◽  
Xinming Wang
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Low Temperature ◽  
Wear Mechanisms ◽  
Retained Austenite ◽  
Cryogenic Treatment ◽  
Austenite Content ◽  
Cryogenic Process ◽  
Carburized Gear ◽  
Gear Steels

The effects of cryogenic treatment and low temperature tempering on the microstructure, mechanical properties and distortion of the 20Cr2Ni4A and 17Cr2Ni2MoVNb carburized gear steels were investigated. The results showed that the case hardness of the experimental steels was increased after the cryogenic treatment, due to the decrease of the retained austenite content and the precipitation of the tiny carbides. The wear resistance of the two steels after cryogenic treatment was improved, although the wear mechanisms were different for 17Cr2Ni2MoVNb and 20Cr2Ni4A steels. The distortion of the Navy C-ring specimens underwent shrinkage before expansion during the cryogenic process, and the distortion of 17Cr2Ni2MoVNb steel was smaller than that of 20Cr2Ni4A steel.

scholarly journals Cryogenic Hardening of EN 19 Alloy Steel

2019 ◽  
Vol 8 (10) ◽  
pp. 158-161
Keyword(s):  
Heat Treatment ◽  
Wear Resistance ◽  
Treatment Process ◽  
Cryogenic Treatment ◽  
Heat Treatment Process ◽  
Wear Protection ◽  
Hardening Process ◽  
Alloy Steels ◽  
Increase Wear Resistance ◽  
The Impact

This paper includes the study of heat treatment process that we carried out on En 19 steel in cryogenic atmosphere. Cryogenic treatments of alloy steels have been significantly increase wear resistance and toughness. These investigations of warmth treatment cryogenic medicines of amalgam steels have been asserted to altogether expand wear protection and sturdiness. Cryogenic handling is a supplementary procedure to customary warmth treatment process in steels. The cryogenic treatment on apparatus materials builds the life of instruments, gear, parts and materials by boosting elasticity, sturdiness and strength. This cryogenic hardening process is an onetime treatment influencing the whole part — not only the surface. Cryogenic treatment has been broadly embraced as a cost decrease and execution upgrading innovation. Cryogenic treatment is likewise utilized as an empowering innovation, when its pressure alleviating benefits are used to allow the manufacture (or machining) of basic resistance parts. With regards to great outcomes about the use of profound cryogenic treatment (DCT) on materials, the impact on the microstructure and properties (hardness, strength and the substance of held austenite) are observed to be made strides. Cryogenic treatment has been distinguished to improve the properties of Tools steels. It is discovered that cryogenic treatment confers almost 110% change in apparatus life.

Experimental Research on Wear Resistance of Deep Cryogenic Treated HSS Twist Drill

2009 ◽  
Vol 407-408 ◽  
pp. 77-80
Author(s):  
Hong Hai Xu ◽  
Hong Yan Wang ◽  
Xin Min Li
Keyword(s):  
Wear Resistance ◽  
Experimental Research ◽  
Retained Austenite ◽  
Cryogenic Treatment ◽  
Twist Drill ◽  
Deep Cryogenic Treatment ◽  
Fine Carbide ◽  
Twist Drills ◽  
Hardness Values ◽  
Carbide Particles

On the base of deep cryogenic treatment(DCT) and drilling experiments of W9Mo3Cr4V, W6Mo5Cr4V2 and W4Mo3Cr4VSi HSS twist drills, the influence of deep cryogenic treatment on hardness, wear resistance and microstructure was studied. The experimental results indicated that deep cryogenic treatment induced transformation of retained austenite to martensite and formation of fine carbide particles, so the toughness, wear resistance and hardness values of HSS twist drill were improved. Life of DCT drills was 2 to 4 times more than untreated drills.

scholarly journals INFLUENCE OF DEEP CRYOGENIC TREATMENT AT ABRASIVE WEAR RESISTANCE IN ASTM 743 CA6NM

2013 ◽  
Vol 12 (1) ◽  
pp. 25
Author(s):  
A. F. Hernandez ◽  
C. R. M. Silva ◽  
J. A. Araujo ◽  
J. D. B. De Mello
Keyword(s):  
Wear Resistance ◽  
Abrasive Wear ◽  
Retained Austenite ◽  
Cryogenic Treatment ◽  
Lath Martensite ◽  
Wear Test ◽  
Abrasive Wear Resistance ◽  
Deep Cryogenic Treatment ◽  
Conventional Heat Treatment ◽  
The Matrix

The Deep Cryogenic Treatment (DCT) has been used for improvement of steel mechanical properties, basically the abrasive wear resistance. At this work the cryogenic treatment at -190oC for 20 hours was applied, after conventional heat treatment, to improve its abrasive wear resistance. The specimens, divided in two groups, had been austenitized for forty five minutes at 965oC and 1065oC, respectively, then quenched in oil at room temperature. Afterwards they were tempered at 565oC for 90 minutes, and then cooled in air. Subsequently some samples were treated cryogenically, and some of them were submitted to a new cycle of tempering at 565oC for 90 minutes. The performed experiment included: hardness brinell, Xraydifratometry, metallography and micro-abrasive wear test. Variations in the microstructure with an improvement in the abrasive wear coefficient were found. These variations are probably a positive effect of the DCT on the samples microstructure. The microstructure were transformed from blocks of parallel lath martensite to small parallel or almost parallel packages of fine needles forming austenite. Traces of previous or retained austenite were found delimiting the grains. It is presumed that micro-carbide homogeneously distributed in the matrix and in the grain´s contours of the retained austenite was formed.

The Effects of Quenching and Tempering Treatment on the Hardness and Microstructures of a Cold Work Steel

2019 ◽  
Vol 4 (1) ◽  
pp. 286-294
Author(s):  
László Tóth ◽  
Réka Fábián
Keyword(s):  
Heat Treatment ◽  
Retained Austenite ◽  
Elevated Temperatures ◽  
Cryogenic Treatment ◽  
Cold Work ◽  
Chromium Steel ◽  
Primary Carbide ◽  
Tempering Temperature ◽  
Tempering Treatment ◽  
Primary Carbides

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, increasing the tempering temperature the quantity of finely dispersed carbides increased, which result higher hardness. The important issues in heat treatment of this steels are the reduction or elimination of retained austenite due to cryogenic treatment.

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