scholarly journals Microstructure and Mechanical Properties of Heat-treated T92 Martensitic Heat Resistant Steel

2017 ◽  
Vol 36 (8) ◽  
pp. 771-778 ◽  
Author(s):  
P. Rajesh Kannan ◽  
V. Muthupandi ◽  
B. Arivazhagan ◽  
K. Devakumaran
Keyword(s):  
Lath Martensite ◽  
Austenite Grain Size ◽  
Heat Resistant Steel ◽  
Hardness Tester ◽  
Heat Treated ◽  
Prior Austenite Grain Size ◽  
Grain Boundary Decohesion ◽  
The Given ◽  
Hardness Values ◽  
Martensite Microstructure

AbstractT92 samples were solutionized at 1,050 °C, 1,100 °C and 1,150 °C for 20 min and then tempered at 730 °C, 745 °C and 760 °C for 60 min. Optical microscopy studies were carried out to understand the microstructural evolution due to heat treatment. These heat-treated samples comprised of lath martensite microstructure in all the cases. Prior austenite grain size of the heat-treated samples increased with solutionizing temperature. Tensile properties were evaluated using micro-tensile samples. Hardness values of the heat-treated samples were estimated using Vickers hardness tester. Interestingly, for all the given tempering condition, the hardness values showed an increasing trend with solutionizing temperature while their tensile strength values tend to decrease. Fractograph analysis depicted that increasing the solutionizing temperature led to grain boundary decohesion.

Effect of a Complex Heat Treatment on the Structure of 300M Steel

1981 ◽  
Vol 39 ◽  
pp. 312-313
Author(s):  
R. Padmanabhan ◽  
W. E. Wood
Keyword(s):  
Heat Treatment ◽  
Metal Carbides ◽  
Austenite Grain Size ◽  
300M Steel ◽  
Heat Treated ◽  
Strain Fracture ◽  
Prior Austenite Grain Size ◽  
Short Time ◽  
Final Tempering ◽  
Similar Yield

Intermediate high temperature tempering prior to subsequent reaustenitization has been shown to double the plane strain fracture toughness as compared to conventionally heat treated UHSLA steels, at similar yield strength levels. The precipitation (during tempering) of metal carbides and their subsequent partial redissolution and refinement (during reaustenitization), in addition to the reduction in the prior austenite grain size during the cycling operation have all been suggested to contribute to the observed improvement in the mechanical properties. In this investigation, 300M steel was initially austenitized at 1143°K and then subjected to intermediate tempering at 923°K for 1 hr. before reaustenitizing at 1123°K for a short time and final tempering at 583°K. The changes in the microstructure responsible for the improvement in the properties have been studied and compared with conventionally heat treated steel. Fig. 1 shows interlath films of retained austenite produced during conventionally heat treatment.

scholarly journals Heat Treatment Effect on Lath Martensite

2018 ◽  
Vol 1 (1) ◽  
pp. 26-30
Author(s):  
Enikő Réka Fábián ◽  
Áron Kótai
Keyword(s):  
Heat Treatment ◽  
Lath Martensite ◽  
Carbon Steels ◽  
Low Carbon ◽  
Low Carbon Steels ◽  
Heat Treated ◽  
Different Temperatures ◽  
Cold Rolled ◽  
Ice Water ◽  
Martensite Microstructure

Abstract During our investigation lath martensite was produced in low carbon steels by austenitization at 1200 °C/20 min, and the cooling of samples in ice water. The samples were tempered at a range of temperatures. The tempering effects on microstructure and on mechanical proprieties were investigated. Some samples with lath martensite microstructure were cold rolled and heat treated at different temperatures. Recrystallization was observed after heat treatment at 600-700 °C.

Carbide composition changes in a low alloy steel

1990 ◽  
Vol 48 (2) ◽  
pp. 420-421
Author(s):  
Z. Larouk ◽  
R. Pilkington
Keyword(s):  
Alloy Steel ◽  
Prior Austenite ◽  
Creep Behaviour ◽  
Low Alloy Steel ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
Heat Treated ◽  
Prior Austenite Grain Size ◽  
Composition Changes ◽  
Prior Austenite Grain

Durehete 1055 is a 1%Cr1%Mo¾%V low alloy steel used as bolting material at 565°C. It also contains 0.08%Ti and 0.005%B to improve the creep behaviour, but deleterious properties have been reported, due to the presence of trace elements such as P and Sn. The present work has been an attempt to understand this problem by examining three vacuum melted casts of this steel containing selected additions (wt.%) of 1) 0.08 Ti, 2) 0.08 Ti and 0.02 P; and 3) 0.08 Ti and 0.02 Sn. The material was heat treated for 2h at 980°C, W.Q., and tempered 4h at 680°C, giving a prior austenite grain size of 8 μm. Specimens were then crept for various times at 565°C. After test, metallographic samples were prepared from both the gauge lengths (stressed) and heads (unstressed) to enable the production of carbon extraction replicas. These replicas were examined in a Philips 400T electron microscope, and carbides analysed using EDS.

Microstructure Evolution during Quenching and Tempering of Martensite in a Medium C Steel

2012 ◽  
Vol 715-716 ◽  
pp. 860-865 ◽  
Author(s):  
Andrea di Schino ◽  
Laura Alleva ◽  
Mauro Guagnelli
Keyword(s):  
Thermal Strain ◽  
Orientation Imaging Microscopy ◽  
Austenite Grain Size ◽  
Tempering Temperature ◽  
Orientation Imaging ◽  
Bainitic Steels ◽  
Heat Treated ◽  
Quenching Process ◽  
Prior Austenite Grain Size ◽  
Quenching And Tempering

The microstructural evolution of a quenched medium-C steel during tempering was analyzed by means of Orientation Imaging Microscopy (OIM). The steel was heat treated in order to develop fully martensitic microstructures after quenching with a different prior austenite grain size (AGS). Main results can be summarized as below: A very poor effect of AGS on packet size was found in comparison to bainitic steels. A finer packet was measured at mid-thickness with respect to surface after the quenching process. This phenomenon was attributed to the effect of thermal strain path on phase transformation during quenching. The through-thickness microstructural gradient remains after tempering. High-angle boundary grains do not significantly grow after tempering; on the contrary, low-angle grain boundaries (cells) move, fully justifying the hardness evolution with tempering temperature.

scholarly journals On a Modified Approach of Measuring Quench Severity and its Application

2021 ◽  
Author(s):  
Viraj A. Athavale ◽  
Mario Buchely ◽  
Laura Bartlett ◽  
Ronald O’Malley ◽  
David C. Van Aken
Keyword(s):  
Grain Size ◽  
Prior Austenite ◽  
Empirical Method ◽  
Hardness Profile ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
Profile Matching ◽  
Heat Treated ◽  
Prior Austenite Grain Size ◽  
Prior Austenite Grain

Abstract Instrumented methods for measuring the coefficient of heat transfer are difficult to implement in industrial quench systems. In 1985 Roy Kern presented a simple empirical method for calculating the quench severity of commercial quench systems using measured Jominy hardenability and a mid-radius (r/R=0.5) hardness of a 3-inch diameter 8640 or 4140 steel bar. A more general approach using the Kern methodology is presented here with hardness profile matching to determine the quench severity. Experiments were performed using 2-inch diameter bars of 8620 with a length to diameter ratio of 4. Test bars and Jominy bars were heat-treated following ASTM A255. Test bars were quenched using an experimental draft tube with a water velocity of 6 ft/s. An excel workbook was programmed to calculate the quenched hardness profile as a function of quench severity using prior austenite grain size and steel chemistry. Measured Jominy hardness and calculated hardenability were in good agreement provided the prior austenite grain size was incorporated into the calculations. Both the Kern method and hardness profile matching produced a quench severity equal to 1.45.

Effect of Cooling Rate on Microstructure of Simulated CGHAZ for Modified High-Cr Ferritic Heat-Resistant Steel

2011 ◽  
Vol 418-420 ◽  
pp. 1320-1323
Author(s):  
Xin Jie Di ◽  
Dan Xu ◽  
Yong Chang Liu
Keyword(s):  
Cooling Rate ◽  
Lath Martensite ◽  
Optical Microscope ◽  
Resistant Steel ◽  
Austenite Grain Size ◽  
Heat Resistant Steel ◽  
Heat Resistant ◽  
Δ Ferrite ◽  
Size And Morphology ◽  
Carbide Precipitate

The microstructure and carbide precipitate of simulated coarse grain heat affected zone(CGHAZ) in modified high Cr ferritic heat-resistant steel at different cooling rates have been investigated by means of thermal simulator, optical microscope, SEM and TEM . It was found that the microstructure of CGHAZ of testing steel was mainly lath martensite and δ-ferrite under the different welding thermal cycles. However, the prior austenite grain size reduced with increasing the cooling rate. Furthermore, with increasing the cooling rate, the amount of carbide precipitate inside laths of martensite increased, and the size and morphology of precipitates have changed from elongated and coarse to needlelike and fine.

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