Influence of Specimen Design on Maximum Heating Rate and Temperature Variation During Induction Heating in an 805L Dilatometer

2021 ◽  
Author(s):  
Robert Cryderman ◽  
Finn Bamrud ◽  
Tareq Eddir ◽  
Robert Goldstein
Keyword(s):  
Heating Rate ◽  
Induction Heating ◽  
Induction Hardening ◽  
Test Sample ◽  
Carbon Steels ◽  
Transient Temperature ◽  
Thin Wall ◽  
Heating Rates ◽  
Temperature Variations ◽  
Metallurgical Analysis

Abstract Commercially, carbon steels are induction heated at heating rates on the order of 100 to 1,000 °C·s-1 for surface hardening. The high precision DIL 805L dilatometer employs induction heating and is often used to study transformation characteristics and prepare test specimens for metallurgical analysis. However, heating the commonly used 4 mm diameter by 10 mm long specimens at rates above 50 °C·s-1 results in non-linear heating rates during transformation to austenite and large transient temperature variations along the specimen length. These limitations in heating rate and variances from ideal uniform heating can lead to inaccurate characterization of the transformation behavior compared to commercial induction hardening practices. In this study it is shown that changing the specimen design to a thin wall tube allows faster heating rates up to 600 °C·s-1 and modifies the pattern of temperature variations within the test sample. The response of selected specimen geometries to induction heating in the dilatometer is characterized by modelling and tests using multiple thermocouples are used to verify the models. It is demonstrated that the use of properly designed tubular test specimens can aid in more accurately establishing transformation characteristics during commercial induction hardening.

Induction Hardening of a 0.40 % C Novel Microalloyed Steel: Effects of Heating Rate on the Prior Austenite Grain Size

2018 ◽  
Vol 941 ◽  
pp. 64-70
Author(s):  
Vahid Javaheri ◽  
Nasseh Khodaei ◽  
Tun Tun Nyo ◽  
David A. Porter
Keyword(s):  
Grain Size ◽  
Heating Rate ◽  
Prior Austenite ◽  
Induction Hardening ◽  
High Wear Resistance ◽  
Heating Rates ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
Prior Austenite Grain Size ◽  
Prior Austenite Grain

This work explores the effect of heating rate on the prior austenite grain size and hardness of a thermomechanically processed novel niobium-microalloyed 0.40 % carbon low-alloyed steel intended for use in induction hardened slurry pipelines. The aim was to identify the heating rates that lead to the maximum hardness, for high wear resistance, and minimum prior austenite grain size, for high toughness. For this purpose, a Gleeble 3800 machine has been employed to simulate the induction hardening process and provide dilatometric phase transformation data. The prior austenite grain structure has been reconstructed from the EBSD results using a MatlabR script supplemented with MTEX texture and crystallography analyses. Heating rates ranged from 1 to 50 °C/s and the cooling rate was 50 °C/s. The results show that the prior austenite grain size greatly depended on the heating rate: compared to the lower heating rates, the maximum heating rate of 50 C/s produces remarkably fine prior austenite grains and a fine final martensitic microstructure after quenching. In addition, a relation between the heating rate and the deviation from equilibrium temperature has been established.

scholarly journals Effect of Heating Rate on Accelerated Carbide Spheroidisation (ASR) in 100CrMnSi6-4 Bearing Steel

2014 ◽  
Vol 59 (3) ◽  
pp. 1199-1203 ◽  
Author(s):  
D. Hauserova ◽  
J. Dlouhy ◽  
Z. Novy
Keyword(s):  
Thermal Cycling ◽  
Heating Rate ◽  
Induction Heating ◽  
Transformation Temperature ◽  
Bearing Steel ◽  
Heating Rates ◽  
Annealing Stage ◽  
Ferritic Matrix ◽  
Bearing Steels

Abstract Typical processing routes for bearing steels include a soft annealing stage, the purpose of which is to obtain a microstructure containing globular carbides in ferritic matrix. A newly developed process called ASR cuts the carbide spheroidisation times several fold, producing considerably finer globular carbides than conventional soft annealing. The present paper explores the effect of the heating rate and temperature on the accelerated carbide spheroidisation process and on the resulting hardness. Accelerated spheroidisation was achieved by thermal cycling for several minutes around various temperatures close to the transformation temperature at various heating rates applied by induction heating.

Coupled Effects of Heating Method and Rate on the Measured Nonisothermal Austenization Temperature of Steel SUS420J1 in Heat Treatment

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Hongze Wang ◽  
Yosuke Kawahito ◽  
Yuya Nakashima ◽  
Kunio Shiokawa
Keyword(s):  
Heat Treatment ◽  
Temperature Distribution ◽  
Heating Rate ◽  
Induction Heating ◽  
Laser Heating ◽  
Treatment Method ◽  
Infrared Heating ◽  
Heating Rates ◽  
Element Analysis ◽  
Heating Method

Steel SUS420J1, which is the key material of turbine blade, is generally treated by heat to improve the strength prior to use. And the austenization process at different heating rates would determine the depth and width of heat treatment. In this paper, the austenization temperatures in heat treatment with the heat from induction wire, infrared lamp, and laser are measured, respectively. The effect of heating rate on the austenization temperature has been investigated. The research results show that the measured austenization temperature increases with the heating rate. And this trend is specially enlarged in the heat treatment method with larger gradient of temperature distribution, e.g., laser. The calculated phase transformation threshold shows that negative linear relationship exists between the logarithmic heating rate and the logarithmic austenization threshold for both induction heating and infrared heating, while abnormal relationship exists for laser heating. Thermal finite element analysis (FEA) models are then developed to calculate the temperature distributions in these three heating methods, and the calculated results show that the nonuniform temperature distribution leads to the gap between the measured austenization temperature and that of the material, which also leads to the abnormal variation law of austenization threshold in laser heating. The measured austenization temperature in induction heating method is thought to be the closest to the actual austenization temperature of the material among these three methods. This paper provides a guide for choosing the proper parameters to heat the steel SUS420J1 in hardening.

The Effects of Heating Rate and Cold Work on the Development of Dual-Phase Steel Microstructures

2014 ◽  
Vol 922 ◽  
pp. 755-760
Author(s):  
L.S. Thomas ◽  
David K. Matlock ◽  
John G. Speer
Keyword(s):  
Heating Rate ◽  
Dual Phase Steel ◽  
Thermomechanical Processing ◽  
Cold Work ◽  
Carbon Steels ◽  
Dual Phase ◽  
Low Carbon ◽  
Heating Rates ◽  
Contributing Factors ◽  
Transformation Temperatures

The effects of heating rate and prior cold work on the development of dual-phase steel microstructures in three low carbon steels were evaluated with samples processed on a Gleeble 3500 thermomechanical processing simulator. The nominally 0.2 wt pct carbon steels included a plain carbon steel and modified alloys incorporating higher manganese contents, boron additions, and microalloy additions. Each alloy was prepared with two different cold rolled reductions. Heating rates from 1 to 1000 oC/s were selected to span the rates typically experienced in conventional furnace heat treating up to rates for induction heating. Critical transformation temperatures were obtained from dilatometric curves. Dual-Phase microstructures after heat treatment with different heating rates were compared. Transformation temperatures decreased with an increase in cold work and increased with an increase in heating rate. The steels with higher manganese and carbon additions exhibited lower Ac3 values across all heating rates and the steels with higher silicon higher Ac1 temperatures across all heating rates. Ac1 increased less than Ac3 with increasing heating rate. The increase in transformation temperatures between 100 and 1000 °C/s was smaller than values exhibited over other increments in heating rate, and decreased in one steel; contributing factors were identified for this behavior.

Maximum heating rates for producing undistorted glassy carbon ware determined by wedge-shaped samples

1996 ◽  
Vol 11 (9) ◽  
pp. 2368-2375 ◽  
Author(s):  
Hossein Maleki ◽  
Lawrence R. Holland ◽  
Gwyn M. Jenkins ◽  
R. L. Zimmerman ◽  
Wally Porter
Keyword(s):  
Heating Rate ◽  
Treatment Process ◽  
Gaseous Product ◽  
Pyrolysis Mass Spectrometry ◽  
Heating Rates ◽  
Gaseous Products ◽  
Volatile Products ◽  
Solid Bodies ◽  
Polymeric Carbon ◽  
Maximum Heating

Polymeric carbon artifacts are particularly difficult to make in thick section. Heating rate, temperature, and sample thickness determine the outcome of carbonization of resin leading to a glassy polymeric carbon ware. Using wedge-shaped samples, we found the maximum thickness for various heating rates during gelling (300 K–360 K), curing (360 K–400 K), postcuring (400 K–500 K), and precarbonization (500 K–875 K). Excessive heating rate causes failure. In postcuring the critical heating rate varies inversely as the fifth power of thickness; in precarbonization this varies inversely as the third power of thickness. From thermogravimetric evidence we attribute such failure to low rates of diffusion of gaseous products of reactions occurring within the solid during pyrolysis. Mass spectrometry shows the main gaseous product is water vapor; some carboniferous gases are also evolved during precarbonization. We discuss a diffusion model applicable to any heat-treatment process in which volatile products are removed from solid bodies.

scholarly journals Towards a better representation of the solar cycle in general circulation models

2007 ◽  
Vol 7 (20) ◽  
pp. 5391-5400 ◽  
Author(s):  
K. M. Nissen ◽  
K. Matthes ◽  
U. Langematz ◽  
B. Mayer
Keyword(s):  
Solar Cycle ◽  
Heating Rate ◽  
General Circulation ◽  
Temperature Response ◽  
General Circulation Models ◽  
Short Wave ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Heating Rates ◽  
Radiation Scheme

Abstract. We introduce the improved Freie Universität Berlin (FUB) high-resolution radiation scheme FUBRad and compare it to the 4-band standard ECHAM5 SW radiation scheme of Fouquart and Bonnel (FB). Both schemes are validated against the detailed radiative transfer model libRadtran. FUBRad produces realistic heating rate variations during the solar cycle. The SW heating rate response with the FB scheme is about 20 times smaller than with FUBRad and cannot produce the observed temperature signal. A reduction of the spectral resolution to 6 bands for solar irradiance and ozone absorption cross sections leads to a degradation (reduction) of the solar SW heating rate signal by about 20%. The simulated temperature response agrees qualitatively well with observations in the summer upper stratosphere and mesosphere where irradiance variations dominate the signal. Comparison of the total short-wave heating rates under solar minimum conditions shows good agreement between FUBRad, FB and libRadtran up to the middle mesosphere (60–70 km) indicating that both parameterizations are well suited for climate integrations that do not take solar variability into account. The FUBRad scheme has been implemented as a sub-submodel of the Modular Earth Submodel System (MESSy).

INVESTIGATION OF THERMAL DEGRADATION OF POULTRY PROCESSING DEWATERED SLUDGE USING THERMOGRAVIMETRIC ANALYSIS METHOD

2015 ◽  
Vol 76 (5) ◽  
Author(s):  
N. Aniza ◽  
S. Hassan ◽  
M. F. M. Nor ◽  
K. E. Kee ◽  
Aklilu T.
Keyword(s):  
Particle Size ◽  
Thermogravimetric Analysis ◽  
Thermal Degradation ◽  
Heating Rate ◽  
Degradation Process ◽  
Heating Rates ◽  
Initial Stage ◽  
Poultry Processing ◽  
Effect Of Particle Size ◽  
Dewatered Sludge

Thermal degradation of Poultry Processing Dewatered Sludge (PPDS) was studied using thermogravimetric analysis (TGA) method. The effect of particle size on PPDS samples and operational condition such as heating rates were investigated. The non-isothermal TGA was run under a constant flow of oxygen at a rate of 30 mL/min with temperature ranging from 30ºC to 800ºC. Four sample particle sizes ranging between 0.425 mm to 2 mm, and heating rate between 5 K/min to 20 K/min were used in this study. The TGA results showed that particle size does not have any significant effect on the thermogravimetry (TG) curves at the initial stage, but the TG curves started to separate explicitly at the second stage. Particle size may affect the reactivity of sample and combustion performance due to the heat transfer and temperature gradient. The TG and peak of derivative thermogravimetry (DTG) curves tend to alter at high temperature when heating rate is increased most likely due to the limitation of mass transfer and the delay of degradation process. 

scholarly journals Effect of heating rates on the microstructure and gas permeation properties of carbon membranes

2018 ◽  
Vol 14 (3) ◽  
pp. 378-381
Author(s):  
Norazlianie Sazali ◽  
Wan Norharyati Wan Salleh ◽  
Ahmad Fauzi Ismail ◽  
Kumaran Kadirgama ◽  
Mohamad Shahrizan Moslan ◽  
...  
Keyword(s):  
Heating Rate ◽  
High Performance ◽  
Room Temperature ◽  
Gas Permeation ◽  
Carbon Membrane ◽  
Heating Rates ◽  
Polymer Blending ◽  
Carbon Membranes ◽  
Permeation Properties ◽  
Fine Turning

High performance tubular carbon membrane (TCM’s) for CO2 separation were prepared by controlling the carbonization heating rates in range of 1-7 oC/min carbonized at 800 oC under Argon environment. A single permeation apparatus was used to determine the gas permeation properties of the membrane at room temperature. Fine turning of the carbonization condition was necessary to obtain the desired permeation properties. The preparation of PI/NCC-based TCM at low heating rate caused the gas permeance for the examined gas N2 and CO2 decreased whereas the selectivity of CO2/N2 increased. It was also identified that the gas permeation properties of the resultant TCM and its structure was highly affected by the heating rate. The best carbonization heating rate was found at 3oC/min for the fabrication of TCM derived via polymer blending of PI/NCC for CO2/N2 separation.

scholarly journals Heat transfer on simplified pre-period stage of tunnel fire

2019 ◽  
Vol 23 (Suppl. 3) ◽  
pp. 799-808
Author(s):  
Hungwei Liu ◽  
Wei Yao
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Heating Rate ◽  
Theoretical Solution ◽  
Theoretical Equation ◽  
Thermal Engineering ◽  
Transient Temperature ◽  
Tunnel Fire ◽  
Transient Temperature Distribution ◽  
Heat Transfer Theory

Tunnel fire is a part of applied thermal problems. With increase of transient temperature of the tunnel fire on the structure surface (i.e. tunnel lining), the heat transfer from the surface is possibly varying transient temperature distribution within the structure. The transient temperature distribution is also possibly damaging the composition of structure (micro-crack) because of critical damage temperature. Therefore, the transient temperature distribution has a significantly important role on defining mechanical and physical properties of structure and determining thermal-induced damaged region. The damage at pre-period stage of tunnel fire is perhaps more significant than that at the other period stages because of thermal gradient. Consequently, a theoretical model was developed for simplifying complicated thermal engineering during pre-period stage of tunnel fire. A hollow solid model (HSM) in a combination of dimensional analysis and heat transfer theory with Bessel?s Function and Duhamel?s Theorem were employed to verify a theoretical equation for dimensionless transient temperature distribution (DTTD) under linear transient thermal loading (LTTL). Experimental and numerical methods were also adopted to approve the results from this theoretical equation. The heating rate (M) is a primary variable for discussing DTTD on three means. The heating rate of 10.191, 10 and 240?C/min were applied to experimental and numerical studies. The experimental and numerical results are consistent with the theoretical solution, successfully verifying that the theoretical solution can predict the DTTD well in field. This equation can be used for thermal/tunnel engineers to evaluate the damaged region and to obtain the parameters related to DTTD.

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