Effect of Heating Temperature and Heating Rate on Austenite in the Heating Process of 300M Steel

2013 ◽  
Vol 749 ◽  
pp. 260-267 ◽  
Author(s):  
Yin Gang Liu ◽  
Miao Quan Li ◽  
Xiao Ling Dang
Keyword(s):  
Grain Size ◽  
Grain Boundaries ◽  
Heating Rate ◽  
Heating Temperature ◽  
Heating Process ◽  
Analysis Software ◽  
Heating Rates ◽  
300M Steel ◽  
Coarse Grains ◽  
Gleeble 3500

The growth behavior of 300M steel was investigated on a Gleeble-3500 simulator at the heating temperatures ranging from 1273 K to 1453 K and the heating rates ranging from 0.83 K/s to 40 K/s. The grain size of austenite was measured by using SISC IAS V8.0 image analysis software on Olympus PMG3 microscope. The experimental results showed that the coarse grains of austenite occurred at the heating temperature above 1413 K and the grain size of austenite increased with the increasing of heating temperature and decreased with the increasing of heating rate. The grain boundaries of austenite became flat and the angel of grain boundaries tended to 120˚ with the increasing of heating temperature. The grain boundaries of austenite increased and changed from flat to bend with the increasing of heating rate.

Effects of Induction Heat Treatment on Austenitic Transformation, Microstructure and Mechanical Properties of Pipeline Steels

2013 ◽  
Vol 773-774 ◽  
pp. 741-749 ◽  
Author(s):  
Fu Ren Xiao ◽  
Xiu Lin Han ◽  
Yan Mei Liu ◽  
Guang Ping Lu ◽  
Bo Liao
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Heating Rate ◽  
Heating Temperature ◽  
Phase Transformation Temperature ◽  
Heating Rates ◽  
Pipeline Steels ◽  
Austenitic Transformation ◽  
Gleeble 3500 ◽  
Welded Pipe

The effects of heating rate, heating temperature and cooling rate on the microstructures and mechanical properties of four pipeline steels for high frequency electric resistance welded pipe have been studied by using a Gleeble-3500 thermo-mechanical simulator. The results show that the heating rates have an effect on austenizing phase transformation temperature (Ac1 and Ac3). It shows that there is a linear relationship between heating rate and austennizing temperature (Ac1 and Ac3) in the range of tested heating rate. With the heating temperature increasing, the strength property goes up, on the contrary, the strength begins to go down when the heating temperature exceeds 900 °C, then a lowest strength point appears on 925 °C in the testing scope. As the further increase of the heating temperature, the strength goes up again. Moreover, the cooling rate has a great effect on the microstructure and the mechanical properties. With the decrease of cooling rate, the strength decrease significantly, meanwhile, the microstructure becomes coarse, even the banded structure can be found. As the conclusion, the optimum heating temperature is 950 °C, and cooling rate is from 8.5 to 13 °C/s.

Microwave Processing of Ceramics

2006 ◽  
Vol 45 ◽  
pp. 857-862 ◽  
Author(s):  
Isabel K. Lloyd ◽  
Yuval Carmel ◽  
Otto C. Wilson Jr. ◽  
Geng Fu Xu
Keyword(s):  
Thermal Conductivity ◽  
Grain Size ◽  
Heating Rate ◽  
Thermal Gradients ◽  
Heating Rates ◽  
Volumetric Heating ◽  
Wide Range ◽  
Conventional Sintering ◽  
Atmosphere Control ◽  
Very High

Microwave (MW) processing is advantageous for processing ceramics with tailored microstructures. Its combination of volumetric heating, a wide range of controlled heating rates, atmosphere control and the ability to reach very high temperatures allows processing of 'difficult' materials like high thermal conductivity AlN and AlN composites and microstructure control in more readily sintered ceramics such as ZnO. MW sintering promotes development of thermal conductivity in AlN (225 W/mK) and its composites (up to 150W/mK inAlN-TiB2 and up to 129 W/mK in AlN-SiC when solid solution is avoided). In ZnO, heating rate controls sintered grain size. Increasing the heating rate from 5°C/min. to 4900°C decreases grain size from ~10 μm (comparable to conventional sintering of the same powder) to nearly the starting particle size (~ 1μm). Microstructural uniformity increases with sintering rate since ultra-rapid MW sintering minimizes the development of thermal gradients due to heat loss.

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.

Effect of the Annealing Conditions on the Microstructure and Mechanical Properties of a 0.04% C Al Killed Steel

2007 ◽  
Vol 539-543 ◽  
pp. 4208-4213
Author(s):  
Jacobo J. Cardozo ◽  
A.L. Rivas ◽  
R. Colas
Keyword(s):  
Mechanical Properties ◽  
Heating Rate ◽  
Deep Drawing ◽  
Heating Temperature ◽  
Grain Structure ◽  
Major Influence ◽  
Heating Rates ◽  
Annealing Conditions ◽  
Static Annealing ◽  
Initial Heating

The present investigation evaluates the effect of static annealing variables on the grain structure and mechanical properties of a 0.04 %C-Al killed steel. The experimental variables selected were the heating rate and the initial heating temperature. The results showed that an increase in the initial heating temperature and heating rates inferior to 500°C and 100°C/h, respectively, do not have a major influence in the grain structure of the material. These annealing conditions lead to a full "pancake" type of microstructure of the recrystallized ferrite grain, and as consequence, the mechanical properties of the material are in the intervals required for deep drawing applications.

Bake Hardening Properties of Ultra-Rapid Annealed Ultra-Low Carbon Bake Hardening Steel

2014 ◽  
Vol 941-944 ◽  
pp. 127-131 ◽  
Author(s):  
De Chao Xu ◽  
Jun Li ◽  
Yan Dong Liu ◽  
Xiang Wei Kong
Keyword(s):  
Grain Size ◽  
Heating Rate ◽  
Rolling Reduction ◽  
Temper Rolling ◽  
Low Carbon ◽  
Heating Rates ◽  
Bake Hardening ◽  
Soaking Time ◽  
Rapid Annealing ◽  
Bake Hardening Steel

Ultra-rapid annealing (URA) experiments were carried out to study the effect of heating rate on the recrystallization kinetics, grain size and Bake-hardening (BH) properties of Ultra-low carbon Bake Hardening Steel annealing with different heating rates followed by gas cooling (about 100°C/s) with variation of soaking times. It was shown that the degree of grain refinement is controlled by the parameters of heating rates and soaking time of the Ultra-rapid annealing cycles. For the steels investigated, the final grain size decreases with increasing heating rate and increases with increasing soaking time. The effects of dislocation density, varied by means of non-temper rolling reduction and a temper rolling reduction of 1% on the Bake-hardening properties were investigated within an aging temperature of 170°C for 20 min.

Influence of Thermal History on Microstructure and Mechanical Properties of Steels for Hot Stamping

2010 ◽  
Vol 654-656 ◽  
pp. 330-333 ◽  
Author(s):  
Takehide Senuma ◽  
Yoshito Takemoto
Keyword(s):  
Mechanical Properties ◽  
Heating Rate ◽  
Heating Temperature ◽  
Hot Stamping ◽  
High Strength ◽  
Heating Process ◽  
High Heating Rate ◽  
Transformation Behavior ◽  
Microstructure And Mechanical Properties ◽  
Heat Treated

Hot stamping is an attractive method to produce extra high strength automotive components. In the conventional hot stamping, the furnace heating is employed and the heating rate is quite low. To improve the productivity of the hot stamping technology, the reduction of time for the heating process is required. In this study, the influence of the heating rate in a range up to 200°C/s, heating temperatures between 650°C and 950°C and cooling condition on microstructure and mechanical properties of 0.22% C -3%Mn steel has been investigated. The steel is a promising material for the highly productive new hot stamping technology because this steel transformed into martensite from austenite even at cooling in free air. The specimens heat-treated at a high heating rate and for short holding time at the heating temperature just above Ac3 show significantly fine martensite microstructure and a good strength-toughness balance. In this paper, the α→ γ transformation behavior and the γ→ α transformation behavior after inter-critical annealing are discussed to explain the evolution of the microstructures and mechanical properties.

The Effect of Heating Process on Strength and the Original Austenite Grain Size of Hot Forming Parts

2014 ◽  
Vol 1063 ◽  
pp. 28-31
Author(s):  
Kuan Hui Hu ◽  
Xiang Dong Liu ◽  
Guan Wen Feng ◽  
Rong Dong Han
Keyword(s):  
Grain Size ◽  
Heating Temperature ◽  
Hot Stamping ◽  
Lath Martensite ◽  
Testing Machine ◽  
Heating Process ◽  
Austenite Grain Size ◽  
Heat Temperature ◽  
Austenite Grain ◽  
Austenite Grains

Strength, microstructure and austenitic grain size of a hot formed steel WHT1300HF after simulative hot stamping were studied by using universal testing machine for materials and optical microscopy. The results show that the yield strength of the hot stamping parts presented the tendency of earlier decrease and later increase with the extension of holding time, tensile strength was first reduced and then hold above 1400 MPa. In addition, the microstructure of the hot stamping parts was lath martensite, and martensite lath length and packet width increases with the heating temperature increased from 850 °C to 1050 °C. Especially, the effect of heat temperature on the original austenite grain size was more obvious, such as the austenite grains grew up quickly with the increase of heating temperature, and the original austenite grain diameter was 37.8 μm when the temperature reached 1050 °C.

Study on the Dynamic Recrystallization of Austenite in the Isothermal Compression of 300M Steel

2013 ◽  
Vol 773-774 ◽  
pp. 39-46
Author(s):  
Yin Gang Liu ◽  
Miao Quan Li
Keyword(s):  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Deformation Temperature ◽  
Austenite Grain Size ◽  
High Deformation ◽  
300M Steel ◽  
Coarse Grains ◽  
Austenite Grains ◽  
Gleeble 3500 ◽  
Rate Dynamic

The 300M steel was isothermally compressed on a Gleeble-3500 simulator at the deformation temperatures ranging from 1123 K to 1473 K, the strain rates ranging from 0.1 s-1 to 25.0 s-1 and a strain of 0.51. The morphology of austenite grains in the isothermally compressed 300M steel was observed using an OLYMPUS PMG3 microscope. The experimental results show that the deformation temperature and strain rate have an interaction effect on austenite grains in the isothermally compressed 300M steel. Dynamic recrystallization occurs more easily at high deformation temperature and low strain rate. Dynamic recrystallization occurs completely and the coarse grains occur at the deformation temperature above 1413 K. The austenite grain size increases as the deformation temperature increases while it decreases as the strain rate increases.

scholarly journals Kinetics of Austenite Grain Growth during a Continuous Heating of a Niobium Microalloyed Steel

2004 ◽  
Vol 467-470 ◽  
pp. 929-934 ◽  
Author(s):  
David San Martín ◽  
Francisca García Caballero ◽  
Carlos Capdevila ◽  
C. Carcía de Andrés
Keyword(s):  
Grain Size ◽  
Grain Boundaries ◽  
Heating Rate ◽  
Grain Growth ◽  
Continuous Heating ◽  
Second Phase ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
Average Grain Size ◽  
The Matrix

Grain growth is a thermally activated process in which the average grain size increases as temperature and time increases. The driving force for grain growth results from the decrease in the free energy associated with the reduction in total grain boundary energy. There are several known factors that influence the migration of grain boundaries such as second phase particles precipitated in the matrix and the solute elements segregated at grain boundaries. The austenite grain boundaries are revealed using the thermal etching method. Carbon extraction replicas were prepared to determine the composition and size of precipitates present in the matrix. In this work, the evolution of the average prior austenite grain size (PAGS) of a low carbon steel microalloyed with niobium is studied as a function of temperature and heating rate. Austenite grains show a two-stage growth. It has been found that as heating rate increases, the grain coarsening temperature (TGC) increases and the grain size at that temperature decreases. TGC temperature lies around 40-60°C below the temperature for complete dissolution of carbonitrides (TDISS).

The Effect of Heating Rate on Texture and Formability of Ti-Nb Stabilized Ferritic Stainless Steel

2018 ◽  
Vol 786 ◽  
pp. 3-9
Author(s):  
Matias Jaskari ◽  
Antti Järvenpää ◽  
Pentti L. Karjalainen
Keyword(s):  
Stainless Steel ◽  
Heating Rate ◽  
Ferritic Stainless Steel ◽  
Heating Temperature ◽  
Diffraction Method ◽  
Processing Route ◽  
High Heating Rate ◽  
Rolled Sheet ◽  
Heating Rates ◽  
Cold Rolled

Typical applications of ferritic stainless steels require good formability of the material that is highly dependent on the processing route. In this study, the effects of the heating rate and peak heating temperature on the texture and deep drawability (R-value) of a 78% cold rolled, stabilized 18Cr (AISI 441) ferritic stainless steel were studied. Pieces of cold rolled sheet were heated in a Gleeble 3800 simulator at the heating rates of 25 °C/s and 500 °C/s to various temperatures up to 1150 °C for 10 s holding before cooling at a rate of 35 °C/s. Microstructures were characterized and the texture of the annealed samples determined by the electron backscatter diffraction method. It was established that the high heating rate of 500 °C/s promotes the nucleation of grains with the near {111}<uvw> orientations during the early state of the recrystallization. The maximum texture intensities were found at {554}<225>. The more effective nucleation of these grains resulted in a finer grain size and an increased intensity of the gamma-fibre texture which led to enhanced R-values. At high peak temperatures, the intense grain growth took place.

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