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.

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.

Deterioration of Mechanical Properties of High-Strength Pumpcrete after Exposure to High Temperatures

2010 ◽  
Vol 168-170 ◽  
pp. 564-569
Author(s):  
Guang Lin Yuan ◽  
Jing Wei Zhang ◽  
Jian Wen Chen ◽  
Dan Yu Zhu
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Heating Rate ◽  
High Strength Concrete ◽  
Heating Temperature ◽  
High Strength ◽  
Air Cooling ◽  
Test Results ◽  
Strength Deterioration ◽  
Residual Compressive Strength

This paper makes an experimental study of mechanical properties of high-strength pumpcrete under fire, and the effects of heating rate, heating temperature and cooling mode on the residual compressive strength(RCS) of high-strength pumpcrete are investigated. The results show that under air cooling, the strength deterioration speed of high-strength concrete after high temperature increases with the increase of concrete strength grade. Also, the higher heating temperature is, the lower residual compressive strength value is. At the same heating rate (10°C/min), the residual compressive strength of C45 concrete after water cooling is a little higher than that after air cooling; but the test results are just the opposite for C55 and C65 concrete. The strength deterioration speed of high-strength concrete after high temperature increases with the increase of heating rate, but not in proportion. And when the heating temperature rises up between 200°C and 500°C, heating rate has the most remarkable effect on the residual compressive strength of concrete. These test results provide scientific proofs for further evaluation and analysis of mechanical properties of reinforced-concrete after exposure to high temperatures.

Influence of Rate of Heating to Aging Temperature on Precipitation Hardening in a Metastable β Titanium Alloy

2014 ◽  
Vol 1025-1026 ◽  
pp. 445-450 ◽  
Author(s):  
Ashwary Pande ◽  
Salil Sainis ◽  
Santhosh Rajaraman ◽  
Geetha Manivasagam ◽  
M. Nageswara Rao
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
Heating Rate ◽  
Aging Temperature ◽  
Alpha Phase ◽  
Slow Heating ◽  
Precipitation Reaction ◽  
Heating Rates ◽  
Rate Of Heating ◽  
Reduction In Area

A comparison between slow heating to aging temperature and direct charging at aging temperature on the microstructure and mechanical properties obtained after the aging was established for the metastable beta (β) titanium alloy Ti-15V-3Cr-3Al-3Sn. The alloy was subjected to two single aging (SA) and two duplex aging (DA) conditions, with two heating rates to aging temperature: (i) low heating rate of 5 oC/min (ii) direct charging into a furnace heated to aging temperature. The microstructure analysis was carried out using Field Emission Scanning Electron Microscopy. Mechanical Testing was carried to evaluate Ultimate Tensile Strength (UTS), 0.2% Yield Strength (YS), % Elongation (%El.), % Reduction in area (%RA) and hardness. In the case of SA samples aged at 500 °C for 8 h and 500 °C for 10 h, heating rate of 5 °C/min to aging temperature resulted in a finer microstructure but did not help in achieving better strength-ductility combination compared to direct charging. Lower rate of heating allows enough dwell time in the temperature range 250-300 oC for pre-precipitation reaction to occur which aids in fine scale precipitation of alpha phase during aging. In the case of DA samples aged at 250 oC for 24 h followed by 500 oC for 8 h and 300 oC for 10 h followed by 500 oC for 10 h, no tangible difference between lower rate of heating and direct charging was observed in mechanical properties or microstructure. This is believed to be due to the pre-aging steps 250 oC/24 h or 300 oC/10h in the two DA treatments, which create finely distributed precursors thereby leaving no scope for the heating rate to play a role.

The Effects of Laser and Mechanical Forming on the Hardness and Microstructural Layout of Commercially Pure Grade 2 Titanium Alloy Plates

2017 ◽  
Author(s):  
Kadephi V. Mjali ◽  
Annelize Els-Botes ◽  
Peter M. Mashinini
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
Scanning Speed ◽  
Grain Structure ◽  
Laser Forming ◽  
Major Influence ◽  
Forming Process ◽  
Commercially Pure ◽  
Profound Influence ◽  
Pure Grade

This paper illustrates the effects of the laser and mechanical forming on the hardness and microstructural distribution in commercially pure grade 2 Titanium alloy plates. The two processes were used to bend commercially pure grade 2 Titanium alloy plates to a similar radius also investigate if the laser forming process could replace the mechanical forming process in the future. The results from both processes are discussed in relation to the mechanical properties of the material. Observations from hardness testing indicate that the laser forming process results in increased hardness in all the samples evaluated, and on the other hand, the mechanical forming process did not influence hardness on the samples evaluated. There was no change in microstructure as a result of the mechanical forming process while the laser forming process had a major influence on the overall microstructure in samples evaluated. The size of the grains became larger with increases in thermal gradient and heat flux, causing changes to the overall mechanical properties of the material. The thermal heat generated has a profound influence on the grain structure and the hardness of Titanium. It is evident that the higher the thermal energy the higher is the hardness, but this only applies up to a power of 2.5kW. Afterwards, there is a reduction in hardness and an increase in grain size. The cooling rate of the plates has been proved to play a significant role in the resulting microstructure of Titanium alloys. The scanning speed plays a role in maintaining the surface temperatures of laser formed Titanium plates resulting in changes to both hardness and the microstructure. An increase in heat results in grain growth affecting the hardness of Titanium.

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.

scholarly journals Modeling the Failure Behavior of CFRP Laminates Subjected to Combined Thermal and Mechanical Loadings

2017 ◽  
Vol 09 (03) ◽  
pp. 1750033 ◽  
Author(s):  
Weina Zhao ◽  
Hongwei Song ◽  
Chenguang Huang ◽  
Yihui Huang
Keyword(s):  
Mechanical Properties ◽  
Thermal Decomposition ◽  
Carbon Fiber ◽  
Heating Rate ◽  
High Temperatures ◽  
Level Structure ◽  
Failure Behavior ◽  
Failure Strength ◽  
Heating Rates ◽  
Cfrp Laminates

This paper proposes a theoretical approach to predict the failure behavior of laminated carbon fiber reinforced polymer (CFRP) under combined thermal and mechanical loadings. Two types of CFRP Laminates, i.e., CCF300/BA9916 and T700/BA9916, are investigated, and TGA tests in both nitrogen and oxidation environments at different heating rates are carried out to obtain the thermal decomposition kinetic parameters of polymer matrix and carbon fiber. Based on the thermal decomposition behavior and a multi-level structure model, the thermal physical properties, mechanical properties and thermal deformations of the laminated composites at high temperatures are obtained. Then substituting thermally degraded properties into constitutive equations of composite materials as macroscopic defects, the damage mode and failure strength of the laminated composite under thermo-mechanical loadings is obtained. Predicted elastic properties and failure strength are compared with experimental results as well as previous models. Effects of heating rates and heating environments through rigorous physical model are considered in the present work. It is found that the heating rate significantly affects the thermal and mechanical properties, the higher the heating rate, the less degraded are the thermo-mechanical properties and failure strength at a given temperature. Young’s modulus and failure strength of T700/BA9916 are higher than those of CCF300/BA9916 at high temperatures, due to the higher volume fraction of carbon fibers, which are less weakened in thermal environment.

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.

Physical and Mechanical Properties of Fired Clay Bricks Incorporated with Cigarette Butts: Comparison between Slow and Fast Heating Rates

2013 ◽  
Vol 421 ◽  
pp. 201-204
Author(s):  
Aeslina binti Abdul Kadir ◽  
Abbas Mohajerani
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Heating Rate ◽  
Initial Rate ◽  
Physical And Mechanical Properties ◽  
Slow Heating ◽  
Firing Process ◽  
Heating Rates ◽  
Fast Heating ◽  
Rate Of Absorption

In general, firing process in brick manufacturing could affect the properties, colours and appearance of the brick. The main purpose of this study was to evaluate the effect of different heating rates on physical and mechanical properties during the firing of standard bricks and bricks incorporated with cigarette butt (CB). In this investigation, two different heating rates were used: slow heating rate (2oC min-1) and fast heating rate (5oC min-1). Samples were fired in solid forms from room temperature to 1050oC. All bricks were tested for their physical and mechanical properties including compressive strength, initial rate of absorption and density. Higher heating rates decrease compressive strength value but slightly increase the initial rate of absorption and density properties respectively. In conclusion, higher heating rates are able to produce adequate physical and mechanical properties especially for CB Brick.

scholarly journals Influence of Heating Rate on the Structure and Mechanical Properties of Aromatic BPDA–PDA Polyimide Fiber

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 510 ◽  
Author(s):  
Wenke Yang ◽  
Fangfang Liu ◽  
Hongxiang Chen ◽  
Xuemin Dai ◽  
Wei Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Treatment ◽  
Heating Rate ◽  
Tensile Modulus ◽  
High Mobility ◽  
Polymer Chains ◽  
Degree Of Crystallinity ◽  
High Heating Rate ◽  
Heating Rates ◽  
Polyimide Fibers

Aromatic polyimide fibers (PI) are usually produced in two steps. The precursor fibers of polyamic acid (PAA) are fabricated first, and then the fabricated fibers are converted into PI fibers through thermal treatment. In the second step (thermal treatment), the mechanical properties of the obtained PI fibers are remarkably affected. Here, the PAA fibers derived from 3,3’,4,4’-biphenyltetra-carboxylic dianhydride and p-phenylenediamine are fabricated by a dry-jet wet-spinning method. Then, the PI fibers are prepared by heating PAA fibers from room temperature to 300, 350 and 400 °C under different heating rates, ranging from 1 °C/min to 80 °C/min. When the heating rate is low, the crystallization lags behind the imidization process, and begins only when the imidization degree reaches a high level. As the heating rate increases, the crystallization tends to occur simultaneously with the imidization process, and the degree of crystallinity of the PI fibers also greatly increases. Our findings suggest that a high heating rate causes the polymer chains to undergo high mobility during thermal treatment. The tensile modulus of the PI fiber further demonstrates a high dependence on the heating rate. Moreover, a short annealing process after treatment proves to be efficient in releasing residual stress and improving tensile strength.

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.

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