Effect of cooling rate during hot deformation on formation of cube-on-edge texture in electric sheet

1975 ◽  
Vol 17 (3) ◽  
pp. 252-254
Author(s):  
G. M. Vorob'ev ◽  
L. S. Krivusha ◽  
M. T. Velichko ◽  
V. A. Kozina
Keyword(s):  
Cooling Rate ◽  
Hot Deformation ◽  
Electric Sheet

Influence of Chromium Content and Prior Deformation on the Continuous Cooling Transformation Diagram of Low-Carbon Bainitic Steels

2020 ◽  
Vol 835 ◽  
pp. 58-67
Author(s):  
Mohammed Ali ◽  
Antti J. Kaijalainen ◽  
Jaakko Hannula ◽  
David Porter ◽  
Jukka I. Kömi
Keyword(s):  
Cooling Rate ◽  
Hot Deformation ◽  
Laser Scanning ◽  
Chromium Content ◽  
Bainitic Ferrite ◽  
Granular Bainite ◽  
Low Carbon ◽  
Cooling Rates ◽  
Continuous Cooling Transformation ◽  
Continuous Cooling

The effect of chromium content and prior hot deformation of the austenite on the continuous cooling transformation (CCT) diagram of a newly developed low-carbon bainitic steel has been studied using dilatometer measurements conducted on a Gleeble 3800 simulator with cooling rates ranging from 2-80 °C/s. After austenitization at 1100 °C, specimens were either cooled without strain or given 0.6 strain at 880 °C prior to dilatometer measurements. The resultant microstructures have been studied using laser scanning confocal microscopy, scanning electron microscopy and macrohardness measurements. CCT and deformation continuous cooling transformation (DCCT) diagrams were constructed based on the dilatation curves, final microstructures and hardness values. Depending on the cooling rate, the microstructures of the investigated steels after cooling from the austenite region consist of one or more of the following microstructural components: lath-like upper bainite, i.e. bainitic ferrite (BF), granular bainite (GB), polygonal ferrite (PF) and pearlite (P). The proportion of BF to GB as well as the hardness of the transformation products decreased with decreasing cooling rate. The cooling rate at which PF starts to appear depends on the steel composition. With both undeformed and deformed austenite, increasing the chromium content led to higher hardenability and refinement of the microstructure, promoting the formation of BF and shifting the ferrite start curve to lower cooling rates. Prior hot deformation shifted the transformation curves to shorter times and higher temperatures and led to a reduction in hardness at the low cooling rates through the promotion of ferrite formation.

Investigation of Nickel Aluminum Bronze Alloy under Hot Compression Test

2014 ◽  
Vol 931-932 ◽  
pp. 365-369
Author(s):  
Jutamas Anantapong ◽  
Surasak Suranuntchai ◽  
Anchalee Manonukul ◽  
Vitoon Uthaisangsuk
Keyword(s):  
Strain Rate ◽  
Cooling Rate ◽  
Hot Deformation ◽  
Deformation Temperature ◽  
Volume Fraction ◽  
Constant Strain Rate ◽  
Aluminum Bronze ◽  
Nickel Aluminum ◽  
Bronze Alloy ◽  
Nickel Aluminum Bronze

The characteristics of Nickel Aluminum Bronze alloy (NAB) after hot deformation were investigated. The NAB alloy have been studied by dilatometer according to study the influence of hot deformation on microstructure of NAB alloy by dilatometer in the temperature range 800 - 950 °C, strain rate 10s-1 and cooling rate 40 and 100 °C/s. The experimental results showed that peak stress in relation to the involved deformation temperature, peak stresses at a constant strain rate decreased with an increase of deformation temperature. It was found that volume fraction of the β phase significantly increased with increasing temperature and cooling rate. The variation of this phase affected macro hardness of the investigated alloy. By higher temperatures, amount of β phase increased as well as the macro hardness of the NAB alloy.

Continuous Cooling Transformation Behavior of X70 Pipeline Steel

2013 ◽  
Vol 690-693 ◽  
pp. 2205-2209
Author(s):  
Hong Mei Yang
Keyword(s):  
Cooling Rate ◽  
Hot Deformation ◽  
Acicular Ferrite ◽  
Transformation Temperature ◽  
Pipeline Steel ◽  
Continuous Cooling Transformation ◽  
X70 Pipeline Steel ◽  
Continuous Cooling ◽  
Transformation Curve ◽  
Continuous Cooling Transformation Curve

The continuous cooling transformation behaviors were researched on X70 pipeline steel through two pass deformation and non-deformed austenite using Gleeble-3500 thermal mechanical simulator, and static continuous cooling transformation curve and dynamic continuous cooling transformation curve were measured through thermal dilation method and metallographic method. The influence of cooling rate and deformation parameters on microstructure was analyzed. The results show that the hot deformation accelerates the acicular ferrite and polygonal ferrite phase transformation, increases the starting transformation temperature and the finishing transformation temperature significantly, and shifts the CCT curve moving upward to the left side corner. Acicular ferrite is obtained in practice using accelerated cooling rate after deformation Acicular ferrite can be obtained in wider range of cooling rates, and microstructure and island structure is finer through hot deformation.

Effects of Cooling Rate and Direct Hot Deformation Conditions after Solidification on the Austenitic Microstructure Evolved by Simulated Strip Casting and Thin Slab Casting Processes in HSLA Steels

2006 ◽  
Vol 15-17 ◽  
pp. 726-731
Author(s):  
S. Hotta ◽  
Taichi Murakami ◽  
Takayuki Narushima ◽  
Yasutaka Iguchi ◽  
Chiaki Ouchi
Keyword(s):  
Grain Size ◽  
Cooling Rate ◽  
Hot Deformation ◽  
Casting Machine ◽  
Strip Casting ◽  
Thin Slab ◽  
Slab Caster ◽  
Thick Slab ◽  
Hsla Steels ◽  
Austenitic Grain Size

Currently new continuous casting processes such as thin slab caster or strip casting are industrialized or under developing in the world steel makers. In these casting processes, cooling rate after solidification becomes much faster compared with thick slab caster, and hot rolling mill connected directly with casting machine tends to be installed. The present study was conducted to investigate variations of austenitic grain size and micro segregation with cooling rate after solidification and also direct hot deformation conditions in austenite immediately after solidification in HSLA steels. HSLA steels were 0.15%C-0.25%Si-1.50%Mn, 0.028%Nb and 0.028%Nb-0.015%Ti with the same basic compositions. A hot working simulator of THERMECMASTER-Z was used, and the center part of tensile specimen set up in this machine was partially or fully levitation-melted by induction heating under argon gas atmosphere. After melting, specimens were cooled at cooling rate from 0.4K/s to 40K/s, and this range covered cooling rates after solidification in heavy thick slab caster and strip casting. Direct hot tensile straining in austenite after solidification was conducted at strain rates from 1.4×10-3s-1 to 2.6s-1, corresponding to an extracting speed in a respective caster. The increase of cooling rate refined continuously as cast austenitic grain size, and it was enhanced in micro alloyed steels. Micro segregation such as Mn was improved by faster cooling. Direct straining after solidification markedly refined austenitic grain size through dynamic or static recrystallization occurring depending on strain rate.

Dynamic CCT Curve of Hot Deformation Austenite in 55SiCr Steel

2012 ◽  
Vol 548 ◽  
pp. 225-228
Author(s):  
Yong Jun Zhang ◽  
Chuan Da Cui ◽  
Jing Tao Han
Keyword(s):  
Cooling Rate ◽  
Hot Deformation ◽  
Transformation Products ◽  
Thermal Simulation ◽  
Continuous Cooling Transformation ◽  
Continuous Cooling ◽  
Microstructure Transformation ◽  
Cct Curve ◽  
Rate Form ◽  
Transformation Curve

The CCT (Continuous Cooling Transformation) curve of hot deformation austenite in 55SiCr steel was measured on Gleeble-1500 thermal simulation machine, the microstructure and hardness of transformation products under different cooling velocities were observed. The microstructure transformation regularity with being cooled continuously were emphatically researched at the cooling rate form 0.1°C/s to 15 °C/s. The results can provide a instruction for producing 55SiCr steel.

Effects of cooling rate on the mechanical properties of dual phase treated vanadium steels

1983 ◽  
Vol 41 ◽  
pp. 220-221
Author(s):  
L.J. Chen ◽  
H.C. Cheng ◽  
J.R. Gong ◽  
J.G. Yang
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Automobile Industry ◽  
High Strength ◽  
Weight Percent ◽  
Low Alloy Steels ◽  
Dual Phase ◽  
Resource Requirement ◽  
Alloy Steels ◽  
Potential Weight

For fuel savings as well as energy and resource requirement, high strength low alloy steels (HSLA) are of particular interest to automobile industry because of the potential weight reduction which can be achieved by using thinner section of these steels to carry the same load and thus to improve the fuel mileage. Dual phase treatment has been utilized to obtain superior strength and ductility combinations compared to the HSLA of identical composition. Recently, cooling rate following heat treatment was found to be important to the tensile properties of the dual phase steels. In this paper, we report the results of the investigation of cooling rate on the microstructures and mechanical properties of several vanadium HSLA steels.The steels with composition (in weight percent) listed below were supplied by China Steel Corporation: 1. low V steel (0.11C, 0.65Si, 1.63Mn, 0.015P, 0.008S, 0.084Aℓ, 0.004V), 2. 0.059V steel (0.13C, 0.62S1, 1.59Mn, 0.012P, 0.008S, 0.065Aℓ, 0.059V), 3. 0.10V steel (0.11C, 0.58Si, 1.58Mn, 0.017P, 0.008S, 0.068Aℓ, 0.10V).

Suppression of γ’ Precipitation in a Laser-Melted Nickel-Base Alloy

1977 ◽  
Vol 35 ◽  
pp. 270-271
Author(s):  
J. M. Walsh ◽  
J. C. Whittles ◽  
B. H. Kear ◽  
E. M. Breinan
Keyword(s):  
Cooling Rate ◽  
Base Alloy ◽  
Material Surface ◽  
Intimate Contact ◽  
Absorbed Power ◽  
Perfect Contact ◽  
Nickel Base ◽  
Rapidly Solidified ◽  
Limiting Case ◽  
The Heat Transfer Coefficient

Conventionally cast γ’ precipitation hardened nickel-base superalloys possess well-defined dendritic structures and normally exhibit pronounced segregation. Splat quenched, or rapidly solidified alloys, on the other hand, show little or no evidence for phase decomposition and markedly reduced segregation. In what follows, it is shown that comparable results have been obtained in superalloys processed by the LASERGLAZE™ method.In laser glazing, a sharply focused laser beam is traversed across the material surface at a rate that induces surface localized melting, while avoiding significant surface vaporization. Under these conditions, computations of the average cooling rate can be made with confidence, since intimate contact between the melt and the self-substrate ensures that the heat transfer coefficient is reproducibly constant (h=∞ for perfect contact) in contrast to the variable h characteristic of splat quenching. Results of such computations for pure nickel are presented in Fig. 1, which shows that there is a maximum cooling rate for a given absorbed power density, corresponding to the limiting case in which melt depth approaches zero.

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