scholarly journals Ausztenites korrózióálló acél szemcsehatármenti korrózióra való hajlamának elemzése fizikai szimulációval

2021 ◽  
Vol 11 (4) ◽  
pp. 15-30
Author(s):  
Ádám Dobosy ◽  
Marcell Gáspár ◽  
Gyula Nagy
Keyword(s):  
Gleeble 3500

Mint ismeretes, az ausztenites korrózióálló acélok, ha azok karbontartalma meghaladja a 0,03-0,04%-ot, nagyobb hőmérsékletről lassan hűtve, vagy 500 - 900 ˚C hőmérséklet közben hőn tartva, nem lesznek homogén szövetszerkezetűek. Az ausztenit mellet számos intermetallikus vegyület válik ki, amelyek közül a szemcsehatármenti korrózió kialakulása szempontjából a M23C6 karbid kiválása a meghatározó. A kiváló nagy krómtartalmú (kb. 65%) fázis környezetében az ausztenit Cr tartalma 10,5% alá csökkenhet, így az acél kristályközi korrózióra hajlamossá válhat. A szemcsehatármenti korrózióra hajlamos ausztenites korrózióálló acélok esetén a hegesztési hőfolyamat hatására is kialakulhat a nem kívánt kiválás. Az egyes ausztenites korrózióálló acélok érzékenységének jellemzése érdekében ún. szenzibilizációs diagramokat célszerű meghatározni, amelyeknél a hőntartás hőmérséklete és ideje függvényében a karbidok elhelyezkedési, előfordulási területeit jelenítik meg. Tekintettel arra, hogy a hegesztés hőciklusa jelentősen különbözik az állandó hőmérsékletű kezelésnél alkalmazottól, a szemcsehatármenti korróziós hajlamot a hegesztési hőfolyamat paramétereinek függvényében célszerű elemezni. Jelen kutatómunkában fizikai szimulációval előállított hegesztési hőciklus(ok)nak kitett próbatesteken (X5CrNi18-10, 1.4301) végeztünk kísérleteket egy Gleeble 3500 típusú berendezésen, amelynek során különböző maximális hőmérsékleteket létrehozva, változó lehűlési profilokat vizsgáltunk. A vizsgálati eredmények felhasználásával különválasztottunk néhány olyan hegesztési hőciklust, amelyek alkalmazása esetén bekövetkezhet szemcsehatármenti korrózió, illetve az elkerülhető a vizsgált ausztenites alapanyagon.

Continuous Cooling Transformation of Overcooling Austenite and Structure Evolution of Si Steel

2013 ◽  
Vol 652-654 ◽  
pp. 947-951
Author(s):  
Hui Li ◽  
Yun Li Feng ◽  
Da Qiang Cang ◽  
Meng Song
Keyword(s):  
Phase Transformation ◽  
Cooling Rate ◽  
Optical Microscope ◽  
Structure Evolution ◽  
Upward Trend ◽  
Continuous Cooling Transformation ◽  
Continuous Cooling ◽  
Hardness Tester ◽  
Gleeble 3500 ◽  
Evolution Of Microstructure

The static continuous cooling transformation (CCT)curves of 3.15 Si-0.036 C-0.21 Mn-0.008 S-0.008 N-0.022 Al are measured on Gleeble-3500 thermal mechanical simulator, the evolution of microstructure and the tendency of hardness are investigated by optical microscope (OM) and hardness tester. The results show that there is no evident change in microstructure which mainly are ferrite and little pearlite under different cooling rates, but the transition temperature of ferrite is gradually reduced with the increase of cooling rate. When the cooling rate is increased from 0.5°C/s to 20°C/s, the ending temperatures of phase transformation are decreased by 118°C, when cooling rate reaches to 10, Widmanstatten ferrite appears. The hardness of the steel turns out gradual upward trend with the increase of cooling rate.

Material Constants of Ferritic Spheroidal Cast Iron during Hot Deformation

2008 ◽  
Vol 575-578 ◽  
pp. 164-168 ◽  
Author(s):  
Xin Zhao
Keyword(s):  
Cast Iron ◽  
Strain Rate ◽  
Hot Deformation ◽  
Flow Curves ◽  
Material Constants ◽  
Thermally Activated ◽  
Straight Line ◽  
Deformation Behaviors ◽  
Gleeble 3500 ◽  
Joint Laboratory

The hot deformation behaviors of a ferritic spheroidal cast iron (FSCI) have been investigated by compression testing on a Gleeble 3500 machine of the DSI-YSU Joint Laboratory. The temperature rang was from 1073K to 1273K and strain rate from 10-3 to 1 s-1. The total true stain was 0.7. The result shows that the flow curves obtained are typical of dynamic recrystallization processes. The plots of either the natural logarithms of the corresponding temperature or the natural logarithms of strain rate against the hyperbolic of flow stresses satisfy straight line relationships over the experimental data, indicating that the hot compression of the FSCI is thermally activated. The material constants, including activation energy 0H as 240.8 kJ/mol, stress-level coefficient α as 1.352×10-8 Pa-1, stress exponential n as 3.9937, structural factor A as 5.64×108 s-1, are derived .

scholarly journals Comparative HAZ softening analysis of three different automotive aluminium alloys by physical simulation

2021 ◽  
Vol 66 (1) ◽  
pp. 23-38
Author(s):  
Singh Pratap ◽  
Judit Kovácsb
Keyword(s):  
Aluminium Alloy ◽  
Heat Affected Zone ◽  
Heat Input ◽  
Aluminium Alloys ◽  
Physical Simulation ◽  
Hardness Test ◽  
Optical Microscope ◽  
Automotive Application ◽  
Welding Parameters ◽  
Gleeble 3500

The development of high strength aluminium alloy has revolutionized the automotive industry with innovative manufacturing and technological process to provide high-performance components, weight reduction and also diversified the application field and design consideration for the automotive parts that work under severe conditions, but the selection of proper production parameters is most challenging task to get excellent results. Growing industrial demand of aluminium alloys led to the development of new welding technologies, processes and studies of various parameters effects for its intended purposes. The microstructural changes lead to loss of hardening and thereby mechanical strength in the HAZ welded joint even though the base materials are heat treatable and precipitation hardened. So, our goal is to analyse HAZ softening and analyse the sub-zones as a function of the parameter. In this paper, the influence of weld heat cycle on the heat-affected zone (HAZ) is physically simulated for Tungsten Inert Gas Welding (TIG) using Gleeble 3500 thermomechanical simulator for three different automotive aluminium alloy (AA5754-H22, AA6082-T6 & AA7075-T6) plate of 1 mm thickness. In order to simulate the sub-zones of the heat-affected zone, samples were heated to four different HAZ peak temperatures (550 °C, 440 °C, 380 °C and 280 °C), two linear heat input (100 J/mm and 200 J/mm) by the application of Rykalin 2D model. A series of experiments were performed to understand the behaviour, which make it possible to measure the objective data on the basis of the obtained image of the aluminium alloys tested with heat-affected zone tests in a Gleeble 3500 physical simulator. The main objective is to achieve the weldability of three different automotive aluminium alloys and their comparison based on the welding parameters like heat input. Further, the investigation of HAZ softening and microstructure of the specimens were tested and analysed using Vicker's hardness test and optical microscope respectively. The paper focuses on HAZ softening analysis of different grades of aluminium alloys for automotive application.

Microstructure Evolution of near α Titanium Alloy during Multi-Step Thermomechanical Deformation Process

2021 ◽  
Vol 1035 ◽  
pp. 305-311
Author(s):  
Qing Shan Liu ◽  
Bo Long Li ◽  
Tong Bo Wang ◽  
Cong Cong Wang ◽  
Peng Qi ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
High Temperature ◽  
Hot Deformation ◽  
Deformation Temperature ◽  
Strain Curve ◽  
Optical Microscope ◽  
Phase Content ◽  
Β Phase ◽  
Α Phase ◽  
Gleeble 3500

A new type of near α high temperature titanium alloy of Ti-Al-Sn-Zr-Mo-Si-Er was studied. The samples with different primary α phase content were prepared by solid solution at 950 °C/1 h—1010 °C/1 h. The multi-step hot compression experiments were carried out by Gleeble-3500 in a sequence of upper region of α + β phase, then followed by lower region of α + β phase. The effects of primary α phase content and deformation temperature on the microstructure of the alloy were studied by means of true stress-strain curve and optical microscope. The results show that the content of primary α phase gradually decreases from 45.4% at 950°C to 0% at 1010°C. As the deformation temperature decreases from 940°C to 900°C, the content of α phase increases gradually from 65% to 94%, which is changed from dynamic recrystallization to deformed structure elongated along RD direction. It is found that the arrangement of α phase along RD direction is the longest at 920°C. With the increase of the deformation temperature in the multi-step high temperature region from 970°C to 990°C, the width of deformed α phase decreases from 3.64 μm at 970°C to 2.71 μm at 990°C. The optimized microstructure is composed of 20% primary α phase arranged along RD direction. This process has a certain potential in the process of hot deformation of the alloy. Key words: high temperature titanium alloy, primary α phase, multi-step hot deformation

Microstructure and Properties Formed at Different Cooling Rates of Low Carbon Alloy Steel for Welding Wire Production

2020 ◽  
Vol 304 ◽  
pp. 99-106
Author(s):  
Natalya Koptseva ◽  
Yulia Efimova ◽  
Mikhail Chukin ◽  
Alexander Pesin ◽  
N. Tokareva ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Physical Simulation ◽  
Low Carbon ◽  
Welding Wire ◽  
Continuous Cooling ◽  
Hardware Processing ◽  
Gleeble 3500 ◽  
Hot Rolled ◽  
Continuous Cooling Transformation Diagram ◽  
Undercooled Austenite

Physical simulation of steel Mn3Ni1CrMo continuous cooling with different speeds from austenitic state was performed using GLEEBLE 3500 complex. The phase transformations are analyzed and the effect of the cooling rate on the structure and hardness is investigated. A continuous cooling transformation diagram of the undercooled austenite decomposition is constructed. It was concluded that it is possible to reduce the hardness of the hot-rolled billet by reducing the cooling rate compared to the existing in the processing at the STELMOR line of PJSC “MMK”, and this will eliminate the heat treatment of welding wire on the hardware processing.

Simulation and Experimental Based Analysis of the Laser Beam Welding of DP Steels

2020 ◽  
Vol 1157 ◽  
pp. 73-82
Author(s):  
Raghawendra Pratap Singh Sisodia ◽  
Marcell Gáspár ◽  
Béla Fodor ◽  
László Draskóczi
Keyword(s):  
Laser Beam ◽  
Heat Affected Zone ◽  
Physical Simulation ◽  
Welded Joint ◽  
Laser Beam Welding ◽  
Base Material ◽  
Hardness Tests ◽  
Welding Thermal Cycle ◽  
Diode Laser Beam ◽  
Gleeble 3500

In this paper, heat affected zone characteristics of DP1000 steels was investigated during diode laser beam welding (LBW). A butt-welded joint of specimen in dimension of 300 x 150 mm each (according to EN15614-11:2002) with 1 mm thickness is used for the experimental purpose. The welding thermal cycle and the cooling circumstances in the HAZ was determined by real experiment and the physical simulation. A Gleeble 3500 thermo-physical simulator was used to physically simulate the coarse grain heat affected zone (CGHAZ) on the base material specimens by the utilization of the thermal cycles for t8/5 =2.5 s. The results of the physical simulation were validated by real welding experiments. The properties of the simulated and the real HAZ was examined by optical microscopic, scanning electron microscope and hardness tests.

scholarly journals Effects of Sn and Sb on the Hot Ductility of Nb+Ti Microalloyed Steels

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1679
Author(s):  
Chunyu He ◽  
Jianguang Wang ◽  
Yulai Chen ◽  
Wei Yu ◽  
Di Tang
Keyword(s):  
Laser Scanning ◽  
Microalloyed Steel ◽  
Confocal Laser Scanning Microscope ◽  
Microalloyed Steels ◽  
Confocal Laser ◽  
Hot Ductility ◽  
High Temperature Mechanical Properties ◽  
Ductility Trough ◽  
Gleeble 3500 ◽  
Fracture Morphologies

Referencing the composition of a typical Nb+Ti microalloyed steel (Q345B), two kinds of steels, one microalloyed with Sn and Sb, and the other one only microalloyed with Sb were designed to study the effects of Sn and Sb on the hot ductility of Nb+Ti microalloyed steels. The Gleeble-3500 tester was adopted to determine the high-temperature mechanical properties of the two test steels. Fracture morphologies, microstructures and interior precipitation status were analyzed by SEM, CLSM (Confocal laser scanning microscope) and EDS, respectively. Results revealed that within the range of 950–650 °C, there existed the ductility trough for the two steels, which were mainly attributed to the precipitation of TiN and Nb (C, N). Additionally, precipitation of Sn and Sb were not observed in this research and the hot ductility was not affected by the addition of Sn and Sb, as compared with the Nb+Ti microalloyed steel. Therefore, addition of a small amount of Sn and Sb (≤0.05 wt.%) to the Nb+Ti microalloyed steel is favorable due to the improvement on corrosion resistance.

Mechanical Behavior and Microstructure of Hot Deformation of with Er 7N01 Aluminum Alloy

2020 ◽  
Vol 993 ◽  
pp. 294-298
Author(s):  
Bo Hou Zhang ◽  
Bo Long Li ◽  
Peng Qi ◽  
Ning Li ◽  
Tong Bo Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Aluminum Alloy ◽  
Deformation Temperature ◽  
Electron Backscatter Diffraction ◽  
Strain Curve ◽  
Recrystallization Process ◽  
Compression Process ◽  
Thermal Compression ◽  
Transmission Electron ◽  
Gleeble 3500

In this paper, an Al-Zn-Mg-Cu alloy with a small amount of Er and Zr added was used as the research object. The homogenization annealing was carried out, and the 7N01 aluminum alloy was used at 300 °C, 350 °C, 400 °C, 450 °C and 0.1 s-1, 1 s-1, 10 s-1 deformation conditions by Gleeble-3500 thermal simulator. Optical Microscopy (OM), Scanning Electron Microscopy (SEM), Electron Backscatter Diffraction (EBSD) and Transmission Electron Microscopy (TEM) were used for microstructure analysis. The results show that the stress-strain curve of with Er 7N01 aluminum alloy can be divided into micro-strain stage, uniform deformation stage and steady-state flow stage during the thermal compression process. The flow stress of 7N01 aluminum alloy achieved peaks at the initial stage of strain, and then increased with the increase of strain rate and the decrease of deformation temperature. With the increase of deformation temperature and the decrease of deformation rate, the recrystallization process was significantly increased.

The Selection of Appropriate Process Parameters of Diffusion Bonding in Heterogeneous Weld of 355J2/AISI 316L Steels

2017 ◽  
Vol 737 ◽  
pp. 101-106 ◽  
Author(s):  
Jaromír Moravec ◽  
Iva Nováková
Keyword(s):  
Diffusion Bonding ◽  
Strength Properties ◽  
Aisi 316L ◽  
Fundamental Theory ◽  
Technological Parameters ◽  
High Alloy ◽  
Parameters Selection ◽  
316L Steel ◽  
Gleeble 3500 ◽  
Selection Of

The aim of this article is to present possibilities of diffusion bonding utilization at creation heterogeneous joints where strength properties are taken into account. The joint was implemented to low-alloy structural ferrite-pearlite S355J2 steel and high-alloy austenitic AISI 316L steel. The fundamental theory of diffusion and also design and realisation of experimental creation of diffusion joint in thermal-mechanical simulator Gleeble 3500 is described in the article. Furthermore, procedure of technological parameters selection, when optimisation of strength properties of heterogeneous joint including metallographic evaluation are taken into account, are presented.

scholarly journals Influence of Rare Earth on Dynamic Recrystallization Behavior of As-Cast 30Mn Steel

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Honghong Yan ◽  
Yong Hu ◽  
Dawen Zhao
Keyword(s):  
Rare Earth ◽  
Dynamic Recrystallization ◽  
Strain Rate Range ◽  
Compression Tests ◽  
Forming Process ◽  
Cast Slab ◽  
Forming Technology ◽  
Alloy Addition ◽  
Dynamic Recrystallization Behavior ◽  
Gleeble 3500

Based on casting-rolling compound forming process, the effect of rare earth on dynamic recrystallization (DRX) of as-cast 30Mn steel was investigated by the single-pass hot compression tests performed using a Gleeble-3500 thermomechanical simulator, and the deformation temperature range was 950°C–1150°C and strain rate range was 0.1–1 s−1. With the assistance of the process parameters, constitutive equations were used to obtain the activation energy and hot working equation. The dynamic recrystallization kinetics models of the tested steel were constructed. The results show that rare earth ferrosilicon alloy addition (0.2%, mass fraction) can delay the onset of DRX significantly and refine the hot deformation microstructures. All of the results indicate that the addition of rare earth into as-cast 30Mn steel is helpful to prepare excellent cast slab for the casting-rolling compound forming technology.

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