scholarly journals Effect of Sub-Zero Treatments and Tempering on Corrosion Behaviour of Vanadis 6 Tool Steel

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3759
Author(s):  
Peter Jurči ◽  
Aneta Bartkowska ◽  
Mária Hudáková ◽  
Mária Dománková ◽  
Mária Čaplovičová ◽  
...  
Keyword(s):  
Population Density ◽  
Corrosion Rate ◽  
Tool Steel ◽  
Retained Austenite ◽  
Corrosion Behaviour ◽  
Considerable Reduction ◽  
Treated Steel ◽  
Precipitation Behaviour ◽  
Quenched Steel

Sub-zero treatment of Vanadis 6 steel resulted in a considerable reduction of retained austenite amount, refinement of martensite, enhancement of population density of carbides, and modification of precipitation behaviour. Tempering of sub-zero-treated steel led to a decrease in population density of carbides, to a further reduction of retained austenite, and to precipitation of M3C carbides, while M7C3 carbides precipitated only in the case of conventionally quenched steel. Complementary effects of these microstructural variations resulted in more noble behaviour of sub-zero-treated steel compared to the conventionally room-quenched one, and to clear inhibition of the corrosion rate at the same time.

Relationships between the Microstructure, Hardness and Fracture Toughness of Differently Sub-Zero Treated Tool Steel

2019 ◽  
Vol 395 ◽  
pp. 95-112 ◽  
Author(s):  
Peter Jurči ◽  
Ivo Dlouhý ◽  
Jakub Horník ◽  
Petra Priknerová ◽  
Zdeněk Mrštný
Keyword(s):  
Fracture Toughness ◽  
Low Temperature ◽  
Population Density ◽  
Tool Steel ◽  
Retained Austenite ◽  
Room Temperature ◽  
Secondary Hardening ◽  
Temperature Quenching ◽  
Treated Steel ◽  
Different Temperatures

A PM made Cr-V ledeburitic tool steel Vanadis 6 has been subjected to conventional austenitizing and quenching, which was followed by sub-zero treatment at different temperatures, and by tempering treatments. The microstructure, hardness and fracture toughness of sub-zero treated steel have been investigated with reference to the same material after conventional room temperature quenching. The main findings are that sub-zero treatments reduce the retained austenite amount, enhance the population density of small carbides, refine the martensite and change the precipitation of carbides during tempering. These alterations are reflected in elevated hardness after low-temperature tempering but slightly lowered hardness after tempering within the normal secondary hardening temperature range, except the specimens treated at-140 °C where the hardness improvement was maintained. The fracture toughness is rather negatively influence by the sub-zero treatments, except the treatment at-140 °C where no impact or rather improvement has been recorded; thus, the treatment at a temperature of-140 °C seems to be a promising way how to improve the hardness and the fracture toughness pf the Vanadis 6 steel simultaneously.

scholarly journals Can Sub-zero Treatment at −75 °C Bring Any Benefits to Tools Manufacturing?

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3827 ◽  
Author(s):  
Kusý ◽  
Rízeková-Trnková ◽  
Krajčovič ◽  
Dlouhý ◽  
Jurči
Keyword(s):  
Fracture Toughness ◽  
Population Density ◽  
Flexural Strength ◽  
Tool Steel ◽  
Retained Austenite ◽  
Subsequent Tempering ◽  
Secondary Hardness ◽  
Hardness Peak ◽  
Quenched Steel ◽  
The Impact

: Vanadis 6 ledeburitic tool steel was subjected to sub-zero treatment at −75 °C for different durations, and for different subsequent tempering regimes. The impact of these treatments on the microstructure, hardness variations, and toughness characteristics of the steel was investigated. The obtained results infer that the retained austenite amount was reduced to one fourth by sub-zero treatment (SZT), and the population density of add-on carbides was increased by factor of three to seven, depending on the duration of SZT. Tempering always reduced the population density of these particles. A hardness increased by 30–60 HV10 was recorded after sub-zero treatment but tempering to the secondary hardness peak induced much more significant hardness decrease than what was established in conventionally quenched steel. The flexural strength was not negatively influenced by sub-zero treatment at −75 °C while the fracture toughness tests gave worse values of this quantity, except the case of steel tempered to the secondary hardness peak.

Microstructural Characterization of Ledeburitic Tool Steel after Sub-Zero Treatment and Tempering

2020 ◽  
Vol 403 ◽  
pp. 103-109
Author(s):  
Jana Ptačinová ◽  
Juraj Ďurica ◽  
Matej Pašák ◽  
Martin Kusy ◽  
Peter Jurči
Keyword(s):  
Population Density ◽  
Tool Steel ◽  
Retained Austenite ◽  
Microstructural Characterization ◽  
Vacuum Furnace ◽  
Nitrogen Gas ◽  
Tempering Temperature ◽  
Heat Treated ◽  
Gas Quenching

Microstructural characterization of ledeburitic tool steel Vanadis 6 after sub-zero treatment and tempering has been examined. The samples were heat treated using following schedules: heating to the austenitizing temperature (TA = 1050 °C) in a vacuum furnace, hold at the final temperature for 30 min. and nitrogen gas quenching (5 bar). The sub-zero treatments consisted of immediate (after quenching) immersion of the material into the liquid helium (-269 °C), hold at the soaking temperature and removal the samples to be heated to a room temperature. Double tempering has been performed at the temperatures from the range 170 – 530 °C, whereas each tempering cycle was realized with a hold of 2 h. Typical heat treated microstructure of ledeburitic steels consists, besides of the martensitic matrix with certain amount of retained austenite, of several types of carbides – eutectic, secondary and small globular carbides. In sub-zero treated steel the amount of retained austenite is significantly reduced. The population density of small globular carbides increase as a result of sub-zero treating. Tempering of the material resulted in decrease in population density of small globular carbides with increasing the tempering temperature. The hardness of sub-zero treated material is higher than that of conventionally quenched one. Also, this tendency is preserved when the steel is low-temperature tempered. On the other hand, the hardness of conventionally quenched steel becomes higher than that of SZT one when tempered at the temperature of secondary hardening.

scholarly journals IMPROVED REPRODUCIBILITY OF D2 TOOL STEEL AFTER CRYO-TREATING AT -78°C (DRY ICE)

2020 ◽  
Vol 1 (1) ◽  
pp. 21-24
Author(s):  
G.K. Egert ◽  
T. D. Burleigh
Keyword(s):  
Weight Loss ◽  
Internal Stress ◽  
Liquid Nitrogen ◽  
Tool Steel ◽  
Retained Austenite ◽  
Cyclic Polarization ◽  
Cold Temperatures ◽  
Dry Ice ◽  
Treated Steel ◽  
D2 Steel

The exposure of steel to very cold temperatures (cryogenics) as a means to improve properties of the metal has had a controversial history. This study employed several tests to determine differences between D2 tool steel cryo-treated in dry ice (-78°C) versus in liquid nitrogen (-196°C), as compared to control D2 steel (not cryo-treated). These tests showed no major changes between the control and the liquid nitrogen treated steel, but the dry ice (-78°C) treated steel showed narrower XRD peaks, more reproducible hardness measurements, less scatter in the corrosion weight loss, and lower corrosion currents in the cyclic polarization tests in saltwater. All these differences were measured even though there was no measurable difference in retained austenite. The authors hypothesize that the -78°C (dry ice) allowed internal stress reductions, while the -196°C (liquid nitrogen) was too cold to allow any transformations.

Cementite Precipitation of a H21 Tool Steel after Hot Compression and Double Temper

2014 ◽  
Vol 1043 ◽  
pp. 154-158
Author(s):  
Meilinda Nurbanasari ◽  
Panos Tsakiropoulos ◽  
Eric J. Palmiere
Keyword(s):  
High Temperature ◽  
Applied Stress ◽  
Tool Steel ◽  
Hot Deformation ◽  
Lower Bainite ◽  
Precipitation Behavior ◽  
Transformation Mechanism ◽  
Tempered Martensite ◽  
Bainite Transformation ◽  
Precipitation Behaviour

The cementite precipitation behavior in the martensite and banite of the H21 tool steel under high temperature axisymmetric compression test and double temper was investigated. The main purpose on this work is to develop a better understanding regarding the transformation mechanism of bainite and martensite in a H21 tool steel. The selected deformation temperatures were 1100 oC and 1000 oC and the double temper process was carried out at 650 oC for 1 hour respectively. The results showed that the cementite was sensitive to the stress. The applied stress has affected the Fe3C precipitation behaviour by decreasing the number of variants carbides in tempered martensite and decreasing the number of a single variant carbides in tempered lower bainite. The results were in agreement with a displacive mechanism of martensite and bainite transformation. It was also found that hot deformation temperatures selected in this work have the same contribution in decreasing number of variant carbides in tempered martensite and decreasing number of single variant carbides occurred in tempered lower bainite.

scholarly journals The influence of gelatine on the corrosion behaviour of cold worked copper wire in alkaline media

2006 ◽  
Vol 42 (1) ◽  
pp. 33-43 ◽  
Author(s):  
Svetlana Ivanov ◽  
Mirjana Rajcic-Vujasinovic ◽  
Zoran Stevic
Keyword(s):  
Corrosion Rate ◽  
Corrosion Behaviour ◽  
Copper Wire ◽  
Positive Influence ◽  
Open Circuit ◽  
Alkaline Media ◽  
Forming Process ◽  
Deformation Degree ◽  
Cold Worked ◽  
Potentiodynamic Method

Copper wire obtained by dip-forming process was cold worked to the deformation degrees of 83, 87, 91, 95 and 99 %. Electrochemical potentiodynamic method was used to investigate corrosion behavior of these wires in aqueous solutions of Na2CO3 (1 mol/dm3). Open circuit potentials as well as peak potentials are given as a function of deformation degree in Na2CO3 without and with addition of gelatine in concentration between 0.1 and 0.5 g/l. It was found that the addition of gelatine does not change the mechanism of the process, but influences on current density. Small concentrations of gelatine (0.1 g/l or less) have positive influence on the corrosion protection of copper in alkaline solution, but the addition of gelatine in concentration 0.5 g/l causes the increasing of its corrosion rate.

scholarly journals Corrosion behaviour of an AlZnSnSrGa alloy in aqueous solutions of NaCl and Na2So4

2000 ◽  
Vol 65 (1) ◽  
pp. 73-81
Author(s):  
P. Zivkovic ◽  
J. Pjescic ◽  
S. Mentus
Keyword(s):  
Corrosion Rate ◽  
Aqueous Solutions ◽  
Polarization Resistance ◽  
Corrosion Current Density ◽  
Corrosion Behaviour ◽  
Base Material ◽  
Corrosion Current ◽  
Open Circuit ◽  
Base Metals ◽  
Aluminium Plant

The alloy composed of Al(95.53%), Zn(2.85%), Sn(0.515%), Ga(0.1%) and Sr(0.009%), with the weight percents in the parentheses, was prepared by melting, using Al(99.84%), a product of the Aluminium Plant-Podgorica, as the base material. The corrosion behaviour of this alloy was tested in relation to the behaviour of the base metals, by both open curcuit potential and polarization resistance methods, in aqueous solutions of both NaCl and Na2SO4, the concentration of which varied within the range 0.00051 - 0.51 mol dm -3. Over the whole salt concentration ranges, the corrosion parameters indicate that the corrosion rate of the alloy is significantly higher than the rate of the base material. For instance, for the concentration range 0.00051 - 0.51 mol dm -3 , the stationary open circuit potentials, related to SCE, in NaCl solutions were - 1.200 to - 1.460 V for the alloy and - 0.693 to - 0.920 V for Al, while in Na2SO4 solutions, the stationary open circuit potentials were - 1.190 to - 1.465V for the alloy and - 0.780 to - 0.860V for Al. At the same time, the corrosion current density in NaCl solutions varied within 11-89 mA cm -2 for the alloy and 0.35 - 0.80 for Al, while in Na2SO4 solutions it amounted to 5.7.52 mA cm -2 for the alloy and 0.28 - 0.88 mA cm -2 for Al.

scholarly journals Ethanolamines as Corrosion Inhibitors for Zinc in (HNO3+H2SO4) Binary Acid Mixture

2010 ◽  
Vol 7 (2) ◽  
pp. 665-668 ◽  
Author(s):  
R. T. Vashi ◽  
H. M. Bhajiwala ◽  
S. A. Desai
Keyword(s):  
Corrosion Rate ◽  
Acid Concentration ◽  
Corrosion Inhibitors ◽  
Inhibition Efficiency ◽  
Corrosion Behaviour ◽  
Acid Mixture ◽  
Inhibitor Concentration

This work deals with the study of corrosion behaviour for zinc in (HNO3+ H2SO4) binary acid mixture containing ethanolamines. Corrosion rate increases with concentration of acid and temperature. At constant acid concentration, the inhibition efficiency of ethanolamines increases with the inhibitor concentration. Value of ΔGa increases and inhibition decreases with temperature. The mode of inhibition action appears to be chemisorption.

Effect of nickel content in the corrosion process of TiC/Cu-Ni composites immersed in synthetic seawater

MRS Advances ◽  
2019 ◽  
Vol 4 (63) ◽  
pp. 3475-3484
Author(s):  
Miguel A. Téllez-Villaseñor ◽  
Carlos A. León Patino ◽  
Ricardo Galván Martínez ◽  
Ena A. Aguilar Reyes
Keyword(s):  
Corrosion Rate ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Nickel Content ◽  
Corrosion Mechanism ◽  
Composite Surface ◽  
Synthetic Seawater ◽  
Ni Content ◽  
The Matrix ◽  
Static Conditions

ABSTRACTThe work presents an electrochemical study of the corrosion behaviour of two TiC/Cu-Ni metal matrix composites with a content of 10 and 20 wt.% Ni immersed in synthetic seawater. The composites were synthesized by a capillary infiltration technique, obtaining dense materials TiC/Cu-10Ni and TiC/Cu-20 Ni with a residual porosity of 1.8 and 1.7%, respectively. The corrosion rate (CR) was evaluated from the techniques of polarization curves (PC), linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS). Electrochemical measurements were carried out under static conditions, ambient temperature and atmospheric pressure at 24 hours exposure in the electrolytic medium. The corrosion rate is affected by the Ni content in the matrix, with less corrosion in the composite with a higher Ni content. The higher content of Ni in the Cu-Ni alloy provides higher passivation and stability to the corrosion products film that are absorbed on the composite surface. Microscopic examination (SEM) showed a characteristic morphology of a corrosion mechanism of the localized type (pits and crevices) generated by a differential aeration, where the TiC/Cu-10Ni composite showed greater degradation.

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