Optimal Precipitation Hardening Conditions in Lead Base Anodes for Copper Electrowinning

2010 ◽  
Vol 638-642 ◽  
pp. 1091-1097
Author(s):  
Carlos Camurri ◽  
Claudia Carrasco ◽  
Antonio Pagliero ◽  
Rafael Colás
Keyword(s):  
Cooling Rate ◽  
Yield Stress ◽  
Hot Rolling ◽  
Precipitation Hardening ◽  
Working Life ◽  
Cooling Conditions ◽  
Roll Temperature ◽  
Copper Electrowinning ◽  
Stable Conditions ◽  
Useful Life

The suitable yield stress of Pb-0.07%Ca-1.3%Sn anodes of 6 mm thickness for copper electrowinning is achieved by means of deformation and precipitation hardening processes, being its useful life dependant of this yield stress. In such sense the objective of the present work is to optimize the precipitation hardening, finding for this purpose the best cooling conditions of the anodes in the molds and of the hot rolling temperature. The results show that increasing cooling rate of ingots from natural cooling the precipitation hardening is enhanced, with increases of 10% and 12.5 % on the yield stress and working life of the anodes respectively, and that a minimum of 45 days of ageing is necessary to reach stable conditions for the precipitation hardening, with precipitates formation as CaSn3. The hot roll temperature as not significant effect on the precipitation hardening of the anodes.

scholarly journals Simulation of Thermal Stress and Fatigue Life Prediction of High Speed Steel Work Roll during Hot Rolling Considering the Initial Residual Stress

Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 966 ◽  
Author(s):  
Kejun Hu ◽  
Fuxian Zhu ◽  
Jufang Chen ◽  
Nao-Aki Noda ◽  
Wenqin Han ◽  
...  
Keyword(s):  
Residual Stress ◽  
Thermal Stress ◽  
Fatigue Life ◽  
Hot Rolling ◽  
Work Roll ◽  
Roll Surface ◽  
Initial Residual Stress ◽  
Thermal Fatigue Life ◽  
Cooling Conditions ◽  
Roll Temperature

Considerable residual stress is produced during heat treatment. Compressive residual stress at the shell is conductive to improving the thermal fatigue life of a work roll, while tensile stress in the core could cause thermal breakage. In hot rolling, thermal stress occurs under the heating-cooling cycles over the roll surface due to the contact with the hot strip and water spray cooling. The combination of thermal stress and residual stress remarkably influences the life of a work roll. In this paper, finite element method (FEM) simulation of hot rolling is performed by treating the residual stress as the initial stress. Afterwards, the effects of the initial roll temperature and cooling conditions on thermal stress considering the initial residual stress are discussed. Lastly, the thermal fatigue life of a work roll is estimated based on the strain life model. The higher initial roll temperature causes a higher temperature but a lower compressive thermal stress at the roll surface. The surface temperature and compressive stress increase significantly in the insufficient cooling conditions, as well as the center tensile stress. The calculation of the fatigue life of a work roll based on the universal slopes model according to the 10% rule and 20% rule is reasonable compared with experimental results.

Optimal Deformation Hardening in Lead Base Anodes for Copper Electrowinning for an Appropiate Working Life

2016 ◽  
Vol 879 ◽  
pp. 284-288 ◽  
Author(s):  
Carlos Camurri ◽  
Claudia Carrasco ◽  
Yazmín Maril
Keyword(s):  
Corrosion Rate ◽  
Yield Stress ◽  
Maximum Yield ◽  
Working Life ◽  
Compression Tests ◽  
Area Reduction ◽  
Copper Electrowinning ◽  
A Cell ◽  
Deformation Hardening ◽  
Plane Compression

The lead base anodes (Pb-0.07% Ca-1.3% Sn) of 6 mm thick have limited working life due to their loss of thickness and corrosion during the electrowinning process. If this loss of thickness is combined with a low yield stress of the anodes, these are much more likely to suffer premature deformations and distortions in cells. The aim of this study is to optimize the deformation hardening of the anodes, so as to achieve the best combination of yield stress and corrosion resistance to increase their working life. To achieve this the aged anodes were cold rolled to different area reductions from the standard 50% to 75%. To each one of these rolled anodes its yield stress was determined by plane compression tests, their grain sizes was measured by means of optical microscopy and their corrosion rate was determined by coulomb metric assays in a cell using an electrolyte concentration of sulfuric acid of 180 g/l and a oxidation current density of 300 A/m2.It was found that the maximum yield stress of the anodes increases from 58 MPa to 64 MPa when cold reduction goes up from 50% and reach 70% . Regarding the corrosion rate, the maximum and minimum values were 0.33 mm/ year and 0.30 mm / year, i.e., with no significant differences between the different rolled anodes. Based on the above results it is concluded that an increase in the working life of the anodes is obtained simply by giving them greater cold rolling deformation from the current 50% to 70% of area reduction.

Influence of Vanadium Microaddition on the Microstructure and Mechanical Properties of High Strength Large Diameter Wire-Rods

2005 ◽  
Vol 500-501 ◽  
pp. 761-770 ◽  
Author(s):  
L. Mendizabal ◽  
Amaia Iza-Mendia ◽  
Beatriz López ◽  
J.M. Rodriguez-Ibabe
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Hot Rolling ◽  
Precipitation Hardening ◽  
Large Diameter ◽  
High Strength ◽  
Unit Size ◽  
Cooling Conditions ◽  
Microstructure And Mechanical Properties ◽  
Made In

This paper analyses the application of vanadium microaddition for the production of high strength 16mm diameter wire-rods. Laboratory trials, simulating industrial cooling conditions after hot rolling, were made in a range between 3 and 8°C/s. The results show that introducing vanadium means that it is possible to optimise chemical composition by reducing elements susceptible to segregation. Besides, high strength values are maintained by means of precipitation hardening. The influence of vanadium microalloying on the crystallographic ferrite unit size was also evaluated.

scholarly journals Effect of Cooling Rate on Oxidation Behaviour of Microalloyed Steel

2013 ◽  
Vol 395-396 ◽  
pp. 273-278 ◽  
Author(s):  
Xiang Long Yu ◽  
Zheng Yi Jiang ◽  
Jing Wei Zhao ◽  
Dong Bin Wei ◽  
Cun Long Zhou
Keyword(s):  
Oxide Scale ◽  
Cooling Rate ◽  
Hot Rolling ◽  
Cooling System ◽  
Low Carbon Steel ◽  
Potential Contribution ◽  
Low Carbon ◽  
Cooling Conditions ◽  
Hot Rolling Mill ◽  
Iron Precipitates

Oxidation characteristics of a microalloyed low carbon steel were investigated by a hot rolling mill combined with acceleration cooling system over the cooling rate range from 20 to 70°C/s. The effects of cooling rate after hot rolling on microstructure and phase composition of oxide scale were examined. The results showed that the increase of the cooling rate has a significant influence on the decrease of the grain size and surface roughness of oxide scale. A higher cooling rate promotes the formation of retain wustite and primary magnetite precipitation while suppression of eutectoid α-iron precipitates. This provides the possibility to enhance potential contribution of magnetite precipitates with preferable ductility, and hence fabricates a desired oxide-scale structure under continuous post cooling conditions considering a suitable cooling rate.

Microstructure and Properties of a Non-Quenched Prehardened Steel at Different Cooling Rate

2012 ◽  
Vol 524-527 ◽  
pp. 1976-1979
Author(s):  
Yi Luo ◽  
Jin Ming Peng
Keyword(s):  
Mechanical Properties ◽  
Fine Structure ◽  
Optical Microscopy ◽  
Cooling Rate ◽  
Retained Austenite ◽  
Transformation Products ◽  
Electronic Microscopy ◽  
Transmission Electronic Microscopy ◽  
Microstructure And Properties ◽  
Cooling Conditions

Mechanical properties of non-quenched prehardened (NQP) steel air cooled and sand cooled after forged were tested and their microstructure was investigated by optical microscopy and transmission electronic microscopy(TEM). The results show that mechanical properties of the NQP steel are similar at both cooling conditions, and their microstructure is bainite, whose fine structure is main bainite ferrite laths, retained austenite films, retained austenite islands and their transformation products. Bainite ferrite laths of the NQP steel air cooled are narrower than that sand cooled, while more retained austenite islands exist in latter.

scholarly journals Correlation of Processing, Inner Structure, and Part Properties of Injection Moulded Thin-Wall Parts on Example of Polyamide 66

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Dietmar Drummer ◽  
Steve Meister
Keyword(s):  
Cooling Rate ◽  
Injection Moulding ◽  
Degree Of Crystallinity ◽  
Process Conditions ◽  
Thin Wall ◽  
Polyamide 66 ◽  
Slow Cooling ◽  
Cooling Conditions ◽  
Internal Structures ◽  
Wall Injection

In micro- and thin-wall injection moulding the process conditions affect the developed internal structures and thus the resulting part properties. This paper investigates exemplarily on polyamide 66 the interactions of different cooling conditions on the morphological and crystalline structures. The investigations reveal that a slow cooling rate of the melt results in a homogeneous morphology and a higher degree of crystallinity and also a favoured crystalline structure. Consequently, the dielectric behaviour and light transmitting part properties are affected.

scholarly journals Effect of hot rolling history and cooling rate on the phase transformation of plain carbon steel

2017 ◽  
Vol 55 (04) ◽  
pp. 229-236
Author(s):  
I. SCHINDLER ◽  
S. RUSZ ◽  
P. OPĚLA ◽  
J. RUSZ ◽  
Z. SOLOWSKI ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Carbon Steel ◽  
Cooling Rate ◽  
Hot Rolling ◽  
Plain Carbon Steel ◽  
Effect Of Hot Rolling

Ferritic Microstructures

2015 ◽  
pp. 113-131
Keyword(s):  
Carbon Atom ◽  
Cooling Rate ◽  
Classification System ◽  
Acicular Ferrite ◽  
Carbon Steels ◽  
Atom Diffusion ◽  
Continuous Cooling ◽  
Cooling Conditions ◽  
Induced Changes

This chapter describes the ferritic microstructures that form in carbon steels under continuous cooling conditions. It begins with a review of the Dubé classification system for crystal morphologies. It then explains how cooling-rate-induced changes involving carbon atom diffusion and the associated rearrangement of iron atoms produce the wide variety of morphologies and microstructures observed in ferrite. The chapter also describes a classification system developed specifically for ferritic microstructures and uses it to compare common forms of ferrite, including polygonal or equiaxed ferrite, Widmanstatten ferrite, quasi-polygonal or massive ferrite, acicular ferrite, and granular ferrite.

The Precipitation Behavior of γ' Phase in Superalloy FGH96 during Continuous Solution Cooling Conditions

2013 ◽  
Vol 652-654 ◽  
pp. 1092-1095
Author(s):  
H.S. Liu ◽  
Lin Zhang ◽  
Xin Bo He ◽  
Xuan Hui Qu ◽  
Zhou Li ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Continuous Solution ◽  
Water Cooling ◽  
Precipitation Behavior ◽  
Cooling Conditions ◽  
Mean Diameter ◽  
The Mean ◽  
Shape Changes

The precipitation behavior of γ' phase after continuous solution cooling tests was examined in superalloy FGH96. The results indicate that, with the increase of cooling rate, the mean diameter of secondary γ' precipitates decreases as well as the shape changes from cuboid to spherical. Either under water cooling or cooling at 10 °C/min and 25 °C/min, the highest strength can not be obtained.

scholarly journals Influence of Al and N Content and Cooling Rate on the Characteristics of Complex MnS Inclusions in AHSS

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1054
Author(s):  
Muhammad Nabeel ◽  
Michelia Alba ◽  
Neslihan Dogan
Keyword(s):  
Cooling Rate ◽  
High Strength Steels ◽  
High Strength ◽  
Slow Cooling ◽  
N Content ◽  
Al Content ◽  
Advanced High Strength Steels ◽  
Cooling Conditions ◽  
Mns Precipitation ◽  
Precipitation Ratio

This study focused on the characteristics of complex MnS inclusions in advanced high strength steels. The effect of metal chemistry (Al and N) and the cooling rate of steel were evaluated by analyzing the inclusions present in five laboratory produced steels. The observed complex MnS inclusions contained Al2O3-MnS, AlN-MnS, and AlON-MnS. An increase in Al content from 0.5% to 6% increased the number of complex MnS inclusions by ~4 times. In comparison, a decrease of ~80% was observed due to the increased N content of steel from <10 ppm to ~50 ppm. MnS precipitation ratio was used to determine the potency of different inclusions forming complex MnS inclusions due to heterogeneous nucleation. It was found that the MnS precipitation ratio of the observed inclusions was related to their misfit with MnS, and it decreased in the order of AlN > AlON > Al2O3. Moreover, it was determined that AlN particles could be easily engulfed at the solidification front relative to Al2O3, which resulted in a higher MnS precipitation ratio for Al2O3 under slow cooling conditions.

Sign in / Sign up

Export Citation Format

Share Document