scholarly journals The influence of microstructure deformation on the corrosion resistance of cold formed stainless steel

2018 ◽  
Vol 190 ◽  
pp. 04002 ◽  
Author(s):  
Ingmar Bösing ◽  
Marius Herrmann ◽  
Ilya Bobrov ◽  
Jorg Thöming ◽  
Bernd Kuhfuss ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Corrosion Rate ◽  
Electrochemical Properties ◽  
Corrosion Behavior ◽  
Behavior Changes ◽  
Forming Process ◽  
Cold Forming ◽  
Feed Velocity ◽  
Rotary Swaging ◽  
Micro Parts

Rotary swaging is an incremental cold forming process to produce axisymmetric workpieces from rods and tubes. The process also induces changes of the microstructure of the material depending on the process parameters. This in turn influences the mechanical properties like hardness as well as the electrochemical properties. As a result of changed electrochemical properties, the passivity of the material and thus the corrosion behavior changes. In order to investigate the influence of rotary swaging on the corrosion behavior of the stainless steel AISI304, deformed micro parts are electrochemically analyzed. The measurements reveal a dependency of corrosion rate and impedance on both feed velocity and final diameter of the rotary swaging process. A higher feed velocity decreases the corrosion rate and increases the impedance indicating a better resistance against corrosion as a side effect of rotary swaging.

Grain Size Modification by Micro Rotary Swaging

2015 ◽  
Vol 651-653 ◽  
pp. 627-632 ◽  
Author(s):  
Svetlana Ishkina ◽  
Bernd Kuhfuss ◽  
Christian Schenck
Keyword(s):  
Grain Size ◽  
Longitudinal Section ◽  
Forming Process ◽  
Boundary Area ◽  
Cold Forming ◽  
Flat Surfaces ◽  
Rotary Swaging ◽  
2D Simulation ◽  
Physical Tests ◽  
Formed Part

Rotary swaging is a well established cold forming process e.g. in the automotive industry. In order to modify the material properties by swaging systematically, a new process of swaging with asymmetrical strokes of the forming dies is investigated. The newly developed tools feature flat surfaces and do not represent the geometry of the formed part as in conventional swaging. Numerical simulation and physical tests are carried out with special regard to the resulting geometry, mechanical properties and the microstructure. During these tests copper wires with diameter d0=1 mm are formed. Regarding the microstructure in the longitudinal section of formed specimens, elongation of grains in the central part and grain size reduction in the boundary area are observed. Furthermore, this approach opens up new possibilities to configure the geometry of wires. 2D-simulation is applied and discussed in the paper to investigate change of the processed geometry (cross-section) and shear strain distribution during the rotary swaging process.

Corrosion Behavior of Duplex Stainless Steel in Industrial White Liquor

CORROSION ◽  
10.5006/2558 ◽  
2017 ◽  
Vol 74 (5) ◽  
pp. 543-550 ◽  
Author(s):  
Luiza Esteves ◽  
Mônica M.A.M. Schvartzman ◽  
Wagner Reis da Costa Campos ◽  
Vanessa F.C. Lins
Keyword(s):  
Weight Loss ◽  
Stainless Steel ◽  
Corrosion Rate ◽  
Duplex Stainless Steel ◽  
Corrosion Behavior ◽  
Extrapolation Method ◽  
White Liquor ◽  
Duplex Steel ◽  
Kraft Mill ◽  
Lower Corrosion Rate

Specimens of lean duplex and duplex stainless steel were exposed at 200°C in industrial white liquor from a Brazilian kraft mill using an autoclave to simulate the same conditions of digester processing. Tafel extrapolation method and weight loss were used to evaluate corrosion behavior of duplex steel in white liquor. The higher alloy steel, although presenting a lower corrosion rate than the lean duplex, presents a more severe selective attack on ferrite, at 200°C and 1.8 MPa, after Tafel extrapolation method in industrial white liquor.

scholarly journals High productivity micro rotary swaging

2018 ◽  
Vol 190 ◽  
pp. 15002 ◽  
Author(s):  
Eric Moumi ◽  
Marius Herrmann ◽  
Christian Schenck ◽  
Bernd Kuhfuss
Keyword(s):  
Material Flow ◽  
Process Variations ◽  
Main Process ◽  
Forming Process ◽  
Workpiece Material ◽  
High Productivity ◽  
Rotary Swaging ◽  
Micro Parts ◽  
Intensive Investigation ◽  
Clamping Device

Rotary swaging is an incremental forming process with two main process variations plunge and infeed rotary swaging. With plunge rotary swaging, the diameter is reduced within a limited section whereas the infeed rotary swaging enables a diameter reduction over the entire workpiece length. The process is now subject to intensive investigation for manufacturing of micro parts. By increasing the process speed, failures occur particularly due to inappropriate material flow. In plunge rotary swaging, the workpiece material can flow radially into the gap between the dies and thus the workpiece quality suffers. In infeed rotary swaging the workpiece material flows against the feeding direction and can provoke bending or braking of the workpiece. Therefore, additional measures to control both the radial and the axial material flow to enable high productivity micro rotary swaging are investigated. The radial material flow during plunge rotary swaging can be controlled by elastic intermediate elements that enable an increase of productivity by factor three. A spring-loaded clamping device that enables an increase of the productivity by factor four can temporarily buffer the axial material flow in infeed rotary swaging against the feeding direction.

Effect of the Flow Velocity on the Corrosion Behavior of UNS S41426 Stainless Steel in the Extremely Aggressive Oilfield Environment for the Tarim Area

CORROSION ◽  
10.5006/2813 ◽  
2020 ◽  
Vol 76 (7) ◽  
pp. 654-665 ◽  
Author(s):  
Yang Zhao ◽  
Limin Chang ◽  
Tao Zhang ◽  
Junfeng Xie ◽  
Yan Chen ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Corrosion Rate ◽  
Phase Boundary ◽  
Flow Velocity ◽  
Passive Film ◽  
Corrosion Behavior ◽  
Pitting Corrosion ◽  
Defect Density ◽  
Electrochemical Techniques ◽  
Experimental Results

Effect of flow velocity on the passive film and pitting corrosion behavior of UNS S41426 stainless steel (SS) under the extreme oilfield environment was investigated using different techniques such as microscopy, nanoindentation, and electrochemical techniques. The experimental results show that the corrosion rate of UNS S41426 SS increased with velocity. The increase in flow velocity decreased the thickness and content of amorphous Cr(OH)3 (s) in the film. This in turn increased the density of phase boundary, resulting in a higher defect density. Thus, the UNS S41426 SS film became susceptible to breaking. Furthermore, the pitting had a higher susceptibility to grow to a larger size both in the vertical and horizontal directions with the increase in flow velocity.

scholarly journals Effect of Minor Alloying Elements on the Corrosion Behavior of Fe40Al in NaCl-KCl Molten Salts

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
G. Salinas ◽  
J. G. Gonzalez-Rodriguez ◽  
J. Porcayo-Calderon ◽  
V. M. Salinas-Bravo ◽  
M. A. Espinoza-Medina
Keyword(s):  
Weight Loss ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Molten Salts ◽  
Electrochemical Techniques ◽  
The Other ◽  
Type Stainless Steel ◽  
Waste Gasification

The hot corrosion behavior of Fe40Al intermetallic alloyed with Ag, Cu, Li, and Ni (1–5 at.%) in NaCl-KCl (1 : 1 M) at 670°C, typical of waste gasification environments, has been evaluated by using polarization curves and weight loss techniques and compared with a 304-type stainless steel. Both gravimetric and electrochemical techniques showed that all different Fe40Al-base alloys have a much higher corrosion resistance than that for stainless steel. Among the different Fe40Al-based alloys, the corrosion rate was very similar among each other, but it was evident that the addition of Li decreased their corrosion rate whereas all the other elements increased it. Results have been explained in terms of the formation and stability of an external, protective Al2O3layer.

scholarly journals Corrosion Behavior of Materials Al5083 Alloy, 316L Stainless Steel and A681 Carbon Steel in Seawater

2021 ◽  
Vol 44 (2) ◽  
pp. 39-46
Author(s):  
Gina Genoveva ISTRATE ◽  
Alina Crina MUREȘAN
Keyword(s):  
Weight Loss ◽  
Stainless Steel ◽  
Carbon Steel ◽  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Aluminium Alloys ◽  
Saturated Calomel Electrode ◽  
Open Circuit ◽  
Carbon Steels ◽  
Test Technique

In this paper the corrosion behavior of different materials has been evaluated based on exposure in seawater. The laboratory immersion test technique has been applied to evaluate the effect of seawater on the corrosion behavior of different materials. In three sets of experiments, carbon steels (A681 Type O7), austenitic stainless steels (316L) and aluminium alloys (Al5083) were utilized. The specimens were fixed fully submerged in seawater. The corrosion process was evaluated using weight loss method, open-circuit potential measurements (OCP) and polarization techniques. To determine gravimetric index and the rate of penetration, samples were immersed in corrosive environment for 89 days and weighed periodically. The electrochemical experiments were conducted with a Potentiostat/Galvanostat (PGP 201) analyzer. It was connected to a PC. The Voltamaster software was used for electrochemical data analysis. A three-electrode cell composed of a specimen as a working electrode, Pt as counter electrode, and saturated calomel electrode (SCE) (Hg (l)/ Hg2Cl2 (s)) as a reference electrode were used for the tests. The weight loss tests revealed the lowest corrosion rate values for stainless steel and aluminium alloys, indicating a beneficial use for these materials in marine environments. The potentiodynamic method shows that the lowest corrosion rate in seawater (2.8 μm /year) was obtained for the Al5083 alloy, and the highest value of the corrosion rate (41.67 μm/year) for A681 carbon steel.

Dry Rotary Swaging - Tube Forming

2015 ◽  
Vol 651-653 ◽  
pp. 1042-1047 ◽  
Author(s):  
Marius Herrmann ◽  
Bernd Kuhfuss ◽  
Christian Schenck
Keyword(s):  
Friction And Wear ◽  
Work Piece ◽  
Forming Process ◽  
Cold Forming ◽  
Working Zone ◽  
Rotary Swaging ◽  
Additional Process ◽  
Points Of View ◽  
Micro Structuring ◽  
The Cost

Rotary swaging is an incremental cold forming process for tubes and rods. The established processes use lubricants based on mineral oil. The functions of the lubricant are the reduction of friction, wear and tool load, furthermore it cools the tools and flushes the working zone. But the use of lubricant increases the cost due to additional process steps and lubricant is diverted with the work piece during the process. Thus from economic and ecological points of view it is worthwhile to eliminate the use of lubricant. Therefore it is necessary to realize the functions of the lubricant in another way. For example by means of coating and micro-structuring of the tools the friction and wear can be influenced. In this study dry rotary swaging is tested with conventional tools and machine settings. The analysis of the recorded process parameters and the formed geometry of the workpiece reveal the potential of dry rotary swaging, but also the difficulties that arise. Dry rotary swaging needs a modification of the process and system parameters as well as an adjustment of the tools.

Effect of Elemental Sulfur on Corrosion Behavior of Super 13Cr Martensitic Stainless Steel

2014 ◽  
Vol 556-562 ◽  
pp. 162-165 ◽  
Author(s):  
Shi Dong Zhu ◽  
Hai Xia Ma ◽  
Jin Ling Li ◽  
Zhi Gang Yang
Keyword(s):  
Weight Loss ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Elemental Sulfur ◽  
Martensitic Stainless Steel ◽  
Chemical Elements ◽  
Different Temperatures ◽  
Corrosion Scales

Effects of elemental sulfur on corrosion behavior of super 13Cr martensitic stainless steel were investigated by utilizing weight loss test, and the micro morphologies and chemical elements of corrosion scales were characterized by using SEM and EDS. The results showed that corrosion resistance of super 13Cr stainless steel was aggravated by the hydrolytic action of sulfur, the corrosion rate of super 13Cr stainless steel increased with the increasing of sulfur content, and firstly increased and then decreased with the increasing of temperature due to the activated adsorption and existential state of sulfur at the different temperatures.

scholarly journals Eccentric rotary swaging variants

2018 ◽  
Vol 190 ◽  
pp. 15003 ◽  
Author(s):  
Anastasiya Toenjes ◽  
Svetlana Ishkina ◽  
Christian Schenck ◽  
Axel von Hehl ◽  
Hans-Werner Zoch ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Material Flow ◽  
Material Structure ◽  
Thermal Treatments ◽  
Forming Process ◽  
Cold Forming ◽  
Rotary Swaging ◽  
Feed Direction ◽  
Multi Stage ◽  
Stage Process

Rotary swaging is an incremental cold forming process that changes beneath the geometry also the microstructure and mechanical properties of workpiece. Especially a new process design with Eccentric Flat Shaped Dies (EFSD) influences both the kind and amount of stress and plastic strain and consequently the material structure and hence the material and workpiece properties. Eccentric rotary swaging typically provides a helical material flow. According to the process parameters the microstructure features a typical eddy pattern with a spiral shaped grain orientation. The forming process can be carried out in one or more process steps. In a multi-stage process, it is possible to change the feed direction and, hence, the material flow helix direction. This approach can be used as a possibility to improve the homogeneity of the workpiece and material properties. In addition, for this aims an intermediate heat treatment in multi-stage forming operations could be realised. Following the goal of optimising the final properties, the question arises how these mechanical and thermal treatments affect the material microstructure and the forming properties of the workpiece and how they interact. Experiments were conducted with austenitic stainless steel rods of grade AISI304. The effects of the varied feed direction, feed velocity and heat treatment between the forming operations are discussed.

scholarly journals Eccentric rotary swaging variants

2019 ◽  
Vol 6 ◽  
pp. 15
Author(s):  
Svetlana Ortmann Ishkina ◽  
Anastasiya Toenjes ◽  
Christian Schenck ◽  
Axel von Hehl ◽  
Hans-Werner Zoch ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Material Flow ◽  
Material Structure ◽  
Thermal Treatments ◽  
Forming Process ◽  
Material Microstructure ◽  
Cold Forming ◽  
Rotary Swaging ◽  
Feed Direction ◽  
New Process

Rotary swaging is an incremental cold forming process that changes beneath the geometry also the microstructure and mechanical properties of the workpiece. Especially a new process design with Eccentric Flat Shaped Dies (EFSD) influences both the kind and amount of stress and plastic strain and consequently the material structure, and hence the material and workpiece properties. Eccentric rotary swaging typically provides a helical material flow. According to the process parameters the microstructure features a typical eddy pattern with a spiral shaped grain orientation. The forming process can be carried out in one or more process steps. In a multistage process, it is possible to change the feed direction and, hence, the material flow helix direction. This approach can be used as a possibility to improve the homogeneity of the workpiece and material properties. In addition, for this aims an intermediate heat treatment in multistage forming operations could be realized. Following the goal of optimizing the final properties, the question arises how these mechanical and thermal treatments affect the material microstructure and the forming properties of the workpiece and how they interact. Experiments were conducted with austenitic stainless steel rods of grade AISI304. The effects of the varied feed direction, feed velocity and heat treatment between the forming operations are discussed.

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