Numerical Analysis of the Residual Stresses Caused by Forming Process in Case of Conical Mini-Parts

2014 ◽  
Vol 1036 ◽  
pp. 269-273
Author(s):  
Robert Stefanut Teaca ◽  
Gheorghe Brabie
Keyword(s):  
Residual Stresses ◽  
Deep Drawing ◽  
Side Wall ◽  
Zinc Alloy ◽  
Forming Process ◽  
Wall Angle ◽  
Cold Forming ◽  
Copper Zinc ◽  
Dimensional Errors ◽  
Forming Tools

The research presented in this paper refers to numerical simulation related to deep drawing of conical mini-parts having different geometries as a function of side wall angle. The mini-parts are made from copper zinc alloy, having the thickness of 0.2 mm. Very important concerns in cold forming of conical mini-parts are the residual stresses due to their influence on the final shape of the part. During the forming process, due to different angles of the side wall, the residual stresses vary. After the mini-part is removed from the forming tools, the residual stresses modify the geometry of the part, causing dimensional errors. The residual stresses decrease the ability of the designer to draw some specific shapes because it may create forming problems such as wrinkling, tearing, and uncontrollable springback. The Dynaform 5.9.1 software was used to simulate the forming process. The part obtained after each simulation was analyzed and measured to quantify the effect of the residual stresses on the final geometry of part. All the parameters were maintained constant excepting the side wall angle. The obtained results for different side wall angles were compared to realize the behaviour of the conical mini-parts during and after deep drawing process.

Numerical Analysis of the Material Thickness Variation during Forming Process of Conical Mini-Parts

2014 ◽  
Vol 1036 ◽  
pp. 265-268
Author(s):  
Robert Stefanut Teaca ◽  
Gheorghe Brabie
Keyword(s):  
Side Wall ◽  
Zinc Alloy ◽  
Thickness Variation ◽  
Forming Process ◽  
Wall Angle ◽  
Material Thickness ◽  
Electrical Devices ◽  
Punch Radius ◽  
Copper Zinc ◽  
Material Fracture

Due to the trend of miniaturization on electrical devices, medical devices, and energy, etc., the need for micro and mini metal parts is increasing at a tremendous rate. In order to realize the potential of the mini-parts and take advantages from the mini-forming process, innovative modifications of the forming process must be developed. These modifications are particularly important with respect to the mini-parts forming, which offers an excellent opportunity to produce high accurate mini parts and to reduce manufacturing costs and time. However, severe modifications of the material thickness occur during forming of mini-parts. This paper presents a study concerning the material thickness variation during forming process of mini-parts. The main objective is to understand the material behaviour during forming of mini-parts. The material used in this analysis is copper - zinc alloy with anisotropic properties. During forming process of conical mini-parts, the material become very thin around the punch radius and become thicker at the upper end of the part. This phenomenon cause forming problems such: material fracture, wrinkling, part diameter variation, springback etc. There are multiple factors that affect the material thickness variation during forming process as: side wall angle, friction coefficient, punch radius, and punch speed. The Dynaform 5.9.1 software was used to simulate the forming process. The part obtained after each simulation was analyzed and measured to quantify material thickness variation on the final conical mini-part. To analyze the behaviour of the material during deep drawing process the obtained results for different conical mini-parts were compared. In the final part of this paper some conclusions regarding the material thickness variation during forming of conical mini-parts are presented.

Hot Spline Forming of Ultra-High Strength Steel Gear Drum Using Resistance Heating

2014 ◽  
Vol 622-623 ◽  
pp. 201-206 ◽  
Author(s):  
Kenichiro Mori ◽  
Tomoyoshi Maeno ◽  
Shohei Nakamoto
Keyword(s):  
Deep Drawing ◽  
High Strength Steel ◽  
Side Wall ◽  
High Strength ◽  
Axial Direction ◽  
Resistance Heating ◽  
Sectional Area ◽  
Forming Process ◽  
Cross Sectional ◽  
Ultra High Strength Steel

A hot spline forming process of die-quenched gear drums using resistance heating of a side wall of a cup formed by cold deep drawing and ironing was developed. The side wall having uniform cross-sectional area is resistance-heated by passage of the current in the axial direction, the heated side wall of the drawn cup is ironed and is finally die-quenched. The gear drum was successfully formed and the hardness was between 400 and 500 HV. Not only the formability was improved but also the formed dram was hardly oxidised because of rapid resistance heating.

Thermal Influences on Deep Drawing Process of Ferritic and Metastable Austenitic Stainless Steels

2013 ◽  
Vol 769 ◽  
pp. 221-228 ◽  
Author(s):  
Philipp Schmid
Keyword(s):  
Stainless Steels ◽  
Deep Drawing ◽  
Austenitic Stainless Steels ◽  
Forming Limit ◽  
Martensite Formation ◽  
Forming Process ◽  
High Dependency ◽  
Forming Tools ◽  
Forming Limit Curves

Sheet metal forming processes, in particular deep drawing processes, are highly influenced by occurrence of latent and friction heat. Especially when forming metastable austenitic stainless steels, strain-induced martensite formation is suppressed by higher temperatures and therefore influences the material behavior and so called TRIP-effect. This study gives an overview about thermal influences on the deep drawing forming process of metastable austenitic CrNi-steel 1.4301 in comparison with ferritic stainless steels such as 1.4016. Measurements on serial and evaluation tools were carried out to determine occurring temperatures within forming tools. Attention is paid to effects on tribological aspects such as behavior of lubricants at higher temperatures, influence of temperature development on the martensite formation, mechanical properties, forming limit curves as well as heat flow within the forming tools. Lubricants with different temperature stability were compared to each other with determination of friction coefficient in strip drawing tests. Martensite and temperature development during forming of material was measured in non-isothermal tensile tests approving a high dependency of martensite formation on temperature. Forming limit curves for temperatures determined from RT to 140°C for EN 1.4301 are showing high dependency of necking behavior especially under plain strain conditions. Determination of thermal contact conductance coefficients for process and tool relevant material combinations allows interpreting heat flow mechanisms in forming tools and improving forming process to higher robustness. Results of this paper can be used to individually set boundary conditions for thermo-mechanical coupled forming simulation of austenitic stainless steel and process layout of tool temperature control systems.

scholarly journals Parametric Analysis of the Mandrel Geometrical Data in a Cold Expansion Process of Small Holes Drilled in Thick Plates

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4105 ◽  
Author(s):  
Jose Calaf-Chica ◽  
Marta María Marín ◽  
Eva María Rubio ◽  
Roberto Teti ◽  
Tiziana Segreto
Keyword(s):  
Fatigue Life ◽  
Residual Stresses ◽  
Parametric Analysis ◽  
Expansion Process ◽  
Forming Process ◽  
Zone Length ◽  
Cold Forming ◽  
Cold Expansion ◽  
Geometrical Data ◽  
Small Holes

Cold expansion technology is a cold-forming process widely used in aeronautics to extend the fatigue life of riveted and bolted holes. During this process, an oversized mandrel is pushed through the hole in order to yield it and generate compressive residual stresses contributing to the fatigue life extension of the hole. In this paper, a parametric analysis of the mandrel geometrical data (inlet angle straight zone length and diametric interference) and their influence on the residual stresses was carried out using a finite element method (FEM). The obtained results were compared with the conclusions presented in a previous parametric FEM analysis on the influence of the swage geometry in a swaging cold-forming process of gun barrels. This process could be considered, in a simplified way, as a scale-up of the cold expansion process of small holes, and this investigation demonstrated the influence of the diameter ratio (K) on the relation between the mandrel or swage geometry and the residual stresses obtained after the cold-forming process.

Comparison of Material Behavior and Economic Effects of Cold and High Temperature Forming Technologies Applied to High-Strength Steels

2005 ◽  
Vol 6-8 ◽  
pp. 101-108 ◽  
Author(s):  
Reimund Neugebauer ◽  
Angela Göschel ◽  
Andreas Sterzing ◽  
Petr Kurka ◽  
Michael Seifert
Keyword(s):  
Elevated Temperatures ◽  
High Strength Steels ◽  
Dimensional Accuracy ◽  
High Strength ◽  
Economic Effects ◽  
Material Behavior ◽  
Spring Back ◽  
Forming Process ◽  
Cold Forming ◽  
Forming Tools

The focus of forming high-strength steel at elevated temperature is to improve its forming properties like elongation and to reduce the power requirements during the forming process in opposite to cold forming. Because of the undefined and large spring-back effects parts made by cold forming are not able to achieve the demanded dimensional accuracy, which is necessary for laser welding operations in car body assembly. The reduction of the spring-back behavior is another advantage of the temperature controlled forming technology. On the other side the forming at elevated temperatures requires increased costs for forming tools and tempering equipment. For a fundamental evaluation of this technology, expenditures for the complete process chain have to be considered.

Multi-Stage Cold Deep Drawing of Pure Titanium Square Cup

2015 ◽  
Vol 651-653 ◽  
pp. 1072-1077 ◽  
Author(s):  
Yasunori Harada ◽  
Minoru Ueyama
Keyword(s):  
Deep Drawing ◽  
Metal Forming ◽  
Pure Titanium ◽  
Oxide Coating ◽  
Drawing Process ◽  
Forming Process ◽  
Titanium Sheet ◽  
Cold Forming ◽  
Deep Drawing Process ◽  
Multi Stage

This paper deals with the formability of pure titanium sheet in square cup deep drawing. Pure titanium has very excellent corrosion resistance. In the metal forming process, pure titanium has very good ductility in cold forming. The normal anisotropy of pure titanium is very high. Therefore, the property is suitable to the sheet metal forming, such as deep drawing process. However, the most important problem is that the occurrence of seizure becomes remarkable in severe forming operations. Many investigations on the effect of processing conditions on the seizure of titanium were carried out. In the present study, the formability of pure titanium sheet in square cup deep drawing was investigated. For the prevention, pure titanium sheets were treated by heat oxide coating. The fresh and clean titanium is not in direct contact with the die during the forming due to the existence of the oxide layer. The material was pure titanium sheets of the JIS grade 2. The initial thickness of the blank was 0.5 mm in thickness. In the deep drawing process, the sheets were employed and a flat sheet blank is formed into a square by a punch. Forming of sheet by multi-stage deep drawing was tried. Various cups were drawn by exchanging the punch and die. The die was taper without a blankholder in the subsequent stages. The effects of the intermediate annealing and tool shape on the occurrence of seizure in square cup deep drawing were also examined. The square cups were successfully drawn by heat oxide coating. The coating of titanium sheet has sufficient ability in preventing the seizure in multi-stage deep drawing operation. The results of the present study revealed that the pure titanium square cups were successfully formed by using heat oxide coating treatment.

CARTRIDGE BRASS 70%

Alloy Digest ◽  
1958 ◽  
Vol 7 (3) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Shear Strength ◽  
Physical Properties ◽  
Tensile Properties ◽  
Deep Drawing ◽  
High Strength ◽  
Heat Treating ◽  
Zinc Alloy ◽  
Good Corrosion Resistance ◽  
Copper Zinc

Abstract Cartridge Brass is a 70-30 copper-zinc alloy having high strength, maximum ductility and good corrosion resistance. It is recommended for deep drawing operations. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fatigue. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-60. Producer or source: Brass mills.

Influence of the Tool Clearances on the Dimensional Accuracy of Mini Drawn Parts

2014 ◽  
Vol 1036 ◽  
pp. 309-313
Author(s):  
Gheorghe Brabie ◽  
Bogdan Chirita ◽  
Elena Costache ◽  
Robert Stefanut Teaca
Keyword(s):  
Process Parameters ◽  
Deep Drawing ◽  
Dimensional Accuracy ◽  
Thin Sheets ◽  
Forming Process ◽  
Cold Forming ◽  
Small Thickness ◽  
Theoretical Profile ◽  
Small Parts

The mini deep drawing is a cold forming process applied in order to realize small parts having dimensions smaller than 20 mm. In the case of such process the small thickness of sheet and the small dimensions of parts are the most important factors that influence the process parameters and can affect the accuracy and quality of the produced mini - parts. A proper clearance between the working tools components is also a very important factor that can permit to obtain mini drawn parts in accordance with their theoretical profile. The present paper analyses the results of investigations made by experiment and simulation concerning the influence of tool clearances values on the accuracy of dimensions in the case of mini scale cylindrical drawn cups made from thin sheets. The deviations from the cups theoretical profile (wall inclination, variation of part diameter) that can occur during deep drawing of such sheets were especially analyzed in the paper.

scholarly journals An Investigation Study of Tool Geometry in Single Point Incremental Forming (SPIF) and their effect on Residual Stresses Using ANOVA Model

2019 ◽  
Vol 14 (2) ◽  
pp. 1-13
Author(s):  
Aqeel S Sabree Bedan ◽  
Halah Ali H Habeeb
Keyword(s):  
Residual Stresses ◽  
Rotational Speed ◽  
Incremental Forming ◽  
Single Point ◽  
Numerical Control ◽  
Tool Geometry ◽  
Single Point Incremental Forming ◽  
Forming Process ◽  
Wall Angle ◽  
Tool Diameter

Incremental forming is a flexible sheet metal forming process which is performed by utilizing simple tools to locally deform a sheet of metal along a predefined tool path without using of dies. This work presents the single point incremental forming process for producing pyramid geometry and studies the effect of tool geometry, tool diameter, and spindle speed on the residual stresses. The residual stresses were measured by ORIONRKS 6000 test measuring instrument. This instrument was used with four angles of (0º,15º,30º, and 45º) and the average value of residual stresses was determined, the value of the residual stress in the original blanks was (10.626 MPa). The X-ray diffraction technology was used to measure the residual stresses. The sheet material used was Aluminum alloy (AL1050) with thickness of (0.9 mm). The experimental tests in this work were done on the computer numerical control (CNC) vertical milling machine. The extracted results from the single point incremental forming process were analyzed using analysis of variance (ANOVA) to predict the effect of forming parameters on the residual stresses. The optimum value of the residual stresses (55.024 MPa) was found when using the flat end with round corner tool and radius of (3 mm), wall angle of (55°) and a rotational speed of the tool of (800 rpm). The minimum value of the residual stresses (24.389MPa) was found when using hemispherical tool with diameter of (12 mm), wall angle of (45°) and a rotational speed of the tool of (800 rpm).  

scholarly journals Formation of residual stresses in austenitic stainless steels by infeed and recess rotary swaging

2020 ◽  
Author(s):  
Holger Hoche ◽  
Fabian Jaeger ◽  
Alessandro Franceschi ◽  
Matthias Oechsner ◽  
Peter Groche
Keyword(s):  
Residual Stresses ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Phase Changes ◽  
Austenitic Steels ◽  
Coarse Grained ◽  
Fatigue Properties ◽  
Forming Process ◽  
Cold Forming ◽  
Rotary Swaging

The austenitic stainless steels 1.4307 and 1.4404 significantly benefit from cold forming, due to their high work hardening capability. Great potential to improve the component's fatigue properties is expected by optimizing the forming process chain such that specific residual stresses are induced in critical component areas. In this work, an analysis of the formation of residual stresses during rotary swaging is carried out. Through this incremental forming process, high strain hardening and a complex material flow history are induced in the workpieces. Therefore, measuring strategies for the residual stress measurement of cold de-formed austenitic steels by X-Ray diffraction, using the sin2Ψ-method, were developed. Here, especially the 1.4307 is a challenging material due to cold forming induced martensite formation. Despite phase changes, both cold formed materials exhibit anisotropic microstructures as well as coarse grained areas. Moreover, particular notched geometries are produced on the workpieces by rotary swaging. The measuring techniques are further developed for these complex geometries and the residual stresses are investigated.

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