Local Strain Hardening of Sheet and Solid Forming Components during Formation of Martensite in Metastable Austenitic Steels

2007 ◽  
Vol 22 ◽  
pp. 5-15 ◽  
Author(s):  
Bernd Arno Behrens ◽  
Sven Hübner ◽  
C. Sunderkötter ◽  
Julian Knigge ◽  
Katrin Weilandt ◽  
...  
Keyword(s):  
Strain Hardening ◽  
Austenitic Steel ◽  
Sheet Metal ◽  
Metal Forming ◽  
High Strength ◽  
Austenitic Steels ◽  
Research Centre ◽  
Bulk Metal ◽  
Metastable Austenitic Steel ◽  
Local Material Properties

The industrial application of stainless steels is of high importance because of their high corrosion resistance and forming behaviour. The evolution of martensite during the deep drawing processes leads to an increasing strain hardening of the material. In the collaborative research centre 675 “Erzeugung hochfester metallischer Strukturen und Verbindungen durch gezieltes Einstellen lokaler Eigenschaften” (Creation of high strength metallic structures and joints by setting up scaled local material properties), metal forming processes is being researched. Emphasis on this part of the project is the stress-induced formation of martensite in sheet metal and bulk metal components in metastable austenitic steel. The aim of the investigations is to develop partial structure fields of martensite in sheet metal components in order to construct a lightweight structure. Therefore, components are divided into stretched and non-stretched parts. This leads to a defined buckling of components, for example in case of a crash. Furthermore, the effect of the transformation induced formation of martensite in metastable austenitic steel should be utilised on bulk metal forming components. Thereby special load adapted components with locally optimized properties are producible, like austenitic ductile regions and martensitic high-strength areas.

scholarly journals Influence of Tailored Surfaces and Superimposed-Oscillation on Sheet-Bulk Metal Forming Operations

2020 ◽  
Vol 4 (2) ◽  
pp. 41
Author(s):  
Bernd-Arno Behrens ◽  
Wolfgang Tillmann ◽  
Dirk Biermann ◽  
Sven Hübner ◽  
Dominic Stangier ◽  
...  
Keyword(s):  
Sheet Metal ◽  
Metal Forming ◽  
High Strength Steels ◽  
High Strength ◽  
Compression Tests ◽  
Forming Process ◽  
Bulk Metal ◽  
Bulk Metal Forming ◽  
Tailored Surfaces ◽  
High Feed

Producing complex sheet metal components in fewer process steps motivated the development of the innovative forming process called sheet-bulk metal forming (SBMF). In this process, sheet metal forming and bulk-metal forming are combined to create a unique forming process in which a component with external and internal gearing is produced in three production steps. However, the high degrees of deformation that occur using high-strength steels and the number of different process steps result in high process forces, strongly limiting the service life of tools. To reduce the forming force during SBMF processes, tool and process modifications were investigated. Therefore, plane-strain compression tests were conducted to examine the influence of a CrAlN PVD coating and tailored surfaces produced by high-feed milling (HF) of tool-active elements on the material flow of the specimens. In addition to the tool-sided modifications, the influence of an oscillation overlay during the forming process was investigated. Based on the results of the compression tests, the surfaces of the active tool elements of the SBMF process were modified in order to transfer the basic experimental results to the production of a functional component. The friction is thus adapted locally in the SBMF process.

scholarly journals Laser Welding of High-strength Aluminium Alloys for the Sheet Metal Forming Process

Procedia CIRP ◽  
2014 ◽  
Vol 18 ◽  
pp. 203-208 ◽  
Author(s):  
J. Enz ◽  
S. Riekehr ◽  
V. Ventzke ◽  
N. Sotirov ◽  
N. Kashaev
Keyword(s):  
Laser Welding ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Aluminium Alloys ◽  
High Strength ◽  
Forming Process ◽  
Metal Forming Process

An Enhanced Hybrid Springback Compensation Approach: Springback Path – Displacement Adjustment Method For Complex Shaped Products of Sheet Metal Forming

2021 ◽  
Author(s):  
Zhihui Gong ◽  
Mandeep Singh ◽  
Bohao Fang ◽  
Dongbin Wei
Keyword(s):  
Sheet Metal ◽  
Automobile Industry ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
High Strength Steels ◽  
Fem Analysis ◽  
High Strength ◽  
Design Stage ◽  
Springback Compensation ◽  
Compensation Approach

Abstract Springback compensation is critical in sheet metal forming. Advanced techniques have been adopted in the design stage of various sheet metal forming processes, e.g. stamping, some of which are for complex shaped products. However, the currently available numerical approaches are not always sufficiently accurate and reliable. To improve the accuracy of springback compensation, an enhanced hybrid springback compensation method named Springback Path – Displacement Adjustment (SP-DA) method has been developed in this study based on the well-known conventional displacement adjustment (DA) method. Its effectiveness is demonstrated using FEM analysis of low, medium and high strength steels adopted in automobile industry, in which a symmetrical model owning geometry complexity similar to an auto body panel was established. The results show this new enhanced SP-DA method is able to significantly improve the accuracy of springback compensation comparing to conventional displacement adjustment technique.

scholarly journals Extension of the forming limits of extrusion processes in sheet-bulk metal forming for production of minute functional elements

2020 ◽  
Vol 7 ◽  
pp. 9 ◽  
Author(s):  
Florian Pilz ◽  
Johannes Henneberg ◽  
Marion Merklein
Keyword(s):  
Sheet Metal ◽  
Metal Forming ◽  
Extrusion Process ◽  
Process Conditions ◽  
Functional Elements ◽  
Bulk Metal ◽  
Bulk Metal Forming ◽  
Lateral Extrusion ◽  
Component Design ◽  
Tailored Surfaces

Increasing demands in modern production pose new challenges to established forming processes. One approach to meet these challenges is the combined use of established process classes such as sheet and bulk forming. This innovative process class, also called sheet-bulk metal forming (SBMF), facilitates the forming of minute functional elements such as lock toothing and gear toothing on sheet-metal bodies. High tool loads and a complex material flow that is hard to control are characteristic of SBMF. Due to these challenging process conditions, the forming of functional elements is often insufficient and necessitates rework. This negatively affects economic efficiency. In order to make use of SBMF in industrial contexts, it is necessary to develop measures for improving the forming of functional elements and thereby push existing forming boundaries. This paper describes the design and numerical replication of both a forward and a lateral extrusion process so as to create involute gearing in combination with carrier teeth. In a combined numerical-experimental approach, measures for extending the die filling in sheet-metal extrusion processes are identified and investigated. Here, the focus is on approaches such as process parameters, component design and locally adjusted tribological conditions; so-called ‘tailored surfaces’. Based on the findings, fundamental mechanisms of action are identified, and measures are assessed with regard to their potential for application. The examined approaches show their potential for improving the forming of functional elements and, consequently, the improvement of geometrical accuracies in functional areas of the workpieces.

Advanced Materials in Sheet Metal Forming

2013 ◽  
Vol 581 ◽  
pp. 137-142 ◽  
Author(s):  
Miklós Tisza
Keyword(s):  
Sheet Metal ◽  
Automotive Industry ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Driving Forces ◽  
High Strength Steels ◽  
High Strength ◽  
Advanced Materials ◽  
Harmful Emission ◽  
Application Fields

In this paper, some recent developments in materials applied in sheet metal forming processes will be overviewed mainly from the viewpoint of automotive industry as one of the most important application fields. If we consider the main requirements in the automotive industry we can state that there are very contradictory demands on developments. Better performance with lower consumption and lower harmful emission, more safety and comfort are hardly available simultaneously with conventional materials and conventional manufacturing processes. These requirements are the main driving forces behind the material and technological developments in sheet metal forming: application of high strength steels, low weight light alloys and the appropriate non-conventional forming processes are the main target fields of developments summarized in this paper.

Experimental Study on Galling Behavior of Advanced High Strength Steel in Sheet Metal Forming

2012 ◽  
Vol 502 ◽  
pp. 36-40
Author(s):  
Ying Ke Hou ◽  
Shu Hui Li ◽  
Yi Xi Zhao ◽  
Zhong Qi Yu
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Sheet Material ◽  
High Strength Steels ◽  
High Strength ◽  
Forming Process ◽  
Advanced High Strength Steels ◽  
Sheet Materials ◽  
Materials Used

Galling is a known failure mechanism in many sheet metal forming processes. It limits the lifetime of tools and the quality of the products is affected. In this study, U-channel stamping experiments are performed to investigate the galling behavior of the advanced high strength steels in sheet metal forming . The sheet materials used in the tests are DP590 and DP780. In addition to the DP steels, the mild steel B170P1 is tested as a reference material in this study. Experimental results indicate that galling problem becomes severe in the forming process and the galling tendency can be divided into three different stages. The results also show that sheet material and tool hardness have crucial effects on galling performance in the forming of advanced high strength steels. In this study, DP780 results in the most heaviest galling among the three types of sheet materials. Galling performance are improved with increased hardness of the forming tool.

Multi-Objective Optimization for High Strength Steel Sheet Metal Forming Process Based on Response Surface Methodology

2010 ◽  
Vol 154-155 ◽  
pp. 1223-1227 ◽  
Author(s):  
Zhi Guo An ◽  
Yu Zhang
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
High Strength Steel ◽  
High Strength ◽  
Forming Process ◽  
Multi Objective ◽  
Metal Forming Process

In sheet metal forming process, the input process parameters scatter and considerably result in unreliablity in practical production. Optimization for sheet metal forming process is often considered as a multi-objective problem. An optimizition strategy for high strength steel (HSS) sheet metal forming process was suggested based on response surface methodology (RSM). Latin Hypercube Sampling (LHS) method was introduced to design the rational experimental samples; the objective function was defined based on cracking factor wrinkle factor and severe thinning factor; the accurate response surface for sheet metal forming problem was built by Least Square Method; Multi-objective Genetic Algorithm(MOGA) was adoped in optimization and Pareto solution was selected. The strategy was applied to analyze a HSS auto-part, the result has proved this method suitable for optimization design of HSS sheet metal forming process.

Sheet-Bulk Metal Forming of Preformed Sheet Metal Parts

2011 ◽  
Vol 473 ◽  
pp. 83-90 ◽  
Author(s):  
Thomas Schneider ◽  
Marion Merklein
Keyword(s):  
Sheet Metal ◽  
Deep Drawing ◽  
Metal Forming ◽  
Sheet Plane ◽  
Bulk Metal ◽  
Bulk Metal Forming ◽  
Sheet Metal Parts ◽  
Bulk Forming ◽  
Process Factors ◽  
Functional Components

Due to ecological and economic challenges there is a rising demand on closely-tolerated complex functional components. Regarding short process chains and improved mechanical properties conventional forming processes are often limited. A promising approach to meet these requirements can be seen in the combination of traditional sheet and bulk metal forming processes, to form sheet metals out of the sheet plane with typical bulk forming operations. The challenge of applying conventional bulk forming operations on sheet metal is the interaction between regions of high and low deformation, which is largely unknown in literature. To analyze this topic fundamentally, a process combination of deep drawing and upsetting is developed for manufacturing tooth-like elements at pre-drawn cups. To fully understand material flow out of the sheet plane into the tooth cavity and to identify and qualify process factors depending on the functional elements´ geometry and friction, a single upsetting stage forming a simplified model of the blank is virtually analyzed with finite-element simulation. By inhibiting the forming history of the pre-drawn blank, the upsetting process can be investigated without interactions with a previous deep drawing operation.

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