Effect of nano-particulate sol-gel coatings on the oxidation resistance of high-strength steel alloys during the press-hardening process

2012 ◽  
Vol 63 (10) ◽  
pp. 940-947 ◽  
Author(s):  
M. Yekehtaz ◽  
C. Klesen ◽  
S. Benfer ◽  
W. Bleck ◽  
W. Fürbeth
Keyword(s):  
Oxidation Resistance ◽  
High Strength Steel ◽  
Sol Gel ◽  
High Strength ◽  
Steel Alloys ◽  
Press Hardening ◽  
Hardening Process ◽  
The Press

Heuristic-Based Evaluation of Energy Flows in Press Hardening Process Chains

2011 ◽  
Vol 473 ◽  
pp. 816-823 ◽  
Author(s):  
Reimund Neugebauer ◽  
Frank Schieck ◽  
Angela Göschel ◽  
Julia Schönherr
Keyword(s):  
Qualitative Evaluation ◽  
Resource Efficiency ◽  
Process Chain ◽  
Press Hardening ◽  
Whole Process ◽  
Quantitative Calculation ◽  
Hardening Process ◽  
Energy Flows ◽  
Process Chains ◽  
The Press

Energy and resource efficiency is a pressing issue for technological markets in the 21st century. In the field of production technology the development of energy and resource efficient processes and process chains is of particular importance. In order to meet these needs sustainable methods and standards have to be developed. This paper presents a new procedure to calculate and evaluate the energy and resource efficiency of process chains. The method consists of 4 stages that proceed from the real world to the quantitative calculation and qualitative evaluation of material and energy flows. The method is explained and validated using press hardening process chains as an example. The procedure enables the user to systematically capture and structure the press hardening process chain and subsequently develop a comprehensive model of the whole process chain. As a result, it allows to calculate the energy requirements for each stage of the process chain, and later on the process chain as a whole. The intention of the developed procedure is to provide a tool to detect the most energy efficient variant from a range of possible process chains.

Development of the Projection Welding Technology for High-Strength Steel Sheets

2018 ◽  
Vol 941 ◽  
pp. 182-189
Author(s):  
Seiji Furusako ◽  
Shinji Kodama ◽  
Masanori Yasuyama ◽  
Yasunobu Miyazaki
Keyword(s):  
Fracture Surface ◽  
High Strength Steel ◽  
Peak Load ◽  
Peel Test ◽  
High Strength ◽  
Maximum Load ◽  
Weld Region ◽  
Projection Welding ◽  
Steel Sheets ◽  
The Press

High-strength steel sheets (HSSs) have been increasingly used to reduce the weight of automobile bodies. It is necessary to enhance the reliability of their joint strength in order to realize optimal usage. Projection welding (PW) is one of the important welding methods for HSSs; however, research on PW is insufficient. In this research, therefore, the effect of welding conditions on maximum load in the press-peel test for joints, made by PW HSS of 590 MPa grade and square weld nuts, was investigated. It is found that the maximum load showed a tendency to increase with an increase in the current and a decrease in the electrode force. In several cases of the press-peel test, four welds of one joint fractured one by one in sequence and showed a peak load each time it broke. The first or second peak load became the maximum load of each joint. SEM (Scanning Electron Microscope) observation of the welds fractured at the early stage in the press-peel test revealed that the fractured surface can be classified into a good weld region and a bad one. The former was a dimple fracture surface or cleavage one and the latter was a relatively flat fracture surface with many oxides. The same analysis was conducted for joints with several welding conditions. It was consequently found that there is a good correlation between the area of good weld region and the maximum load. In addition, it was considered that the scattering of moderate expulsion during PW was effective for reducing oxides.

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