scholarly journals Applied Research of Applicability of High-Strength Steel for a Track of a Demining Machine in Term of Its Tribological Properties

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 505
Author(s):  
Miroslav Blatnický ◽  
Ján Dižo ◽  
Milan Sága ◽  
Peter Kopas

Even today, there are countries that are affected by war and its pitfalls. The authors have decided to present a part of the accompanying research results in this article. This research precedes the design of a demining machine Božena 5. The main goal of the authors’ activities was to design optimal material and geometry for a track of this machine. To achieve this goal, the authors conducted research to evaluate the microstructure of the material S960QL and its tribological lifetime. As the track of the demining machine is a welded component, the authors also investigated the influence of different welding technologies on the given parameters. The tribological research was performed on an original test device. The obtained results show that welding joints have the typical microstructure of martensitic high-strength steels and that mechanical properties can be influenced by individual welding technologies. Meanwhile, the use of the electron beam significantly extends the adhesive-abrasive lifespan compared with the MAG (metal active gas) conventional method as well as to the base material. It is interesting that the absolute value of material loss over time reached the identity for both the laser beam and the electron beam. The obtained data provide changes to apply the proposed material for the production of the solved component.

2021 ◽  
Vol 1178 (1) ◽  
pp. 012010
Author(s):  
J Capek ◽  
J Kec ◽  
S Nemecek ◽  
K Trojan ◽  
N Ganev ◽  
...  

Author(s):  
Miklós Berczeli ◽  
Zoltán Weltsch

Nowadays the stakeholders of vehicle industry are focusing on making materials and technologies for motor-vehicle bodies that satisfy the newest requirements. Reduction of the manufactured vehicle’s dead load - while the important material properties of proper functioning only change in a small degree – is such a requirement. There exist many solutions to satisfy this requirement. One of them is when the materials are in the same group, but the material with higher strength is used with less thickness. Reducing mass should be searched in recent high strength steels. Evidently, to reduce dead load, manufacturers use steels with different strength, depending on the function of the given structural component. The advantages of steels with increased strength is the reduced cost of manufacturing and to make the hybrid material couplings cheaper as well. However, malleability is one of the key issues of manufacturing body components, so common use of basic and increased strength steels is necessary. The connection between the standard (DC) and increased strength (DP) steels design is one way for the binding established by brazing, which has several advantages over welding. In this paper MIG brazing is formed between the DC-DP steel pairs and examine changes in the surface properties and the interfacial layer. The results shows there are differences between the DC and DP side of the joint.


2016 ◽  
Vol 1812 ◽  
pp. 35-40 ◽  
Author(s):  
Humberto Hernández-Belmontes ◽  
Ignacio Mejía ◽  
Cuauhtémoc Maldonado

ABSTRACTHigh-Mn Twinning-Induced Plasticity (TWIP) steels are advanced high-strength steels (AHSS) currently under development; they are fully austenitic and characterized by twinning as the predominant strengthening mechanism. TWIP steels have high strength and formability with an elongation up to 80%, which allows reduction in automotive components weight and fuel consumption. Since the targeted application field of TWIP steels is the automotive industry, steels need high mechanical performance with good weldability and excellent corrosion resistance. However, there is lack of information about the weldability behavior of these advanced steels. This research work aims to study the weldability of a new generation of high-Mn austenitic TWIP steels microalloyed with B. Weldability was examined using spot welds produced by Gas Tungsten Arc Welding. Microstructural changes were examined using light optical metallography. Segregation of elements in the weld joint was evaluated using point and elemental mapping chemical analysis by Scanning Electron Microscopy and Electron-Dispersive Spectroscopy; while the hardness properties were examined with Vickers microhardness testing (HV25). Experimental results show that the welded joint microstructure consists of austenitic dendritic grains in the fusion zone, and equiaxed grains in the heat affected zone. Notably, the boron microalloyed TWIP steel exhibited poor weldability, showing hot cracking. Additionally, the studied TWIP steels showed a high degree of segregation in the fusion zone; Mn and Si segregated into the interdendritic regions, while Al and C preferentially segregated in dendritic areas. Finally, the welded joints of the TWIP steels showed microhardness values lower than the base material. In general, the present TWIP steels have problems of weldability, which are corroborated with microstructural changes, elements segregation and microhardness loss.


2020 ◽  
Vol 59 (1) ◽  
pp. 54-66
Author(s):  
Francois Njock Bayock ◽  
Paul Kah ◽  
Antti Salminen ◽  
Mvola Belinga ◽  
Xiaochen Yang

AbstractThis study concerns the weldability of dissimilar Ultra high-strength steel (UHSS) and advanced high-strength steel (AHSS), which is used in the modern machine industry. The materials offered superior strength as well as relatively low weight, which reduces microstructure contamination during a live cycle. The choice of the welding process base of the base material (BM) and welding parameters is essential to improve the weld joint quality. S700MC/S960QC was welded using a gas metal arc welding (GMAW) process and overmatched filler wire, which was performed using three heat input (7, 10, and 15 kJ/cm). The weld samples were characterized by a Vickers-hardness test, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The test reveals a decrease of softening areas in the HAZ and the formation of the stable formation of Bainite-Ferrite for S700MC and Bainite-martensite for S960QC when the heat input of 10 kJ/cm is used. It is recommended to use the GMAW process and Laser welding (Laser beam-MIG), with an optimal welding parameter, which will be achieved a high quality of manufacturing products.


2014 ◽  
Vol 611-612 ◽  
pp. 955-962 ◽  
Author(s):  
Thomas Mennecart ◽  
Alper Güner ◽  
Nooman Ben Khalifa ◽  
A. Erman Tekkaya

Due to the increase of lightweight design in car bodies, there is a raise in use of tailored welded blanks (TWB). With these blanks it is possible to strengthen the car body where it is necessary. This can lead to less weight. In the case of tailored welded blanks, there is a weld line, which influences the deep drawing behavior significantly during forming. In the presented results two different high strength steels (HCT980X and HCT600X) are welded together. One forming operation is performed, in which the weld line is positioned differently. The results show the influence of the weld line on the forming behavior which is realized by the comparison of deep drawn monolithic parts with the deep drawn tailored welded blanks. While the monolithic parts could be formed without failure, the forming of tailored welded blanks was accompanied by cracks in dependency to the weld line orientation and the applied load in this region. The results also show that the failure occurs in the base material and that the weld line is not damaged by the applied load. After the characterization of the base materials and the weld material, a numerical modelling of the whole TWB could be realized in this work. Two different ways of modelling techniques of the weld line are compared and the necessity of the consideration of the weld line properties is demonstrated. Furthermore, in consideration of the weld line properties in the FE-Model, it is possible to show that the weld line resists the forming operation without failure.


Author(s):  
Carey L. Walters ◽  
Lars O. Voormeeren ◽  
Michael Janssen ◽  
Kim Wallin

Standards have traditionally required that fracture toughness specimens be the full thickness of the base material. However, this requirement may be unnecessary, especially if minimum specimen size dimensions based on plastic zone are met and the subsized specimens are statistically adjusted for the size effect. The current paper presents the results for full-thickness proportional Single Edge Notched Bending (SENB) specimens according to BS7448-1 that are 25 mm by 50 mm in cross-section and then compares these results to specimens of the same material that are 10 mm by 20 mm in cross section. The result is that for a temperature near the lower portion of the transition curve (−60°C to −70°C), the subsize specimens are in very good agreement. These results hold for two different loading rates. After correction for statistical size effect, the fracture toughnesses of the subsize specimens are within 10% of the full-size specimens. This is conservative. The difference is attributed to the statistical nature of fracture in the transition region.


2015 ◽  
Vol 817 ◽  
pp. 312-318
Author(s):  
Kai Wang ◽  
Jiang Long Yi ◽  
Shi Da Zheng ◽  
Chun Fu Guo ◽  
He Xin Chen ◽  
...  

Using the prepared gas-shielded flux-cored wire for welding 600MPa high strength steel, the 921A high strength steels were welded at different weld heat input condition of 10 kJ/cm, 15 kJ/cm and 20 kJ/cm. The influence of weld heat input on the electrochemical behavior of the 921A high strength steel welding joints were studied in this paper. The results show that, at different weld heat input condition, the linear polarization resistances (LPR) of all the welding joints welded by using the prepared flux-cored wire were close to that of the 921A base steel, as can be identified as the same LPR value at 15 kJ/cm weld heat input condition. By observing the surfaces of the linear polarized welding joints samples, it was found that the welding joint at 15 kJ/cm weld heat input had the smallest corrosive area by macro observing, showing the pitting corrosion by micro observing and presents the least corrosion pit.


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