Investigation of Weld Seam Structures of Tailor Welded Blanks for Hot Stamping

2015 ◽  
Vol 639 ◽  
pp. 235-242 ◽  
Author(s):  
Ralf Kolleck ◽  
Robert Vollmer ◽  
Christian Both ◽  
Arndt Breuer
Keyword(s):  
Mechanical Properties ◽  
Weld Seam ◽  
Hot Stamping ◽  
Fem Analysis ◽  
Body Parts ◽  
Welding Seam ◽  
Press Hardening ◽  
Safety Requirements ◽  
Tailor Welded Blanks ◽  
Testing Tool

Increasing safety requirements for hot stamped structural car body parts are demanding sufficient mechanical properties of integrated welding seams. Especially conventional tailor welded AlSi-coated 22MnB5 sheets are only fulfilling these requirements when ablated before laser welding and thermo-mechanically treated in a correct way. This paper shows a method that evaluates the hot stamping process of tailor welded blanks by press hardening different sheet thicknesses and thickness combinations in a testing tool. Furthermore, appropriate testing methods for the evaluation of mechanical properties of the welding seam are introduced. The results are ultimately compared with a special developed FEM analysis to predict failure cases in future.

Thermal and Mechanical Characteristics of a HSLA Steel as Joint Partner for Hot Stamping Tailor Welded Boron Steel

2014 ◽  
Vol 1063 ◽  
pp. 104-107
Author(s):  
Bing Tao Tang ◽  
Qiao Ling Wang ◽  
Wei Zheng ◽  
Zheng Jun Yuan
Keyword(s):  
Mechanical Properties ◽  
Mechanical Characteristics ◽  
Hsla Steel ◽  
Hot Stamping ◽  
Boron Steel ◽  
Thermal And Mechanical Properties ◽  
Safety Requirements ◽  
Automobile Safety ◽  
Tailor Welded Blanks ◽  
Body Components

In order to further reduce the weight and at the same time guarantee the automobile safety, hot stamping of Tailor-Welded Blanks (TWBs), is developed recently to meet the environmental and safety requirements by supplying car structural body components with functionally optimized and tailored mechanical properties. In the article, an appropriate partner material for the quenchenable boron steel B1500HS based on the phase transformation and deformation behavior under process relevant conditions is determined. Microhardness is measured and metallographic is investigated. It is verified that the B340LA steel is an appropriate joint partner with ideal thermal and mechanical properties.

scholarly journals Investigation of diffusion behavior of carburized sheet metal in hot stamping

2019 ◽  
Vol 6 ◽  
pp. 16
Author(s):  
Alexander Horn ◽  
Marion Merklein
Keyword(s):  
Mechanical Properties ◽  
Sheet Metal ◽  
Lightweight Design ◽  
Hot Stamping ◽  
Carbon Diffusion ◽  
Tensile Tests ◽  
Process Window ◽  
Uniaxial Tensile ◽  
Body Parts ◽  
Passenger Safety

Today, manufacturing of structural car body parts faces several challenges, like forming accuracy, passenger safety and lightweight design. One possibility to fulfill these partially rivalling demands is the application of hot stamped components. The combination of hot forming and in-die quenching reduces not only springback, but also results in tensile strengths of more than 1500 MPa. Besides conventional hot stamping, the process can be adapted to manufacture parts with tailored properties. One of the biggest issues of these state-of-the-art processes is the formation of extensive transition zones due to heat transfer. A promising approach to adjust the mechanical properties with a minimized transition zone is tailored carburization of sheet metal. Therefore, the parts are locally coated with graphite, heat treated and subsequently quenched. In this work, the time variant process of carbon diffusion is investigated. Sheets with two different thicknesses are carburized and quenched. The resulting mechanical properties are analyzed using uniaxial tensile tests and microhardness measurements. On this basis, a process window is identified. Furthermore, the applicability of EDX and WDX analysis for the measurement of carbon concentration is investigated within this work.

scholarly journals Investigation of diffusion behavior of carburized sheet metal in hot stamping

2018 ◽  
Vol 190 ◽  
pp. 08004 ◽  
Author(s):  
Alexander Horn ◽  
Marion Merklein
Keyword(s):  
Mechanical Properties ◽  
Transition Zone ◽  
Sheet Metal ◽  
Lightweight Design ◽  
Hot Stamping ◽  
Sheet Thickness ◽  
Carbon Diffusion ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Body Parts

Today’s manufacturing of structural car body parts faces several challenges, like forming accuracy and passenger safety. Besides these two requirements, lightweight design plays an important role. One possibility to fulfill these partially rivalling demands is the application of hot stamped parts. The combination of hot forming and in die quenching reduces not only springback, but also results in tensile strengths of up to 1500 MPa. This makes a simultaneous reduction of sheet thickness and therefore weight reduction possible. Further development enabled a tailored adjustment of mechanical properties, for example by applying different cooling conditions along the parts. One of the biggest issues of these state of the art processes is the formation of a transition zone due to heat transfer. A promising approach to adjust the mechanical properties with a minimized transition zone is the carburization of sheet metal. Therefore, the parts are coated with graphite, heat treated and subsequently quenched. In this work, the time variant process of carbon diffusion is investigated. Sheets with two different thicknesses are carburized and quenched. The resulting mechanical properties are analyzed using uniaxial tensile tests and microhardness measurements. The results are correlated with the carbon content measured by EDX-analysis.

scholarly journals FEM Analysis of the Welding Seams Geometry in Case of Fillet Welds

2021 ◽  
Vol 343 ◽  
pp. 03006
Author(s):  
Claudiu Babiş ◽  
Andrei Dimitrescu ◽  
Ana Maria Alecusan ◽  
Marcela Babiş
Keyword(s):  
Weld Seam ◽  
Welding Process ◽  
Fem Analysis ◽  
Geometric Shape ◽  
Fillet Welds ◽  
Mechanical Resistance ◽  
Filler Materials ◽  
Welding Seam ◽  
Welding Regime ◽  
Materials Used

The role of the welding seam is to achieve the non-removable joint between two or more parts. In principle, three geometric profiles of the welding seams can be obtained: straight profile; concave profile and convex profile. In practice, this geometric shape of the weld seam profile is very important, both in terms of the resistance of the joint to static stresses and in terms of its fatigue life. There are many factors that can influence the geometric shape of the weld seam: the welding process; welding regime; the nature of the filler materials used, the rehabilitation techniques applied and others. Often, this geometric shape of the weld bead is neglected, which is particularly dangerous due to the fact that an improper geometric shape can generate low mechanical strength in static loads or poor fatigue strength in variable loads. An optimum of the geometric configuration of the welding must be found, which reconciles both situations: the mechanical resistance in case of static stresses and also the fatigue resistance in case of variable loads. In this paper, an analysis will be made with finite elements for the straight and convex profile of the welding seams in the case of fillet welds subjected to fatigue. Several elements will be considered such as: damage; total deformation; fatigue sensitivity versus loading history; equivalent von Misses stress; safety factor.

Effects of Austenitizing Temperature on Microstructure and Properties of Hot-Formed Steel

2014 ◽  
Vol 1063 ◽  
pp. 88-92 ◽  
Author(s):  
He Long Cai ◽  
Peng Ju Du ◽  
Hong Liang Yi ◽  
Di Wu
Keyword(s):  
Mechanical Properties ◽  
Hot Stamping ◽  
High Strength ◽  
Hardened Steel ◽  
Austenitizing Temperature ◽  
Austenitization Temperature ◽  
Press Hardening ◽  
Automotive Structures ◽  
Body In White ◽  
Press Hardening Steel

Press hardening steel is the best solution for application of extremely high strength steel in automotive structures in order to reduce the weight of body-in-white. Effect of austenitizing temperature on the grain coarsening of a press hardening steel has been investigated by using dilatometer at first. The mechanical properties of press-hardened steel austenitized at temperature between 850 to 950oC by using a pilot hot stamping line have been investigated. The strength, especially the ultimate tensile strength, was improved by the grain refinement with lower austenitization temperature.

scholarly journals Use of CAx systems in the design of the construction and technological process of innovative car body parts

Mechanik ◽  
2018 ◽  
Vol 91 (1) ◽  
pp. 39-41
Author(s):  
Ireneusz Wróbel
Keyword(s):  
Technological Process ◽  
Hot Stamping ◽  
Fem Analysis ◽  
Strength Analysis ◽  
Body Parts ◽  
Passenger Car ◽  
Car Body ◽  
Stamping Process

Presented is the process of designing the construction and technological process of the passenger car door beam. The FEM beam strength analysis and FEM analysis of the hot stamping process of this beam were presented. The simulations were discussed. Conclusions and recommendations were made.

scholarly journals Steel sheets partnered with quenchable sheet in hot stamping of tailor-welded blanks and its application to separation prevention of fractured components

2020 ◽  
Vol 111 (3-4) ◽  
pp. 725-734
Author(s):  
Ken-ichiro Mori ◽  
Yasutaka Suzuki ◽  
Daisuke Yokoo ◽  
Michiya Nishikata ◽  
Yohei Abe
Keyword(s):  
Mechanical Properties ◽  
Phase Transformation ◽  
Mild Steel ◽  
Hot Stamping ◽  
High Strength ◽  
Boron Steel ◽  
Air Cooling ◽  
High Ductility ◽  
Steel Sheets ◽  
Tailor Welded Blanks

Abstract The phase transformation and mechanical properties of non-quenchable steels partnered with the quenchable boron steel in hot stamping of tailor-welded blanks were evaluated to produce tailored components with partially balanced strength and ductility. The effect of the forming start temperature after natural air cooling on the phase transformation and mechanical properties for 270 MPa mild steel, non-quenchable steel, 440 MPa high strength steel, and 22MnB5 steel sheets was examined, and the 270 MPa and non-quenchable sheets had enough ductility after hot stamping. Tailored components having a hardness of about 500 HV1 in the high strength zone and a total elongation of about 30% in the high ductility zone were hot-stamped from a tailor-welded blank composed of 22MnB5 and 270 MPa sheets. It was found that the 270 MPa mild steel sheet is sufficient as a partner sheet of tailor-welded blanks. In addition, the safety of hot-stamped components was heightened by welding a 22MnB5 main blank with a 270 MPa steel patch. Even if the main blank is fractured by a collision, the hot-stamped component is not separated by the 270 MPa patch having high ductility.

scholarly journals Protein Hydrogels: The Swiss Army Knife for Enhanced Mechanical and Bioactive Properties of Biomaterials

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1656
Author(s):  
Carla Huerta-López ◽  
Jorge Alegre-Cebollada
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Polymer Networks ◽  
Biological Tissues ◽  
Modern Medicine ◽  
Body Parts ◽  
Biomedical Sciences ◽  
Protein Hydrogels ◽  
Large Water ◽  
Design Options

Biomaterials are dynamic tools with many applications: from the primitive use of bone and wood in the replacement of lost limbs and body parts, to the refined involvement of smart and responsive biomaterials in modern medicine and biomedical sciences. Hydrogels constitute a subtype of biomaterials built from water-swollen polymer networks. Their large water content and soft mechanical properties are highly similar to most biological tissues, making them ideal for tissue engineering and biomedical applications. The mechanical properties of hydrogels and their modulation have attracted a lot of attention from the field of mechanobiology. Protein-based hydrogels are becoming increasingly attractive due to their endless design options and array of functionalities, as well as their responsiveness to stimuli. Furthermore, just like the extracellular matrix, they are inherently viscoelastic in part due to mechanical unfolding/refolding transitions of folded protein domains. This review summarizes different natural and engineered protein hydrogels focusing on different strategies followed to modulate their mechanical properties. Applications of mechanically tunable protein-based hydrogels in drug delivery, tissue engineering and mechanobiology are discussed.

Investigation on the mechanical properties of press-hardened boron steel sheets using the conductive heating technique

2020 ◽  
Vol 234 (8) ◽  
pp. 1084-1098
Author(s):  
O Kocar ◽  
H Livatyalı
Keyword(s):  
Mechanical Properties ◽  
High Speed ◽  
Boron Steel ◽  
Fast Heating ◽  
Heating Method ◽  
Conductive Heating ◽  
Press Hardening ◽  
High Speed Impact ◽  
Significant Difference ◽  
Structural Parts

An aluminized 22MnB5 (Boron) steel sheet, used for structural parts in the automotive industry, was subjected to press-hardening followed by austenitizing, both in a conventional furnace and via the conductive (electric resistance) heating method, an innovative technique based on the Joule’s principle for fast heating of the sheet metal. Conductive heating presents a number of advantages over the in-furnace heating method. These include a more efficient use of energy, as well as the requirement of less time and space for heating, thus lowering costs. After press-hardening was performed using both methods, the microstructural and mechanical characterizations of both specimens were examined for optical microscopy, hardness, tensile strength, and high-speed impact tests. The results showed that the press-hardening process transformed the ferritic–pearlitic microstructure in the as-received state into martensite after die quenching and caused a substantial increase in hardness and strength at the expense of ductility and impact toughness. On the other hand, no significant difference was observed in either the microstructure or mechanical properties with respect to the heating method used. The results obtained in the present investigation concur with the findings of current literature.

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