scholarly journals Formability of Medium Mn Steel Welded Joints

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 706
Author(s):  
Yang Cao ◽  
Bo Wang ◽  
Lin Zhao ◽  
Yun Peng ◽  
Minlin Zhong ◽  
...  
Keyword(s):  
Welded Joints ◽  
Welded Joint ◽  
High Strength ◽  
Welding Parameters ◽  
Factors Affecting ◽  
Gas Tungsten Arc ◽  
Deformation Limit ◽  
Medium Mn Steel ◽  
Erichsen Cupping Test ◽  
Mn Steel

In this study, a new-generation high-strength and high-ductility medium Mn steel (0.1C-5Mn-Fe) for the automotive industry was joined by the fiber laser and gas tungsten arc welding (GTAW) methods. Formability testing of the welded joints was done by the Erichsen cupping test and finite element (FE) analysis. The results showed that the formability of medium Mn steel welded joints was sensitive to the welding parameters and inferior to that of the base metal (BM). The hardening zone (HZ) was formed in the welded joint, which was composed of the fusion zone and two symmetrical parts of the heat-affected zone. The width of the HZ was one of the primary factors affecting the formability of the welded joints, while the tensile strength and ductility of the HZ were secondary factors. FE simulation of the Erichsen cupping test results indicated that the forming strain of the welded joint with narrow HZ concentrated on the BM, while the forming strain of the welded joint with wide HZ concentrated on the HZ. The HZ strain reached the deformation limit first due to its weak ductility; therefore, the welded joint with wide HZ had the worst formability. It was also observed that adopting high-velocity and high-laser power welding could greatly improve the formability of the welded joint as a result of reducing the width of the HZ.

Investigation on Microstructure and Martensitic Transformation Mechanism for the Warm-Stamped Third-Generation Automotive Medium-Mn Steel

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Xiaodong Li ◽  
Ying Chang ◽  
Cunyu Wang ◽  
Shuo Han ◽  
Daxin Ren ◽  
...  
Keyword(s):  
Martensitic Transformation ◽  
Strain Rate ◽  
Compressive Load ◽  
High Strength ◽  
Third Generation ◽  
Transformation Mechanism ◽  
Loading Method ◽  
Strain And Strain Rate ◽  
Medium Mn Steel ◽  
Mn Steel

With the development of the automotive industry, the application of the high-strength steel (HSS) becomes an effective way to improve the lightweight and safety. In this paper, the third-generation automotive medium-Mn steel (TAMM steel) is studied. The warm-stamped TAMM steel holds the complete and fine-grained martensitic microstructure without decarbonization layer, which contributes to high and well-balanced mechanical properties. Furthermore, the martensitic transformation mechanism of the TAMM steel is investigated by the dilatation tests. The results indicate that the effects of the loading method on the Ms temperature under different loads are different. The Ms temperature is hardly influenced under the tensile loads and low compressive load. However, it is slightly decreased under the high compressive load. Moreover, the effects of the strain and strain rate on the Ms temperature are insignificant and can be neglected. As a result, this research proves that the martensitic transformation of the TAMM steel is rarely influenced by the process parameters, such as stamping temperature, loading method, load, strain, and strain rate. The actual stamping process can be designed and controlled accurately referring to the continuous cooling transformation (CCT) curves to realize the required properties and improve the formability of the automotive part.

scholarly journals Influence of welding method on microstructural creation of welded joints  

2011 ◽  
Vol 57 (Special Issue) ◽  
pp. S50-S56 ◽  
Author(s):  
P. Čičo ◽  
D. Kalincová ◽  
M. Kotus
Keyword(s):  
Welded Joints ◽  
Arc Welding ◽  
Welded Joint ◽  
Gas Metal Arc Welding ◽  
Structural Phase ◽  
Welding Parameters ◽  
Welding Method ◽  
Welding Technology ◽  
Metal Arc Welding

This paper is focused on the analysis of the welding technology influence on the microstructure production and quality of the welded joint. Steel of class STN 41 1375 was selected for the experiment, the samples were welded by arc welding including two methods: a manual one by coated electrode and gas metal arc welding method. Macro and microstructural analyses of the experimental welded joints confirmed that the welding parameters affected the welded joint structure in terms of the grain size and character of the structural phase.

scholarly journals JOINING THE COMBINATION OF AHSS STEEL AND HSLA STEEL BY RESISTANCE SPOT WELDING

2013 ◽  
Vol 7 (2) ◽  
pp. 75-78 ◽  
Author(s):  
Ľuboš Kaščák ◽  
Emil Spišák ◽  
Ivan Gajdoš
Keyword(s):  
Fuel Consumption ◽  
Welded Joints ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
High Strength ◽  
Quality Analysis ◽  
Vehicle Body ◽  
Welding Parameters ◽  
Resistance Spot ◽  
Ahss Steel

Abstract The paper deals with the optimization of parameters of resistance spot welding and quality analysis of welded joints made by combination of galvanized Advanced High Strength Steel and High Strength Low Alloy steel. It is an advanced material combination utilized in automotive industry to reduce weight of the vehicle body and consequently lowering the fuel consumption to achieve the lowest possible fuel consumption, high active and passive safety of passengers while decreasing the amount of emission. The quality of welded joints was evaluated by destructive tests and non-destructive tests. The shear tensile test according to STN 05 1122 standard was used. Some samples were prepared for metallographic analysis, where the influence of the welding parameters on the structure of welded joint and occurrence of pores in the weld metal caused by evaporation of zinc from the coating was observed.

scholarly journals The structure and properties of laser seam stepper system (LSS) welded the low alloy high strength steel DOCOL 1200M with martensitic structure

2018 ◽  
Vol 2 (1) ◽  
Author(s):  
Jacek Górka 1 ◽  
Andrzej Ozgowicz 2
Keyword(s):  
Welded Joints ◽  
Base Material ◽  
High Strength ◽  
Hardness Measurement ◽  
Welding Parameters ◽  
Martensitic Structure ◽  
Structure And Properties ◽  
Destructive Testing ◽  
Metallographic Examination ◽  
Actual Length

This paper will present the influence of joining process parameters on the structure and properties of overlapped welded joints of 1.8 mm DOCOL 1200M steel. The obtained welded joints were subjected to micro- and macroscopic metallographic examination and hardness measurement. The visual inspections and non-destructive testing made it possible to develop the field of welding parameters to allow obtaining full penetration joints (depending on requirements) or partial penetration joints. For present welding parameters, i.e. feed rate and weld length, which are constant, the actual length of weld is determined by welding frequency. In each case, the microscopic examinations revealed martensitic structure in the weld area, and with the increase in linear welding energy the size of martensite needles became larger, especially in relation to the base material. In HAZ, the martensitic structure is tempered. It has been shown that with appropriately selected parameters the Laser SEAM Stepper method is suitable for welding the DOCOL 1200M steel. With the increase in welding power, the penetration depth increases.

scholarly journals Analysis of Selected Properties of Welded Joints of the HSLA Steels

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1301 ◽  
Author(s):  
Ivan Miletić ◽  
Andreja Ilić ◽  
Ružica R. Nikolić ◽  
Robert Ulewicz ◽  
Lozica Ivanović ◽  
...  
Keyword(s):  
Impact Toughness ◽  
Welded Joints ◽  
Welded Joint ◽  
High Strength ◽  
Hardness Distribution ◽  
Micro Hardness ◽  
Hsla Steels ◽  
Applied Technology ◽  
Welding Procedure ◽  
The Impact

This paper presents research of the impact toughness and hardness distribution in specific zones of a ‘single V’butt multiple-pass welded joints of the high-strength low-alloyed steels. Obtained values of the impact toughness are analyzed in correlation with a microstructure in specific zones of the welded joint, together with the micro hardness distribution found in the related zones. Based on the carried out analysis and results obtained in experiments, the applied technology of welding was evaluated. The original conclusions on influence of the selected welding procedure manual metal arc (MMA) for the root passes and metal active gas (MAG) for the filling and covering passes) on impact toughness of the high-strength low-alloyed steels are drawn. The paper also presents discussion on the valid standards and recommendations related to welding of those steels, from the aspect of applications in design of steel welded constructions.

scholarly journals Effect of Reversed Austenite on Mechanical Properties of ZG06Cr13Ni4Mo Repair Welded Joint

Coatings ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 1
Author(s):  
Yunhai Su ◽  
Zuyong Wei ◽  
Gang Li ◽  
Xiangwen Zhang ◽  
Hedi Ci ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Base Metal ◽  
Welded Joints ◽  
Welded Joint ◽  
Lath Martensite ◽  
Optical Microscope ◽  
Reversed Austenite ◽  
Repair Welding ◽  
Gas Tungsten Arc

In this work, gas tungsten arc welding (GTAW) was used to repair ZG06Cr13Ni4Mo martensitic stainless steel. Repair welding occurred either once or twice. The changes in the microstructure and properties of the repair welded joints were characterized by optical microscope (OM), scanning electron microscope (SEM), electron backscattering diffraction (EBSD), tensile and impact tests. The effects of reversed austenite in repair welded joints on microstructure and mechanical properties were studied. The results show that the microstructure of the welded joint after repair welding consists of a large amount of martensite (M) and a small amount of reversed austenite (A), and the reversed austenite is distributed at the boundary of martensite lath in fine strips. With the increase in the number of welding repairs, the content of reversed austenite in the welded joint increases. The microstructure in the repair welded joints is gradually refined, the microstructure in the once and twice repaired joints is 45.2% and 65.1% finer than that in the casting base metal, respectively. The reversed austenite presented in the repair welded joints decreases the tensile strength by 4.8% and 6.7%, increases the yield strength by 21.3% and 26.4%, and increases the elongation by 25% and 56%, respectively, compared with the casting base metal. In addition, the reversed austenite mainly nucleates and grows at the boundary of lath martensite. The refinement of the martensite structure was due to the generation of reversed austenite and the refinement of original austenite grain by the welding thermal cycle. After repair welding, the reverse austenite appeared in the repair welded joints and the tensile strength decreased slightly, but the plastic toughness was significantly improved, which was conducive to the subsequent service process.

scholarly journals The effect of welded joint properties on the surface characteristics of laser-welded 2205 duplex stainless steel

2018 ◽  
Vol 10 (9) ◽  
pp. 168781401879744 ◽  
Author(s):  
Shanshan Hu ◽  
Dongrui Zheng ◽  
Guolin Zhao ◽  
Guangliang Li ◽  
Hongqun Tang
Keyword(s):  
Tensile Strength ◽  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Surface Quality ◽  
Welded Joints ◽  
Welded Joint ◽  
Surface Characteristics ◽  
Welding Parameters ◽  
Joint Properties ◽  
Welding Surface

Welded joints of poor welding surface quality are sensitive to stress concentrations, affecting both the tensile strength of workpieces and the fluidity of liquids and gases in pressure and liquid containers. Orthogonal experiments involving the laser welding of 1-mm-thick duplex stainless steel sheets were conducted using different electric current, pulse width and frequency values in order to analyse the effect of welding properties on the surface characteristics of the welded joints. Rapid judgement regarding the welded joint properties was made based on the observed welding surface quality. The results show that an even phase proportion and grain refinement are not necessarily guaranteed to provide good welding surface quality. A satisfactory welding surface quality characterised by a smaller spot pitch or spot pitch difference, smaller weld width, reduced surface roughness and valley depth of surface waviness implies better welded joint mechanical characteristics and a more even microstructure. The specimen with the most suitable welding parameters and the greatest heat input can reach the lowest volume fraction of ferrite phase of 42.5% and the highest tensile strength of 848 MPa, and its surface quality is the best.

Research on Welding Process of Low Alloy High Strength Steel 20MnTiB

2019 ◽  
Vol 815 ◽  
pp. 114-119
Author(s):  
Zhen Liang Li ◽  
Hao Ke ◽  
Yang Shen ◽  
Xi Wang ◽  
Jiao Zhong
Keyword(s):  
Mechanical Properties ◽  
Welded Joints ◽  
High Strength Steel ◽  
Welded Joint ◽  
Welding Process ◽  
High Strength ◽  
Post Heat Treatment ◽  
Line Energy ◽  
Metallographic Structure ◽  
Strength Change

In this paper, the properties of the base metal of the low-alloy high-strength steel 20MnTiB, the welding process and the microstructure and properties of the welded joints were studied. The results are as follows: post-heat treatment below 400°C, the strength change of the steel decreases slowly, the elongation does not change significantly, and the metallographic structure is not obvious. When the temperature is above 400, the strength is greatly reduced. And its plasticity increases remarkably, and precipitates on the grain boundary are precipitated and grown on the metallographic structure. When the line energy is in the range of 9.6~12.0kJ/cm, the mechanical properties and microstructure of the welded joints meet the requirements, and the welding process that meets the requirements is studied. Finally, the mechanical properties and microstructure of the welded joint are studied. Provide a reference for the research and application of steel.

Sign in / Sign up

Export Citation Format

Share Document