scholarly journals Mechanical properties of wire and arc additively manufactured high-strength steel structures

Author(s):  
Johanna Müller ◽  
Jonas Hensel ◽  
Klaus Dilger

AbstractAdditive manufacturing with steel opens up new possibilities for the construction sector. Especially direct energy deposition processes like DED-arc, also known as wire arc additive manufacturing (WAAM), is capable of manufacturing large structures with a high degree of geometric freedom, which makes the process suitable for the manufacturing of force flow-optimized steel nodes and spaceframes. By the use of high strength steel, the manufacturing times can be reduced since less material needs to be deposited. To keep the advantages of the high strength steel, the effect of thermal cycling during WAAM needs to be understood, since it influences the phase transformation, the resulting microstructure, and hence the mechanical properties of the material. In this study, the influences of energy input, interpass temperature, and cooling rate were investigated by welding thin walled samples. From each sample, microsections were analyzed, and tensile test and Charpy-V specimens were extracted and tested. The specimens with an interpass temperature of 200 °C, low energy input and applied active cooling showed a tensile strength of ~ 860–900 MPa, a yield strength of 700–780 MPa, and an elongation at fracture between 17 and 22%. The results showed the formation of martensite for specimens with high interpass temperatures which led to low yield and high tensile strengths (Rp0.2 = 520–590 MPa, Rm = 780–940 MPa) for the specimens without active cooling. At low interpass temperatures, the increase of the energy input led to a decrease of the tensile and the yield strength while the elongation at fracture as well as the Charpy impact energy increased. The formation of upper bainite due to the higher energy input can be avoided by accelerated cooling while martensite caused by high interpass temperatures need to be counteracted by heat treatment.

2020 ◽  
Vol 285 ◽  
pp. 116759
Author(s):  
Clément Bourlet ◽  
Sandra Zimmer-Chevret ◽  
Raphaël Pesci ◽  
Régis Bigot ◽  
Aurélien Robineau ◽  
...  

2020 ◽  
Vol 65 (3) ◽  
pp. 125-136
Author(s):  
Yildiz Suat ◽  
Baris Koc ◽  
Oguzhan Yilmaz

Wire arc additive manufacturing (WAAM) which is literally based on continuously fed material deposition type of welding processes such as metal inert gas (MIG), tungsten inert gas (TIG) and plasma welding, is a variant of additive manufacturing technologies. WAAM steps forward with its high deposition rate and low equipment cost as compared to the powder feed and laser/electron beam heated processes among various additive manufacturing processes. In this work, sample parts made of low allow high strength steel (ER120S-G) was additively manufactured via WAAM method using robotic cold metal transfer technology (CMT). The process parameters and building strategies were investigated and correlated with the geometrical, metallurgical and mechanical properties on the produced wall geometries. The results obtained from the thin wall sample parts have showed that with increasing heat input, mechanical properties decreases, since higher heat accumulation and lower cooling rate increases the grain size. The tensile tests results have showed that casting steel (G24Mn6+QT2) mechanical properties which requires 500 MPa yield strength can be compared to with as build WAAM process having 640 MPa yield strength. Tensile strength were fulfilled for S690Q and yield strength is very close to the reference value.


2019 ◽  
Vol 269 ◽  
pp. 05001 ◽  
Author(s):  
Karan Derekar ◽  
Jonathan Lawrence ◽  
Geoff Melton ◽  
Adrian Addison ◽  
Xiang Zhang ◽  
...  

Wire arc additive manufacturing (WAAM) technique has revealed the potential of replacing existing aerospace industry parts manufactured by traditional manufacturing routes. The reduced mechanical properties compared to wrought products, the porosity formation, and solidification cracking are the prime constraints that are restricting wide-spread applications of WAAM products using aluminium alloys. An interpass temperature is less studied in robotic WAAM and is the vital aspect affecting the properties of a formed product. This paper highlights the effects of change in interpass temperature on porosity content and mechanical properties of WAAM parts prepared using DC pulsed GMAW process, with 5356 aluminium consumable wire. The samples prepared with different interpass temperatures were studied for the distribution of pores with the help of computed tomography radiography (CT radiography) technique. A WAAM sample produced with higher interpass temperature revealed 10.41% less porosity than the sample prepared with lower interpass temperature. The pores with size less than 0.15mm3 were contributing over 95% of the overall porosity content. Additionally, on a volumetric scale, small pores (<0.15mm3) in the higher interpass temperature sample contributed 81.47% of overall volume of pores whereas only 67.92% volume was occupied in lower interpass temperature sample with same sized pores. The different solidification rates believed to have influence on the hydrogen evolution mechanism. Tensile properties of higher interpass temperature sample were comparatively better than lower interpass temperature sample. For the deposition pattern used in this study, horizontal specimens were superior to vertical specimens in tensile properties.


Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2671 ◽  
Author(s):  
Maximilian Gierth ◽  
Philipp Henckell ◽  
Yarop Ali ◽  
Jonas Scholl ◽  
Jean Pierre Bergmann

Large-scale aluminum parts are used in aerospace and automotive industries, due to excellent strength, light weight, and the good corrosion resistance of the material. Additive manufacturing processes enable both cost and time savings in the context of component manufacturing. Thereby, wire arc additive manufacturing (WAAM) is particularly suitable for the production of large volume parts due to deposition rates in the range of kilograms per hour. Challenges during the manufacturing process of aluminum alloys, such as porosity or poor mechanical properties, can be overcome by using arc technologies with adaptable energy input. In this study, WAAM of AlMg5Mn alloy was systematically investigated by using the gas metal arc welding (GMAW) process. Herein, correlations between the energy input and the resulting temperature–time-regimes show the effect on resulting microstructure, weld seam irregularities and the mechanical properties of additively manufactured aluminum parts. Therefore, multilayer walls were built layer wise using the cold metal transfer (CMT) process including conventional CMT, CMT advanced and CMT pulse advanced arc modes. These processing strategies were analyzed by means of energy input, whereby the geometrical features of the layers could be controlled as well as the porosity to area portion to below 1% in the WAAM parts. Furthermore, the investigations show the that mechanical properties like tensile strength and material hardness can be adapted throughout the energy input per unit length significantly.


1988 ◽  
Vol 110 (3) ◽  
pp. 171-176
Author(s):  
Y. Nakano ◽  
Y. Saito ◽  
K. Amano ◽  
M. Koda ◽  
Y. Sannomiya ◽  
...  

This paper describes the metallurgical approaches for producing 415MPa and 460MPa yield strength offshore structural steel plates and the mechanical properties of the steel plates and their welded joints. A thermo-mechanical control process (TMCP) was adopted to manufacture YP415MPa and YP460MPa steel plates with weldability comparable to conventional YP355MPa steel plates. The Charpy impact and CTOD tests of the steel plates and their welded joints proved to be very good.


2016 ◽  
Vol 61 (2) ◽  
pp. 475-480
Author(s):  
K. Bolanowski

Abstract The paper analyzes the influence of different heat treatment processes on the mechanical properties of low-alloy high-strength steel denoted by Polish Standard (PN) as 10MnVNb6. One of the findings is that, after aging, the mechanical properties of rolled steel are high: the yield strength may reach > 600 MPa, and the ultimate tensile strength is > 700 MPa. These properties are largely dependent on the grain size and dispersion of the strengthening phase in the ferrite matrix. Aging applied after hot rolling contributes to a considerable rise in the yield strength and ultimate tensile strength. The process of normalization causes a decrease in the average grain size and coalescence (reduction of dispersion) of the strengthening phase. When 10MnVNb6 steel was aged after normalization, there was not a complete recovery in its strength properties.


Author(s):  
Pradipta Kumar Jena ◽  
K. Siva Kumar ◽  
A.K. Singh

This work describes the microstructure, texture and anisotropy in mechanical behavior of a high strength steel in various tempered conditions. The microstructures and mechanical properties change considerably with varying tempering temperatures. The material exhibits low in-plane anisotropy and low anisotropic index in terms of yield strength and elongation with increase in tempering temperature. The anisotropy of the material displays similar behavior to that of the yield strength.


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