scholarly journals Highly Molybdenum-Alloyed Materials Hastelloy BC-1 (2.4708) and B3 (2.4600): Diffusion Bonding Experiments and Evaluation of both Mechanical Behavior and Corrosion Resistance in Hot 70% Sulfuric Acid

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 376
Author(s):  
Thomas Gietzelt ◽  
Mario Walter ◽  
Volker Toth ◽  
Florian Messerschmidt ◽  
Ralf Dahm

Sulfuric acid is a widely used raw material in the chemical industry. Its corrosive effect on materials varies considerably, depending on impurities, temperature and water content. This is an issue for micro process apparatuses with thin walls. Such devices are often joint by diffusion bonding what may alter materials properties due to high temperatures and long dwell times. In this paper, two high molybdenum alloys, namely Hastelloy B3 and BC-1, were investigated. Diffusion bonding tests were performed at different temperatures. Tensile tests were carried out for different material conditions, to determine the change in mechanical strength and elongation at fracture values. The fracture behavior of both alloys was ductile and the fracture surfaces showed dimple structure. For diffusion bonded samples, weak spots or rather non-bonded areas were found. These obviously caused the onset of material failure and thus, degradation of mechanical properties. Tensile samples, aged in 70% sulfuric acid at 100 °C for 1000 h showed local corrosion attacks at the grain boundaries at the circumferential surfaces and joining planes—for Hastelloy B3 more pronounced than for Hastelloy BC-1. Accordingly, a further decrease of stress and elongation at fracture values was observed. However, 0.2% yield strength used for dimensioning components are found to be reasonable. As conclusion, at least Hastelloy BC-1 reveals both good mechanical properties and an excellent corrosion resistance, regardless of the heat treatment. This is a significant advance compared to the results obtained from a previously research project on four different alloys.

Author(s):  
Thomas Gietzelt ◽  
Mario Walter ◽  
Volker Toth ◽  
Florian Messerschmidt ◽  
Ralf Dahm

Sulphuric acid is a widely used raw material in the chemical industry. Its corrosive effect on materials varies considerably, depending on impurities, temperature and water content. Accordingly, good corrosion resistance under all conditions is very difficult to achieve. This is especially an issue for micro process apparatus with very thin walls. Furthermore, such devices are often joint by diffusion bonding what may alter materials properties due to high temperatures and long dwell times. In fact, for each new material, the diffusion bonding parameters must be optimized and the impact on mechanical as well as corrosion properties must be investigated. In this paper, two high molybdenum alloys, namely Hastelloy B3 and BC-1, were evaluated. Diffusion bonding tests were performed using ten layers of sheet material in between round stock. Corrosion tests were performed in 70 % sulphuric acid at 100°C for 1000 h. Tensile tests on both alloys were carried out for different material conditions, to determine the change in mechanical strength and elongation at fracture values. In general, independent of the condition of the materials, the fracture behavior of both alloys was found to be ductile and the specimens show the typical dimple structure, in the case of diffusion bonded samples, interrupted by weak spots or rather non-bonded areas. These areas are obviously causing the onset of material failure and thus, a degradation of mechanical properties. Tensile samples, that were aged in 70% sulphuric acid at 100°C for 1000 hours showed local corrosion attacks at the grain boundaries at the circumferential surfaces and especially at the joining planes – for Hastelloy B3 much more pronounced than for Hastelloy BC-1. Accordingly, a further decrease of both, the stress- and elongation at fracture values is observed. However, the typical material parameters like 0.2 % yield strength used for dimensioning components are found to be sufficient high, even when operating the materials under such harsh conditions. When concluding the results, at least Hastelloy BC-1 reveals both sufficient good mechanical properties and an excellent corrosion resistance, regardless of the heat treatment, and could be considered for manufacturing micro-process engineering apparatuses operated in a sulphuric acid environment. This is a significant advance compared to the results obtained within a AiF project, previously carried out on four different materials to investigate the corrosion resistance in sulphuric acid.


Metals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 152
Author(s):  
Peng Peng ◽  
Shaosong Jiang ◽  
Zhonghuan Qin ◽  
Zhen Lu

This work fabricated a double hollow structural component of Mg-8.3Gd-2.9Y-0.8Zn-0.2Zr alloy by superplastic forming (SPF) and reaction-diffusion bonding (RDB). The superplastic characteristic and mechanical properties of Mg-8.3Gd-2.9Y-0.8Zn-0.2Zr alloy sheets at 250–450 °C were studied. Tensile tests showed that the maximum elongation of tensile specimens was about 1276.3% at 400 °C under a strain rate of 1 × 10−3 s−1. Besides, the effect of bonding temperature and interface roughness on microstructure and mechanical properties of the reaction diffusion-bonded joints with a Cu interlayer was investigated. With the increase of temperature, the diffusion coefficient of Cu increases, and the diffusion transition region becomes wider, leading to tightening bonding of the joint. However, the bonding quality of the joint will deteriorate due to grain size growth at higher temperatures. Shear tests showed that the highest strength of the joints was 152 MPa (joint efficiency = 98.7%), which was performed at 460 °C.


Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1212
Author(s):  
Xiong ◽  
Yang ◽  
Deng ◽  
Li ◽  
Li ◽  
...  

The effect of Ca addition on the microstructure, mechanical properties, and corrosion behaviors of the extruded Mg–7Li–3Al alloys was investigated. The results showed that the extruded Mg–7Li–3Al–xCa alloys consisted of α-Mg (hcp) + β-Li (bcc) matrix phases and Al2Ca. With increasing Ca content, the amount and morphology of the Al2Ca phase changed significantly. The grains of the extruded Mg–7Li–3Al–xCa alloys were refined by dynamic recrystallization during the extrusion process. The tensile tests results indicated that the extruded Mg–7Li–3Al–0.4Ca alloy exhibited favorable comprehensive mechanical properties; its ultimate tensile strength was 286 MPa, the yield strength was 249 MPa, and the elongation was 18.7%. The corrosion results showed that this alloy with 0.4 wt.% Ca addition exhibited superior corrosion resistance, with a corrosion potential Ecorr of −1.48742 VVSE, attributed to the formation of protective Al2Ca phases.


2017 ◽  
Vol 17 (2) ◽  
pp. 125-130 ◽  
Author(s):  
M. Uludağ ◽  
M. Kocabaş ◽  
D. Dışpınar ◽  
R. Çetin ◽  
N. Cansever

AbstractIn the present study, the corrosion behaviour of A356 (Al-7Si-0.3Mg) alloy in 3.5% NaCl solution has been evaluated using cyclic/potentiodynamic polarization tests. The alloy was provided in the unmodified form and it was then modified with AlTi5B1 for grain refinement and with AlSr15 for Si modifications. These modifications yield to better mechanical properties. Tensile tests were performed. In addition, bifilm index and SDAS values were calculated and microstructure of the samples was investigated. As a result of the corrosion test, the Ecorr values for all conditions were determined approximately equal, and the samples were pitted rapidly. The degassing of the melt decreased the bifilm index (i.e. higher melt quality) and thereby the corrosion resistance was increased. The lowest corrosion rate was founded at degassing and as-received condition (3.9x10-3mm/year). However, additive elements do not show the effect which degassing process shows.


2007 ◽  
Vol 546-549 ◽  
pp. 1467-1470
Author(s):  
Shu Suo Li ◽  
Chun Xiao Zhang ◽  
Yong Wang Kang ◽  
Ya Fang Han

The effect of NiCr-CrAl coating on the microstructure, oxidation and corrosion resistance, as well as mechanical properties of Ni3Al base alloy IC6AE has been studied in the present investigation. NiCr-CrAl coating for alloy IC6AE was prepared by the powder pack cementation method. The oxidation resistance tests were carried out under the condition of 1050°C/100h, while the hot corrosion resistance tests were under 900°C/100h. The tensile tests at the room temperature and the stress rupture life tests under 1050°C/90Mpa have been also conducted. The experimental results showed that NiCr-CrAl as-coated specimens had excellent oxidation and hot corrosion resistance compared with the alloy IC6AE blank specimens, and NiCr-CrAl coating has no obvious effect on the mechanical properties of alloy IC6AE. It may be concluded that NiCr-CrAl coating is suitable for the alloy IC6AE.


2012 ◽  
Vol 427 ◽  
pp. 26-31 ◽  
Author(s):  
Wen Jin Ding ◽  
Tong Jiang Peng ◽  
Ji Ming Chen

By utilizing chrysotile asbestos tailing from Shannan ore in Sichuan as the main raw material, diopside-based glass-ceramics were successfully synthesized in the laboratory by adding some limestone, quartz sand, Al2O3, H3BO3, Na2CO3 and CaF2. The optimum procedure for glass-ceramics was as follows: melting at 1400 for 60 min, sintering at 1100 for 120 min. Through the tests of physical and mechanical properties, the glass-ceramics materials with more crystalline phase had high density, fine performance of resisting compression (366MPa) and negligible water absorption. Through chemical resistance tests, the glass-ceramics samples showed strong corrosion resistance. Overall result indicated that it was a feasible attempt to produce glass-ceramics materials for building and decorative materials from chrysotile asbestos tailing.


2005 ◽  
Vol 488-489 ◽  
pp. 839-844 ◽  
Author(s):  
Young Gee Na ◽  
Dan Eliezer ◽  
Kwang Seon Shin

The development of new components with magnesium alloys for the automotive industry has increased in recent years due to their high potential as structural materials for low density and high strength/weight ratio demands. However, the limited mechanical properties of the magnesium alloys have led to search new kind of magnesium alloys for better strength and ductility. The main objective of this research is to investigate the mechanical properties and the corrosion behavior of new wrought magnesium alloys; Mg-Zn-Ag (ZQ) and Mg-Zn-Si (ZS) alloys. The ZQ6X and ZS6X samples were fabricated using hot extrusion method. Tensile tests and immersion tests were carried out on the specimens from the extruded rods, which contained different amounts of silver or silicon, in order to evaluate the mechanical properties and corrosion behavior. The microstructure was examined using optical and electron microscopy (TEM and SEM) and EDS. The results showed that the addition of silver improved the mechanical properties but decreased the corrosion resistance. The addition of silicon improved both mechanical properties and corrosion resistance. These results can be explained by the effects of alloying elements on the microstructures of the Mg-Zn alloys such as grain size and precipitates caused by the change in precipitation and recrystallization behavior.


CORROSION ◽  
1963 ◽  
Vol 19 (6) ◽  
pp. 210t-216t ◽  
Author(s):  
F. NAIR ◽  
M. SEMCHYSHEN

Abstract The corrosion resistance of nine Cr-Ni-Mn austenitic and duplex austenitic-ferritic stainless steels, containing up to 5 percent molybdenum, in hot deaerated sulfuric acid and boiling concentrated nitric acid was determined and compared to the behavior of recognized commercial grades. A limited evaluation of mechanical properties was performed. The corrosion resistance of these alloys was affected by molybdenum additions in a manner similar to that observed in Cr-Ni austenitic steels:The ability to tolerate minimal oxidizing environments such as sulfuric acid was markedly improved.The resistance toward strongly oxidizing acidic conditions was reduced. The presence of delta ferrite effected improved resistance in sulfuric acid and materially diminished corrosion resistance in hot nitric acid.


Alloy Digest ◽  
1966 ◽  
Vol 15 (6) ◽  

Abstract Carpenter Stainless 20Cb-3 is an austenitic stainless steel designed for improved resistance to sulfuric acid. It finds wide use in all phases of the chemical industry. It has good mechanical properties and comparative ease of fabrication. Columbium stabilizes the alloy to minimize carbide precipitation during welding. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-182. Producer or source: Carpenter.


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