Hydrogen-Assisted Degradation of High-Strength Stainless Steel With a Newly Developed Aluminum-Based Coating in High-Pressure Hydrogen Gas Environment

2017 ◽  
Author(s):  
Junichiro Yamabe ◽  
Tohru Awane ◽  
Osamu Takakuwa ◽  
Saburo Matsuoka
Keyword(s):  
Stainless Steel ◽  
High Strength ◽  
Tensile Tests ◽  
Fatigue Tests ◽  
Hydrogen Gas ◽  
Experimental Result ◽  
Fatigue Properties ◽  
Hydrogen Trapping ◽  
Hydrogen Diffusivity ◽  
Effective Hydrogen

The paper presents the hydrogen-entry, tensile, and fatigue properties of a precipitation-hardened martensitic stainless steel, JIS-SUS630, with a newly developed coating, whose thickness ranges from 10 to 20 μm. The newly developed coating consists of alumina, aluminum, and ferroaluminum, and has an excellent resistance to hydrogen entry in 100-MPa hydrogen gas at 270°C. The hydrogen entry in the coated specimen occurred under a diffusion-controlled process and the effective hydrogen diffusivity was approximately one thousandth of that of the base steel. Although the hydrogen diffusivity of JIS-SUS630 was two orders of magnitude larger than that of JIS-SUS304, the effective hydrogen diffusivity of the coated JIS-SUS630 was nearly equal to that of the coated SUS304. In our previous study with secondary-mass ion spectroscopy (SIMS), the coating’s excellent resistance to hydrogen entry was attributed to interfacial hydrogen trapping between the aluminum and ferroaluminum layers. The experimental result obtained in this study suggested that the excellent resistance to hydrogen entry demonstrated by the developed coating can be attributed to the reduction in the permeation area induced by the interfacial trapping of hydrogen. The tensile tests of a smooth, round-bar specimen and fatigue tests of a circumferentially notched specimen with exposure to 100-MPa hydrogen gas at 270°C were performed in air at room temperature (RT). The test results showed that the tensile and fatigue properties of the coated specimens were not degraded by hydrogen exposure, whereas those for the non-coated specimens were significantly degraded. Hydrogen-pressure cycle tests of the coated, tubular specimens with an inner notch were also carried out with 95-MPa hydrogen gas at 85°C, demonstrating that the fatigue life of the tubular specimen was improved by the developed coating.

Hydrogen Uptake, Tensile, and Fatigue Properties of a Barrier-Coated, Precipitation-Hardened Martensitic Stainless Steel With Exposure to High-Pressure Hydrogen Gas

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Junichiro Yamabe ◽  
Saburo Matsuoka
Keyword(s):  
Stainless Steel ◽  
Secondary Ion Mass Spectrometry ◽  
Martensitic Stainless Steel ◽  
Hydrogen Uptake ◽  
Tensile Tests ◽  
Fatigue Tests ◽  
Hydrogen Gas ◽  
Fatigue Properties ◽  
Hydrogen Trapping ◽  
Pressure Cycle

Abstract Hydrogen uptake, tensile, and fatigue properties of a precipitation-hardened martensitic stainless steel with a newly developed coating (alumina/aluminum/Fe–Al) were presented. The developed coating had an excellent resistance to hydrogen entry in 100-MPa hydrogen gas at 270 °C. Measurements of bulk and local hydrogen by thermal desorption analysis and secondary-ion mass spectrometry (SIMS) suggested that the excellent resistance was attributed to the reduction in permeation areas by interfacial hydrogen trapping between the aluminum and Fe–Al layers. Tensile tests of a smooth, round-bar specimen, and fatigue tests of a circumferentially notched specimen after exposure to 100-MPa hydrogen gas at 270 °C were performed in air at room temperature (RT). These properties of the coated specimens were not degraded by hydrogen exposure, whereas those of the noncoated specimens were significantly degraded. Hydrogen-pressure cycle tests of coated, tubular specimens with an inner notch in 95-MPa hydrogen gas at 85 °C also demonstrated that the fatigue life was improved by the coating.

Fatigue Lives of a Ferritic Stainless Steel Containing Deformation Twins

2007 ◽  
Vol 353-358 ◽  
pp. 283-286 ◽  
Author(s):  
T. Taniguchi ◽  
Yoshihisa Kaneko ◽  
Satoshi Hashimoto
Keyword(s):  
Stainless Steel ◽  
Twin Boundary ◽  
Ferritic Stainless Steel ◽  
Dislocation Structure ◽  
Deformation Twin ◽  
Fatigue Cracking ◽  
Tensile Tests ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Deformation Twins

The fatigue properties of ferritic stainless steel containing deformation twins were investigated. Monotonic tensile tests and push-pull fatigue tests were conducted on the specimens both with and without twins. Fatigue lives of the twinned specimens were about four times shorter than those without the deformation twins, although yield stresses of both specimens were almost equal. It was found that the fatigue cracking along the deformation twin boundaries caused the reduction in fatigue life. Dislocation structure observation using the ECCI method revealed that no specific dislocation structure was formed near the cracked deformation twin boundary, although the ladder-like PSB structure was developed along an annealing twin boundary in an austenitic stainless steel.

Experimental and Simulation Study on Effective Hydrogen Diffusivity of Cold-Worked Type-304 Austenitic Stainless Steel

2019 ◽  
Author(s):  
Jean-Gabriel Sezgin ◽  
Daichi Takatori ◽  
Junichiro Yamabe
Keyword(s):  
Stainless Steel ◽  
Rolling Direction ◽  
Hydrogen Gas ◽  
Ebsd Analysis ◽  
Inhomogeneous Distribution ◽  
Hydrogen Diffusivity ◽  
Α Phase ◽  
Cold Rolled ◽  
Type 304 ◽  
Effective Hydrogen

Abstract This study presents some measurements of the effective hydrogen diffusivity in a cold-rolled, Type-304 stainless steel. Steel plates rolled under various cold working (CW) ratios were prepared. Disk specimens, referred to as LT and SL specimens, were sampled from the plates to determine the diffusivity. The rolling direction is perpendicular to the thickness direction for LT specimens and parallel for the SL specimens. Fraction and distribution of α′ phase islands resulting from strain-induced martensite were characterized by electromagnetic induction (EMI) method and electron backscatter diffraction (EBSD) analysis, respectively. The diffusivity of the LT and SL specimens exposed to high-pressure hydrogen gas was determined experimentally through desorption methods. Hydrogen permeation tests for LT and SL specimens were simulated using the finite element method (FEM) by considering a model material containing an inhomogeneous distribution of α′ phase islands. The EMI measurements established that the fraction of the α′ phase increases with the CW ratio. The phase maps from the EBSD analysis revealed an important difference in α′ phase distribution on planes perpendicular and parallel to the rolling direction (LT and SL planes). For CW = 60%, the diffusivity of the SL specimen was five times larger as compared to the LT specimen, although the fraction of the α′ phase is equal. The simulation of the permeation tests also showed a strong difference in the diffusivity between both specimens, and therefore supports the experimental results. Both experiments and simulations suggested that the anisotropic nature of the effective hydrogen diffusivity (in LT and SL specimens) could be attributed to the inhomogeneous distribution of the α′ phase islands in the cold-rolled material.

scholarly journals Changing in Fatigue Life of 300 M Bainitic Steel After Laser Carburizing and Plasma Nitriding

2018 ◽  
Vol 165 ◽  
pp. 21002 ◽  
Author(s):  
Antonio J. Abdalla ◽  
Douglas Santos ◽  
Getúlio Vasconcelos ◽  
Vladimir H. Baggio-Scheid ◽  
Deivid F. Silva
Keyword(s):  
Mechanical Properties ◽  
Fatigue Life ◽  
Plasma Nitriding ◽  
Fatigue Behavior ◽  
High Strength ◽  
Tensile Tests ◽  
Steel Sample ◽  
Fatigue Tests ◽  
300M Steel ◽  
Structural Applications

In this work 300M steel samples is used. This high-strength steel is used in aeronautic and aerospace industry and other structural applications. Initially the 300 M steel sample was submitted to a heat treatment to obtain a bainític structure. It was heated at 850 °C for 30 minutes and after that, cooled at 300 °C for 60 minutes. Afterwards two types of surface treatments have been employed: (a) using low-power laser CO2 (125 W) for introducing carbon into the surface and (b) plasma nitriding at a temperature of 500° C for 3 hours. After surface treatment, the metallographic preparation was carried out and the observations with optical and electronic microscopy have been made. The analysis of the coating showed an increase in the hardness of layer formed on the surface, mainly, among the nitriding layers. The mechanical properties were analyzed using tensile and fatigue tests. The results showed that the mechanical properties in tensile tests were strongly affected by the bainitic microstructure. The steel that received the nitriding surface by plasma treatment showed better fatigue behavior. The results are very promising because the layer formed on steel surface, in addition to improving the fatigue life, still improves protection against corrosion and wear.

Fatigue Properties of 3D Welded Thin Structures

2020 ◽  
Author(s):  
Seyed M. Allameh ◽  
Avery Lenihan ◽  
Roger Miller ◽  
Hadi Allameh
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Fatigue Testing ◽  
Interfacial Area ◽  
Tensile Tests ◽  
Orientation Dependence ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Mig Welding ◽  
Welded Structures

Abstract Additive manufacturing technology has matured enough to produce real industrial components. A newer method of 3D printing is the deposition of molten metal beads using a MIG weld torch. This involves a 3D printer equipped with a MIG torch layering the metals in desired shapes. It allows the fabrication of components made of MIG weld wires, currently available from various elements including Cu, Al, steel and alloys. Some of these structures made by 3D welding will have applications in critical load bearing conditions. The reliability of such components will be vital in applications where human lives are at stake. Tensile tests are conducted to verify the required strength of the fabricated parts which will undergo monotonic loading; however, fatigue tests are required for cases where cyclic loading will take place. Conventional tensile and fatigue testing requires macro-scale samples. With MIG welding, it is possible to make thin-walled structures. Fatigue testing on samples extracted from thin walls is made possible by microtesting. This study is focused on the mechanical properties of 3D welded structures made from MIG welding wires. Our earlier results showed orientation dependence of mechanical properties in 3D welded structures. They also showed the effect of substrates in expression of the orientation dependence. Welding on metal substrate produces weld beads that are harder at the substrate interfacial area. However, for structures welded on ceramics, the opposite is true. They exhibit a softer substrate interfacial area and a relatively harder top. Our newer results show fatigue properties of structures made by 3D welding. Microsamples measuring 0.2 mm × 0.2 mm × 1.0 mm were extracted from metal beads using a CNC mill along with an EDM. The contours of the samples were machined by milling and the back side was cut by electro discharge machining. Specimens were then polished to the desired size and mounted in the grippers of an E1000 Instron load frame. WaveMatrix® application software from Instron was used to control the machine and to obtain testing data. Fatigue tests were performed, and life cycles were determined for various stress levels up to over 5 million cycles. The preliminary results of tensile tests of these samples show strength levels that are comparable to those of parent metal, in the range of 600–950MPa. Results of fatigue tests show high fatigue lives associated with relatively high stresses. The preliminary results will be presented and the implications of the use of 3D welded rebar in 3D printing of reinforced concrete structures will be discussed.

scholarly journals On the Microstructures and Fatigue Behaviors of 316L Stainless Steel Metal Injection Molded with Gas- and Water-Atomized Powders

Metals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 893 ◽  
Author(s):  
Yongyun Zhang ◽  
Ensheng Feng ◽  
Wei Mo ◽  
Yonghu Lv ◽  
Rui Ma ◽  
...  
Keyword(s):  
Stainless Steel ◽  
316L Stainless Steel ◽  
Fatigue Cracks ◽  
Selective Laser Sintering ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Metal Injection Molding ◽  
Strengthening Effect ◽  
Lower Oxygen ◽  
Order Of Magnitude

316L stainless steel samples are fabricated by metal injection molding using water-atomized and gas-atomized powder with different oxygen contents. The influences of oxygen on the microstructural evolution and fatigue properties of the samples are investigated. The oxygen tends to react with Mn and Si to form oxide particles during sintering. The oxides hamper the densification process and result in decreased sintered density. Moreover, their existence reduces the Mn and Si dissolving into the base metal and compromises the solution strengthening effect. The oxides lead to stress concentration in the tensile and fatigue tests and become the initiation sites of fatigue cracks. After sintering, the samples made from the gas-atomized powder have a much lower oxygen content compared to those made from the water-atomized powder, therefore, exhibiting much better mechanical properties. The tensile strength, yield strength and the elongation of the samples made from the gas-atomized powder are 560 MPa, 205 MPa, and 58%, respectively. Their fatigue lives are about one order of magnitude longer than the samples made from water-atomized powder, and also longer than those fabricated by powder metallurgy and selective laser sintering which were reported in other studies.

Fatigue Properties of Al-Li Plates Joined by Friction Stir Welding

2008 ◽  
Vol 385-387 ◽  
pp. 849-852 ◽  
Author(s):  
Pasquale Cavaliere ◽  
Francesco W. Panella ◽  
Antonio Squillace
Keyword(s):  
Mechanical Properties ◽  
Cross Sections ◽  
Testing Machine ◽  
Rolling Direction ◽  
Tensile Tests ◽  
Fatigue Tests ◽  
Control Mode ◽  
Fatigue Properties ◽  
Amplitude Control ◽  
Friction Stir

Al-Li alloys are characterized by a strong anisotropy in mechanical properties and microstructure with respect to the rolling direction. Plates of 2198 Al-Li alloy were friction stir welded by employing maximum rotation speed: 1000 rev/min and welding speed of 80 mm/min, both in parallel and orthogonal directions with respect to the rolling one. The joints mechanical properties were evaluated by means of tensile tests at room temperature. In addition, fatigue tests performed with a resonant electro-mechanical testing machine under constant amplitude control up to 250 Hz loading, were conducted in axial control mode with R(σmin/σmax)=0.33, for all the welding and rotating speed conditions. The fatigue crack propagation experiments were performed by employing single edge notched specimens.With the aim to characterize the weld performances, both the microstructure evolution at jointed cross sections, related to the welding variables, and the fractured surfaces were respectively analyzed by means of optical and scanning electron microscopy.

Effect of Thermal Exposure on Tensile and Fatigue Properties of Clay Reinforced Nylon Nanocomposites

2015 ◽  
Vol 833 ◽  
pp. 52-55
Author(s):  
Yukiko Nakahara ◽  
Yusuke Kodama ◽  
Shi Jie Zhu ◽  
Arimitsu Usuki ◽  
Makoto Kato
Keyword(s):  
Tensile Strength ◽  
Room Temperature ◽  
Thermal Exposure ◽  
Tensile Tests ◽  
Nylon 6 ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Oxidation Treatment ◽  
Exposure Temperature ◽  
Matrix Nanocomposite

In this paper, both nylon 6 and 2 wt% clay reinforced nylon 6 matrix nanocomposite were used for thermal exposure tests at temperatures of 80 oC and 120 oC and 150 oC, respectively. Then, the tensile tests and fatigue tests of the exposed specimens were conducted at room temperature. It was shown that the tensile strength in both nylon 6 and NCH-2 decreased with an increase in thermal exposure temperature. The brittle fracture occurred in the specimens exposed at 120 oC and 150 oC. After pre-oxidation treatment at 80 °C for 100 hours, the fatigue strength decreased 14% in nylon 6, and 8% in NCH-2. From this result, it was understood that the addition of clay in nylon 6 could suppress the decrease of fatigue strengths.

scholarly journals Usage of Ti-surface-modified filler material to increase the joint strength of High-Strength Low Alloyed (HSLA) steels under different load types

2020 ◽  
Vol 2 (12) ◽  
Author(s):  
Kai Treutler ◽  
Volker Wesling
Keyword(s):  
Dynamic Load ◽  
Base Material ◽  
High Strength ◽  
Tensile Tests ◽  
Fatigue Tests ◽  
Structural Steels ◽  
Titanium Coating ◽  
Fine Grained ◽  
Weld Toe ◽  
Load Types

AbstractWelding-related loss of strength, especially in the case of fatigue, significantly reduces the range of applications for high-strength fine-grained structural steels. In order to counteract this situation, the aim of the work is to increase the strength of welded joints made of high-strength fine-grained structural steels by using coated welding consumables. This is described using the example of a titanium coating for quasi-static and abrupt dynamic load and fatigue. The thermomechanical rolled fine-grained structural steel S700MC is used as the base material, using a welding filler of the same type. MAG welding was used to produce the fillet welds on a T-joint. In addition to tensile tests at four different load speeds up to 2 m/s, the results of fatigue tests are presented. In addition, the microstructure of the weld seams is examined by metallographic methods and the scanning electron microscope. A comparison with two joints from an unmodified variant and another steel grade with comparable properties (S690QL) serves to classify the results. It is shown that the use of modified filler metals has a significant influence on the overall strength of the welded joint due to the rounding of the weld toe. Thus, the fatigue strength can be increased by around 50%. In addition, the strength under sudden dynamic load can be increased by 10%.

Mechanical Properties of a New Nitrogen-Strengthened Stainless Steel With Reduced Amount of Ni and Mo in High Pressure Gaseous Hydrogen

2013 ◽  
Author(s):  
Kazuhisa Matsumoto ◽  
Shinichi Ohmiya ◽  
Hideki Fujii ◽  
Masaharu Hatano
Keyword(s):  
High Pressure ◽  
Stainless Steel ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
High Strength ◽  
Hydrogen Gas ◽  
Fracture Surfaces ◽  
Growth Properties ◽  
Pressure Hydrogen

To confirm a compatibility of a newly developed high strength stainless steel “NSSC STH®2” for hydrogen related applications, tensile and fatigue crack growth properties were evaluated in high pressure hydrogen gas up to 90MPa. At temperatures between −40 and 85°C, no conspicuous deterioration of tensile properties including ductility was observed even in 90 MPa hydrogen gas at −40°C while strength of STH®2 was higher than SUS316L. Although a slight drop of reduction of area was recognized in one specimen tested in 90 MPa hydrogen gas at −40°C, caused by the segregation of Mn, Ni and Cu in the laboratory manufactured 15mm-thick plate, it was considerably improved in the large mill products having less segregation. Fatigue crack growth rates of STH®2 in high pressure hydrogen gas were almost the same as that of SUS316L in air. Although fatigue crack growth rate in air was considerably decelerated and lower than that in hydrogen gas at lower ΔK region, this was probably caused by crack closure brought by oxide debris formed on the fracture surfaces near the crack tip by the strong contact of the fracture surfaces after the fatigue crack was propagated. By taking the obtained results into account, it is concluded that NSSC STH®2 has excellent properties in high pressure hydrogen gas in addition to high strength compared with standard JIS SUS316L.

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