Stress corrosion property of 304 stainless steel and Q345 steel laser-MAG hybrid welded joints

2019 ◽  
Vol 34 (01n03) ◽  
pp. 2040057
Author(s):  
Hang Lv ◽  
Guoqing Gou ◽  
Zhenghong Fu ◽  
Wei Gao
Keyword(s):  
Stainless Steel ◽  
Crack Propagation ◽  
Stress Corrosion ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Corrosion Property ◽  
304 Stainless Steel ◽  
Propagation Path ◽  
Crack Propagation Path ◽  
Immersion Testing

The stress corrosion cracking (SCC) property of laser-MAG hybrid welded 304 stainless steel and Q345 steel was evaluated through cycle-immersion testing in 3.5 wt.% NaCl solution. The average SCC crack propagation rate of different zones under different initial stress intensity factors was calculated, and the SCC fracture and crack propagation path were observed. The microstructure and mechanical properties of the weld joint have also been examined. The result indicates that the fusion zone (FZ) is extremely prone to SCC. The average SCC crack propagation rate in FZ is [Formula: see text] mm/h, while no obvious SCC was found in the base metal (BM) and heat-affected zone (HAZ). The steel BM and HAZ may also suffer SCC, but not as fast as in FZ. Grooves caused by SCC were found on the fracture surface with a large amount of corrosion products accumulated close to the interface between the pre-crack section and SCC section. Crystallized-sugar-shaped pattern was found on the SCC zone of FZ. Crack jumping, deflection and crack closure occurred in the crack propagation path. Martensite on the FZ was considered to be the major reason that the FZ has a higher SCC propagation rate.

Application of J-Integral to High-Temperature Crack Propagation: Part I—Creep Crack Propagation

1979 ◽  
Vol 101 (2) ◽  
pp. 154-161 ◽  
Author(s):  
Shuji Taira ◽  
Ryuichi Ohtani ◽  
Takayuki Kitamura
Keyword(s):  
Stainless Steel ◽  
Crack Propagation ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
304 Stainless Steel ◽  
J Integral ◽  
Creep Crack ◽  
Controlling Parameter ◽  
Testing Environments ◽  
Type 304

Crack propagation tests in creep were carried out on 0.16 percent carbon steel at 400 and 500°C in air and at 400°C in vacuum, on Type 316 stainless steel at 600 and 650°C in air, and on Type 304 stainless steel at 650°C in air and vacuum. As a nonlinear fracture mechanics approach, the applicability of the creep J-integral for a controlling parameter of the crack propagation rate was investigated using a few types of specimens subjected to constant tensile loads. A good correlation was obtained between crack propagation rate and creep J-integral. Crack propagation rate was nearly proportional to the creep J-integral, and the relationship was almost independent on the width of plate specimens, the test temperatures, the testing environments, and the fracture mode. The creep crack propagation rate in round notched bar specimens was a little smaller than that in the center notched plate specimens at the same magnitude of the creep J-integral.

scholarly journals Crack Propagation Behavior of a Ni-Based Single-Crystal Superalloy during In Situ SEM Tensile Test at 1000 °C

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1047
Author(s):  
Wenxiang Jiang ◽  
Xiaoyi Ren ◽  
Jinghao Zhao ◽  
Jianli Zhou ◽  
Jinyao Ma ◽  
...  
Keyword(s):  
Crack Propagation ◽  
Tensile Test ◽  
Single Crystal ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Single Crystal Superalloy ◽  
Propagation Path ◽  
Propagation Behavior ◽  
Crack Propagation Behavior

An in situ scanning electron microscope (SEM) tensile test for Ni-based single-crystal superalloy was carried out at 1000 °C. The stress displacement was obtained, and the yield strength and tensile strength of the superalloy were 699 MPa and 826 MPa, respectively. The crack propagation process, consisting of Model I crack and crystallographic shearing crack, was determined. More interestingly, the crack propagation path and rate affected by eutectics was directly observed and counted. Results show that the coalescence of the primary crack and second microcrack at the interface of a γ/γ′ matrix and eutectics would make the crack propagation rate increase from 0.3 μm/s to 0.4 μm/s. On the other hand, crack deflection decreased the rate to 0.05 μm/s. Moreover, movement of dislocations in front of the crack was also analyzed to explain the different crack propagation behavior in the superalloy.

FATIGUE CRACK GROWTH BEHAVIOR OF STAINLESS STEEL COATED WITH TiN FILM

2012 ◽  
Vol 06 ◽  
pp. 282-287
Author(s):  
SATOSHI FUKUI ◽  
DAISUKE YONEKURA ◽  
RI-ICHI MURAKAMI
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Propagation ◽  
Crack Growth ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Crack Growth Behavior ◽  
Tin Film

In our previous study, we examined the influence of the fatigue properties of the stainless steel coated with TiN film and clarified the influence of TiN coating and the surface roughness on the fatigue property. In this study, the four point bending fatigue crack growth tests were carried out for martensitic stainless steel coated with TiN film deposited by arc ion plating method in order to investigate the effect of surface finishing on the fatigue crack behavior for film coated material. The fatigue crack growth behavior was evaluated using the replica method. As a result, the crack propagation rate of mirror polished specimens were lower than that of rough surface specimens. The crack propagation rate was especially decreased for TiN coatings deposited on the mirror polished substrate. The surface roughness near the crack initiation site increased after fatigue test. It concludes that the surface roughness of substrate influences crack propagation rate and the deposition of TiN film affected influenced crack propagation rate and fatigue strength when the surface roughness of substrate is small enough.

The Material Discontinuous Zone Influence on the Behavior of Crack Propagation in the Matrix Material

2013 ◽  
Vol 345 ◽  
pp. 263-267
Author(s):  
Zhi Jia Sun ◽  
You Tang Li
Keyword(s):  
Crack Propagation ◽  
Deflection Angle ◽  
Matrix Material ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Propagation Path ◽  
Propagation Behavior ◽  
The Matrix ◽  
The Deflection Angle ◽  
Simulation Results

A numerical method to simulate the crack propagation is presented in this paper. The FEM is used to estimate the influence of the material discontinuous zone on the propagation behavior of the crack placed in close to it in the matrix. The crack propagation paths in the matrix with different material discontinuous zone are simulated. The simulation results show that the crack propagation path will deviate toward the material discontinuous zone when the crack grows in closed to it and the property of the material discontinuous zone influences the deflection angle and the crack propagation rate.

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