Effect of dissolved oxygen concentration on stress corrosion cracking behavior of pre-corroded X100 steel base metal and the welded joint in wet–dry cycle conditions

2020 ◽  
Vol 77 ◽  
pp. 103264
Author(s):  
Ke Gong ◽  
Ming Wu ◽  
Fei Xie ◽  
Guangxin Liu
Keyword(s):  
Dissolved Oxygen ◽  
Stress Corrosion ◽  
Oxygen Concentration ◽  
Base Metal ◽  
Stress Corrosion Cracking ◽  
Welded Joint ◽  
Corrosion Cracking ◽  
Dissolved Oxygen Concentration ◽  
Cracking Behavior ◽  
Steel Base

Probing the stress corrosion cracking resistance of laser beam welded AISI 316LN austenitic stainless steel

2020 ◽  
pp. 095440622096563
Author(s):  
R Rajasekaran ◽  
AK Lakshminarayanan
Keyword(s):  
Electron Microscopy ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Laser Beam ◽  
Stress Corrosion ◽  
Base Metal ◽  
Stress Corrosion Cracking ◽  
Welded Joint ◽  
Corrosion Cracking ◽  
Time To Failure

The stress corrosion cracking (SCC) resistance of the laser beam welded (LBW) AISI 316LN austenitic stainless steel (SS) was assessed and compared to the base metal (BM). The weld joint was produced using a 2.5 kW laser power source at 1500 mm/min welding speed. Microstructural characterization of the base metal and weld joint were done by the following techniques: (i) Optical Microscopy (OM), (ii) Scanning Electron Microscopy (SEM) and (iii) Transmission Electron Microscopy (TEM). The primary mechanical properties such as strength, toughness and hardness of the welded joint were evaluated and compared with the base metal. Stress Corrosion Cracking (SCC) assessment was done in boiling 45 wt% MgCl2 solution at constant load condition as per American Society for Testing and Materials (ASTM) standard G36-94. From the SCC experiment data, steady-state elongation rate ([Formula: see text]), transition time ([Formula: see text]) and time to failure ([Formula: see text]) were found and generalized equations to predict the time to failure of the base metal and LBW joint were successfully derived. The passive film rupture mechanism majorly influenced the SCC failure for 316LN and welded joint. The formation of the discontinuous δ-ferrite network, residual stress and nitrogen pore nucleation at the fusion zone of the LBW joint deteriorated the SCC resistance. The metallographic and fractographic studies revealed brittle transgranular SCC failure of the base metal as well as the LBW joint in all the stress conditions.

Influence of Ultrasonic Nanocrystal Surface Modification on the Corrosion and Stress Corrosion Cracking Behavior of Low Carbon Steel (ASTM A139) Welded Joint in the Simulated District Heating Environment

CORROSION ◽  
10.5006/2429 ◽  
2017 ◽  
Vol 74 (1) ◽  
pp. 112-122 ◽  
Author(s):  
Yong-Sang Kim ◽  
Woo-Cheol Kim ◽  
Jung-Gu Kim
Keyword(s):  
Surface Modification ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Welded Joint ◽  
Low Carbon Steel ◽  
District Heating ◽  
Corrosion Cracking ◽  
Low Carbon ◽  
Cracking Behavior ◽  
Heating Water

The effect of ultrasonic nanocrystal surface modification (UNSM) on the corrosion and stress corrosion cracking behavior of low carbon steel (ASTM A139) welded joint in the simulated district heating water (internal heating water) were investigated. After UNSM treatment, the microstructures of welded joint were transformed from the grain boundary ferrite and widmanstätten ferrite to polygonal ferrite accompanied by grain refinement. In electrochemical tests, the corrosion resistance of the welded joint was increased after UNSM treatment as a result of the grain refinement and improved stability of the oxide film. The stress corrosion cracking behavior was measured by slow strain rate tests with accelerated anodic and cathodic reactions. The results indicated that the UNSM treatment had a significant effect on the corrosion condition, whereas UNSM had no effect on hydrogen embrittlement.

Stress Corrosion Cracking Behavior of Tungsten Inert Gas Welded Age-Hardenable AA6061 Alloy

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Simge Gencalp Irizalp ◽  
Burcak Kardelen Koroglu
Keyword(s):  
Heat Treatment ◽  
Stress Corrosion ◽  
Base Metal ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
Inert Gas ◽  
Precipitate Morphology ◽  
Cracking Behavior ◽  
Particle Distributions ◽  
Aa6061 Alloy

The effects of two temper conditions (T4 and T6 heat treatments) upon the stress corrosion cracking (SCC) of AA6061 plates have been investigated in this work. AA6061 alloys were double-side-welded by the tungsten inert gas (TIG) welding method. SCC behavior of both the as-welded and as-received alloys was reported. Optical microscopy (OM) and scanning electron microscopy (SEM) were used to determine the precipitate structure of the thermal-altered zones and the base metal (BM), and also the hardness variations were examined using microhardness testing (Vickers hardness). The small-size precipitate structures in the T6 tempered alloy and the coarser precipitate structures in the T4 tempered alloy were found by microstructural investigations. As a result, T4 temper heat treatment of this alloy considerably reduced its susceptibility to stress corrosion cracks due to relatively coarse and more separate precipitate morphology. In welded specimens, SCC failure occurred in the area between the heat-affected zone (HAZ) and the base metal. Stress corrosion resistance in the fusion zone was strong in both temper conditions. The aim of this work was to obtain the effects of heat treatment and welding on SCC behavior of the age-hardenable aluminum alloy. The authors conclude that a deep insight into the SCC resistance of AA6061 alloy indicates the precipitate particle distributions and they are the key point for AA6061 alloy joints in chloride solution.

Studies on the influence of sodium hydroxide concentration on stress corrosion cracking behavior of P91 steel weldment

CORROSION ◽  
10.5006/3860 ◽  
2021 ◽  
Author(s):  
Anita Toppo ◽  
Sivai Bharasi N ◽  
C Das ◽  
R.P. George
Keyword(s):  
Weld Metal ◽  
Stress Corrosion ◽  
Sodium Hydroxide ◽  
Base Metal ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
Shielded Metal Arc Welding ◽  
P91 Steel ◽  
Cracking Behavior ◽  
Steel Weldment

Influence of sodium hydroxide (NaOH) concentration on the behavior of modified 9Cr- 1Mo (P91) steel weldment with respect to stress corrosion cracking (SCC) resistance was studied in this work. Weldment of P91 steel was prepared by shielded metal arc welding (SMAW) process using modified 9Cr- 1Mo electrode followed by weld heat treatment at 1033 K/1h. SCC experiments were carried out at 473 K at a strain rate (SR) of 1 × 10-6 s-1 in Millipore water (MP) (inert medium) as well as in 1, 2, 3 and 4 M sodium hydroxide (NaOH) medium. Ultimate tensile strength (UTS), yield strength (YS) and % total elongation (%TE) determined from stress-strain plots were found to decrease with increasing concentration of NaOH. SCC susceptibility index (Iscc) evaluated using UTS and % TE was highest for specimen tested in 4M NaOH. Number density of cracks determined by optical microscopy increased with the concentration of NaOH. Also, number of cracks was higher in the base metal than in the weld metal. At highest concentration of 4M NaOH, cracks were also observed in the heat affected zone (HAZ) of the weldmetal. Fractographic studies by Scanning electron microscopic (SEM) showed mixed mode from intergranular to transgranular cracking and vice versa at all concentrations of NaOH. Failure in the base metal was attributed to coarse precipitates, facilitating easy pitting at the precipitate /matrix interface. From the studies it was inferred that weld metal showed better resistance than base metal to SCC in 1-4 M NaOH concentrations.

STUDY OF MICROSTRUCTURE AND STRESS CORROSION CRACKING BEHAVIOR IN WELDING TRANSITION ZONE OF Ni--BASED ALLOYS

2011 ◽  
Vol 46 (10) ◽  
pp. 1258-1266 ◽  
Author(s):  
Juan HOU ◽  
Qunjia PENG ◽  
SHOJI Testuo ◽  
Jianqiu WANG ◽  
Wei KE ◽  
...  
Keyword(s):  
Stress Corrosion ◽  
Transition Zone ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
Cracking Behavior
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