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.

The Effect of Cold Work on the Stress-Corrosion Cracking of Type 302 Austenitic Stainless Steel

CORROSION ◽  
1965 ◽  
Vol 21 (10) ◽  
pp. 327-331 ◽  
Author(s):  
P. J. GREELEY ◽  
V. J. RUSSO ◽  
R. K. SAXER ◽  
J. R. MYERS
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Stress Corrosion ◽  
Applied Stress ◽  
Stress Corrosion Cracking ◽  
Cold Work ◽  
Corrosion Cracking ◽  
Time To Failure ◽  
Annealed Material ◽  
Cold Worked

Abstract The effect of cold work on stress-corrosion cracking of Type 302 austenitic stainless steel wire exposed to boiling (154 C, 309 F) 42 weight-percent aqueous magnesium chloride solution was determined. Wire specimens of 0.02-in diameter were stressed in uniaxial tension using specially designed glass test cells containing the corrosive environment. Tests were conducted at five applied stresses over the range 10,000 to 30,000 psi with laboratory-annealed wire and as-received (bright-annealed) material which had been cold worked 10, 20 and 30 percent. It was established that: (1) failure generally occurred in the vapor phase above the boiling MgCl2 solution, (2) the time-to-failure varied inversely with the applied stress, (3) the 10 percent cold-worked material exhibited the shortest time-to-failure, and (4) the 30 percent cold-worked material had the maximum resistance to stress-corrosion cracking. The short times-to-failure recorded for the 10 percent cold-worked material were attributed to introduction of large amounts of localized residual stresses in the bright-annealed material by the cold-working process. The longer times-to-failure associated with the more heavily cold-worked material were explained by the transformation of austenite to “quasi-martensite”. Crack propagation rates, nearly independent of the applied stress, were greatest for 10 percent cold-worked material. Average crack depth decreased with increasing degrees of applied stress and cold work. In general, a positive correlation existed between the crack density (cracks/inch) and the applied stress.

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