Impact Strength of Austenitic Stainless-Steel Welds at −320 F—Effects of Composition, Ferrite Content, and Heat-Treatment

1966 ◽  
Vol 88 (1) ◽  
pp. 33-36 ◽  
Author(s):  
F. W. Bennett ◽  
C. P. Dillon
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Impact Strength ◽  
Stress Relief ◽  
304 Stainless Steel ◽  
Ferrite Content ◽  
310 Stainless Steel ◽  
Steel Welds ◽  
The Impact

A statistical evaluation has been made of the effect of weld rod composition, ferrite content, and heat-treatment upon the impact strength of certain austenitic stainless-steel welds in 304 stainless-steel plate at −320 F. The data indicate that suitable and approximately equivalent properties are obtained with 310 stainless-steel rod in the as-welded condition, type 308 stainless-steel rod in the as-welded condition (ferrite less than 6 percent), and 308L stainless-steel rod either as-welded or stress-relieved at 1750 F (ferrite less than 9 percent). The impact resistance of 310 stainless steel is adversely affected by stress relief, apparently due to carbide precipitation in this alloy. The 308 and 308L stainless-steel rods are both adversely affected by a stress relief at 1550 F, indicative of sigma formation. The carbon content in 308 stainless-steel rods apparently is not a major factor, as indicated by the lack of adverse effects with a 1750 F stress relief, from which the rate of cooling through the sensitizing range of 800 to 1500 F is identical with that in the 1500 F stress relief. The basic practical conclusion to be drawn from these data is that regular carbon 304 stainless steel welded with 308L stainless-steel rod can be used in cryogenic applications, and that the decision as to whether to stress relieve or not may be left to the mechanical engineer, subject only to the stipulation of a minimum stress-relieving temperature of 1750 F.

scholarly journals Microstructure and Mechanical Properties of Heat-Affected Zone of Repeated Welding AISI 304N Austenitic Stainless Steel by Gleeble Simulator

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 773
Author(s):  
Y.H. Guo ◽  
Li Lin ◽  
Donghui Zhang ◽  
Lili Liu ◽  
M.K. Lei
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Impact Energy ◽  
Heat Affected Zone ◽  
Ferrite Content ◽  
Equipment Safety ◽  
Microstructure And Mechanical Properties ◽  
Δ Ferrite ◽  
The Impact

Heat-affected zone (HAZ) of welding joints critical to the equipment safety service are commonly repeatedly welded in industries. Thus, the effects of repeated welding up to six times on the microstructure and mechanical properties of HAZ for AISI 304N austenitic stainless steel specimens were investigated by a Gleeble simulator. The temperature field of HAZ was measured by in situ thermocouples. The as-welded and one to five times repeated welding were assigned as-welded (AW) and repeated welding 1–5 times (RW1–RW5), respectively. The austenitic matrices with the δ-ferrite were observed in all specimens by the metallography. The δ-ferrite content was also determined using magnetic and metallography methods. The δ-ferrite had a lathy structure with a content of 0.69–3.13 vol.%. The austenitic grains were equiaxial with an average size of 41.4–47.3 μm. The ultimate tensile strength (UTS) and yield strength (YS) mainly depended on the δ-ferrite content; otherwise, the impact energy mainly depended on both the austenitic grain size and the δ-ferrite content. The UTS of the RW1–RW3 specimens was above 550 MPa following the American Society of Mechanical Engineers (ASME) standard. The impact energy of all specimens was higher than that in ASME standard at about 56 J. The repeated welding up to three times could still meet the requirements for strength and toughness of welding specifications.

Effects of heat treatment on the microstructure and metallurgical properties of the explosively bonded 304 stainless steel—CK45 steel

2016 ◽  
Vol 27 (4) ◽  
pp. 488-506 ◽  
Author(s):  
Mohammadreza Khanzadeh Gharah Shiran ◽  
Seyyed Javad Mohammadi Baygi ◽  
Seyed Rahim Kiahoseyni ◽  
Hamid Bakhtiari ◽  
Mohsen Allah Dadi
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Steel Plates ◽  
Standoff Distance ◽  
304 Stainless Steel ◽  
Grain Sizes ◽  
Heat Treated ◽  
Vortex Nature ◽  
Impact Kinetic Energy ◽  
The Impact

In this research, the effects of heat treatment are studied on the microstructure and mechanical properties of the explosive bonding of 304 stainless steel plates and CK45 carbon steel with a constant explosive load and various standoff distances. The samples are heat treated in a furnace for 2-h and 4-h at 250℃ and 350℃. The results imply that by increasing the standoff distance from 4 to 5 mm, the impact kinetic energy increases and severe plastic deformation occurs in the bonding interface. The metallography results indicate the wave-vortex nature of the interface with the increase of standoff distance. In addition, heat treatment for 2 h at 350℃ leads to an increase in the thicknesses of intermetallic compounds in the interface. Also, the hardness decreases from 271 to 171 Vickers, and from 279 to 195 Vickers with 2 h of heat treatment at 350℃ in samples with standoff distances of 4 and 5 mm, respectively. Furthermore, the strengths of the samples decrease from 449 to 371 MPa, and from 510 to 433 MPa, respectively. Hardness and strength changes occur due to changes in the thickness of the intermetallic area and an increase in grain sizes.

scholarly journals Evolution of Microstructure and Residual Stress under Various Vibration Modes in 304 Stainless Steel Welds

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Chih-Chun Hsieh ◽  
Peng-Shuen Wang ◽  
Jia-Siang Wang ◽  
Weite Wu
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Stress Relief ◽  
304 Stainless Steel ◽  
Vibration Modes ◽  
Vibration Welding ◽  
Steel Welds ◽  
Evolution Of Microstructure ◽  
Relief Effect ◽  
Better Than

Simultaneous vibration welding of 304 stainless steel was carried out with an eccentric circulating vibrator and a magnetic telescopic vibrator at subresonant (362 Hz and 59.3 Hz) and resonant (376 Hz and 60.9 Hz) frequencies. The experimental results indicate that the temperature gradient can be increased, accelerating nucleation and causing grain refinement during this process. During simultaneous vibration welding primaryδ-ferrite can be refined and the morphologies of retainedδ-ferrite become discontinuous so thatδ-ferrite contents decrease. The smallest content ofδ-ferrite (5.5%) occurred using the eccentric circulating vibrator. The diffraction intensities decreased and the FWHM widened with both vibration and no vibration. A residual stress can obviously be increased, producing an excellent effect on stress relief at a resonant frequency. The stress relief effect with an eccentric circulating vibrator was better than that obtained using a magnetic telescopic vibrator.

Cyclic Crack Growth Rate of Irradiated Austenitic Stainless Steel Welds in Simulated BWR Environment

2011 ◽  
Author(s):  
Y. Chen ◽  
B. Alexandreanu ◽  
W. J. Shack ◽  
K. Natesan ◽  
A. S. Rao
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Crack Growth ◽  
Neutron Irradiation ◽  
Growth Rates ◽  
Reactor Core ◽  
Cracking Behavior ◽  
Steel Welds ◽  
The Impact ◽  
Crack Growth Rates

Reactor core internal components in light water reactors are subjected to neutron irradiation. It has been shown that the austenitic stainless steels used in reactor core internals are susceptible to stress corrosion cracking after extended neutron exposure. This form of material degradation is a complex phenomenon that involves concomitant conditions of irradiation, stress, and corrosion. Interacting with fatigue damage, irradiation-enhanced environmental effects could also contribute to cyclic crack growth. In this paper, the effects of neutron irradiation on cyclic cracking behavior were investigated for austenitic stainless steel welds. Post-irradiation cracking growth tests were performed on weld heat-affected zone specimens in a simulated boiling water reactor environment, and cyclic crack growth rates were obtained at two doses. Environmentally enhanced cracking was readily established in irradiated specimens. Crack growth rates of irradiated specimens were significantly higher than those of nonirradiated specimens. The impact of neutron irradiation on environmentally enhanced cyclic cracking behavior is discussed for different load ratios.

Microstructures in HAZ after Heat Treatment of Carbon Steel and Austenitic Stainless Steel Welds

2020 ◽  
Vol 985 ◽  
pp. 137-146
Author(s):  
Le Thi Nhung ◽  
Pham Mai Khanh ◽  
Nguyen Duc Thang ◽  
Bui Sy Hoang
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Carbon Steel ◽  
Austenitic Stainless Steel ◽  
Weld Metal ◽  
Carbon Diffusion ◽  
Peak Hardness ◽  
Dissimilar Welds ◽  
Fine Pearlite ◽  
Steel Welds

The influence of post weld heat treatments (PWHT) at 400°C, 600°C, 900°C on microstructures in heat affected zone (HAZ) of dissimilar welds between carbon steel and austenitic stainless steel was studied. As-welded condition, the fully Martensitic layer along the fusion line, Widmanstatten Ferrite, Bainite, Pearlite phases in the HAZ of carbon side and the fully austenitic zone in the weld metal can be observed. After PWHT, the microstructures of these zones were dramatically modified as a result of carbon diffusion from the carbon steel toward the weld metal. Decarburization of the base metal led to the formation of a zone with large Ferrite grains. Bainite or fine Pearlite were formed by carbon diffused to both the interfacial Martensite and the purely Austenite zone. The lowest hardness value in the decarburization zone was 92HV on average after PWHT at 900°C and the peak hardness value that was documented in the carburize zone with 366HV at 600°C. Carbides precipitation (M23C6, M7C3) were found in both the HAZ of carbon steel and austenitic stainless steel.

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