scholarly journals Development and Comparison of Quantitative Phase Analysis for Duplex Stainless Steel Weld

2018 ◽  
Vol 62 (3) ◽  
pp. 247-253 ◽  
Author(s):  
Balázs Varbai ◽  
Timothy Pickle ◽  
Kornél Májlinger
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Heat Affected Zone ◽  
Heat Input ◽  
Welding Process ◽  
Phase Ratio ◽  
Quantitative Phase Analysis ◽  
Point Count ◽  
Count Method ◽  
Point Count Method

In duplex stainless steels the ideally 1:1 ratio of austenite-to-ferrite phases ensures the outstanding mechanical and corrosion properties compared to other, conventional stainless steel grades. However, this phase balance can be easily shifted to a mostly austenitic or mostly ferritic microstructures, depending on the welding process and heat input. In order to determine the phase ratio, several methods are available to use, such as Feritscope measurements, ASTM E562 manual point count method (on metallographic images) or quantitative image analysis. From these methods, Feritscope measurements cannot be applied to determine phase quantification in the narrow heat affected zone of duplex stainless steel welds – because of the very limited heat input. The manual point count method is very dependent of the assessor and cannot be automated. In this paper a histogram-based image analyzing process was developed, using Beraha's etchant solution. The results were compared to Feritscope measurements and a very good correlation (R2 = 0.9995) was found. This method will give the ability to easily and automatically measure phase ratio in weld metal, heat affected zone or in subsurface regions of multi-pass welds.

scholarly journals Corrosion Behavior of Welded Joints in Different Stainless Steels

2001 ◽  
Vol 71 (3) ◽  
pp. 440-449
Author(s):  
Eniko Reka Fabian ◽  
Janos Kuti ◽  
Jozsef Gati ◽  
Laszlo Toth
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Pitting Corrosion ◽  
Stainless Steels ◽  
Heat Affected Zone ◽  
Welding Speed ◽  
Welded Joints ◽  
Heat Input ◽  
Laser Power ◽  
Base Material

The welded metals characteristics produced by TIG welding or laser beam welding depend on heat input as a function of laser power and welding speed. High laser power and high welding speed have produced welded joint with a remarkable decrease in fusion zone size and an acceptable weld profile with high weld depth/width ratio. At duplex stainless steels the microstructure of welded metal, and heat affected zone is strongly influenced by cooling rate, which is depend on heat input as a function of laser power and/or welding speed. It was found that increasing welding speed the corrosion rate of welded joints decreased. In austenitic stainless steels appeared pitting corrosion in the base material as well as in the welding zone. In case of 2304 duplex stainless steel pitting corrosion appeared in welded metal and heat affected zone in case of autogenously welding, but at 2404 duplex stainless steel pitting appear more in the heat affected zone.

Welding Technology of Ultra-Low Carbon and Nitrogen Ferrite Stainless Steel

2010 ◽  
Vol 654-656 ◽  
pp. 354-357
Author(s):  
Bao Sen Wang ◽  
Shuang Chun Zhu ◽  
Xia Ning Ye
Keyword(s):  
Stainless Steel ◽  
Heat Affected Zone ◽  
Heat Input ◽  
Welding Process ◽  
Low Carbon ◽  
Carbon And Nitrogen ◽  
Welding Joint ◽  
High Toughness ◽  
Process Gas ◽  
Welding Technology

Weldability of ultra low carbon and nitrogen, low chromium ferrite stainless steel is analysed by using Thermol-cal software and welding metallurgy. Eembrittlement of welding joint is the failure reason during application of ultra low carbon and nitrogen 12% chromium FSS. Comparing welding joint performance of different welding process, Gas Metal Arc Weldinng with high toughness welding material and proper welding heat input is economical and feasible welding process. Controlling growth of ferrite grain is the key to improve toughness of the heat affected zone (HAZ). Presence of titanium carbides or nitrides and the amount of martensite located along ferrite grain intergranular boundaties are very important for toughness of HAZ in low chromium FSS. It was found that the best size of Ti(C/N) grain is 2-5μm and content of martensite is 40%.

Influence of Thermal Simulated and Real Tandem Submerged Arc Welding Process on the Microstructure and Mechanical Properties of the Coarse Grained Heat Affected Zone

2011 ◽  
Vol 110-116 ◽  
pp. 3191-3198
Author(s):  
Sadegh Moeinifar
Keyword(s):  
Grain Boundaries ◽  
Heat Affected Zone ◽  
Heat Input ◽  
Arc Welding ◽  
Welding Process ◽  
Submerged Arc Welding ◽  
Rolled Plate ◽  
Arc Welding Process ◽  
Submerged Arc ◽  
Tandem Submerged Arc Welding

The high-strength low-alloy microalloyed steel was procured as a hot rolled plate with accelerated cooling. The Gleeble thermal simulated process involved heating the steel specimens to the peak temperature of 1400 °C, with constant cooling rates of 3.75 °C/s and 2 °C/s to room temperature. The four-wire tandem submerged arc welding process, with different heat input, was used to generate a welded microstructure. The martensite/austenite constituent appeared in the microstructure of the heat affected zone region for all the specimens along the prior-austenite grain boundaries and between bainitic ferrite laths. The blocky-like and stringer martensite/austenite morphology were observed in the heat affected zone regions. The martensite/austenite constituents were obtained by a combination of field emission scanning electron microscopes and image analysis software The Charpy absorbed energy of specimens was assessed using Charpy impact testing at-50 °C. Brittle particles, such as martensite/austenite constituent along the grain boundaries, can make an easy path for crack propagation. Similar crack initiation sites and growth mechanism were investigated for specimens welded with different heat input values.

METALLURGICAL AND CORROSION CHARACTERIZATION OF POST WELD HEAT TREATED DUPLEX STAINLESS STEEL (UNS S31803) JOINTS BY FRICTION WELDING PROCESS

2016 ◽  
Vol 23 (03) ◽  
pp. 1650013 ◽  
Author(s):  
MOHAMMED ASIF M. ◽  
KULKARNI ANUP SHRIKRISHNA ◽  
P. SATHIYA
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Friction Welding ◽  
Volume Fraction ◽  
Welding Process ◽  
Equilibrium Temperature ◽  
Weld Interface ◽  
Heat Treated ◽  
Weld Heat

The present study focuses on the metallurgical and corrosion characterization of post weld heat treated duplex stainless steel joints. After friction welding, it was confirmed that there is an increase in ferrite content at weld interface due to dynamic recrystallization. This caused the weldments prone to pitting corrosion attack. Hence the post weld heat treatments were performed at three temperatures 1080[Formula: see text]C, 1150[Formula: see text]C and 1200[Formula: see text]C with 15[Formula: see text]min of aging time. This was followed by water and oil quenching. The volume fraction of ferrite to austenite ratio was balanced and highest pit nucleation resistance were achieved after PWHT at 1080[Formula: see text]C followed by water quench and at 1150[Formula: see text]C followed by oil quench. This had happened exactly at parameter set containing heating pressure (HP):40 heating time (HT):4 upsetting pressure (UP):80 upsetting time (UP):2 (experiment no. 5). Dual phase presence and absence of precipitates were conformed through TEM which follow Kurdjumov–Sachs relationship. PREN of ferrite was decreasing with increase in temperature and that of austenite increased. The equilibrium temperature for water quenching was around 1100[Formula: see text]C and that for oil quenching was around 1140[Formula: see text]C. The pit depths were found to be in the range of 100[Formula: see text]nm and width of 1.5–2[Formula: see text][Formula: see text]m.

scholarly journals KEANEKARAGAMAN JENIS BURUNG DI KAWASAN HUTAN LINDUNG GUNUNG SIRIMAU

2017 ◽  
Vol 1 (3) ◽  
pp. 247
Author(s):  
John F. Sahusilawane
Keyword(s):  
Bird Species ◽  
Bird Diversity ◽  
Mountain Forests ◽  
Point Count ◽  
Red Eye ◽  
Count Method ◽  
Protected Forests ◽  
Point Count Method ◽  
Habitat Variables

This study was conducted to determine the composition of bird diversity and vegetation stages and composition, to determine the variables that most influence the diversity of birds in protected forests Sirimau, This study was conducted for three months from September 2015 to November 2015. Bird observations and habitat variables performed using the Point Count method, and found thirty observation points at each location, with 30 cm trellis and 200 m plot distance. The analysis of birds and vegetation in Sirimau mountain forests shows that, bird species are dominated by Red Eye (Aplonis Motalica), and more than 50 species of vegetation exist in the research location, dominated by fruits.  

Sign in / Sign up

Export Citation Format

Share Document