Effect of Post-Weld Heat Treatment on Hardness in Superduplex Stainless Steel ASTM A890/A890M - Grade 6A

2020 ◽  
Vol 1012 ◽  
pp. 296-301
Author(s):  
Clélia Ribeiro de Oliveira ◽  
Eloá Lopes Maia ◽  
Solange T. da Fonseca ◽  
Marcelo Martins ◽  
Julián Arnaldo Ávila Díaz ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Arc Welding ◽  
Treatment Condition ◽  
Heat Treatment Condition ◽  
Shielded Metal Arc Welding ◽  
Metal Arc Welding ◽  
Superduplex Stainless Steel ◽  
Secondary Austenite ◽  
Welding Processes

Superduplex stainless steel alloy exhibit high mechanical and corrosion resistance, which main industrial application is in the petrochemical industry. The manufacture and maintenance of such equipment usually involve welding processes, followed by post-welded heat treatment and it often becomes impossible to apply heat treatments. Thereby, the purpose of this work is to verify the effect of a post-welded heat treatment on shielded metal arc welding in steel grade ASTM A890/A890M - grade 6A. The microstructure in the as-welded condition consisted of austenite, secondary austenite, and ferrite phases and, the post-welded heat treatment condition exhibited only austenite and ferrite. The hardness in the melt zone reached values of 300 HV after welding and, the value was reduced to 260 HV in the post-welded heat treatment condition.

scholarly journals A New Approach to the Study of Multi-Pass Welds–Microstructure and Properties of Welded 20-mm-Thick Superduplex Stainless Steel

2019 ◽  
Vol 9 (6) ◽  
pp. 1050 ◽  
Author(s):  
Maria Valiente Bermejo ◽  
Kjell Hurtig ◽  
Daniel Eyzop ◽  
Leif Karlsson
Keyword(s):  
Stainless Steel ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Secondary Phases ◽  
Σ Phase ◽  
Flux Cored Arc Welding ◽  
Welding Sequence ◽  
Superduplex Stainless Steel ◽  
Secondary Austenite ◽  
The Impact

Type 2507 superduplex stainless steel 20 mm in thickness was multi-pass-welded with Gas Metal Arc Welding (GMAW) and Flux-Cored Arc Welding (FCAW) processes. Recommended and higher arc energies and inter-pass temperatures were used. Thermal cycles were monitored using a recently developed procedure involving the successive instrumentation of the multi-pass welds, pass by pass, by addition of thermocouples in each weld pass. The repeatability of temperature measurements and survival rate of more than 90% of thermocouples confirmed the reliability of the procedure. Reheating by subsequent passes caused a progressive increase in the austenite content of the weld metal. The as-deposited GMAW passes with higher-than-recommended arc energy showed the lowest presence of nitrides. Therefore, the cooling rate—and not the time exposed at the critical temperature range—seems to be the key factor for nitride formation. The welding sequence layout also plays an important role in the distribution of secondary phases. A larger amount and concentration of secondary austenite and σ-phase was found for a larger number of subsequent passes in the immediate vicinity of a specific weld pass. The impact toughness exceeded requirements for all welds. Differences in absorbed energies were related to the amount of micro-inclusions found with the FCAW weld showing the lowest absorbed energies and highest amount of micro-inclusions. Pitting corrosion preferentially initiated in locations with secondary austenite and σ-phase. However, in the absence of these secondary phases, the HAZ containing nitrides was the weakest location where pitting initiated. The results of this work have implications on practical welding for superduplex stainless steels: the current recommendations on maximum arc energy should be revised for large thickness weldments, and the importance of the welding sequence layout on the formation of secondary phases should be considered.

scholarly journals Sensitization and Corrosion of 409M Ferritic Stainless Steel by Different Welding Processes

2019 ◽  
Vol 8 (2) ◽  
pp. 3904-3911
Keyword(s):  
Stainless Steel ◽  
Tensile Properties ◽  
Ferritic Stainless Steel ◽  
Arc Welding ◽  
Research Work ◽  
Chemical Exposure ◽  
Constant Current ◽  
Metal Arc Welding ◽  
Acidic Environments ◽  
Welding Processes

The aim of this research work was to analyze the sensitization due to the effect of welding (Shielded Metal Arc Welding, Gas Tungsten Arc Welding & Gas Metal Arc Welding) heat in heat affected zone area in terms of metallurgical properties, mechanical properties and corrosion of base metal comparatively. Also the effect of different chemicals / acidic environments on tensile properties was investigated. The plates of 3 mm thickness of 409M Ferritic Stainless Steel welded at constant current of 90A by three different welding processes with the same filler metal. The microstructure observation was made after Marble reagent chemical etched. Then tensile properties were investigated and comparative analysis done between the tensile properties i.e. before and after the chemical exposure given to it with the parent metal. After completion of experimental work it is found that SMAW, GMAW and GTAW have affected the microstructure of 409M Ferritic Stainless Steel. Due to the acidic environments/ Chemical exposures the strength and ductility of the metal affects. But comparatively GTAW has shown better process than GMAW and SMAW for welding of 409M Ferritic Stainless Steel. It should be used with caution in sulphuric acid environments than chloride environments to resist corrosion.

Influence of Heat Input on Grain Size in the Structure of 316LN Stainless Steel Welded Joints

2014 ◽  
Vol 1033-1034 ◽  
pp. 834-838 ◽  
Author(s):  
Li Chan Li ◽  
Can Liang ◽  
Dong Dong Wang ◽  
Yong Quan Li ◽  
Quan Duan
Keyword(s):  
Grain Size ◽  
Stainless Steel ◽  
Welded Joints ◽  
Heat Input ◽  
Arc Welding ◽  
Great Influence ◽  
Shielded Metal Arc Welding ◽  
316Ln Stainless Steel ◽  
Metal Arc Welding ◽  
Δ Ferrite

316LN stainless steel is a material with excellent mechanical properties, good resistance to intergranular corrosion and good weldability, and it has been used in many fields of industry. Welding quality has great influence on the strength and corrosion resistance of weldment. In this study, one group of submerged arc welding and three groups of shielded metal arc welding were taken to study the influence of heat input on grain size in the structure of 316LN welded joints. The results show that the microstructures of the weld zones in experiment were all consist of austenite and a small amount of banding or dendritic δ-ferrite and the amount of ferrite decrease with the increase of heat input. It also can be concluded from the experiment that with the increase of welding heat input the grain size of overheated zone decrease.

Fatigue and Fracture Toughness Properties of 9 Percent Nickel Steel at LNG Temperatures

1973 ◽  
Vol 95 (4) ◽  
pp. 1069-1075 ◽  
Author(s):  
D. A. Sarno ◽  
D. E. McCabe ◽  
T. G. Heberling
Keyword(s):  
Fracture Toughness ◽  
Arc Welding ◽  
Base Plate ◽  
Nickel Steel ◽  
Rotating Beam ◽  
Shielded Metal Arc Welding ◽  
Percent Nickel ◽  
Metal Arc Welding ◽  
Fatigue And Fracture ◽  
Welding Processes

9 percent nickel steel has been evaluated for use in a semimembrane LNG containment design. Fatigue and fracture toughness properties of 1/4 in. thick base plate and weldments have been determined at cryogenic temperatures. Results of rotating beam fatigue, stress intensity (Kc) and fatigue crack growth rate (da/dN versus ΔK) studies are presented. Data predict that 9 percent nickel steel, fabricated with the gas metal arc and shielded metal arc welding processes, may be successfully applied as the primary tank material for this LNG design.

Sign in / Sign up

Export Citation Format

Share Document