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Soman, Sanjay N.
- An Experimental Comparative Review of Ferrite Measurement Techniques Used in Duplex Stainless Steel (UNS S32205) Welds
Abstract Views :320 |
PDF Views:15
Authors
Affiliations
1 Metallurgy Department, Government Engineering College, Sec-28, Gandhinagar, Gujarat, IN
2 Metallurgical and Materials Engineering Department, The M.S.University of Baroda, Vadodara, Gujarat, IN
1 Metallurgy Department, Government Engineering College, Sec-28, Gandhinagar, Gujarat, IN
2 Metallurgical and Materials Engineering Department, The M.S.University of Baroda, Vadodara, Gujarat, IN
Source
Indian Welding Journal, Vol 51, No 2 (2018), Pagination: 75-83Abstract
Duplex stainless steels (DSS) have proven to be very promising engineering materials as substitutes to conventional austenitic stainless steels for structure of off-shore platforms, parts and equipment in petrochemicals and refinery industries, predominantly for sour service applications where corrosion resistance including stress corrosion cracking (SCC) resistance is required in aggressive chloride and/or sulphide environments. Resistance to SCC in chloride containing environment depends on the available ferrite content in the carefully welded duplex (ferritic-austenitic) stainless steel structure. There is, of course, a degree of variation in weld metal ferrite content and in reproducibility of measurement which deserve a review and comparative study on different weld metal ferrite measurement techniques being widely used. So, present work has been carried out by collaborating with a reputed filler metal manufacturer who deliberately produced special batches of standard DSS compositions matching SMAW electrodes with nickel varied content in the range of 9-9.5 %, 9.5-10.5, 10.5-11.5 and 11.5 to 12.5 % to obtain weld deposits in varied ferrite content range15% to 40%, or 20 FN to 50 FN to be experimentally investigated by (1) Feritscope® instrument method, (2) ASTM E 562-11 volume fraction measurement by systematic manual point count method and (3) theoretically by WRC-1992 Diagram. The purpose of this paper is to give a comparative overview of above methods. According to the findings of the study, readings on the top surface of weld metal were consistent with those on the cross section, this indicates proper guidelines can be given for selecting location of testing Feritscope® instrument measurement. FN estimates in predictive methods like image analysis/manual point count methods depends on proper placement of the points on ferrite grains morphology, fineness, discreteness and its irregularity.Keywords
Duplex Stainless Steels, % Ferrite, Ferrite Number, Feritscope®, Volume Fraction Measurements, WRC-1992 Diagram, Weld Metal Dilution, Grain Morphology.
References
- API Technical report 938-C (2015); Use of duplex stainless steels in the oil refining industry, 9th Edition, pp. 2-7.
- Messer B, Oprea V and Wright A (2007); Duplex stainless steel welding: best practices, Stainl. Steel World, (December), pp. 53–63.
- IMOA (2001); Practical Guidelines for the Fabrication of Duplex Stainless Steels, Revised Edition, International Molybdenum Association, USA. pp. 14-17.
- Arnaldo FJ, et al. (2011); Comparative study of ferrite quantification methods applied to duplex stainless steel, Proceedings of the 7th European Stainless Steel Conference- Science and Market; Milan, Italy.
- Tavares SSM, Pardal JM, Abreu HFG, Nunes CS, Silva MR (2012); Tensile properties of duplex UNS S32205 and lean duplex UNS S32304 steels and the influence of short duration 475 °C aging, Materials Research, 15(6), pp. 859-864.
- Arnaldo FJ, Otubo J, Magnabosco R (2016); Ferrite Quantification Methodologies for Duplex Stainless Steel, J. of Aerosp Technol. and Manag., 8(3).
- Bermejo MAV (2012); Predictive and measurement methods for delta ferrite determination in stainless steels, Welding Journal, 91, pp.113s-121s.
- ASTM A800/A800M-14, Standard Practice for Steel Casting, Austenitic Alloy, Estimating Ferrite Content Thereof.
- ISO 8249:2000, Welding-Determination of Ferrite Number (FN) in austenitic and duplex ferritic-austenitic Cr-Ni stainless steel weld metals.
- ASTM E562 -2011, Standard Practice for Determining Volume Fraction by Systematic Manual Point Count.
- Kotecki DJ and Siewert TA (1992); WRC-1992 constitution diagram for stainless steel weld metals : a modification of the WRC-1988 diagram, Welding Journal, 71(5), pp. 171-s–178-s.
- Lippod JC, Kotecki D (2005); Welding Metallurgy & Weldability of Stainless Steels, John Wiley and Sons, pp. 234-262.
- Kotecki D (1986); Ferrite control in duplex stainless steel weld metal, Weld. J., 65(10), pp. 273-s-278-s.
- Kotecki DJ (1997); Ferrite determination in stainless steel welds-advances since 1974, Welding Journal, 76(1), pp.24-s to 37-s.
- Kotecki DJ and Siewert TA (1992); WRC-1992 constitution diagram for stainless steel weld metals: a modification of the WRC-1988 diagram, Welding Journal, 71(5), pp. 171-s to178-s.
- Solidification Behavior of Duplex Stainless Steel (UNS S32205) Welds as a Function of WRC–1992 Diagram Equivalents and Cooling Rate
Abstract Views :361 |
PDF Views:5
Authors
Affiliations
1 Metallurgy Department, Government Engineering College, Sec-28, Gandhinagar, Gujarat, IN
2 Metallurgical and Materials Engineering Department, The M.S. University of Baroda, Vadodara, Gujarat, IN
1 Metallurgy Department, Government Engineering College, Sec-28, Gandhinagar, Gujarat, IN
2 Metallurgical and Materials Engineering Department, The M.S. University of Baroda, Vadodara, Gujarat, IN
Source
Indian Welding Journal, Vol 52, No 2 (2019), Pagination: 65-73Abstract
Duplex stainless steels solidify as 100 % Ferrite, however solidification of Duplex Stainless steel welds is a function of Chromium equivalent and Nickel equivalent alloying elements, filler metal and base metal composition and associated weld thermal cycle. Resultant solidification mode behavior and hence final weld metal microstructure is always a matter of interest among researcher because mechanical properties and corrosion properties are depending on weld metal ferrite content. The present research is to investigate the solidification mode behavior of duplex stainless steel welds with varying Chromium equivalent and Nickel equivalent ratios and associated weld cooling rate. In order to meet this objective, weld coupon were prepared using experimental Low Nickel, Medium Nickel and High Nickel electrodes using SMAW process, step wise increased in Nickel content from commercially available standard 09 weight percentage Nickel in E2209 design. WRC-1992 Diagram has been used to calculate Chromium Equivalent and Nickel equivalent and predict Ferrite Number using compositions of Base metal and Nickel enriched experimental electrodes. Microstructure characterization of all weld coupons is carried out using ASTM A 923 Method. Calculated values were correlated with the different microstructures developed. According to the findings of the studies, weld produced with higher Nickel content electrode, when cooled with maximum rate approximately 100.8 °C/ Sec , considered under study, exhibited FA-mode of solidification with as low as 1.71 Creq/Nieq ratio and there was no noteworthy presence of intermetallic phases and precipitations in as-weld microstructures at approximate retained ferrite level of 15 Ferrite Number.Keywords
Duplex Stainless Steel, Ferrite Number, Cooling Rate, Solidification Mode, WRC-1992 Diagram, Chromium Equivalent, Nickel Equivalent.References
- API Technical report 938-C (2015); Use of duplex stainless steels in the oil refining industry, 9th Edition, pp.2-7.
- Lippod JC and Kotecki D J (2005); Welding Metallurgy & Weldability of Stainless Steels, John Wiley and Sons, pp.234- 262
- Kotecki DJ and Siewert TA (1992); WRC-1992 constitution diagram for stainless steel weld metals: a modification of the WRC-1988 diagram, Welding Journal, 71(5), pp. 171-s-178-s.
- Kou S (2003); Welding Metallurgy, John Willey, 2nd Edition, USA, pp- 55-56
- Adams C. M. Jr. (1958); Cooling rates and peak temperatures in fusion welding, Welding Journal, 37(5), pp.210-s-215s
- Jhaveri P, Moffatt WF and Adams Jr. CM (1962); Effect of plate thickness and radiation on heat flow in welding and cutting, Welding Journal, 41(1), pp.12-s-16-s
- Welding Handbook, American Welding Society, 2087, 8th Edition, Vol. 1, USA, pp.99-105.
- IMOA (2001); Practical Guidelines for the Fabrication of Duplex Stainless Steels, Revised Edition, International Molybdenum Association, USA. pp.14-17.
- http://www.matweb.com/search/datasheet.aspx?matguid=000b4e364a7d41b78d23ea8ede78491e &ckck=1
- Xavier CR, Guimarães H, Junior D and de Castro JA (2015); An experimental and numerical approach for the welding effects on the duplex stainless steel microstructure, Materials research, DOI: http://dx.doi.org/10.1590/1516-1439.302014.
- Kotecki D J (1986); Ferrite control in duplex stainless steel weld metal, Welding Journal, 65(10), pp.273s-278s.
- ASTM A800/ A800M- 14, Standard Practice for Steel Casting, Austenitic Alloy, Estimating Ferrite Content Thereof.
- ISO 8249:2000, Welding- Determination of Ferrite Number (FN) in Austenitic and Duplex Ferritic-Austenitic Cr-Ni Stainless Steel Weld Metals.
- ASTM A 923 Standard Practices for Detecting Intermetallic Phases in Duplex Austenitic/ Ferritic Stainless Steel, ASTM International, West Conshohocken, PA
- Kotecki DJ (2013); A Guide for Troubleshooting Stainless Steel Welding-Related Problems: Welding Stainless SteelQuestions and Answers, AWS Publication, 1st Edition, pp.172-173.73