mizing joint restraint, the making of oversized welds, or using improper weld bead sequencing. • Understand the service environment of the weldment and the proposed materials to be used. Avoid a susceptible microstructure via the compositional control of the base metal/weld filler metal — scrutinize hardness values. • Calculate the CEIIW or CEPCM value to offer an indication of the base metal’s weldability based upon the hardness and hardenability. • Utilize low-hydrogen practices: FCAW with a gaseous fluorideenhanced shielding gas; SMAW electrodes with an H4R designation (diffusible hydrogen content) (Ref. 25). • Prevent stress concentrations at toe and root weld locations by using proper welding techniques and weld bead sequencing. Remove stress riser sites resulting from undercut, overlap/ incomplete fusion, incomplete penetration, and excessive weld bead reinforcement. Weld contact angles are crucial. Sharp/blunted edges must have a gradual transition to the adjacent base metal surface by smooth contoured blending. • Eliminate accelerated cooling rates as the result of air drafts, insufficient preheating, and melting snow. Control the weld region cooling rate via proper temperature management: heat-input, preheat, interpass, and postweld heat treatment. Executing an effective postweld hydrogen bakeout provides an opportunity for diffusible hydrogen to effuse out of the weld deposit/HAZ. Conclusion In the land of the midnight sun, cold climate and/or sour service conditions magnify the criticality of the PQR qualification process. Thoughtful welding engineering consideration must be given to the methods and variables involved to achieve a compliant weld joint that will meet the specified service design and performance requirements of oil/gas project weldments. References 1. ASTM G48, Standard Test Methods for Pitting and Crevice Corrosion Resistance of Stainless Steels and Related Alloys by Use of Ferric Chloride Solution, 2011. 2. ASTM A262, Standard Practices for Detecting Susceptibility to Intergranular Attack in Austenitic Stainless Steels, 2015. 3. ASTM E23, Standard Test Methods for Notched Bar Impact Testing of Metallic Materials, 2012. 4. ASTM A370, Standard Test Methods, and Definitions for Mechanical Testing of Steel Products, 2015. 5. ASTM E1820, Standard Test Method for Measurement of Fracture Toughness, 2015. 6. API 5L, Specification for Line Pipe, 45th Edition, 2012. 7. AWS A5.5/A5.5M:2014, Specification For Low-Alloy Steel Electrodes For Shielded Metal Arc Welding. A. API 5L, Specification for Line Pipe, 45th Edition, 2012. B. API 5CT, Specification for Casing and Tubing, 9th Edition, 2011. C. API Standard 1104, Welding of Pipelines and Related Facilities, 21st Edition, 2013. D. API Standard 650, Welded Steel Tanks for Fuel Storage, 12th Edition, 2013. E. API Standard 653, Tank Inspection, Repair, Alteration and Reconstruction, 5th Edition, 2014. F. AWS D1.1/D1.1M:2015, Structural Welding Code — Steel. G. AWS D1.5/D1.5M:2015, Bridge Welding Code. H. AWS D1.6/D1.6M:2007, Structural Welding Code Stainless Steel. I. AWS D1.8/D1.8M:2009, Structural Welding Code Seismic Supplement. J. ANSI/NACE MR0175/ISO 15156- 1:2009, Petroleum and natural gas industries — Materials for use in H2S-containing environments in oil and gas production — Part 1: General principles for selection of crackingresistant materials, 2nd Edition. K. NACE MR0103:2012, Materials Resistant to Sulfide Stress Cracking in Corrosive Petroleum Refining Environments. L. NACE SP047215:2015, Methods and Controls to Prevent In-Service Environmental Cracking of Carbon Steel Weldments in Corrosive Petroleum Refining Environments. M. ASME Boiler and Pressure Vessel Code, Section VIII: Rules for Construction of Pressure Vessels Division 1, 2015. N. ASME Boiler and Pressure Vessel Code, Section IX: Welding, Brazing, and Fusing Qualifications, 2015. O. ASME Construction Code, B31.3, Process Piping, 2014. P. ASME Construction Code, B31.4, Pipeline Transportation Systems for Liquids and Slurries, 2012. Q. ASME Construction Code, B31.8, Gas Transmission and Distribution Piping Systems, 2014. R. DOT CFR-49-195, Transportation of Hazardous Liquids by Pipeline, 2015. JUNE 2016 / WELDING JOURNAL 77 WJ WILLIAM C. LAPLANTE (wlaplante.cwi@gmail.com) is a welding engineer, CWI, CWE, Anchorage/Prudhoe Bay, Alaska. For info, go to aws.org/adindex
Welding Journal | June 2016
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