creases. Alleviating HIC conditions in a cold climate and/or in a sour service environment is decisive. For example, relative to PQRs, NACE MR0175/ISO 15156-1 restricts the maximum acceptable weld deposit/HAZ hardness limits for carbon and low-alloy steels to 22 Rockwell C hardness/250 Vickers hardness (Ref. 10). Evaluating Weldability The composition of carbon and a low-alloy steel drives hardness and hardenability. Thereupon, to evaluate a base metal’s weldability and susceptibility to HIC, this author recommends that depending upon the base metal’s carbon content, the carbon Project Weld Codes, Standards, and Regulations For pipeline, pipework, structural, and vessel applications, various codes, standards, and relevant regulations are employed, including the following • API Standards 1104 (Ref. C), 650 (Ref. D), and 653 (Ref. E) • AWS Codes D1.1 (Ref. F), D1.5 (Ref. G), D1.6 (Ref. H), and D1.8 (Ref. I) • NACE Codes such as MR0175/ISO 15156-1 (Ref. J), MR0103 (Ref. K), and SP047215 (Ref. L) • ASME Boiler and Pressure Vessel Code Sections VIII (Ref. M), IX (Ref. N), and construction-codes B31.3 (Ref. O), B31.4 (Ref. P), and B31.8 (Ref. Q) • Department of Transportation (DOT) regulations (e.g., CFR-49-195 (Ref. R)) for pertinent pipelines. A PQR and a welding procedure specification (WPS) are based on meeting respective code/standard requirements. Additionally, PQRs/WPSs must be in accordance with the engineering authority and any applicable DOT regulatory requirements. NACE Codes apply to corrosion prevention and control, including when materials are subjected to a hydrogen sulfide (H2S) sour service environment. JUNE 2016 / WELDING JOURNAL 75 Fig. 4 — Oilfield welding of API 5L X65 pipe of different diameters and wall thicknesses.
Welding Journal | June 2016
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