Within the Welding Neck Flange Joint market, application segmentation drives the bulk of revenue. The Oil & Gas sector accounts for the largest share, approximately 35 % of total sales, due to the high‑pressure pipelines and offshore platforms that demand the joint’s superior weld‑neck strength and leak‑tight performance. Power Generation follows with roughly 25 % as thermal and nuclear plants rely on these flanges for boiler, turbine, and steam‑line connections where temperature cycling is critical. The Chemical & Petrochemical segment contributes about 20 %, reflecting the need for corrosion‑resistant alloys in reactors and distillation columns. Construction applications, representing 12 % of the market, use welding‑neck flanges in structural steel frameworks and building services where load‑bearing capacity is essential. Finally, the Marine niche, at 8 %, supports shipbuilding and offshore wind foundations that require robust, seawater‑compatible joints. This Welding Neck Flange Joint segmentation by application outlines how each vertical underpins the overall market size.