ZKZ LLC (Завод Кольцевых Заготовок — Ring Blank Factory), founded in 2002 and headquartered in Omsk, Russia, manufactures weld-neck steel flanges — Type 11 per GOST 33259-2015 — for high-integrity piping connections. The weld-neck design features a tapered hub that is butt-welded directly to the pipe, distributing stress across the joint and delivering higher strength and rigidity than flat-welded alternatives.
These flanges handle working media including steam, water, natural gas, and petroleum products, as well as chemically aggressive fluids, covering a temperature range from -253 °C to +600 °C and nominal pressures up to 25.0 MPa. Bore sizes span DN 15 to DN 1400, and steel grades available include carbon St.20 and 09G2S, alloy 15Kh5M and 13KhFA, and austenitic stainless 12Kh18N10T for corrosive or cryogenic service.
Manufacturing routes — closed-die forging, centrifugal electroslag casting (CESL), rolled-ring forging, and plasma or laser cutting from plate — are chosen to match size, grade, and pressure class requirements. Every batch is tested for tensile strength, yield strength, and impact toughness, with results documented in quality passports.
Products comply with EAEU Technical Regulation TR CU 032/2013 and carry a 24-month warranty from the date of supply.
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