METHOD FOR PRODUCTION OF SEAMLESS COLD-DEFORMED HIGH-STRENGTH PIPES FROM ALLOY UNS N06625 Russian patent published in 2020 - IPC B21B21/00 

FIELD: metal forming.

SUBSTANCE: invention can be used in production of pipes from chromium-nickel alloy used mainly in field underwater pipelines. Proposed method comprises plastic deformation and heat treatment of tubes of intermediate dimensions, plastic deformation to finished size with final heat treatment, as well as straightening, while material for pipes is UNS N06625 alloy with content of basic chemical elements, wt%: nickel ≥ 58; chromium 20.0–23.0; molybdenum 8.0–10.0; iron ≤ 5.0; niobium + tantalum 3.15–4.15; cobalt ≤ 1.0; manganese ≤ 0.50; silicon ≤ 0.50; aluminum ≤ 0.40; titanium ≤ 0.40; carbon ≤ 0.10, final heat treatment of pipes is carried out at temperature of 960–980 °C for 10–15 minutes, after which it is cooled in air.

EFFECT: invention makes it possible to manufacture pipes having mechanical properties corresponding to following values: ultimate strength σ_v – not less than 827 MPa; yield point σ_{0_2} – not less than 414 MPa; 50 mm specific elongation δ₅₀ – not less than 30 %; hardness – no more than 25 HRC.

1 cl, 1 tbl, 2 ex, 1 dwg