LOW-ALLOYED STEEL Russian patent published in 2006 - IPC C22C38/46 C22C38/24 

FIELD: metallurgy; making of low-alloy steels for manufacture of articles operating in aggressive media containing hydrogen sulfide and carbon dioxide.

SUBSTANCE: proposed low-alloyed steel contains the following components, mass-%: carbon, 0.05-0.15; manganese, 0.40-0.65; chromium, 0.50-0.80; silicon, 0.30-0.80; vanadium, 0.04-0.09; aluminum, 0.02-0.05; the remainder being iron and admixtures. Content of admixtures is limited as follows, mass-%: nitrogen, no more than 0.008; nickel, no more than 0.30; copper, no more than 0.25; hydrogen, no more than 0.0002; total calcium/sulfur ratio shall be no less than 1. In particular case, proposed steel may contain titanium and niobium; total amount of vanadium, titanium and niobium shall not exceed 0.15 mass-%. Proposed steel may be used for manufacture of pipes and joints for handling aggressive media, watery oil and formation water in particular characterized by high degree of mineralization and containing H₂S and CO₂.

EFFECT: enhanced strength characteristics and corrosion resistance.

2 cl, 4 tbl