ROLLED SECTION FOR MANUFACTURING OF BALL PINS Russian patent published in 2009 - IPC C21D8/06 C22C38/60 C22C38/40 C22C38/18 

FIELD: metallurgy.

SUBSTANCE: invention relates to manufacturing of rolled section of diametre from 15 up to 30 mm from medium-carbon chrome-bearing steel for manufacturing of ball pins, used in ball-and-socket hinges of car suspensions. Steel contain carbon, manganese, silicon, chrome, sulphur, nickel, phosphorus, iron and unavoidable admixtures at following ratio of components, wt %: carbon 0.38 - 0.47, manganese 0.58 - 0.94, silicon up to 0.40, chrome 0.87 - 1.25, sulphur 0.02 - 0.045, nickel up to 0.30, phosphorus up to 0.035, iron and unavoidable admixtures are the rest. There are observed following correlations carbon +manganese ≥ 1.00 and silicon + phosphorus - nickel ≥ - 0.25. In steel microstructure content of globular pearlite is not less than 65%, tensile strength σ_t is not more than 590 MPa, percent elongation δ₅ is not less than 18%, contraction ratio ψ is not less than 55%, and effective grain size is in the range 6-9 points.

EFFECT: it is improved machining quality, it is achieved high plasticity and stable hardening characteristics.

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