METHOD OF PRODUCING THE HOT-ROLLED STOCK FOR COLD DIE FORGING OF FASTENERS Russian patent published in 2014 - IPC C21D8/06 

FIELD: metallurgy.

SUBSTANCE: proposed process comprises twofold annealing of rolled stock induction heating by HF current at t=760-780°C in bundles and threefold drawing at draw bench with different degrees of reduction. Note here that annealing is carried out. First drawing before first annealing is performed from diameter 12.0 mm to diameter of 11.0 mm at reduction of 15-16%. Second drawing before first annealing is performed from diameter 11.0 mm to diameter of 9.00 mm at reduction of 20-21%. Third drawing after second annealing is performed via spinneret from diameter 9.8 mm to diameter of 9.65 mm at reduction of 2-3%.

EFFECT: uniform mechanical properties, sufficient strength and ductility before upset of fasteners.

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