METHOD OF MANUFACTURE OF ROD PARTS WITH HEADS OF CORROSION-RESISTANT NITROGEN-CONTAINING SPARINGLY ALLOYED STEELS Russian patent published in 2008 - IPC C21D1/78 C21D8/00 C21D7/06 C21D1/44 

FIELD: metallurgy.

SUBSTANCE: said utility invention relates to the field of metallurgy and may be used in the automotive industry, ship building, and chemical equipment building industry. For the manufacture of complex shape hardware with a tensile strength exceeding 1400 MPa and high ductility properties (Ψ>55% and δ>25%), a preliminary heat treated workpiece is machined; the machining includes heading by cold working and thread rolling; after the thread rolling, the parts are quenched by heating in a salt bath at 1000-1050°C and water cooling, and tempered in a caustic bath at 400-450°C during 1-2 hours, with subsequent additional treatment in a rotary drum, with a mixture of steel balls with a diameter of 0.002-0.005 m and wooden cubes with an edge height of 0.02-0.03 m during no less than 10 hours. Besides that, the treatment in the rotary drum is performed at a drum rotation speed of 40-50 rpm alternating the rotation direction every 2 minutes.

EFFECT: complex shape hardware with high tensile strength and enhanced ductility.

2 cl, 2 ex