Abstract: A billet of steel has a composition comprising small amounts of hardenability agents. The billet is hot rolled into a continuous bar, in two hot rolling stages with an intervening cooling step employing a turbulent cooling liquid. After the second hot rolling stage, the bar is gathered into a succession of closely overlaying loops and moved along a roller conveyor where the overlapping loops are cooled by air blowers, after which the bar is coiled. The resulting hot rolled bar has a microstincture consisting essentially of bainite in fine-sized packets reflecting an average austenitic grain size, before the gathering and cooling steps, of 8-11 ASTM. A threaded fastener in its final form can be produced from the hot rolled bar by a cold deforming operation without a heat treating operation before or after cold deforming. The threaded fastener is undistorted and contains residual compressive stresses.

Abstract: A metal bar undergoing hot rolling is sheared by a pair of shear knives which form a rounded wedge shape at a downstream end of the bar to minimize split ends and cobbles during the rolling operation. The two knives have respective, mating male and female sections which have peripheral cutting edges defining the rounded wedge shape. The shape and angular parameters of the peripheral cutting edges on the two knives provide a progressive, scissors-like, shearing action along the cutting edges from their upstream ends to their downstream tips.