The present invention provides a rail inserted into the longitudinal joint of a pre-cast concrete or other type of pre-fabricated deck that is used as formwork to support concrete during construction of a suspended concrete slab. The cast-in soffit connector rail has a perforated vertical element that extends below the soffit level of the deck. The rail and the perforations are used for the connection of suspended elements like ceilings, cable trays, mechanical services etc. The cast-in soffit connector rail has a cross section profile that allows it to simply hook or wedge between the deck elements. The rail is used to not only simply, easily and quickly fix elements that need to be hung from the soffit, but it will also help to reduce the amount of slurry that typically falls between the deck joints during the concrete pour.

The present invention provides a rail inserted into the longitudinal joint of a pre-cast concrete or other type of pre-fabricated deck that is used as formwork to support concrete during construction of a suspended concrete slab. The cast-in soffit connector rail has a perforated vertical element that extends below the soffit level of the deck. The rail and the perforations are used for the connection of suspended elements like ceilings, cable trays, mechanical services etc. The cast-in soffit connector rail has a cross section profile that allows it to simply hook or wedge between the deck elements. The rail is used to not only simply, easily and quickly fix elements that need to be hung from the soffit, but it will also help to reduce the amount of slurry that typically falls between the deck joints during the concrete pour.

According to one aspect of the present invention, what is provided is a rail including, by mass %: C: 0.75% to 1.20%; Si: 0.10% to 2.00%; Mn: 0.10% to 2.00%; Cr: 0.10% to 1.20%; V: 0.010% to 0.200%; N: 0.0030% to 0.0200%; P0.0250%; S0.0250%; Mo: 0% to 0.50%, Co: 0% to 1.00%; B: 0% to 0.0050%; Cu: 0% to 1.00%; Ni: 0% to 1.00%; Nb: 0% to 0.0500%; Ti: 0% to 0.0500%; Mg: 0% to 0.0200%; Ca: 0% to 0.0200%; REM: 0% to 0.0500%; Zr: 0% to 0.0200%; Al: 0% to 1.00%; and a remainder consisting of Fe and impurities, in which a structure ranging from an outer surface of a head portion as an origin to a depth of 25 mm includes 95% or greater of a pearlite structure by area ratio, the hardness of the structure is in a range of Hv 360 to 500, and in ferrite of the pearlite structure at a position at a depth of 25 mm from the outer surface of the head portion as the origin, the number density of a V nitride having a grain size of 0.5 to 4.0 nm and including Cr is in a range of 1.010.sup.17 to 5.010.sup.17 cm.sup.3.

According to one aspect of the present invention, what is provided is a rail including, by mass %: C: 0.75% to 1.20%; Si: 0.10% to 2.00%; Mn: 0.10% to 2.00%; Cr: 0.10% to 1.20%; V: 0.010% to 0.200%; N: 0.0030% to 0.0200%; P0.0250%; S0.0250%; Mo: 0% to 0.50%, Co: 0% to 1.00%; B: 0% to 0.0050%; Cu: 0% to 1.00%; Ni: 0% to 1.00%; Nb: 0% to 0.0500%; Ti: 0% to 0.0500%; Mg: 0% to 0.0200%; Ca: 0% to 0.0200%; REM: 0% to 0.0500%; Zr: 0% to 0.0200%; Al: 0% to 1.00%; and a remainder consisting of Fe and impurities, in which a structure ranging from an outer surface of a head portion as an origin to a depth of 25 mm includes 95% or greater of a pearlite structure by area ratio, the hardness of the structure is in a range of Hv 360 to 500, and in ferrite of the pearlite structure at a position at a depth of 25 mm from the outer surface of the head portion as the origin, the number density of a V nitride having a grain size of 0.5 to 4.0 nm and including Cr is in a range of 1.010.sup.17 to 5.010.sup.17 cm.sup.3.

A metal material processing machine along a feeding direction includes a feeding device, a moving device, a guiding device, and first to fourth rail driven devices. The feeding device feeds a metal material along the feeding direction. The moving device moves the metal material forward. The metal material is guided by the guiding device. The metal material is disengaged from the moving device. The metal material moves along a direction opposite to the feeding direction until backs a starting point. The first rail driven device is aligned with the feeding direction. The second rail driven device is aligned with the third rail driven device. The second and third rail driven devices are perpendicular to the feeding direction respectively. The second and third rail driven devices are disposed at two sides of the feeding direction respectively. The fourth rail driven device is aligned with the feeding direction.

A metal material processing machine along a feeding direction includes a feeding device, a moving device, a guiding device, and first to fourth rail driven devices. The feeding device feeds a metal material along the feeding direction. The moving device moves the metal material forward. The metal material is guided by the guiding device. The metal material is disengaged from the moving device. The metal material moves along a direction opposite to the feeding direction until backs a starting point. The first rail driven device is aligned with the feeding direction. The second rail driven device is aligned with the third rail driven device. The second and third rail driven devices are perpendicular to the feeding direction respectively. The second and third rail driven devices are disposed at two sides of the feeding direction respectively. The fourth rail driven device is aligned with the feeding direction.

A method for manufacturing a rail includes casting a steel to obtain a semi-product. The steel has a composition comprising 0.20%C0.60%, 1.0%Si2.0%, 0.60%Mn 1.60% and 0.5Cr2.2%, optionally 0.01%Mo0.3%, 0.01%V0.30%; the remainder being Fe and impurities. The method also includes hot rolling the semi-product into a hot rolled semi-product having the shape of the rail and comprising a head, with a final rolling temperature T.sub.FRT higher than Ar3; and cooling the head to a cooling stop temperature T.sub.CS between 200 C. and 520 C. The method also includes maintaining the head in a temperature range comprised between 300 C. and 520 C. during a holding time t.sub.hold of at least 12 minutes, and; cooling down the hot rolled semi-product to room temperature to obtain the rail.

A moderate-strength steel rail is provided. The chemical composition of the moderate-strength steel rail in weight percentages includes carbon 0.70-0.90 wt %, silicon 0.08-0.65 wt %, manganese 0.69-1.31 wt %, chromium 0.10-0.25 wt %, phosphorus 0.020 wt %, sulfur 0.020 wt %, and iron 96.85-98.41 wt %. According to a production method for the moderate-strength steel rail of the present invention, the moderate-strength steel rail produced has a rail hardness of 350-370 HB, a wear amount of 0.40 g, a contact fatigue life of 50,000 times, and a 610 mm steel rail waist opening 3.0 mm/400 mm.

A moderate-strength steel rail is provided. The chemical composition of the moderate-strength steel rail in weight percentages includes carbon 0.70-0.90 wt %, silicon 0.08-0.65 wt %, manganese 0.69-1.31 wt %, chromium 0.10-0.25 wt %, phosphorus 0.020 wt %, sulfur 0.020 wt %, and iron 96.85-98.41 wt %. According to a production method for the moderate-strength steel rail of the present invention, the moderate-strength steel rail produced has a rail hardness of 350-370 HB, a wear amount of 0.40 g, a contact fatigue life of 50,000 times, and a 610 mm steel rail waist opening 3.0 mm/400 mm.