Provided is a steel sheet which can be used for automobile parts and the like, and relates to a steel sheet having a superior balance of strength and ductility and strength and hole expansion ratio and superior bending formability, and a method for manufacturing same.

Provided are a wire rod for cold heading having high resistance to delayed facture, a part having high resistance to delayed facture, and methods for manufacturing the wire rod and the part. The wire rod of the present disclosure has a chemical composition including, by wt %, C: 0.3% to 0.5%, Si: 0.01% to 0.3%, Mn: 0.3% to 1.0%, Cr: 0.5% to 1.5%, Mo: 0.5% to 1.5%, Ni: 0.5% to 2.0%, V: 0.01% to 0.4%, and a balance of Fe and other impurities, and the chemical composition satisfies the relational expression 1, wherein the high-strength wire rod has a microstructure including, by area %, 5% to 20% martensite, 0.1% to 1% pearlite, and a balance of bainite.

Provided are a high-strength wire rod having high hydrogen embrittlement resistance for cold heading, and a method for manufacturing the high-strength wire rod. The high-strength wire rod for cold heading has a chemical composition including, by weight %, C: 0.3% to 0.5%, Si: 0.01% to 0.3%, Mn: 0.3% to 1.0%, Cr: 0.5% to 1.5%, Mo: 0.5% to 1.5%, V: 0.01% to 0.4%, and a balance of Fe and other impurities, and the chemical composition satisfies the relational expression 1. The high-strength wire rod for cold heading has a microstructure including, by area %, 1% to 15% martensite, 0.1% to 5% pearlite, and a balance of bainite, and the fraction of martensite formed along grain boundaries of prior austenite in the martensite of the microstructure is 60% or more.

A steel material for a vacuum tube according to an aspect of the present disclosure may include C: 0.1˜0.2%, Si: 0.05∞0.5%, Mn: 1.0∞1.6%, Ni: 0.5∞1.0%, Cr: 1.5∞4.0%, and the balance of Fe and unavoidable impurities in percentage by weight, and may have a complex structure of ferrite and pearlite as a microstructure.

Provided are a non-heat treated wire rod having high drawability and impact toughness, and a method for manufacturing the non-heat treated wire rod. The non-heat treated wire rod includes, by wt%, C: 0.02% to 0.30%, Si: 0.05% to 0.8%, Mn: 0.5% to 2.0%, Cr: 1.0% or less, P: 0.03% or less, S: 0.03% or less, sol.Al: 0.01% to 0.07%, N: from greater than 0.01% to 0.02%, Nb: 0.1% or less, V: 0.5% or less, and Ti: 0.1% or less, and a balance of Fe and inevitable impurities, wherein the non-heat treated wire rod has a microstructure including ferrite and pearlite.

The subject matter of this invention is a heat distribution management device in a treatment device of yarns in movement on a means of transport, said means of transport being able to be traversed by a flow of heat at or through the of orifices, characterized in that the device comprises at least one means of sealing by coverage of at least one part of the orifices of the means of transport, said means of sealing being independent of the means of transport.

The subject matter of this invention is a heat distribution management device in a treatment device of yarns in movement on a means of transport, said means of transport being able to be traversed by a flow of heat at or through the of orifices, characterized in that the device comprises at least one means of sealing by coverage of at least one part of the orifices of the means of transport, said means of sealing being independent of the means of transport.

Provided is a non-oriented electrical steel sheet that contains substantially no Al and contains large amounts of Si and Mn and has low iron loss, comprising a chemical composition containing C: 0.0050% or less, Si: 2.0% or more and 6.0% or less, Mn: 1.0% or more and 3.0% or less, P: 0.20% or less, S: 0.0050% or less, N: 0.0050% or less, Al: 0.0050% or less, and one or more selected from B: 0.0001% or more and 0.0050% or less, Nb: 0.0001% or more and 0.0050% or less, and V: 0.0005% or more and 0.0500% or less, with a balance consisting of Fe and inevitable impurities, wherein a number density of Si—Mn nitrides with an average diameter of 50 nm or more and 500 nm or less is 1 or less per μm.sup.3.

Provided is a non-oriented electrical steel sheet that contains substantially no Al and contains large amounts of Si and Mn and has low iron loss, comprising a chemical composition containing C: 0.0050% or less, Si: 2.0% or more and 6.0% or less, Mn: 1.0% or more and 3.0% or less, P: 0.20% or less, S: 0.0050% or less, N: 0.0050% or less, Al: 0.0050% or less, and one or more selected from B: 0.0001% or more and 0.0050% or less, Nb: 0.0001% or more and 0.0050% or less, and V: 0.0005% or more and 0.0500% or less, with a balance consisting of Fe and inevitable impurities, wherein a number density of Si—Mn nitrides with an average diameter of 50 nm or more and 500 nm or less is 1 or less per μm.sup.3.

Device (10) and method for winding/unwinding rolled products (20). The device (10) is interposed between a rolling unit located upstream (102) and a rolling unit located downstream (105). The device (10) comprises a heating furnace (11) and a support structure (16) disposed outside the heating furnace (11). On the support structure (16), substantially in a diametrically opposite position, two winding/unwinding drums (18a, 18b) are assembled, positioned inside the furnace (11). The support structure (16) is selectively rotating to alternatively dispose a first of the two drums (18a or 18b) in its winding position or in its unwinding position of a reel (29). A second of the two drums (18b or 18a) consequently assuming the opposite unwinding or winding position.