Abstract: Provided is a steel for nitrocarburizing that ensures mechanical workability before nitrocarburizing treatment. A steel for nitrocarburizing comprises: a chemical composition containing, in mass %, C: ?0.02% and <0.15%, Si: ?0.30%, Mn: 1.5-2.5%, P: ?0.025%, S: ?0.06%, Cr: 0.5-2.0%, Mo: 0.005-0.2%, V: 0.02-0.20%, Nb: 0.003-0.20%, Al: >0.020% and ?1.0%, Ti: >0.0050% and ?0.015%, N: ?0.0200%, Sb: 0.0030-0.010%, with a balance being Fe and inevitable impurities, satisfying Expression (1) or (2); and a steel microstructure where an area ratio of bainite phase is >50%, a prior austenite grain size is ?100 ?m, ?300/?m2 Ti precipitates with an equivalent circular particle size of ?30 nm disperse, Sb segregates to prior austenite grain boundaries.

Abstract: A press forming method for an automotive outer panel according to the present invention is a method for press forming a metal sheet 51 into an automotive outer panel 61 having a character line 63 and panel surface portions 65a and 65b by using a punch 3, a die 5, and a blank holder 7. The press forming method includes: a step of providing an elastic body 9 protruding toward the punch 3 side on a die-side forming surface portion 5b forming the panel surface portion 65a, and bringing the elastic body 9 into contact with the metal sheet 51 prior to the die 5; and a step of press forming while crushing the elastic body 9 and pressing the metal sheet 51, and the elastic body 9 is caused to protrude from the die-side forming surface portion 5b so that a frictional force of the crushed elastic body 9 and the metal sheet 51 is equal to or greater than an absolute value of a difference between tensions acting on both sides of a portion 53 corresponding to the character line 63.

Abstract: A high-strength galvanized steel sheet and a method for producing the steel sheet. The steel sheet has a composition that includes C: 0.030% to 0.250%, Si: 0.01% to 3.00%, Mn: 2.00% to 10.00%, P: 0.001% to 0.100%, S: 0.0001% to 0.0200%, N: 0.0005% to 0.0100%, Ti: 0.005% to 0.200%, on a mass basis, and Fe and inevitable impurities. Additionally, the steel sheet has concentration of solute Mn at a depth of 5 ?m or less from a surface of the steel sheet that is 1.50% by mass or less, and a value obtained by dividing the average mass percentage of Mn in retained austenite by the average mass percentage of Mn in ferrite is 2.0 or more.

Abstract: This soft magnetic powder is represented by composition formula FeaSibBcPdCue with the exception of unavoidable impurities. In the composition formula, a, b, c, d and e satisfy 79?a?84.5 at %, 0?b<6 at %, 4?c?10 at %, 4<d?11 at %, 0.2?e<0.4 at %, and a+b+c+d+e=100 at %.

Abstract: A method for forming grooves on a surface of a metal strip, having applying a coating agent for etching resist coating formation to a roller; then, irradiating a laser on the roller while scanning the laser in an axial direction of the roller or in a direction inclined to the axial direction to remove a portion of the coating agent for etching resist coating formation irradiated by the laser; then, bringing the roller into contact with at least one side of the metal strip to transfer the coating agent for etching resist coating formation to the at least one side of the metal strip, with an unapplied area corresponding to the removed portion of the coating agent for etching resist coating formation.

Abstract: Provided are a steel sheet dehydrogenation apparatus, a steel sheet production system, and a steel sheet production method capable of producing a steel sheet excellent in hydrogen embrittlement resistance without changing the mechanical properties of the steel sheet. A dehydrogenation apparatus comprises: a housing configured to house a steel sheet coil obtained by coiling a steel strip; and a sound wave irradiator configured to irradiate the steel sheet coil housed in the housing with sound waves to obtain a product coil.

Abstract: A drying system includes: drying furnaces connected in series; an air supply system including an air supply pipe, the air supply system being configured to supply dry air into the furnaces, and an air exhaust system including an air exhaust pipe, the air exhaust system being configured to exhaust wet air in the furnaces, wherein the air supply system and the air exhaust system are being alternately connected between the drying furnaces; a first flow rate regulation valve provided to the air supply system; and a second flow rate regulation valve provided to the air exhaust system.

Abstract: Provided is a device for correcting meandering of a strip material capable of correcting meandering caused in the strip material and conducting stable conveyance even when the meandering amount is small.

Abstract: A surface inspection device of a metal strip includes: a first light source unit configured to emit light to a surface of a metal strip; a first imaging unit configured to image regular reflection light on the surface by emission light from the first light source unit; a second light source unit configured to emit light of a wavelength band different from the first light source unit to the surface; a second imaging unit configured to image irregular reflection light on the surface by emission light from the second light source unit; and a surface defect distinguishing unit configured to distinguish a surface defect by using the regular reflection light and irregular reflection light. The emission light from the first light source unit and the emission light from the second light source unit are simultaneously applied to a same place on the surface of the metal strip.

Abstract: A steel sheet according to the present invention has a specific chemical composition and a steel microstructure including, in terms of area fraction, ferrite: 60% or more and 85% or less, bainite: 3% or more and 15% or less, retained austenite: 3% or more and 15% or less, fresh martensite: 3% or more and 15% or less, and the remainder: 5% or less. Cementite particles are present in the retained austenite, a ratio of an area fraction of the cementite particles in the retained austenite to an area fraction of the retained austenite is 5% or more and 25% or less, and the steel sheet has a tensile strength of 590 MPa or more and less than 780 MPa.

Abstract: A projection welded joint is formed by joining a steel sheet having a tensile strength of 980 MPa or higher and a nut by performing projection welding. In a hardness distribution from the steel sheet to the nut through a weld metal zone, and a hardened region exists on each of the steel sheet side and the nut side. A hardness of each hardened region is higher than that of the base metal on the corresponding side, and each hardened region extends continuously for a distance of 500 µm or more. The maximum hardness NHmax on the nut side is higher than the maximum hardness SHmax on the steel sheet side. A region where the maximum hardness SHmax on the steel sheet side exists is formed of a martensite microstructure having a prior austenite grain size of 20 µm or less.

Abstract: A steel sheet according to the present invention has a specific chemical composition and a steel microstructure including, in terms of area fraction, ferrite: 40% or more and 70% or less, a total of bainite and tempered martensite: 5% or more and 30% or less, retained austenite: 4% or more and 18% or less, fresh martensite: 8% or more and 35% or less, and the remainder: 5% or less. Cementite particles are present in the retained austenite, a ratio of an area fraction of the cementite particles in the retained austenite to an area fraction of the retained austenite is 5% or more and 25% or less, and the steel sheet has a tensile strength of 780 MPa or more and less than 980 MPa.

Abstract: Provided is carbonaceous substance-coated graphite particles that exhibit excellent battery properties when used as a negative electrode material for a lithium ion secondary battery. The carbonaceous substance-coated graphite particles includes: graphite particles; and carbonaceous coatings covering at least part of surfaces of the graphite particles, and the carbonaceous substance-coated graphite particles have a specific surface area SBET determined by BET method of 4.0 to 15.0 m2/g, and a pore volume Vs of pores with a pore size of 7.8 to 36.0 nm is 0.001 to 0.026 cm3/g, and in a pore size distribution graph with the pore size being plotted on a horizontal axis and a dV/dP value obtained by differentiating the pore volume with the pore size being plotted on a vertical axis, a pore size Pmax with which the dV/dP value is maximized is 2.5 to 5.5 nm.

Abstract: Provided are carbonaceous substance-coated graphite particles that include: graphite particles; and carbonaceous coatings covering at least part of surfaces of the graphite particles, the carbonaceous substance-coated graphite particles have a maximum particle diameter of 30.0 to 90.0 ?m, a pore volume Vs of pores with a pore size of 7.8 to 36.0 nm is 0.009 to 0.164 cm3/g, and in a pore size distribution graph with the pore size being plotted on a horizontal axis and a dV/dP value obtained by differentiating the pore volume with the pore size being plotted on a vertical axis, a pore size Pmax with which the dV/dP value is maximized is 2.5 to 5.5 nm.

Abstract: Provided is a method of producing a hot-dip metal coated steel strip with which a hot-dip metal coated steel strip of high quality can be produced by sufficiently suppressing edge overcoating. The method comprises spraying gas from a pair of gas wiping nozzles 20A and 20B onto a steel strip S while being pulled up from a molten metal bath 14, to adjust a coating weight of molten metal on both sides of the steel strip S, wherein a pair of baffle plates 40 and 42 are respectively placed outside of both transverse edges of the steel strip, and a height B of a lower end of each of the pair of baffle plates 40 and 42 with respect to a bath surface of the molten metal bath is set to +50 mm or less, where an upper side in a vertical direction is positive.

Abstract: A molten steel refining method increases a circulating rate using an RH vacuum degassing apparatus. An immersion depth of an immersion tube into molten steel inside a vacuum tank or a circulating gas flow rate is determined such that a stirring power energy density ? for the molten steel meets the following formulae: ? = [371GT × ln{ 1 + (?LgH0/P)}]/Wv, Wv = (?·Dv2/4) × H0 × ?L/1000, H0 = hv + L - hG, hv = (P0 - P)/(?Lg) + 1 -L, 1.35 × 105 × DU/WV < ? < 2.1 × 104.

Abstract: A stainless steel seamless pipe has a component composition containing, in terms of mass%, C: 0.06% or less, Si: 1.0% or less, Mn: 0.01% or more and 0.90% or less, P: 0.05% or less, S: 0.005% or less, Cr: 15.70% or more and 18.00% or less, Mo: 1.60% or more and 3.80% or less, Cu: 1.10% or more and 4.00% or less, Ni: 3.0% or more and 6.0% or less, AI: 0.10% or less, N: 0.10% or less, O: 0.010% or less, V: 0.120% or more and 1.000% or less, C, Si, Mn, Cr, Ni, Mo, Cu, and N satisfying a predetermined formula, and a remainder consisting of Fe and unavoidable impurities, and has a microstructure including 30% or more of a martensitic phase, 60% or less of a ferritic phase, and 40% or less of a retained austenitic phase, and a yield strength is 758 MPa or higher.

Abstract: Provided are a resistance spot welding method and a method for manufacturing a resistance spot welded joint. At least one of the steel sheets used is a high strength steel sheet. The method includes a main current application step in which current is applied with a current Iw and a tempering post-heat treatment step. The tempering post-heat treatment step includes a cooling process and a heating process and can include at least one of a transition process and a holding process. In the heating process, a current is applied at a current value It, shown in formula (2), for a current application time tt. 0.8×Iw?It?1.

Abstract: A metal sheet punching device includes: a die including a circular opening; and a punch configured to form a circular punched hole in the metal sheet supported by the die. The punch includes: a main body part; a cylindrical punching part; a rotating part disposed between the main body part and the punching part; a coated abrasive provided on an outer circumferential surface of the rotating part and configured to polish a sheared edge of the punched hole; a spring disposed between the main body part and the punching part and configured to contract and accumulate a part of a punching load as elastic energy, release the elastic energy and extend after the punching part punches the metal sheet; and a rotational motion conversion device configured to convert a linear motion in the punching direction due to extension of the spring into a rotary motion of the rotating part.

Abstract: A production method for water-atomized metal powder includes: in a region in which the average temperature of a molten metal stream is higher than the melting point by 100° C. or more, spraying primary cooling water from a plurality of directions at a convergence angle of 10° to 25°, where the convergence angle is an angle between an impact direction on the molten metal stream of the primary cooling water from one direction and an impact direction on the molten metal stream of the primary cooling water from any other direction; and in a region in which 0.0004 seconds or more have passed after an impact of the primary cooling water and the average temperature of metal powder is the melting point or higher and (the melting point+50° C.) or lower, spraying secondary cooling water on the metal powder under conditions of an impact pressure of 10 MPa or more.