Patent classifications
C22C38/004
Clad welded pipe or tube and method of producing same
Provided is a clad welded pipe or tube that has improved pipe or tube mechanical properties by reducing the width of a weld without its function as a clad pipe or tube being impaired. A clad welded pipe or tube comprises: a first layer made of base metal; and a second layer placed on one surface of the first layer, and made of first cladding metal that is a material different from the base metal, wherein a pipe or tube circumferential length L1 of weld metal at a pipe or tube inner surface and a pipe or tube circumferential length L2 of the weld metal at a pipe or tube outer surface in a weld are each 0.0010 mm or more and 1.0 mm or less, and the base metal is not exposed at a first cladding metal-side surface of the clad welded pipe or tube in the weld.
Packaging sheet metal product
A packaging sheet metal product from a cold-rolled steel sheet with a thickness of less than 0.6 mm has a specified composition. The packaging sheet metal product during biaxial deformation in a bulge test has a lower yield strength (Sb.sub.eL) of more than 300 MPa and a corresponding elongation at break (Ab) of more than 10% and in the plastic region between the Lüders elongation (Ab.sub.e) and an upper (plastic) elongation limit of ε.sub.max=0.5.Math.Ab.Math.(Sb.sub.eL/Sb.sub.m) has a biaxial stress/strain diagram σ.sub.B(ε) that can be represented by a function ε.sub.B=b.Math.ε.sup.n, with: σ.sub.B is the true biaxial stress in MPa; ε is the amount of true elongation in the thickness direction in %; Sb.sub.m is the absolute strength; b is a proportionality factor; and n is a strain-hardening exponent. A strengthening of the packaging sheet product in the thickness direction is characterized by a strain-hardening exponent of n≥0.353-5.1.Math.Sb.sub.eL/10.sup.4 MPa.
STEEL SHEET WITH EXCELLENT BAKE HARDENING PROPERTIES AND CORROSION RESISTANCE AND METHOD FOR MANUFACTURING SAME
Provided is a steel sheet by weight percentage (wt %), carbon (C): 0.005 to 0.08%, manganese (Mn): 1.25% or less (excluding 0%), phosphorus (P): 0.03% or less (excluding 0%), sulfur (S): 0.01% or less (excluding 0%), nitrogen (N): 0.01% or less (excluding 0%), soluble aluminum (sol.Al): 0.01 to 0.06%, chromium (Cr): 1.15 to 2.5%, antimony (Sb): 0.1% or less (excluding 0%), at least one selected from the group consisting of nickel (Ni): 0.3% or less (excluding 0%), silicon (Si): 0.3% or less (excluding 0%), molybdenum (Mo): 0.2% or less (excluding 0%), and boron (B): 0.003% or less (excluding 0%), and a remainder of iron (Fe) and other unavoidable impurities, satisfying Expression 1: 1.3≤Mn(wt %)+Cr(wt %)/1.5+Sb(wt %)≤2.7, where Mn, Cr, and Sb refer to contents (wt %) of corresponding elements, respectively; and 1 to 5% of martensite and a remainder of ferrite by an area percentage (area %).
STAINLESS STEEL SEAMLESS PIPE AND METHOD FOR MANUFACTURING SAME
A stainless steel seamless pipe having high strength and excellent corrosion resistance, and a method for producing the same. The stainless steel seamless pipe has a specified composition and satisfies a predetermined formula. The stainless steel seamless pipe has a microstructure containing at least 30% martensitic phase, at most 60% ferrite phase, and at most 40% retained austenite phase by volume, the stainless steel seamless pipe having a yield strength of 758 MPa or more.
METHOD FOR MANUFACTURING NON-ORIENTED ELECTRICAL STEEL SHEET
A method for manufacturing a non-oriented electrical steel sheet includes a step of obtaining a hot-rolled steel sheet by performing hot rolling on a steel material having a predetermined chemical composition, a step of performing first cold rolling on the hot-rolled steel sheet, and a step of performing first annealing after the first cold rolling. A final pass of finish rolling is performed in a temperature range equal to or higher than an Ar1 temperature, and cooling of which an average cooling rate is in a range of 50 to 500° C./sec is started in 0.1 sec from completion of rolling of the final pass of the finish rolling and is performed up to a temperature range higher than 250° C. and equal to or lower than 700° C.
STAINLESS STEEL PIPE AND METHOD FOR MANUFACTURING SAME
A stainless steel pipe of a predetermined composition is provided that comprises N, Ti, Al, V, and Nb so as to satisfy the predetermined formula, the stainless steel pipe having an axial tensile yield strength of 757 MPa or more, an axial compressive yield strength/axial tensile yield strength ratio of 0.85 to 1.15, and a microstructure that is 20 to 80% ferrite phase by volume with the remainder containing an austenite phase, the stainless steel pipe having pipe end portions at least one of which has a fastening portion for an external thread or an internal thread, and having a curvature radius of 0.2 mm or more for a corner R formed by a bottom surface of a thread root and a pressure-side flank surface of the thread, measured in an axial plane section of the fastening portion.
DEGASSING METHOD FOR MANUFACTURING ULTRA-LOW CARBON, NITROGEN, SULFUR STEEL
The present disclosure provides a method of making low carbon steel. The method includes tapping the liquid steel out of a primary steelmaking furnace. Deoxidizing the liquid steel. Transferring the deoxidized liquid steel to a ladle metallurgy furnace. Removing sulfur at the ladle metallurgy furnace. Adding fluxes and arcing the liquid steel to prevent sulfur reversion. Transferring the liquid steel from the ladle metallurgy furnace to an RH degasser for carbon removal. The removal of oxygen and sulfur prior to transferring the liquid steel to the RH degasser facilitates nitrogen removal and prevents carbon pick up during the step sulfur removal.
METHOD FOR MANUFACTURING GRAIN-ORIENTED ELECTRICAL STEEL SHEET
The purpose of the present invention is to provide a method for manufacturing a grain-oriented electrical steel sheet, whereby it becomes possible to manufacture a grain-oriented electrical steel sheet having further improved iron loss properties stably. (Solution) According to one aspect of the present invention, a method for manufacturing a grain-oriented electrical steel sheet is provided, the method being characterized by comprising a re-heating step, a hot rolling step, a hot-rolled sheet annealing step, a cold rolling step, a decarburization annealing step and a final annealing step, wherein the decarburization annealing step includes a heating step of heating a cold-rolled sheet from an inlet side temperature T0° C. to a soaking temperature T2° C. and a soaking step of keeping the temperature of the cold-rolled sheet at the soaking temperature T2° C., and the heating rate HR1 from the time point when the temperature of the cold-rolled sheet is an inlet side temperature T0° C. to the time point when the temperature of the cold-rolled sheet reaches a attained temperature T1° C. is 40° C./sec or more and the heating rate HR2 from the time point when the temperature of the cold-rolled sheet is the desired temperature T1° C. to the time point when the temperature of the cold-rolled sheet reaches the soaking temperature T2° C. is more than 15° C./sec to 30° C./sec in the heating in the decarburization annealing step.
GRAIN ORIENTED ELECTRICAL STEEL SHEET
A grain oriented electrical steel sheet includes a base steel sheet, a glass film, and a tension-insulation coating. When a glow discharge emission spectroscopy is conducted from a surface of the glass film toward a depth direction, an analysis starting time Ts, a time T.sup.Al.sub.p at which Al shows a maximum emission intensity, an Al emission intensity F(T.sup.Al.sub.p) at the T.sup.Al.sub.p, a time T.sup.Si.sub.p at which Si shows a maximum emission intensity, and an Al emission intensity F(T.sup.Si.sub.p) at the T.sup.Si.sub.p satisfy 0.05≤F(T.sup.Si.sub.p)/F(T.sup.Al.sub.p)≤0.50 and 2.0≤(T.sup.Al.sub.p−Ts)/(T.sup.Si.sub.p−Ts)≤5.0.
GRAIN-ORIENTED ELECTRICAL STEEL SHEET
[Problem] To provide a grain-oriented electrical steel sheet which is further improved in terms of iron loss before magnetic domain control, while achieving a sufficient iron loss improvement effect even in the control of a heat-resistant magnetic domain where a sufficient iron loss improvement effect has not been achieved. [Solution] A grain-oriented electrical steel sheet according to one aspect of the present invention comprises abase steel sheet and a glass coating that is formed on the surface of the base steel sheet, and is characterized in that: the base steel sheet contains as chemical components, in mass %, 0.010% or less of C, from 2.00% to 4.00% of Si, from 0.05% to 1.00% of Mn, from 0.010% to 0.065% of Al, 0.004% or less of N and 0.010% or less of S, with the balance being made up of Fe and impurities; the oxygen concentration in the glass coating and the base steel sheet is 2,500 ppm or less; and if I.sub.Al_1 is the first peak intensity of Al and I.sub.Al_2 is the second peak intensity of Al in the concentration profile of Al, the relationship of mathematical formula (1) is satisfied.
I.sub.Al_1<I.sub.Al_2 Formula (1):