The martensitic stainless steel seamless pipe according to the present disclosure has a chemical composition containing, in mass %, C: 0.001 to 0.050%, Si: 0.05 to 1.00%, Mn: 0.05 to 2.00%, P: 0.030% or less, S: 0.0100% or less, Al: 0.005 to 0.100%, N: 0.020% or less, Ni: 1.00 to 9.00%, Cr: 8.00 to 16.00%, Cu: 3.50% or less, Mo: 1.00 to 5.00%, W: 0.01 to 0.30%, V: 0.010 to 1.500%, and Co: 0.001 to 0.500%, and also containing one or more elements selected from the group consisting of Ca, Mg, B, and rare earth metal, with the balance being Fe and impurities, and has a yield strength of 655 MPa or more.

The martensitic stainless steel material according to the present disclosure consists of C: less than 0.030%, Si: 1.00% or less, Mn: 0.05 to 2.00%, Cr: 11.50 to 14.00%, Ni: 5.00 to 7.50%, Mo: 1.10 to 3.50%, Cu: 0.50 to 3.50%, Co: 0.01 to 0.30%, Al: 0.001 to 0.100%, N: 0.001 to 0.100%, and the balance: Fe and impurities. The microstructure is composed of retained austenite in an amount of 0 to 15 vol%, and ferrite in an amount of 0 to 10 vol%, with the balance being martensite. The yield strength is 862 MPa or more, and a number density of Cu precipitates is 3.0 x 10.sup.21 to 50.0 x 10.sup.21 /m.sup.3.

A non oriented electrical steel sheet includes, as a chemical composition, by mass%, 1.0% or more and 5.0% or less of Si, wherein a sheet thickness is 0.10 mm or more and 0.35 mm or less, an average grain size is 30 .Math.m or more and 200 .Math.m or less, an X1 value defined by X = (2 × B.sub.50L + B.sub.50C) / (3 × I.sub.s) is less than 0.845, an X2 value defined by X2 = (B.sub.50L + 2 × B.sub.50D + B.sub.50C) / (4 × I.sub.s) is 0.800 or more, and an iron loss W.sub.10/1k is 80 W/kg or less.

A non-oriented electrical steel sheet according to one embodiment of the invention has a chemical composition represented by C: 0.0030% or less, Si: 2.00% or less, Al: 1.00% or less, Mn: 0.10% to 2.00%, S: 0.0030% or less, one or more selected from the group consisting of Mg, Ca, Sr, Ba, Nd, Pr, La, Ce, Zn, and Cd: greater than 0.0100% and not greater than 0.0250% in total, a parameter Q represented by Q=[Si]+2×[Al]−[Mn]: 2.00 or less; Sn: 0.00% to 0.40%, Cu: 0.00% to 1.00%, and a remainder: Fe and impurities, and a parameter R represented by R=(I.sub.100+I.sub.310+I.sub.411+I.sub.521)/(I.sub.111+I.sub.211+I.sub.332+I.sub.221) is 0.80 or greater.

Disclosed is a non-oriented electrical steel sheet with low magnetic anisotropy, which comprises the following chemical elements in mass percentage: 0<C≤0.005%; Si: 2.0-3.5%; Mn: 0.1-2.0%; at least one of Sn and Sb: 0.003-0.2%; Al: 0.2-1.8%; the balance being Fe and inevitable impurities. Further disclosed is a manufacturing method for the above non-oriented electrical steel sheet with low magnetic anisotropy, which includes the following steps: (1) smelting and casting; (2) hot rolling; (3) normalizing; (4) cold rolling; (5) continuous annealing: rapidly heating a cold-rolled steel sheet from an initial temperature of 350° C.-750° C. to a soaking temperature at a heating rate of 50-800° C./s, and performing soaking and heat preservation; and (6) applying an insulating coating to obtain a finished non-oriented electrical steel sheet. The non-oriented electrical steel sheet is characterized by low iron loss and low magnetic anisotropy at high frequency.

Disclosed is a grain-oriented electrical steel sheet capable of obtaining excellent magnetic properties stably over the entire coil length. A grain-oriented electrical steel sheet includes: a chemical composition containing, in mass %, C: 0.005% or less, Si: 2.0% to 4.5%, and Mn: 0.01% to 0.5%, and, in mass ppm, N: 20 ppm or less, each of Se, Te, and O: less than 50 ppm, S: less than 30 ppm, and acid-soluble Al: less than 40 ppm, and Ti: less than 30 ppm, of which 5 ppm or more and 25 ppm or less is acid-soluble Ti, with the balance being Fe and inevitable impurities; and precipitates containing Ti and N with a grain size of 200 nm or more at a frequency of 0.05 grains/mm.sup.2 or more.

A duplex stainless steel having excellent carbon dioxide corrosion resistance, excellent sulfide stress corrosion cracking resistance, and excellent sulfide stress cracking resistance. The duplex stainless steel comprises, by mass %, C: 0.03% or less, Si: 1.0% or less, Mn: 0.10 to 1.5%, P: 0.030% or less, S: 0.005% or less, Cr: 20.0 to 30.0%, Ni: 5.0 to 10.0%, Mo: 2.0 to 5.0%, Cu: 2.0 to 6.0%, N: less than 0.07%, at least one selected from Al: 0.05 to 1.0%, Ti: 0.02 to 1.0%, and Nb: 0.02 to 1.0%, and the balance being Fe and unavoidable impurities, and has a structure that is 20 to 70% austenite phase, and 30 to 80% ferrite phase in terms of a volume fraction.

The present disclosure relates to a method for manufacturing a non-oriented electrical steel sheet and the manufactured non-oriented electrical steel sheet, the method including: heating a slab containing, by wt %, 0.005% or less of C, 2.5 to 4.0% or less of Si, 0.1% or less of P, 0.1 to 2.0% of Al, 0.2 to 2.5% of Mn, 0.003% or less of N, 0.005% or less of Ti and Nb, 0.003% or less of S, 0.005 to 0.025% of V, 0.1% or less of Cu, and a balance of Fe and inevitably mixed impurities, and satisfying the following Expression 1; hot-rolling the slab to manufacture a hot-rolled sheet; cold-rolling the hot-rolled sheet to manufacture a cold-rolled sheet; and performing final annealing on the cold-rolled sheet, wherein [Expression 1] is represented by (51*[C])/12−0.002≤[V]≤(51*[C])/12+0.004 (in Expression 1, [C] and [V] represent contents (wt %) of C and V, respectively).

A cold-rolled steel sheet having excellent heat resistance and moldability according to an exemplary embodiment of the present invention includes 0.002 to 0.01 wt % of C, 0.1 to 1.0 wt % of Mn, less than 0.01 wt % (except for 0 wt %) of P, 0.01 wt % or less (except for 0 wt %) of N, 0.01 to 0.05 wt % of Nb, and 0.01 to 0.08% of Ti, with the balance being Fe and inevitable impurities, and has a microstructure in which the area fraction of recrystallized grains is 5 area % or less, and the dislocation density is 1×10.sup.15/m.sup.2 or less.

A grain oriented electrical steel sheet includes the texture aligned with Goss orientation. In the grain oriented electrical steel sheet, when a grain size RAα.sub.L, a grain size RAβ.sub.L, and a grain size RAγ.sub.L are defined in a rolling direction L, the grain sizes satisfy RAβ.sub.L<RAα.sub.L and RAγ.sub.L<RAα.sub.L.