Disclosed is a steel composition including specified ranges of Ni; Mo; Co; Mo+Co+Si+Mn+Cu+W+V+Nb+Zr+Ta+Cr+C; Co+Mo; Ni+Co+Mo; and traces of Al; Ti; N; Si; Mn; C; S; P; B; H; O; Cr; Cu; W; Zr; Ca; Mg; Nb; V; and Ta in specified ranges; the remainder being iron and impurities. The inclusion population, as observed by image analysis over a polished surface measuring 650 mm.sup.2 if hot-formed or hot-rolled; and measuring 800 mm.sup.2 if cold-rolled, does not contain non-metallic inclusions of diameter >10 μm, and, in the case of a hot-rolled sheet, does not contain more than four non-metallic inclusions of diameter 5-10 μm over 100 mm.sup.2, the observation being performed by image analysis over a polished surface measuring 650 mm.sup.2.

A hot-pressed member having excellent bending collapsibility, a method for manufacturing the same, and a method for manufacturing a steel sheet for the hot-pressed member. The hot-pressed member includes a steel sheet as a base material, the steel sheet having a specified chemical composition. The hot-pressed member has a microstructure in which a martensite microstructure is present in a volume fraction of 70% or greater, and a number density of inclusions having a longest diameter of 25 μm or greater is 0.02/mm.sup.2 or less. The hot-pressed member has a tensile strength of 1.8 GPa or greater.

A hot-pressed member having excellent bending collapsibility, a method for manufacturing the same, and a method for manufacturing a steel sheet for the hot-pressed member. The hot-pressed member includes a steel sheet as a base material, the steel sheet having a specified chemical composition. The hot-pressed member has a microstructure in which a martensite microstructure is present in a volume fraction of 70% or greater, and a number density of inclusions having a longest diameter of 25 μm or greater is 0.02/mm.sup.2 or less. The hot-pressed member has a tensile strength of 1.8 GPa or greater.

A method of producing a CoFe alloy strip is provided. The method comprises hot rolling a CoFe alloy to form a hot rolled strip, followed by quenching the strip from a temperature above 700° C. to a temperature of 200° C. The CoFe alloy comprises an order/disorder temperature T.sub.o/d and a ferritic/austenitic transformation temperature T.sub.α/γ, wherein T.sub.α/γ>T.sub.o/d. The method further comprises cold rolling the hot rolled strip, after cold rolling, continuous annealing the strip at a maximum temperature T.sub.1, wherein 500° C.<T.sub.1<T.sub.o/d, followed by cooling at a cooling rate R.sub.1 of at least 1 K/s in the temperature range of T.sub.1 to 500° C., and after continuous annealing, magnetic annealing the strip, or parts manufactured from the strip, at a temperature between 730° C. and T.sub.α/γ.

In a hot-rolled steel sheet, an average pole density of an orientation group of {100}<011> to {223}<110>, which is represented by an arithmetic average of pole density of each orientation of {100}<011>, {116}<110>, {114}<110>, {112}<110>, and {223}<110> in a center portion of a sheet thickness which is a range of the sheet thickness of ⅝ to ⅜ from a surface of the steel sheet, is 1.0 or more and 4.0 or less, the pole density of a crystal orientation of {332}<113> is 1.0 or more and 4.8 or less, an average grain size in a center in the sheet thickness is 10 μm or less, and a microstructure includes, by a structural fraction, pearlite more than 6% and ferrite in the balance.

Provided are a coated steel sheet and so forth, the coated steel sheet having a tensile strength of 590 MPa or more and good stretch-flangeability. The coated steel sheet includes a specific component composition, in which the area fraction of a ferrite phase is 80% or more and 98% or less, the area fraction of a martensite phase of 2% or more and 15% or less, ferrite grains have an average thickness of 3.0 μm or less in the sheet-thickness direction, the martensite phase has an average grain size of 2.0 μm or less, and a Nb-containing carbide precipitated in the ferrite grains has an average grain size of 8 nm or less, and in which the steel sheet has a tensile strength of 590 MPa or more.

Provided are a coated steel sheet and so forth, the coated steel sheet having a tensile strength of 590 MPa or more and good stretch-flangeability. The coated steel sheet includes a specific component composition, in which the area fraction of a ferrite phase is 80% or more and 98% or less, the area fraction of a martensite phase of 2% or more and 15% or less, ferrite grains have an average thickness of 3.0 μm or less in the sheet-thickness direction, the martensite phase has an average grain size of 2.0 μm or less, and a Nb-containing carbide precipitated in the ferrite grains has an average grain size of 8 nm or less, and in which the steel sheet has a tensile strength of 590 MPa or more.

This glass bonding material (21) is made of a cladding material (1) in which at least a first layer (11) made of an Al-based alloy and configured to be bonded to glass and a second layer (12) made of an Fe—Ni based alloy having a thermal expansion coefficient from 30° C. to 400° C. of 11.5×10.sup.−6 (K.sup.−1) or less are bonded.

Provided is a low thermal expansion alloy that contains, in mass %, not more than 0.015% of C, not more than 0.10% of Si, not more than 0.15% of Mn, 35.0-37.0% of Ni, and less than 2.0% of Co. Ni+0.8Co is 35.0-37.0%, and the remaining portion is Fe and unavoidable impurities. The low thermal expansion alloy has a solidification structure in which the secondary dendrite-arm spacing is 5 μm or less, has an average thermal expansion coefficient in a range of 0±0.2 ppm/° C. at 100° C. to −70° C., and has an Ms point of −196° C. or less.

An RFeB system sintered magnet which does not contain a heavy rare-earth element R.sup.H (Dy, Tb and Ho) in a practically effective amount and yet is suited for applications in which the magnet undergoes a temperature increase during its use. The RFeB system sintered magnet contains at least one element selected from the group consisting of Nd and Pr as a rare-earth element R in addition to Fe and B while containing none of Dy, Tb and Ho, the magnet having a temperature characteristic value t.sub.(100-23) which satisfies −0.58<t.sub.(100-23)<0, where t.sub.(100-23) is defined by the following equation:

[00001]$t_{\left(100-23\right)}=\frac{H_{\mathrm{cj}}\left(100\right)-H_{\mathrm{cj}}\left(23\right)}{\left(100-23\right)\times H_{\mathrm{cj}}\left(23\right)}\times 100$

using H.sub.cj(23) which is the value of the coercivity at a temperature of 23° C. and H.sub.cj(100) which is the value of the coercivity at a temperature of 100° C.