A Sm—Fe—N magnet includes Sm—Fe—N particles each having a surface, a coating layer being provided on at least a portion of the surface or on at least a portion of an interface between at least two of the Sm—Fe—N particles, or being provided on both, wherein the coating layer includes a first layer and a second layer, the first layer being situated closer to the surface or the interface than is the second layer, he first layer includes α-Fe, the second layer includes a Sm—Fe—Zn alloy, and a Zn content contained in the second layer is 1 at % or more and 20 at % or less.

Disclosed is, as a high-strength steel plate of API X80 grade or higher with a thickness of 38 mm or more, a thick steel plate for structural pipes or tubes that exhibits high strength in the rolling direction and excellent Charpy properties at its mid-thickness part without addition of large amounts of alloying elements. The thick steel plate for structural pipes or tubes disclosed herein has: a specific chemical composition; a microstructure at its mid-thickness part that is a dual-phase microstructure of ferrite and bainite with an area fraction of the ferrite being less than 50%, and that contains ferrite grains with a grain size of 15 μm or less in an area fraction of 80% or more with respect to the whole area of the ferrite; a tensile strength of 620 MPa or more; and a Charpy absorption energy vE.sub.−20+ C. at −20° C. at the mid-thickness part of 100 J or more.

Disclosed is, as a high-strength steel plate of API X80 grade or higher with a thickness of 38 mm or more, a thick steel plate for structural pipes or tubes that exhibits high strength in the rolling direction and excellent Charpy properties at its mid-thickness part without addition of large amounts of alloying elements. The thick steel plate for structural pipes or tubes disclosed herein has: a specific chemical composition; a microstructure at its mid-thickness part that is a dual-phase microstructure of ferrite and bainite with an area fraction of the ferrite being less than 50%, and that contains ferrite grains with a grain size of 15 μm or less in an area fraction of 80% or more with respect to the whole area of the ferrite; a tensile strength of 620 MPa or more; and a Charpy absorption energy vE.sub.−20+ C. at −20° C. at the mid-thickness part of 100 J or more.

The present disclosure is directed at methods of preparing rare earth-based permanent magnets having improved coercivity and remanence, the method comprising one or more steps comprising: (a) homogenizing a first population of particles of a first GBM alloy with a second population of particles of a second core alloy to form a composite alloy preform, the first GBM alloy being substantially represented by the formula: AC.sub.bR.sub.xCo.sub.yCu.sub.dM.sub.z, the second core alloy being substantially represented by the formula G.sub.2Fe.sub.14B, where AC, R, M, G, b, x, y, and z are defined; (b) heating the composite alloy preform particles to form a population of mixed alloy particles; (c) compressing the mixed alloy particles, under a magnetic field of a suitable strength to align the magnetic particles with a common direction of magnetization and inert atmosphere, to form a green body; (d) sintering the green body; and (e) annealing the sintered body. Particular embodiments include magnets comprising neodymium-iron-boron core alloys, including Nd.sub.2Fe.sub.14B.

The present disclosure is directed at methods of preparing rare earth-based permanent magnets having improved coercivity and remanence, the method comprising one or more steps comprising: (a) homogenizing a first population of particles of a first GBM alloy with a second population of particles of a second core alloy to form a composite alloy preform, the first GBM alloy being substantially represented by the formula: AC.sub.bR.sub.xCo.sub.yCu.sub.dM.sub.z, the second core alloy being substantially represented by the formula G.sub.2Fe.sub.14B, where AC, R, M, G, b, x, y, and z are defined; (b) heating the composite alloy preform particles to form a population of mixed alloy particles; (c) compressing the mixed alloy particles, under a magnetic field of a suitable strength to align the magnetic particles with a common direction of magnetization and inert atmosphere, to form a green body; (d) sintering the green body; and (e) annealing the sintered body. Particular embodiments include magnets comprising neodymium-iron-boron core alloys, including Nd.sub.2Fe.sub.14B.

The invention relates a duplex ferritic austenitic stainless steel having high formability utilizing the TRIP effect and high corrosion resistance with the balanced pitting resistance equivalent. The duplex stainless steel contains less than 0.04 weight % carbon, less than 0.7 weight % silicon, less than 2.5 weight % manganese, 18.5-22.5 weight % chromium, 0.8-4.5 weight % nickel, 0.6-1.4 weight % molybdenum, less than 1 weight % copper, 0.10-0.24 weight % nitrogen, the rest being iron and inevitable impurities occurring in stainless steels.

To provide an austenitic stainless steel material having a high creep strength and a high creep ductility even in a high-temperature environment at 800° C. or more. An austenitic stainless steel material according to the present disclosure has a chemical composition that includes, in mass %: C: 0.060% or less; Si: 1.0% or less; Mn: 2.00% or less; P: 0.0010 to 0.0400%; S: 0.010% or less; Cr: 10 to 25%; Ni: 25 to 45%; Nb: 0.2 to 2.0%; W: 2.5 to 6.0%; B: 0.0010 to 0.0100%: Al: 2.5 to 4.5%; and the balance being Fe and impurities, and satisfies Formulae (1) and (2), and the sum of the content of dissolved Nb and the content of dissolved W is 3.2 mass % or more.
(W/184+Nb/93)/(C/12)≥5.5  (1)
(W/184+Nb/93)/(B/11)≤450  (2) In Formulae (1) and (2), the content in mass % of the corresponding element is substituted for each symbol of element.

A method of making sintered components made from an iron-based powder composition and the sintered component per se. The method is especially suited for producing components which will be subjected to wear at elevated temperatures, consequently the components consists of a heat resistant stainless steel with hard phases including chromium carbo-nitrides. Examples of such components are parts in turbochargers for internal combustion engines.

A metal powder having a composition including the following elements, expressed in content by weight: 6.5%≤Si≤10%, 4.5%≤Nb≤10%, 0.2%≤B≤2.0%, 0.2%≤Cu≤2.0%, C≤2% and optionally containing Ni≤10 wt % and/or Co≤10 wt % and/or Cr≤7 wt % and/or Zr as a substitute for any part of Nb on a one-to-one basis and/or Mo as a substitute for any part of Nb on a one-to-one basis and/or P as a substitute for any part of Si on a one-to-one basis, the balance being Fe and unavoidable impurities resulting from the elaboration, the metal powder having a microstructure including at least 5% in area fraction of an amorphous phase, the balance being made of crystalline ferritic phases with a grain size below 20 μm and possible precipitates, the metal powder having a mean sphericity SPHT of at least 0.80.

Provided is a valve seat insert for an internal combustion engine, which has both an excellent heat dissipation property and excellent wear resistance. The valve seat insert for an internal combustion engine is used while being press-fitted into an aluminum alloy cylinder head, is made of an iron-based sintered alloy, is formed by integrating two layers of a functional member side layer and a supporting member side layer, and has a plating film on at least an outer peripheral side. The plating film is preferably a copper plating film. The plating film is a plating film having a thickness of 1 to 100 μm and a hardness of 50 to 300 HV, and the hardness of the plating film is adjusted so as to satisfy a range of 1.05 to 4.5 times hardness of the cylinder head in Vickers hardness HV. Pores contained in the valve seat insert are preferably sealed with a curable resin before plating treatment. Consequently, a valve seat insert for an internal combustion engine which does not go through complicated processes, is not accompanied by a significant decrease in wear resistance compared with the prior art, and has an excellent heat dissipation property is provided. If a roughened surface region is further formed at at least one portion on the outer peripheral surface of the valve seat insert in addition to the plating film, a falling out resistance property is improved. The same effect can be obtained even if the valve seat insert is a single layer of only the functional member side layer.