This high strength austenitic stainless steel having excellent resistance to hydrogen embrittlement includes, in terms of mass %, C: 0.2% or less, Si: 0.2% to 1.5%, Mn: 0.5% to 2.5%, P: 0.06% or less, S: 0.008% or less, Ni: 10.0% to 20.0%, Cr: 16.0% to 25.0%, Mo: 3.5% or less, Cu: 3.5% or less, N: 0.01% to 0.50%; and O: 0.015% or less, with the balance being Fe and unavoidable impurities, in which an average size of precipitates is 100 nm or less and an amount of the precipitates is 0.001% to 1.0% in terms of mass %.

A fastener for connecting a first housing part of a steam or gas turbine to a second housing part of the turbine which is made of a parent metal with a high degree of stress relaxation.

A predetermined composition is had, when a C content is represented by (C %), in a case of (C %) being not less than 0.35% nor more than 0.65%, a volume fraction of pearlite is 64×(C %)+52% or more, and in a case of (C %) being greater than 0.65% and 0.85% or less, the volume fraction of pearlite is not less than 94% nor more than 100%, and a structure of the other portion is composed of one or two of proeutectoid ferrite and bainite. Further, in a region to a depth of 1.0 mm from a surface, a volume fraction of pearlite block having an aspect ratio of 2.0 or more is not less than 70% nor more than 95%, and a volume fraction of pearlite having an angle between an axial direction and a lamellar direction on a cross section parallel to the axial direction of 40° or less is 60% or more with respect to all pearlite.

Provided is a method for nitriding a grain-oriented electrical steel sheet which is very useful in obtaining excellent magnetic properties with no variation, that enables generating glow discharge between positive electrodes and negative electrodes disposed in a nitriding zone and irradiating the generated plasma to a strip to perform appropriate nitriding.

The present invention has as its object to provide thickness 60 μm or less ultra-thin stainless steel foil which secures high thickness precision and simultaneously secures plastic deformability and good elongation at break, that is, secures good press-formability (deep drawability). The present invention solves this problem by ultra-thin stainless steel foil which has three or more crystal grains in a thickness direction, has a recrystallization rate of 90% to 100%, and has a nitrogen concentration of a surface layer of 1.0 mass % or less. For this reason, there is provided a method of production of stainless steel foil comprising rolling stainless steel sheet, then performing final annealing and making a thickness 5 μm to 60 μm, wherein a rolling reduction ratio at rolling right before final annealing is 30% or more, a temperature of final annealing after rolling is 950° C. to 1050° C. in the case of austenitic stainless steel and 850° C. to 950° C. in the case of ferritic stainless steel, and a nitrogen content in atmospheric gas in final annealing is 0.1 vol % or less, whereby ultra-thin stainless steel foil can be produced.

An apparatus for manufacturing a rack bar includes a pre-forming machine forming a flattened portion on an outer peripheral surface of a hollow shaft member, a teeth forming machine forming rack teeth on the flattened portion, a heat treatment machine quenching the rack teeth, a first conveying machine carrying the shaft member into and from the pre-forming machine, a second conveying machine carrying the shaft member into and from the teeth forming machine, and a third conveying machine carrying the shaft member into and from the heat treatment machine. The first conveying machine, the second conveying machine, and the third conveying machine hold one end of the shaft member from a radially inner side of the shaft member. The apparatus of the rack bar are suitable for manufacturing a relatively short hollow rack bar having rack teeth formed over substantially an entire length of a shaft member.

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 μm, ≥300/μm.sup.2 Ti precipitates with an equivalent circular particle size of ≤30 nm disperse, Sb segregates to prior austenite grain boundaries.

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 μm, ≥300/μm.sup.2 Ti precipitates with an equivalent circular particle size of ≤30 nm disperse, Sb segregates to prior austenite grain boundaries.

The invention relates to steel with a specific composition of the following elements: 0.25%≤C≤0.35%, 0.80%≤Cr≤1.50%, 0.50%≤Ni≤1.50%, 0.0010%≤B≤0.0050%, 0.010%≤Ti≤0.060%, 0.40%≤Mn≤1.00% and 0.003%≤N≤0.0150%, whereby after being subjected to a quench and tempering treatment, the characteristics required by the ISO 898-1 standard for class 10.9 and class 12.9 bolts, screws and studs are achieved, while at the same time achieving high fatigue strength values. The use of this steel allows achieving the mentioned characteristics in large-sized parts or elements (up to a diameter of 75 mm), considerably reducing the alloying costs compared with the steels used today.

Method of manufacturing of components used in the field of aviation aircraft and, specifically, an aircraft engine nacelle lipskin. Instead of spinning flat plates, this method uses spinning a cylinder, thus eliminating waste material. It also eliminates the need for rivet lines which results in better laminar flow. Further, there is a reduction of other costs in addition to reducing drag.