Kobe Steel, Ltd.

Voestalpine Stahl Gmbh

Keisuke Okita

Shushi Ikeda

Junya Naitou

Toshio Murakami

Mariko Yamada

Tomokazu Nakagawa

Shinji Sato

Hideo Hata

Takemasa Yamasaki

Takeshi Yamada

Andreas Pichler

Thomas Kurz

Atsushi Yoshida

Kenji Murakami

Masahiro Miyagawa

A method for producing an additively manufactured object includes melting and solidifying a filler metal by use of an arc, and depositing and forming a plurality of layers of molten beads to produce a built-up object, and the method includes: shaping the molten bead of a previous layer; and monitoring a temperature of the molten bead of the previous layer. Shaping of the molten bead of a next layer is started when the temperature of the molten bead of the previous layer is equal to or lower than an allowable interpass temperature.

Method and system for manufacturing laminated shaped product

Provided are a residual stress estimation method and a residual stress estimation device capable of estimating residual stress suitable for a structure in which inherent strain occupied mainly by plastic strain occurs. A constraint condition is introduced to a distribution function used in the residual stress estimation method based on an inherent strain method, the constraint condition being that a plastic-worked structure does not undergo volume change before and after working. Residual stress or elastic strain is measured from a T piece collected from the structure, and a parameter of the distribution function is optimized so as to approximate the inherent strain at each measurement point obtained from the measured value of the residual stress or elastic strain. An estimated value of the residual stress in the structure is calculated using the obtained parameter.

Residual stress estimation method and residual stress estimation device

A steel sheet for hot pressing includes in a chemical composition, in percent by mass, C of 0.1% to 0.4%, Si of greater than 0% to 2.0%, Mn of 0.5% to 3.0%, P of greater than 0% to 0.015%, S of greater than 0% to 0.01%, B of 0.0003% to 0.01%, N of greater than 0% to 0.05%, Al in a content of 2&#xd7;[N]% to 0.3% at a Si content of greater than 0.5% to 2.0%; or Al in a content of (0.20+2&#xd7;[N]&#x2212;0.40&#xd7;[Si]N)% to 0.3% at a Si content of 0% to 0.5%, where [N] and [Si] are contents of N and Si, respectively, in mass percent, with the remainder being iron and inevitable impurities, where contents of Ti, Zr, Hf, and Ta, of the inevitable impurities, are each controlled to 0.005% or lower. The steel sheet includes nitride-based inclusions with an equivalent circle diameter of 1 &#x3bc;m or more in a number density of 0.10 per square millimeter.

Steel sheet for hot pressing and hot pressed article using the same

Provided is a residual stress estimation method and a residual stress estimation device capable of suppressing the number of cut pieces to be collected for measuring inherent strain without deteriorating residual stress estimation accuracy. In a case where it is assumed that the inherent strain is uniformly distributed in one direction in a structure, a user measures residual stress from a cut piece collected in a region in which the inherent strain is uniformly distributed and inputs the measured value to the residual stress estimation device. The residual stress estimation device estimates a two-dimensional inherent strain distribution on an analysis surface perpendicular to the one direction in the structure using the input residual stress measured value, transfers the estimated two-dimensional inherent strain distribution to the one direction, and estimates a three-dimensional inherent strain distribution in the structure.

A rotary machine unit equipped with rotary shaft provided so as to penetrate the respective opposing surfaces of a first casing and a second casing arranged opposing one another, said rotary machine unit also being equipped with at least two engagement mechanisms equipped with a first engaging part provided on the opposing surface of the first casing and extending radially along the direction from the center part penetrated by the rotary shaft toward the circumferential edge part, and a second engaging part provided on the opposing surface of the second casing so as to engage the first engaging part in a state in which the first engaging part is able to move in the extension direction of the first engaging part. The engagement mechanisms are provided inclined with respect to one another when viewed from the axial direction of the rotary shaft.

Rotary machine unit

Provided is a residual stress estimation method and a residual stress estimation device which are capable of setting an appropriate analysis range without depending on a user's experience. The residual stress estimation device displays analysis results in which strain generated in a structure is analyzed. A user determines a position and a size of an analysis range based on the analysis results, and inputs the determined position and size of the analysis range and a measured value of residual stress of a cut piece of the structure at a measurement point to the residual stress estimation device. The residual stress estimation device estimates distribution of inherent strain in the analysis range to approximate the inherent strain distribution obtained from the input measured value of the residual stress of the cut piece, thereby estimating the residual stress of the structure based on the inherent strain.

A method capable of accurately measuring, in an object including a columnar shaft section and a tabular section projecting outward radially beyond an outer circumferential surface of the shaft section, a distribution of residual stress near a fillet surface interconnecting the shaft section and the tabular section. The method includes repeating a measurement cycle, which includes cutting the object to form a new cutting surface and measuring residual stress in a plurality of parts on the cutting surface. The cutting surface is a conical or cylindrical surface concentric with the axis of the shaft section, being through a reference position unchanged in the repeated measurement cycle. The reference position is desirably the center position of an arc of the fillet surface having the largest diameter on the central longitudinal cross-section of the object.

Residual stress measuring method

In the present invention, a press-formed product is manufactured by heating a steel sheet for hot pressing use to a temperature of 900&#xb0; C. or above and 1,100&#xb0; C. or below, the steel sheet for hot pressing use having a predetermined chemical component composition, some of Ti-containing precipitates contained in the steel sheet, each of which having an equivalent circle diameter of 30 nm or less, having an average equivalent circle diameter of 6 nm or less, and the precipitated Ti amount and the total Ti amount in the steel fulfilling the relationship represented by formula (1) shown below, thereafter starting press-forming, and holding at the bottom dead point and cooling to a temperature lower than the martensite transformation starting temperature Ms while securing the average cooling rate of 20&#xb0; C./s or more within a tool.Precipitated Ti amount(mass %)&#x2212;3.4[N]&#x3c;0.5&#xd7;[total Ti amount (mass %)&#x2212;3.4[N]]&#x2003;&#x2003;(1)(In the formula (1), [N] represents the content (mass %) of N in the steel.).

Method for manufacturing press-formed product and press-formed product

A hot-press formed product can be achieved which has regions corresponding to a shock resistant portion and an energy absorption portion within a single formed product without applying a welding method and achieves the balance of high strength and elongation with a high level according to each region by means of having a first forming region exhibiting a metal structure containing martensite: 80-97 area % and retained austenite: 3-20 area % respectively, the remaining structure being 5 area % or less, and a second forming region exhibiting a metal structure containing annealed martensite or annealed bainite: 30-97 area %, martensite as quenched: 0-67 area %, and retained austenite: 3-20 area %.

Hot-press formed product and method for manufacturing same

Provided is a hot-press molded article that can achieve a high level of balance between high strength and extension by region and has a region corresponding to an energy absorption site and a shock resistant site within a single molded article without applying a welding method by means of having first region having a metal structure containing both 80-97 area % of martensite and 3-20 area % of residual austenite, the remaining structure comprising no more than 5 area %, and a second region having a metal structure comprising 30-80 area % of ferrite, less than 30 area % (exclusive of 0 area %) of bainitic ferrite, no greater than 30 area % (exclusive of 0 area %) of martensite, and 3-20 area % of residual austenite.

There is provided a hot press-formed product, including a thin steel sheet formed by a hot press-forming method, and having a metallic structure that contains bainitic ferrite at 70% to 97% by area, martensite at 27% by area or lower, and retained austenite at 3% to 20% by area, the remainder structure of which is at 5% by area or lower, whereby balance between strength and elongation can be controlled in a proper range and high ductility can be achieved.

Hot press-formed product and process for producing same

There is provided a hot press-formed product, including a thin steel sheet formed by a hot press-forming method, and having a metallic structure that contains retained austenite at 3% to 20% by volume, whereby balance between strength and elongation can be controlled in a proper range and high ductility can be achieved.

Process for producing hot press-formed product

Provided is a press-forming product manufacturing method of manufacturing a forming product having satisfactory formability for a drawing process by press-forming a metal sheet using a press-forming tool with high productivity, including: heating the metal sheet to a transformation temperature Acor more; cooling the metal sheet to 600&#xb0; C. or lower; forming the metal sheet by a forming tool; ending the forming process at a martensite transformation start temperature Ms or more; taking out the metal sheet from the forming tool; and cooling the metal sheet.

Press-forming product manufacturing method and press-forming facility

There is provided a useful method for producing a press-formed product without making the structure of a press tool complicated, which product has favorable formability in a level so as to be able to be produced by deep drawing, and which product is produced by press-forming a thin steel sheet with a punch and a die, in which the thin steel sheet is heated to a temperature not lower than an Actransformation point thereof, and the press-forming is then started, wherein the forming is carried out so that a temperature difference in the thin steel sheet is adjusted to be not higher than 200&#xb0; C. at a stage when the thin steel sheet has reached one third of a forming height.

Method for producing press-formed product

There is provided a useful method for producing a press-formed product without causing disadvantages such as hardness variation, which product has favorable formability in a level so as to be able to be produced by deep drawing, and which method is carried out by heating a thin steel sheet to a temperature not lower than an Actransformation point thereof; and then cooling the thin steel sheet at a rate not lower than a critical cooling rate, during which the thin steel sheet is formed into the press-formed product, wherein the forming is started from a temperature higher than a martensitic transformation start temperature Ms thereof, the cooling rate is kept to be 10&#xb0; C./sec. or higher during the forming, and the forming is finished in a temperature range not higher than the martensitic transformation start temperature Ms.

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Kobe, Japan

Keisuke Okita