Patent application number | Description | Published |
20080264521 | Chemical conversion film formation-evaluating liquid for steel - A chemical conversion film formation-evaluating liquid for steel comprising an iron-dissolving liquid and a pH indicator, wherein pH value of the evaluating liquid is confined within the range of 4.0-8.0 with a lower limit of pH transition interval of the pH indicator being larger than the pH value, as a whole, of the evaluating liquid by a value of 0.1-3.0. | 10-30-2008 |
20120024436 | HIGH-STRENGTH AND HIGH-DUCTILITY STEEL FOR SPRING, METHOD FOR PRODUCING SAME, AND SPRING - A steel for spring includes C: 0.5 to 0.6%, Si: 1.0 to 1.8%, Mn: 0.1 to 1.0%, Cr: 0.1 to 1.0%, P: 0.035% or less, S: 0.035% or less, by mass %, and residue consisting of iron and inevitable impurities, as the overall composition, wherein an area ratio of an internal structure on an optional cross section comprises bainite: 65% or more, retained austenite: 6 to 13%, and martensite: residue (including 0%), and average C content in the retained austenite is 0.65 to 1.7%. The steel for spring can have high strength in which tensile strength is 1800 MPa or more and have high ductility. | 02-02-2012 |
20120168042 | NANOCRYSTAL TITANIUM ALLOY AND PRODUCTION METHOD FOR SAME - A titanium alloy has high strength and superior workability and is preferably used for various structural materials for automobiles, etc. The titanium alloy is obtained by the following production method. An alloy having a structure of α′ martensite phase is hot worked at conditions at which dynamic recrystallization occurs. The working is performed at a heating rate of 50 to 800° C./second at a strain rate of 0.01 to 10/second when the temperature is 700 to 800° C. or at a strain rate of 0.1 to 10/second when the temperature is more than 800° C. and less than 1000° C. so as to provide a strain of not less than 0.5. Thus, equiaxed crystals with an average grain size of less than 1000 nm are obtained. | 07-05-2012 |
20120318407 | SPRING STEEL AND SURFACE TREATMENT METHOD FOR STEEL MATERIAL - A surface treatment method for a steel material includes carbonitriding, quenching, and tempering. The steel material consists of, by weight %, 0.27 to 0.48% of C, 0.01 to 2.2% of Si, 0.30 to 1.0% of Mn, not more than 0.035% of P, not more than 0.035% of 8, and the balance of Fe and inevitable impurities. The carbonitriding step is performed by heating the steel at a temperature of not less than the A | 12-20-2012 |
20130008566 | SPRING AND METHOD FOR PRODUCING SAME - A spring consists of, by weight %, 0.27 to 0.48% of C, 0.01 to 2.2% of Si, 0.30 to 1.0% of Mn, not more than 0.035% of P, not more than 0.035% of S, and the balance of Fe and inevitable impurities. The spring has a nitrogen compound layer and a carbon compound layer at the surface at a total thickness of not more than 2 μm. The spring has a center portion with hardness of 500 to 700 HV in a cross section and has a compressive residual stress layer at a surface layer. The compressive residual stress layer has a thickness of 0.30 mm to D/4, in which D (mm) is a circle-equivalent diameter of the cross section, and has maximum compressive residual stress of 1400 to 2000 MPa. | 01-10-2013 |
20130118655 | SPRING AND MANUFACTURE METHOD THEREOF - A spring consists of, by mass %, 0.5 to 0.7% of C, 1.0 to 2.0% of Si, 0.1 to 1.0% of Mn, 0.1 to 1.0% of Cr, not more than 0.035% of P, not more than 0.035% of S, and the balance of Fe and inevitable impurities. The spring has a structure including not less than 65% of bainite and 4 to 13% of residual austenite by area ratio in a cross section. The spring has a compressive residual stress layer in a cross section from a surface to a depth of 0.35 mm to D/4, in which D (mm) is a circle-equivalent diameter of the cross section. The spring has a high hardness layer with greater hardness than a center portion by 50 to 500 HV from a surface to a depth of 0.05 to 0.3 mm. | 05-16-2013 |
20130149183 | HIGH-STRENGTH TITANIUM ALLOY MEMBER AND PRODUCTION METHOD FOR SAME - A production method for a titanium alloy member includes preparing a titanium alloy material for sintering as a raw material of a sintered body; nitriding the titanium alloy material for sintering, thereby forming a nitrogen compound layer and/or a nitrogen solid solution layer in a surface layer of the titanium alloy material for sintering and yielding a nitrogen-containing titanium alloy material for sintering; mixing the titanium alloy material for sintering and the nitrogen-containing titanium alloy material for sintering, thereby yielding a titanium alloy material for sintering mixed with nitrogen-containing titanium alloy material; sintering the titanium alloy material for sintering mixed with nitrogen-containing titanium alloy material, thereby bonding the material each other and dispersing nitrogen contained in the nitrogen-containing titanium alloy material for sintering in a condition in which nitrogen is uniformly dispersed into an entire inner portion of the sintered body by solid solution. | 06-13-2013 |
20130195711 | HIGH-STRENGTH MAGNESIUM ALLOY WIRE ROD, PRODUCTION METHOD THEREFOR, HIGH-STRENGTH MAGNESIUM ALLOY PART, AND HIGH-STRENGTH MAGNESIUM ALLOY SPRING - A high-strength magnesium alloy wire rod suitable for products in which at least one of bending stress and twisting stress primarily acts is provided. The wire rod has required elongation and 0.2% proof stress, whereby strength and formability are superior, and has higher strength in the vicinity of the surface. In the wire rod, the surface portion has the highest hardness in a cross section of the wire rod, the highest hardness is 170 HV or more, and the inner portion has a 0.2% proof stress of 550 MPa or more and an elongation of 5% or more. | 08-01-2013 |
20130284325 | NANOCRYSTAL-CONTAINING TITANIUM ALLOY AND PRODUCTION METHOD THEREFOR - An alloy having an α′ martensite which is a processing starting structure is hot worked. The alloy is heated at a temperature increase rate of 50 to 800° C./sec, and strain is given at not less than 0.5 by a processing strain rate of from 0.01 to 10/sec in a case of a temperature range of 700 to 800° C., or by a processing strain rate of 0.1 to 10/sec in a case of a temperature range of 800° C. to 1000° C. By generating equiaxial crystals having average crystal particle diameters of less than 1000 nm through the above processes, a titanium alloy having high strength and high fatigue resistant property can be obtained, in which hardness is less than 400 HV, tensile strength is not less than 1200 MPa, and static strength and dynamic strength are superior. | 10-31-2013 |
20140008852 | SPRING AND MANUFACTURE METHOD THEREOF - A spring with superior fatigue resistance is provided by decreasing the material cost while simplifying the production process. Disclosed is a spring including: a composition consisting of, by mass %, 0.5 to 0.7% of C, 1.0 to 2.0% of Si, 0.1 to 1.0% of Mn, 0.1 to 1.0% of Cr, not more than 0.035% of P, not more than 0.035% of S, and the balance of Fe and impurities; a structure including not less than 95% of tempered martensitic structure; a compressive residual stress layer formed to a depth of 0.35 mm to D/4, in which D (mm) is a diameter; the compressive residual stress layer having maximum compressive residual stress of 800 to 2000 MPa; a center portion with Vickers hardness of 550 to 700 HV; and a high hardness layer with greater hardness than the center portion. | 01-09-2014 |
20140112819 | TITANIUM ALLOY MEMBER AND PRODUCTION METHOD THEREFOR - A titanium alloy member with high strength and high proof stress not only in the surface but also inside, using a general and inexpensive α-β type titanium alloy, and a production method therefor, are provided. The production method includes preparing a raw material made of titanium alloy, nitriding the raw material to form a nitrogen-containing raw material by generating a nitrogen compound layer and/or a nitrogen solid solution layer in a surface layer of the raw material, mixing the raw material and the nitrogen-containing raw material to yield a nitrogen-containing mixed material, sintering the nitrogen-containing mixed material to obtain a sintered titanium alloy member by bonding the material together and uniformly diffusing nitrogen in solid solution from the nitrogen-containing raw material to the entire interior portion of the sintered titanium alloy member, and hot plastic forming the sintered titanium alloy member. | 04-24-2014 |
20140212319 | TITANIUM ALLOY MEMBER AND PRODUCTION METHOD THEREFOR - A high strength titanium alloy member with superior fatigue resistance, and a production method therefor, are provided. The production method includes preparing a raw material made of titanium alloy, nitriding the raw material to form a nitrogen-containing raw material by generating a nitrogen compound layer and/or a nitrogen solid solution layer in a surface layer of the raw material, mixing the raw material and the nitrogen-containing raw material to yield a nitrogen-containing mixed material, sintering the nitrogen-containing mixed material to obtain a sintered titanium alloy member by bonding the material together and uniformly diffusing nitrogen in solid solution from the nitrogen-containing raw material to the entire interior portion of the sintered titanium alloy member, hot plastic forming and/or heat treating the sintered titanium alloy member to obtain a processed member, and surface treating the processed member to provide compressive residual stress. | 07-31-2014 |
20140306389 | COMPRESSION COIL SPRING AND METHOD FOR PRODUCING SAME - A compression coil spring having high durability can be provided by using an inexpensive wire material. The present invention provides a compression coil spring formed by using a steel wire material, the steel wire material made of C: 0.45 to 0.85 mass %, Si: 0.15 to 2.5 mass %, Mn: 0.3 to 1.0 mass %, Fe and inevitable impurities as a remainder, and a circle-equivalent diameter of 1.5 to 9.0 mm, wherein hardness of a freely selected cross-section of the wire material is 570 to 700 HV, and at an inner diameter side of the coil spring, unloaded compressive residual stress at a depth of 0.2 mm from a surface in an approximate maximal main stress direction in a case in which compressive load is loaded on the spring is 200 MPa or more, and unloaded compressive residual stress at a depth of 0.4 mm from surface is 100 MPa or more. | 10-16-2014 |