38 results about "Charpy impact test" patented technology

To provide a welded joint which has excellent low-temperature toughness, is suppressed in stress corrosion cracking caused by liquefied ammonia, and has 490 MPa or more of tensile strength, and a method for manufacturing the welded joint.SOLUTION: A welded joint has a base metal, a weld metal, and a welding heat affected zone. In the welded joint, each of the base metal and the weld metal has a chemical composition of a specific range, the area fraction of bainite structure from 1 / 4 thickness to 3 / 4 thickness in the sheet thickness direction from the surface of the base metal is 90% or more, Vickers hardness at the 1 mm position in the sheet thickness direction from the surface of the base metal is 210 or less, Vickers hardness in the welding heat affected zone is 210 or less, Vickers hardness in the weld metal is HVW or less (HVW=260-200×Ni), the tensile strength of the base metal and the welded joint is 490 MPa or more, and the absorption energy of the base metal and the weld metal in Charpy impact test is 47 J or more at -40°C.SELECTED DRAWING: None

To provide a high strength stainless clad steel plate excellent in stress corrosion cracking resistance and low temperature toughness and a producing method thereof.SOLUTION: A stainless clad steel plate comprises a base material and a laminating material formed on the base material, wherein the laminating material has a specific composition, the base material has a specific composition, a yield strength of 620 MPa or more, a tensile strength of 700 MPa or more, and an absorbed energy of 47 J or more when a Charpy impact test is conducted at -40°C, and the clad steel sheet has a shear strength of SH: 0.87×((t+T)×YSC-T×YSB) / t or more, a yield strength of 620 MPa or more, and a tensile strength of 700 MPa or more.SELECTED DRAWING: None

To provide a welded joint which has excellent low-temperature toughness and is suppressed in stress corrosion cracking caused by liquefied ammonia, and has 570 MPa or more of tensile strength, and a method for manufacturing the joint.SOLUTION: A welded joint is provided, having has a base metal, a weld metal, and a welding heat affected zone, each of the base metal and the weld metal has a chemical composition of a specific range, the area fraction of a bainite structure from 1 / 4 thickness to 3 / 4 thickness in the sheet thickness direction from the surface of the base metal is 90% or more, Vickers hardness at the 1 mm position in the sheet thickness direction from the surface of the base metal is 230 or less, Vickers hardness in the welding heat affected zone is 230 or less, Vickers hardness of the weld metal is HVW or less (HVW=260-100×Ni), the tensile strength of the base metal and the welded joint is 570 MPa or more, and the absorption energy of the base metal and the weld metal in Charpy impact test is 47 J or more at -40°C.SELECTED DRAWING: None

Provided are: a welded joint and a high-strength cladding steel plate that is excellent in ammonia SCC resistance, low-temperature toughness, and bondability and is suitable for conveying liquid ammonia and supplying the same to a storage tank and the like; and a method for manufacturing said cladding steel plate and said welded joint.　The cladding steel plate includes: a base material having a prescribed chemical component; and a cladding material having a prescribed chemical component bonded to at least one surface (the surface serving as the inner surface). The tensile strength of the base material is 780 MPa or more, the absorption energy of the base material according to a Charpy impact test at -40°C is 47 J or more, the maximum hardness of the cladding material is 210 HV or less, and the bonding rate of the base material and the cladding material is 70% or more.

The present invention provides a method for constructing a prediction model for the high-order energy of the ductile-brittle transition of high-strength structural steel. By conducting Charpy impact tests, dynamic tearing tests and tensile tests, a correlation analysis is conducted on the high-order energy of the impact ductile-brittle transition and the high-order energy of the dynamic tearing ductile-brittle transition, and a prediction model for the high-order energy of the impact ductile-brittle transition and the high-order energy of the dynamic tearing ductile-brittle transition is established. The present invention establishes a correlation model between the high-order energy of the impact ductile-brittle transition and the high-order energy of the dynamic tearing ductile-brittle transition and tensile performance characterization parameters through the correlation analysis of the high-order energy of the impact ductile-brittle transition and the high-order energy of the dynamic tearing ductile-brittle transition. The prediction model can be established through the tensile performance parameters measured at room temperature, and can achieve quantitative evaluation of the high-order energy of the ductile-brittle transition of high-strength structural steel, providing a technical basis for the improvement and improvement of the toughness and fracture resistance design of high-strength structural steel. The prediction model has a clear physical mechanism, is simple to construct and is quick to use.

The steel of the present disclosure contains, in mass %, C: 0.100% to 0.700%, Si: 0.05% to 1.00%, Mn: 20.0% to 40.0%, P: ≤0.030%, S: ≤0.0050%, Al: 0.01% to 5.00%, Cr: 0.5% to 7.0%, N: 0.0050% to 0.0500%, O: ≤0.0050%, Ti: ≤0.005%, Nb: ≤0.005%, and at least one selected from Ca: 0.0005% to 0.0100%, Mg: 0.0005% to 0.0100%, and REM: 0.0010% to 0.0200%, and has a microstructure with austenite as matrix, where an average grain size is 50 μm or less, a cleanliness of sulfide inclusion is less than 1.0%, a yield strength is 400 MPa or more, and a percent brittle fracture after a Charpy impact test at −269° C. is less than 5%.

The present invention provides a high-strength clad steel plate and welded joint that are excellent in ammonia SCC resistance, low-temperature toughness and joinability and are suitable for use in tanks for transporting and storing liquid ammonia, and a method for manufacturing the same. This is a clad steel plate having a base material with a specified chemical composition and a clad material with a specified chemical composition on at least one surface (the inner surface), in which the tensile strength of the base material is 620 MPa or more, the absorbed energy of the base material in a Charpy impact test at -50°C is 47 J or more, and the bonding rate between the base material and the clad material is 70% or more.

To provide a low-cost steel sheet having high strength and high toughness, and a method for manufacturing the same.SOLUTION: A steel plate has a chemical composition, by mass %, C:0.080 to 0.160%, Si:0.08 to 0.25%, Mn:0.90 to 1.50%, P:0.020% or less, S:0.010% or less, Cr:0.50 to 1.50%, Mo:0.25 to 0.45%, V:0.020 to 0.060%, Nb:0.005 to 0.020%, Al:0.010 to 0.050%, N:0.0010 to 0.0070%, B:0.0006 to 0.0015% in mass%, and the balance comprised of Fe and impurities, the steel plate has such a metallographic structure that the total area ratio of tempered bainite and tempered martensite is 95.0% or more, the average crystal grain diameter of prior γ grains is 35.0 μm or less, the steel plate has a tensile strength of 710 to 930 MPa, and the yield stress of 630 MPa or more, the absorption energy of Charpy impact test at -20°C is 100 J or more, and the thickness of the steel plate is more than 60 mm and 150 mm or less.SELECTED DRAWING: None

The present invention relates to the technical field of pipeline mechanical property testing, and in particular to a method and system for improving the tensile strain capacity of pipelines and the reliability of girth weld joints. The method and system use testing methods such as hardness cloud diagrams, Charpy impact tests, and wide plate tensile tests to test the performance of pipelines containing girth weld joints, thereby ensuring the reliability of the girth weld joints and ensuring that the tensile failure mode of the pipeline is the yield failure of the pipeline base material of the girth weld joint or the ductile tear failure at the girth weld joint, thereby improving the tensile strain capacity of pipelines such as natural gas pipelines, reducing the risk of low-stress brittle fracture of girth weld joints under geological disaster conditions, and ensuring the safe operation of the pipeline.

The present invention provides a high-strength clad steel plate and welded joint that are excellent in ammonia SCC resistance, low-temperature toughness and joinability and are suitable for use in tanks for transporting and storing liquid ammonia, and a method for manufacturing the same. A clad steel plate having a base material with a specified chemical composition and a clad material with a specified chemical composition bonded to at least one surface (the inner surface), in which the base material has a tensile strength of 780 MPa or more, an absorbed energy of 47 J or more in a Charpy impact test at -40°C, and a bonding rate between the base material and the clad material of 70% or more.

There is provided a martensitic stainless steel seamless pipe having a yield stress of 758 MPa or more, an absorbed energy of 100 J or more at -80°C in a Charpy impact test, and an excellent corrosion resistance. The martensitic stainless steel seamless pipe has a chemical composition including, in % by mass: C: 0.005 to 0.100%; Si: 0.05 to 1.00%; Mn: 0.05 to 1.00%; P: 0.05% or less; S: 0.005% or less; Ni: 6.0 to 9.0%; Cr: 15.0 to 17.5%; Al: 0.001 to 0.10%; Nb: 0.001 to 0.20%; N: 0.1% or less; O: 0.01% or less; Cu: 3.5% or less; Mo: less than 1.0%; and W: 1.0% or less, the balance being Fe and incidental impurities, the composition satisfying particular inequalities (1) and (2).

Provided is a submerged arc welding method that produces little fume, has good weldability, and is suitable for welding high-Mn-containing steel materials to be used in cryogenic environments. The method includes welding with a combination of a wire having a predetermined chemical composition and flux having a basicity [BL] of 1.5 to 2.4, while adjusting a welding heat input according to a groove cross-sectional area. In this way, a weld metal with high strength and excellent cryogenic impact toughness where the 0.2% proof stress at room temperature is 400 MPa or more and an absorbed energy (vE−196) in the Charpy impact test is 28 J or more can be easily manufactured.

Provided are: a high-strength clad steel sheet having excellent ammonia SCC resistance, low temperature toughness, and bondability, and that is suitable for liquid ammonia transport, storage tanks, or the like; a welded joint; and a method for manufacturing these.　The clad steel sheet comprises: a base material having prescribed chemical components; and a cladding material having prescribed chemical components and bonded to at least one surface (surface serving as an inner surface). In the base material, the tensile strength is 780 MPa or more, the absorption energy according to the Charpy impact test at -40°C is 47 J or more, and the bonding rate of the base material and the cladding material is 70% or more.

A method for evaluating the toughness reliability of a tank, comprising the steps of: acquiring a required fracture toughness value on the basis of the change over time of a stress amplification factor and the design life of the tank; a step of acquiring a transition temperature of the material from a Charpy transition curve based on a Charpy impact test of the tank; acquiring a fracture toughness value according to a fracture toughness test of the material of the tank; a step for acquiring design tolerance conditions on the basis of the relationship between a temperature index, which is the reciprocal of the difference between each test temperature and the transition temperature, and the fracture toughness value at each test temperature; acquiring a required temperature index according to the design allowable condition and the required fracture toughness value; a step of acquiring an allowable Charpy transition curve having a required transition temperature based on the required temperature index; and a step for evaluating the toughness reliability of the material of the can on the basis of the allowable Charpy transition curve.

The present invention provides a welded joint having a weld metal obtained by submerged arc welding at a linear energy of 300 kJ / cm or more. A submerged arc welded joint in which the weld metal has a specific composition, a specific yield strength, a specific tensile strength, a specific absorbed energy in a V-notch Charpy impact test at a test temperature of 0°C, and Ceq represented by the following formula (1) is in the range of 0.65 to 1.00, and α represented by the following formula (2) is in the range of 6.0 or less. Ceq = [C] + 0.17[Mn] + 0.04[Si] + 0.025[Ni] + 0.2[Cr] + 0.25[Mo] … (1) α = 30[C] + 0.7[Mn] + [Ni] - ([Si] + 0.5[Cr] + 1.5[Mo]) … (2) Here, [element] in formula (1), formula (2) is the content (mass %) of the element in the above-described weld metal.

Provided is a high strength steel plate for a sour-resistant line pipe with excellent low-temperature toughness as well as HIC and SSCC resistance. The high strength steel plate for a sour-resistant line pipe has a chemical composition containing, by mass%, C: 0.030-0.060%, Si: 0.01-0.50%, Mn: 0.80-1.80%, P: 0.015% or less, S: 0.0015% or less, Al: 0.010-0.080%, Cr: 0.05-0.50%, Nb: 0.005-0.080%, N: 0.0010-0.0080%, and Ca: 0.0005-0.0050%, with the balance being Fe and inevitable impurities, in which a microstructure at 0.25 mm below a surface of the steel plate consists of granular bainite and tempered martensite austenite constituent, a maximum grain size is 80 µm or less and an average grain size is 20 µm or less at a mid-thickness position of the steel plate, a brittle-ductility transition temperature in a Charpy impact test is -100 °C or lower, and a tensile strength is 535 MPa or more.

A liquid hydrogen tank having a tank in contact with liquid hydrogen, made of steel whose absorbed energy sE, measured by impact tests at a measurement temperature of -196°C or below using a three-sided slit Charpy impact test specimen, satisfies the following formula 1 or formula 2. sE≧19+0.68×ΔT···Formula 1 In Equation 1, the measured temperature is in the range of greater than -253°C and less than or equal to -196°C, and ΔT is the temperature difference between the measured temperature and -253°C. sE≧19...Equation 2 In Equation 2, the measurement temperature is -253°C or lower.

Provided is a liquid hydrogen tank that comprises a tank that comes into contact with liquid hydrogen and is formed from a steel material that has absorption energy sE measured by an impact test at a measurement temperature of -196°C or lower using a three-surface slit Charpy impact test specimen, the absorption energy sE satisfying expression 1 or expression 2:　expression 1: sE≥19+0.68×ΔT, in expression 1, the measurement temperature is within a range from more than −253°C to no more than -196°C, and ΔT is a temperature difference between the measurement temperature and −253°C;　expression 2: sE≥19, in expression 2, the measurement temperature is −253°C or less.

The invention discloses a method for positioning the minimum energy absorption position of a Charpy impact sample and related equipment, and belongs to the field of weld Charpy impact tests.The method comprises the steps that firstly, Vickers hardness test data of the Charpy impact sample are obtained; fitting Vickers hardness test data to obtain a hardness point matrix, and drawing a hardness distribution color graph according to the hardness point matrix; and finally, the minimum energy absorption position of the Charpy impact sample is obtained through positioning by analyzing the hardness distribution color graph. According to the method, through fitting of Vickers hardness test data and drawing of a hardness distribution color graph, the position of the center line of the Charpy impact sample can be accurately determined, namely, the position of the minimum absorbed energy of the Charpy impact sample is positioned; according to the method, the distance between the center line of the Charpy impact sample of the pipeline steel pipe with the same specification and the same process and the fusion line can be accurately positioned, an important reference basis is provided for determining the position of the center line of the Charpy impact sample in the subsequent inspection process, and the data accuracy and the working efficiency are improved.

Provided is a steel sheet characterized by having a prescribed chemical composition, the average Vickers hardness (Hs) in a region extending from at least one surface to 10% of the sheet thickness being 0.60 times or less of the average Vickers hardness (Hc) in a position at 1 / 2 of the sheet thickness, the proportion of macroscopic brittle fractures in a Charpy impact test at room temperature being 35.0% or less, and the tensile strength being 1500 MPa or more.

Provided is a fiber-reinforced material obtained from recycled virgin materials, which has sufficient impact resistance. The fiber-reinforced material has quasi-isotropy, and contains fine pieces of a thermoplastic fiber-reinforced resin composite material before disposal, which have a length of greater than 15 mm and less than or equal to 100 mm, as a laminate having at least one fiber-reinforced sheet containing a reinforcing fiber base material and a thermoplastic matrix resin. In a Charpy impact test according to ISO 179-1, the Charpy impact strength of the fiber-reinforced material is 75% or greater of the maximum Charpy impact strength of the thermoplastic fiber-reinforced resin composite material before disposal, which is obtained by the following determination method. The fiber direction of the reinforcing fiber contained in the fiber-reinforced sheet constituting the outermost layer of the thermoplastic fiber-reinforced resin composite material before disposal is defined as 0°, and test pieces are cut out in the 0°, 45°, and 90° directions, respectively. The Charpy impact strength of each test piece is determined according to ISO 179-1. The maximum value among these is defined as the maximum Charpy impact strength.

Provided is a martensitic stainless steel seamless pipe having a yield stress of 758 MPa or more, an absorption energy of 100 J or more in a Charpy impact test at-80 DEG C, and excellent corrosion resistance. A martensitic stainless steel seamless pipe having a component composition that satisfies prescribed formulae (1) and (2) and contains, in mass%, 0.005 to 0.100% of C, 0.05 to 1.00% of Si, 0.05 to 1.00% of Mn, 0.05% or less of P, 0.005% or less of S, 6.0 to 9.0% of Ni, 15.0 to 17.5% of Cr, 0.001 to 0.10% of Al, 0.001 to 0.20% of Nb, 0.1% or less of N, 0.01% or less of O, 3.5% or less of Cu, less than 1.0% of Mo, and 1.0% or less of W, with the remainder being Fe and unavoidable impurities.

The present invention provides a method for manufacturing a welded joint having excellent toughness, and a welded joint.　The manufacturing method according to the present invention is a method for manufacturing a welded joint (1) comprising a steel material (4) and a plurality of layers of weld metal (31), wherein the weld metal (31) has a specific chemical composition, and the manufacturing method includes: a multi-layer overlay welding step in which layers, other than a first layer, are formed by weaving and are welded with a specific welding heat input amount such that the average layer height of each layer of the weld metal (31) in a range between a depth position of 5 mm from one surface of the steel material and a depth position of 5 mm from the other surface of the steel material is more than 0 mm and is 4.0 mm or less; and a heat treatment step in which heat treatment is performed at a temperature of 580°C to 620°C for 2 hours or more. A welded joint (1) according to the present invention comprises a steel material (4) and a plurality of layers of weld metal (31) having the specific chemical composition described above, wherein: the average layer height of each layer in the weld metal (31) is more than 0 mm and 4.0 mm or less; the average width of each layer is 15 mm or more; and the absorbed energy in a Charpy impact test at -40°C is 30 J or more.

To provide a thick steel plate which is excellent in low-temperature toughness, is suppressed in stress corrosion cracking caused by liquefied ammonia, and has 490 MPa or more of tensile strength, and a method for manufacturing the thick steel plate.SOLUTION: A thick steel plate is provided, which has a chemical composition of a specific range. In the thick steel plate, the area fraction of a bainite structure from 1 / 4 thickness to 3 / 4 thickness in the sheet thickness direction from the surface is 90% or more, Vickers hardness at the 1 mm position in the sheet thickness direction from the surface is 210 or less, the maximum value of the maximum hardness test measured on the basis of JIS Z 3101:1990 is 210 or less on Vickers hardness, the tensile strength is 490 MPa or more, and absorption energy in Charpy impact test is 47 J or more at -40°C.SELECTED DRAWING: None

The application provides a prediction and analysis method for the ductile-brittle transition temperature of high-strength structural steel material, which is determined by conducting Charpy impact tests and dynamic tear tests at a specific temperature, and establishing the ETT of the impact sample ductile-brittle transition temperature and the dynamic tear sample ductile-brittle transition temperature at the specific temperature 50 The correlation analysis establishes the impact ductile-brittle transition temperature and the dynamic tear ductile-brittle transition temperature and the specific temperature T 特定 The impact absorbed energy and the dynamic tear energy correlation model at the specific temperature. The prediction and analysis method for the ductile-brittle transition temperature of the high-strength structural steel material has a clear physical mechanism, greatly reduces the evaluation of the ductile-brittle transition test amount and calculation amount of the high-strength structural steel, is simple to construct, fast to use, and realizes the rapid prediction and evaluation of the impact sample ductile-brittle transition temperature and the dynamic tear sample ductile-brittle transition temperature.

The invention belongs to the technical field of Charpy impact tests, solves the problems of accuracy and consistency of test data caused by personal errors in a multi-test-temperature Charpy impact test in the prior art, and provides a multi-temperature Charpy test automatic impact device and equipment for a metal material. Comprising a sample introduction mechanism, a pretreatment mechanism, an impact testing machine and a transfer mechanism, a target sample is transferred in each link by utilizing the transfer mechanism, and the sample introduction mechanism is provided with a first auxiliary mechanism, a first propelling mechanism and a first buffer part matched with the first propelling mechanism; a target sample needing to be tested in the sample introduction mechanism is moved to a first target area of the sample introduction mechanism by utilizing the first auxiliary mechanism, and then the target sample in the first target area is pushed to the first buffer part by utilizing the first pushing mechanism so as to be taken by the transfer mechanism; manual feeding and discharging are not needed when a target sample is subjected to a Charpy impact test, errors caused by human intervention are reduced, and the test efficiency is improved.

The present invention provides a high-strength clad steel plate and welded joint that are excellent in ammonia SCC resistance, low-temperature toughness and joinability and are suitable for use in tanks for transporting and storing liquid ammonia, and a method for manufacturing the same. A clad steel plate having a base material with a specified chemical composition and a clad material with a specified chemical composition bonded to at least one surface (the surface that becomes the inner surface), in which the tensile strength of the base material is 780 MPa or more, the absorbed energy of the base material in a Charpy impact test at -40°C is 47 J or more, the maximum hardness of the clad material is 210 HV or less, and the bonding rate between the base material and the clad material is 70% or more.

The application belongs to the technical field of mechanical property test, and discloses a Charpy impact test sample processing method, which can obtain the impact test sample meeting the test standard by breaking the fracture groove on the second sample blank on the spot before the impact test, cancels the transfer and witness steps of the second transfer stamp, realizes the simplification of the witness process of the impact test sample processing, can effectively shorten the sample processing period, thereby guaranteeing the welding process evaluation progress and the timely feedback of the detection result of the production welding test plate, and further improving the production efficiency.

Provided is a high strength steel plate for a sour-resistant line pipe with excellent low-temperature toughness as well as HIC and SSCC resistance. The high strength steel plate for a sour-resistant line pipe has a chemical composition containing, by mass %, C: 0.030-0.060%, Si: 0.01-0.50%, Mn: 0.80-1.80%, P: 0.015% or less, S: 0.0015% or less, Al: 0.010-0.080%, Cr: 0.05-0.50%, Nb: 0.005-0.080%, N: 0.0010-0.0080%, and Ca: 0.0005-0.0050%, with the balance being Fe and inevitable impurities, in which a microstructure at 0.25 mm below a surface of the steel plate consists of granular bainite and tempered martensite austenite constituent, a maximum grain size is 80 μm or less and an average grain size is 20 μm or less at a mid-thickness position of the steel plate, a brittle-ductility transition temperature in a Charpy impact test is −100° C. or lower, and a tensile strength is 535 MPa or more.

The invention is intended to provide a duplex stainless steel and a method for manufacturing the same. A duplex stainless steel pipe is also provided. A duplex stainless steel of the present invention has a specific composition and microstructure containing an austenitic phase and a ferrite phase. The duplex stainless steel satisfies the following contents of C, Si, Mn, Cr, Mo, Ni, N, Cu, and W in formula (1) below, and has a yield strength YS of 655 MPa or more, and an energy absorption vE-10 of 40 J or more as measured by a Charpy impact test at a test temperature of -10°C. 0.55[%C] - 0.056[%Si] + 0.018[%Mn] - 0.020[%Cr] - 0.087[%Mo] + 0.16[%Ni] + 0.28[%N] - 0.506[%Cu] - 0.035[%W] + [%Cu*F] = 0.94 (1).