130 results about "Stress corrosion cracking" patented technology

The invention relates to the technical field of aluminum alloy, in particular to a high-strength corrosion-resistant aluminum alloy material and a preparation method and application thereof.The high-strength corrosion-resistant aluminum alloy material comprises, by weight, 4.5%-8.5% of Mg, 3.5%-5.5% of Zn, 0.8%-1.6% of Cu, at least two of the following elements with the total content not larger than 0.5%: 0.05%-0.15% of Mn, 0.05%-0.15% of Cr, 0.05%-0.12% of Ti, 0.06%-0.16% of Sc, 0.08%-0.14% of Er, 0.06%-0.12% of Zr and the balance Al and inevitable impurities. The total content of the impurities does not exceed 0.4%, and the balance is Al. Wherein the mass ratio of Mg to Zn is 1.1-2.0, when Sc and Zr exist at the same time, (Sc + Zr) is larger than or equal to 0.15% and smaller than or equal to 0.2%, when Er and Zr exist at the same time, (Er + Zr) is larger than or equal to 0.16% and smaller than or equal to 0.24%, and each impurity element is smaller than or equal to 0.15%. The exfoliation corrosion, stress corrosion and salt spray corrosion performance of the alloy is greatly improved by controlling the content and mass ratio of all the elements, and the exfoliation corrosion performance of the alloy is not lower than the P level; in a slow strain rate tensile test in saline water, the attenuation proportion of the elongation is not greater than 9% compared with that of an inert medium, and good stress corrosion cracking resistance is shown; in a 960h neutral salt spray corrosion test, the average corrosion rate is not greater than 0.1 g / (m < 2 >. H).

The invention discloses corrosion resistance test equipment for a skylight cross beam, relates to the technical field of cross beam tests, and aims to solve the technical problems that a corrosion test of a static placement cross beam sample cannot reflect the influence of dynamic stress on corrosion cracks in the cross beam, and particularly whether stress corrosion cracking can be caused in a salt spray environment or not. Comprising a salt spray testing machine, the salt spray testing machine comprises a test box body, a plurality of test rack assemblies are arranged in an inner cavity of the test box body, each test rack assembly comprises a static test rack and a dynamic test rack, each dynamic test rack comprises a rhombic movable rack, and each rhombic movable rack comprises an upper pressing block, a lower falling block, two symmetrically-arranged bearing blocks and four movable rods. A jolting pressing assembly is arranged at the bottom of the upper pressing block. The device has the advantages that the cross beam sample is in a dynamic stress state in a salt spray corrosion test, the stress condition of the cross beam in actual use is truly simulated, and the test environment is highly close to the actual working condition.

The invention discloses a stress corrosion crack propagation simulation and prediction method and system based on a phase field method. The method comprises the following steps: constructing a stress corrosion dynamic evolution model based on the phase field method; the stress corrosion dynamic evolution model is a control equation set for coupling a displacement field, a material concentration field and a crack phase field to carry out stress corrosion cracking evolution; establishing a discrete numerical value format for analyzing the stress corrosion dynamic evolution model, and performing simulation program development of the stress corrosion dynamic evolution model based on an ABAQUS platform according to the discrete numerical value format; and acquiring a specific load working condition, and performing stress corrosion crack growth rate simulation prediction on the nuclear reactor primary circuit 690 alloy material under different working conditions based on a developed simulation program to obtain the crack growth rate. According to the invention, the phase-field function is introduced to describe the crack morphology to simulate the stress corrosion crack propagation, and the rule of the stress corrosion crack propagation of the primary loop 690 alloy under different working conditions is accurately simulated.

The invention relates to a method for evaluating the influence of hydrogen and anode dissolution coupling on stress corrosion fracture of pipeline steel, which comprises the following steps: (1) respectively carrying out slow strain rate tensile tests in an acid environment and a nitrogen environment, and determining the damage degree of the acid environment on the mechanical property of a pipeline steel sample; (2) carrying out potentiodynamic polarization curve test on the pipeline steel sample by respectively adopting slow-rate scanning and fast-rate scanning, and determining the potential range of a stress corrosion sensitive area; (3) respectively carrying out constant potential slow tensile test on the pipeline steel sample in an acid environment under the anode dissolution independent action starting potential and the hydrogen induced cracking independent action starting potential, and determining the damage degree of the anode dissolution and the hydrogen induced cracking to the mechanical property of the pipeline steel; and (4) determining the influence degree of the anode dissolution and hydrogen coupling effect on the stress corrosion fracture of the pipeline steel sample in the acid environment and the stress corrosion fracture contribution ratio. The method can accurately and quickly evaluate the stress corrosion resistance of the pipeline steel.

The present invention provides a stainless steel material which has high strength, excellent overall corrosion resistance and stress corrosion cracking resistance in a supercritical corrosive environment, and excellent low temperature toughness in an extremely low temperature environment. A stainless steel material according to the present disclosure has the chemical composition set forth in the description, and has a microstructure in which Fn1 defined by formula (1) is 150.0 or more, Fn2 defined by formula (2) is 24.0 or more, and which is composed of 30.0-85.0% by volume of a ferrite phase and 0.1-40.0% by volume of a retained austenite phase, with the balance being made up of a martensite phase. The yield strength is 552-758 MPa, and the amount of precipitated V in the stainless steel material is 0.005-0.130 mass%.　(1): Fn1 = 576.5 - 2660.7 × C - 7.8 × Cr - 11.3 × Mo - 20.9 × Ni - 10.6 × Cu (2): Fn2 = 2 × Cr + 2 × Mo + 19 × V + 28 × N - 887 × C

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

The invention discloses a method for predicting the service behavior of an oil and gas pipeline under a stress corrosion cracking condition, and belongs to the field of material performance analysis and prediction. Firstly, based on a convection diffusion equation, a real stress intensity factor of an oil and gas pipeline crack tip is used as an unknown quantity to obtain a stress distribution condition; then, applying boundary conditions and a crack propagation criterion in fracture mechanics, and performing preliminary calculation to obtain crack propagation behavior characteristics of the one-dimensional semi-analytical model; and finally, calibrating and calculating the diffusion coefficient of the material parameter in the one-dimensional semi-analytical model to obtain real full-life service time information of the oil and gas pipeline material. According to the method, the full-life behavior information of stress corrosion cracking can be quickly obtained, and a partial differential equation does not need to be solved; on the basis of fracture mechanics, the mechanism of repeated fracture and reconstruction of the passivation layer in the fracture process can be reproduced; the full-life service time of the oil and gas pipeline can be effectively predicted, and the parameter calibration method can be applied to other conditions and is wide in application range.

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

The invention relates to the field of material stress corrosion tests, in particular to a tubular clamp for a high-temperature and high-pressure supercritical carbon dioxide corrosion test and a use method. The tubular sample clamp is mainly composed of a stretching shaft adapter, a gantry pipe pressing clamp fixing bolt, a height adjusting nut, a tubular sample, a base threaded rod, a sample plug bolt and a gantry pipe pressing clamp, and the gantry pipe pressing clamp is mainly composed of a main frame, a pipe pressing clamp, a pipe containing frame, a fixing bolt hole, a gantry clamp screw, a rotary disc and a guide groove. The two groups of gantry pipe pressing clamps are respectively fixed on the stretching shaft adapter and the sample table with the height adjusting nut, and a tubular sample can be stably clamped by adjusting the two groups of gantry pipe pressing clamps and the height adjusting nut. The device is used for carrying out stress corrosion test on the tubular sample in a high-temperature and high-pressure S-CO2 medium, the stress corrosion cracking sensitivity of the tubular sample in S-CO2 is evaluated by adopting a slow strain rate tensile test, and the device has the characteristics of simple structure, convenience in operation, low cost and high practicability.

The invention discloses a reinforced high-pressure flange composite material containing nano tungsten carbide and a preparation method thereof.The composite material comprises, by weight, 96.0%-98.3% of base material SAF2205 duplex stainless steel, the duplex stainless steel comprises 21.0%-23.0% of chromium, 4.5%-6.5% of nickel, 2.5%-3.5% of molybdenum, 0.18%-0.25% of nitrogen, 0.01%-0.03% of carbon and the balance iron; a reinforcing phase: 0.5-1.5% of nano tungsten carbide, the particle size of which is 50-100 nm; the substance combination comprises the following components in percentage by weight: (a) 0.3-0.5% of molybdenum disulfide (MoS2) nanosheets with the thickness of 5-20 nm; (b) 0.1-0.3% of graphite fluoride micro powder with a particle size of 1-3 [mu] m; (c) 0.3 to 0.6 percent of V2O5-B2O3 composite oxide, wherein the weight ratio of V2O5 to B2O3 is 3 to 2; (d) 0.2 to 0.5 percent of Y2O3 surface modified nano silver (Ag-Y2O3) composite powder, wherein the diameter of a silver core is 20 to 50nm, and the thickness of a Y2O3 shell layer is 5 to 10nm; (e) 0.3-0.7% of a graphene / zirconium oxide (G / ZrO2) nano composite material, the weight ratio of graphene to ZrO2 is 1: 2, and the particle size of ZrO2 is 15-30 nm; the material combination solves the problem of stress corrosion cracking sensitivity of the duplex stainless steel flange in a high-temperature and high-pressure corrosive medium by forming a multistage interface regulation and control network and a shell-core-shell multilayer structure system.

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

The invention belongs to the technical field of heat exchanger manufacturing, and relates to a low-stress welding expansion forming method for a tube-tube plate of a large tubular heat exchanger. The method comprises the steps of preparation before welding, weld reinforcement size design, connection of a pipe and a pipe plate, welding quality evaluation, adhesion and expansion load determination and implementation and the like. The preparation before welding relates to a groove form, surface pretreatment, preheating and the like; the influence of the welding seam size on residual stress and mechanical strength is disclosed, and a surplus height design method based on residual stress control and meeting the strength requirement is provided so as to reduce stress concentration; carrying out full penetration strength welding on the tube and the tube plate by adopting automatic argon arc welding; the welding quality is ensured through nondestructive testing; hydraulic expansion connection is adopted in the adhesion expansion process, the influence of expansion connection loads on residual stress and sealing performance is revealed, an optimal expansion connection load design method is provided, and meanwhile the pipe expansion rate is evaluated; through the welding expansion method, the risk of stress corrosion cracking is reduced, the service life of equipment is prolonged, and the reliability of the large tubular heat exchanger is improved.

The invention discloses a method for rapidly determining a critical stress value of metal stress corrosion cracking, and belongs to the technical field of metal material corrosion and protection. According to the invention, the critical stress value can be directly and rapidly measured instead of a sensitivity coefficient evaluation index obtained by a conventional stress corrosion test, the sample number and the test period can be obviously reduced, the double-truncated-cone-shaped sample is designed and processed, and the cross section of a single truncated cone of the sample is linearly decreased from one end to the other end; and the continuous stress gradient generated when the constant load is applied is accurately controlled. A stress corrosion test is carried out in a corrosive medium through a constant load method, and a critical stress value of stress corrosion cracking of the material in a corrosive environment is measured according to a loaded load and the maximum cross section area of cracks generated in the double-circular-truncated-cone-shaped sample. By utilizing the method, the stress corrosion cracking critical stress values of different metal materials can be efficiently and quickly measured, so that a basis is provided for section design and allowable load of engineering components and medical instruments.

The invention relates to the technical field of pipe fitting welding, and particularly discloses an automobile air conditioner connecting pipeline welding method.The automobile air conditioner connecting pipeline welding device comprises a welding device, the welding device comprises a bottom plate and bearing pipes, the bearing pipes are symmetrically and fixedly connected to the upper surfaces of the two sides of the bottom plate, and sliding rods are symmetrically and fixedly connected to the upper surface of the middle of the bottom plate; the top of the sliding rod is slidably connected with a high-frequency vibration auxiliary welding gun. According to the bronze drum, the rare earth element cerium is added into the welding wire, a local dehumidification device is combined for use, the chloride ion corrosion problem of an automobile air conditioner pipeline in the marine climate environment is effectively solved, the cerium element reacts with invaded chloride ions to generate a stable cerium-chlorine compound protection layer, the corrosion path is blocked, and the corrosion resistance of the automobile air conditioner pipeline is improved. And meanwhile, the welding environment humidity is strictly controlled to be below 30% through the local dehumidification device, the condition that water participates in electrochemical corrosion is eliminated from the source, stress corrosion cracks are completely eliminated, and the durability of the welding structure in the coastal area is remarkably improved.

There are provided a vacuum pump which can effectively prevent stress corrosion cracking of a rotating body and has excellent corrosion resistance, and a rotating body of the vacuum pump. In a vacuum pump (e.g., a turbo-molecular pump 100) exhausting gas by rotation of a rotating body 103, the rotating body 103 has, on a surface thereof, a first area 1 covered with a first surface treatment layer 1A and a second area 2 covered with a second surface treatment layer 2A, and a boundary portion 3 between the first area 1 and the second area 2 has an area in which the surface treatment layers 1A and 1B of the first and second areas 1 and 2 overlap each other.

To provide a testing and evaluation method for stress corrosion cracking resistance of metallic materials, which is excellent in evaluation reproducibility and evaluation accuracy.SOLUTION: There is provided a method for testing and evaluating stress corrosion cracking resistance of metallic materials, in which a tensile stress is applied to a test piece so as to produce a predetermined initial strain, and the change in the tensile stress is evaluated in a corrosive gas atmosphere.SELECTED DRAWING: Figure 1

Provided are a steel sheet having excellent ammonia stress corrosion cracking resistance, excellent low-temperature toughness, small change in mechanical characteristics due to PWHT treatment, and high strength, and a method for producing the steel sheet.　The steel sheet contains, by mass%, a specific content of C, Si, Mn, P, S, Al, Ti, Mo, Ca, N, and O, and satisfies 0.05 ≤ 2 × Cr + Mo + V + W ≤ 0.60, the remainder being Fe and unavoidable impurities. The steel sheet has a steel structure composed of ferrite and a hard structure other than the ferrite at a position 1 / 4 of the sheet thickness from the surface of the steel sheet, the volume fraction of ferrite is 60-90%, the average crystal grain size of the ferrite is 3-15 μm, the average hardness of the hard structure is 250 HV0.01 to 350 HV-0.01, 60% or more of the hard structure in terms of volume fraction is adjacent to ferrite without being adjacent to the hard structure, and the yield strength is 325-440 MPa.

The disclosure belongs to a technical field of a stress corrosion cracking test, and specifically discloses a quantitative evaluation method and system for stress corrosion susceptibility of a pipeline steel welding connector. Through the disclosure, bending tests in a hydrogen sulfide environment is combined with a slow strain rate tensile test to obtain a limit value / range of the stress corrosion susceptibility of the welding connector. Resistance of the welding connector to stress corrosion cracking is unqualified when it is greater than the limit value / exceeds the limit range, otherwise it is qualified.

To provide forged material of aluminum alloy, the forged material enabling increase of strength and improvement of stress corrosion cracking resistance to be made compatible with each other.SOLUTION: Forged material of aluminum alloy 11 contains Mg:0.50 mass% or more and 1.25 mass% or less, Si:0.40 mass% or more and 1.40 mass% or less, Cu:0.50 mass% or more and 1.00 mass% or less, Fe:0.05 mass% or more and 0.40 mass% or less, and Ti:0.005 mass% or more and 0.10 mass% or less, contains at least one kind selected from Mn and Cr within the range of Mn:0.50 mass% or more and 1.20 mass% or less, and Cr:0.20 mass% or more and 0.33 mass% or less, and the balance consisting of Al and inevitable impurities. Further, an average value [ΔVmax average] of the maximum potential difference between a matrix and an Al-(Fe,Mn,Cr)-Si-based compound having a circle equivalent diameter of 1.0 μm or more is 144 mV or less.SELECTED DRAWING: Figure 1A

The invention discloses a method and a system for regulating and controlling residual stress of a high-strength aluminum alloy thin-wall ribbed member. The invention relates to the field of material processing, and aims to solve the problems that in the prior art, macro-micro coupling residual stress of a high-strength aluminum alloy thin-wall ribbed component is difficult to systematically and cooperatively regulate and control, and processing deformation, size out-of-tolerance and stress corrosion cracking are easily caused. The method comprises the steps that tensile preload is applied to the component, 0.2%-0.8% of global inelastic strain is generated, and unloading is carried out after load holding; high-frequency ultrasonic vibration is applied to the surface of the component, and the local alternating stress amplitude is not lower than 10% of the local residual stress value of a corresponding area; the lowest temperature is less than or equal to-150 DEG C, and the heating and cooling rate is controlled between 0.5 DEG C / min and 5 DEG C / min. After being treated by the method, the residual stress peak value of the component is obviously reduced, the dimensional stability is greatly improved, the microstructure is optimized, and the service performance is enhanced.

The utility model discloses a stress corrosion cracking auxiliary generation device, which is applied to the corrosion degree detection field, and comprises a fixed frame, a fixed plate is welded in the fixed frame, the top of the fixed plate is provided with a placing plate, the bottom of the fixed plate is rotatably connected with a threaded rod through a bearing, and the threaded rod is provided with a screw. The surface of the threaded rod is in threaded connection with a moving plate, connecting rods are symmetrically welded between the top of the moving plate and the placing plate, a fixing seat is mounted at the top of the placing plate, the surface of the fixing seat is in threaded connection with a fixing cylinder, and a mounting mechanism is arranged at the top of the fixing seat. The device can have a height adjusting function, is suitable for corrosion detection of samples with different lengths, is good in flexibility and stability, can have a stress applying function, accelerates the corrosion detection speed of the samples, enables personnel to clearly and visually know the damage degree of the samples, and is high in practicability.

The invention relates to the technical field of alloys, in particular to a high-toughness corrosion-resistant industrial aluminum alloy for a new energy automobile and a preparation method of the high-toughness corrosion-resistant industrial aluminum alloy. According to the aluminum alloy, magnesium-lanthanum co-doped calcium-phosphorus particles are introduced to serve as a sacrificial phase, aluminum-zirconium and aluminum-erbium dispersed phases are combined to form a stable framework, and the solute cluster gradient is constructed in the thickness direction of a plate through a non-isothermal pre-aging process. The preparation method comprises the steps of intermediate alloy preparation, smelting and casting, homogenizing heat treatment, rolling, solid solution quenching, non-isothermal pre-aging and pre-stretching forming. The alloy is excellent in comprehensive performance, corrosion resistance and stress corrosion cracking resistance are remarkably improved while high strength and good bake hardening response are guaranteed, and the alloy is particularly suitable for new energy automobile body structural parts.

A kind of thick-wall acid-resistant pipeline steel X65MS hot rolling process method, the chemical composition of steel is as follows: C=0.03%~0.04%, Si=0.2%~0.4%, Mn=1.0%~1.2%, Cr=0.2%~0.4%, Cu=0.2%~0.3%, Ni=0.1%~0.4%, Mo=0.10%~0.25%, Nb=0.03%~0.04%, Ti=0.01%~0.015%, Ce=0.004%~0.006%, S≤0.004%, P≤0.008%, the balance is Fe and inevitable impurities;Production is carried out using continuous casting billet with thickness of 360mm and above, and the finished product thickness is 40~55mm;Three-stage rolling process and the matched intermediate billet cooling and post-rolling ultra-fast cooling process are used, the obtained pipeline steel has CLR≤10%, CSR≤1%, CTR≤1% in hydrogen-induced cracking (HIC) experiment under the condition of NACE solution immersion for 96 hours;In sulfide stress corrosion cracking (SSCC) experiment, no crack is found under the condition of four-point bending constant load nominal yield of 90% for 720 hours.

The present invention relates to martensitic stainless steel having high strength and hydrogen sulfide stress corrosion resistance, and a manufacturing method therefor. The martensitic stainless steel of the present invention has a high yield strength of 125 ksi or higher level (yield strength being greater than or equal to 862 MPa), also has excellent resistance to sulfide stress corrosion cracking (SSC), is suitable for a service environment having an H2S partial pressure of 0.1 bar, and still maintains good corrosion resistance in a high-concentration CO2 environment at a temperature as high as 177°C. The stainless steel of the present invention can be processed into a variety of product forms such as bars, plates, steel pipes, etc., and is widely applicable to application scenarios that have strict requirements on material strength and corrosion resistance, such as oil and natural gas production equipment and carbon dioxide capture, utilization and storage (CCUS) systems.

The invention discloses austenitic stainless steel resistant to corrosion and stress corrosion cracking in supercritical carbon dioxide and a preparation method thereof.The austenitic stainless steel is prepared from, by mass, 24%-26% of nickel, 19.5%-20.5% of chromium, 0.6%-0.8% of manganese, 0.5%-0.7% of silicon, 0.5%-0.7% of niobium and the balance iron and inevitable impurities, and the mass fraction of nickel is 24%-26%, the mass fraction of chromium is 19.5%-20.5%, the mass fraction of manganese is 0.6%-0.8%, the mass fraction of silicon is 0.5%-0.7%, and the mass fraction of niobium is 0.5%-0.7%. The mass fraction of nitrogen is 0.04-0.12%, the mass fraction of carbon is 0.02-0.05%, and the balance is Fe; and the composite material has excellent corrosion resistance and stress corrosion cracking resistance in a supercritical carbon dioxide environment. The austenitic stainless steel prepared through the method has the advantages of being small in corrosion weight increment, good in creep property, long in stress corrosion crack initiation time, low in stress corrosion crack propagation rate and the like in the 650 DEG C / 15 MPa supercritical carbon dioxide service environment.

The application discloses a kind of based on residual stress threshold value corrosion cracking resistance heat treatment optimization method, belong to heat treatment numerical simulation research technical field, to solve the problem of high risk of stress corrosion cracking in weld heat-affected zone.Method includes determining the postweld residual tensile stress of inner wall weld heat-affected zone according to the cylindrical structure and physical properties of different materials;Four-point bending specimen is prepared, and target sample is prepared by annealing and bending moment loading;Residual tensile stress is loaded and finite element calculation is carried out for loading displacement;The residual stress threshold value of corrosion cracking is defined by electrochemical test on target sample;According to residual stress threshold value and combined with heating strip width basic formula, heat-mechanical coupling finite element simulation is carried out, and the optimized width correction coefficient is screened, to obtain the adaptive heating strip width design formula and complete optimization.The application can accurately determine the residual stress threshold value, optimize the heating strip width, improve the corrosion cracking resistance of component, and has economy and industrial value.

The invention relates to the technical field of sulfur-resistant drill rod testing, in particular to a method for preparing a uniaxial tensile sample for a sulfide stress corrosion cracking test, which comprises the following steps of: polishing the uniaxial tensile sample along the axial direction of the uniaxial tensile sample, so that axial scratches with uniform surface quality are formed on the polished surface; performing anti-hydrogen sulfide coating spraying treatment on the surface of the clamping section of the uniaxial tensile sample; the uniaxial tensile sample is polished in the axial direction of the uniaxial tensile sample, so that annular machining traces are avoided, meanwhile, the surface of the clamping section is subjected to hydrogen sulfide resistant coating spraying treatment, and breakage of the uniaxial tensile sample caused by surface quality defects such as transverse machining traces and transverse scratches in the scale distance and transition arc area is effectively avoided; and meanwhile, the risk of invalid fracture at the sealing part of the clamping section due to crevice corrosion is avoided.

To provide an ammonia stress corrosion cracking (SCC) acceleration test method capable of evaluating ammonia stress corrosion cracking sensitivity of a metal material with excellent accuracy in a short period.SOLUTION: In an ammonia stress corrosion cracking acceleration test method, a metal test piece to which external stress is added or which has residual stress is immersed in ammonium carbamate of 0.01 mass% or more and liquid ammonia containing O2 of 0.002 to 0.200 bar at a gas partial pressure, and is polarized to more than +1.0 V relative to corrosion potential.SELECTED DRAWING: None

Provided are a TIG welding method and a TIG welded joint which are excellent in terms of resistance to SCC by ammonia. This TIG welding method is for forming a weld metal on a steel material using an inert shielding gas and a welding wire, wherein the steel material and the welding wire have specific chemical compositions and welding conditions are set so that the carbon equivalent Ceq of the welding wire shown by expression (1) is 0.24-0.36, the welding heat input Q is 35.0 kJ / cm or less, and the index P shown by expression (2) using the plate thickness t and the welding heat input Q is 0.15-0.45. (1): Ceq=[C]+[Mn] / 6+([Cr]+[Mo]+[V]) / 5+([Ni]+[Cu]) / 15 (2): P=(Ceq+0.06)×t / Q

The utility model relates to a furnace shell repairing structure of a blast furnace top combustion type hot blast stove, belongs to the field of ferrous metallurgy, and aims to solve the problem of cracking of a furnace shell in the using process of the top combustion type hot blast stove. According to the structure, a layer of outer layer furnace shell is welded outside a cracked furnace shell between a burner brick support and a combustion chamber brick support of the top combustion type hot blast stove, so that a new integral structure is formed. And a gap is reserved between the new outer-layer furnace shell and the original inner furnace shell, so that the air pressure borne by the hot blast stove and the gas sealing effect are met. According to the scheme, an outer protective layer is arranged outside the outer-layer furnace shell, so that the temperature of the outer-layer furnace shell is kept higher than the acid dew point temperature, and the influence of extreme climate on the furnace shell is reduced. Meanwhile, a device used for monitoring the displacement change of the inner furnace shell and the outer furnace shell is arranged on the outer furnace shell and used for judging the working state of the inner furnace shell and giving out early warning when the inner furnace shell fails. The scheme can effectively solve the general industrial problem of stress corrosion cracking of the furnace shell, and ensures the safe operation of the hot-blast stove.