48 results about "Crevice corrosion" patented technology

A drive line component for a vehicle includes a half shaft including a housing having an axially outwardly facing surface, a wheel hub assembly including a wheel bearing having an axially inwardly facing surface, and a ring extending about the housing. The ring including a radially inwardly projecting flange portion arranged between the axially outwardly facing surface of the half shaft housing and the axially inwardly facing surface of the wheel bearing, a radially outwardly projecting flange portion, and a transition region extending between the radially inwardly projecting flange portion and the radially outwardly projecting flange portion. The transition region includes a first portion extending axially inwardly from the radially inwardly projecting flange portion, a second portion extending at an angle toward the radially outwardly projecting flange portion, and a third portion including a transition between the first portion and the second portion. The transition having a sharp edge.

The application relates to a Cr-Cu-Mo-Sb high weather-resistant steel and a preparation method thereof, and belongs to the technical field of weather-resistant steel, and solves the problems of insufficient corrosion resistance and insufficient crevice corrosion resistance of the Cr-Cu weather-resistant steel in the prior art. The application provides a Cr-Cu-Mo-Sb high weather-resistant steel, wherein the components in the high weather-resistant steel are as follows in percentage by mass: C: 0.055-0.080%, Si: 0.23-0.50%, Mn: 0.1-0.8%, Cr: 0.5-3.5%, Cu: 0.18-0.32%, Mo: 0.07-0.35%, Sb: 0.06-0.12%, and the balance is Fe and inevitable impurities. The high weather-resistant steel has excellent uniform corrosion resistance and crevice corrosion resistance, and has excellent strength and toughness matching; the yield strength is 250-440 MPa, the yield strength ratio ranges from 0.68 to 0.82, and the elongation after fracture is 20.5-31.0%.

The invention discloses a die-cast energy-saving cathode plate, which belongs to the technical field of electrochemical metallurgical equipment, and comprises a conducting rod, a main plate, an anti-corrosion wrapping material, a copper clamp, a cross beam, a fixing assembly, a lifting lug and a rotating assembly, a first mounting groove is formed in the bottom of the conducting rod, one end, with a hole, of the top of the main board is inserted into the groove and pre-fixed with the clamping block through the elastic piece, the anti-corrosion wrapping material and the clamping block are die-cast into a whole through the die-casting forming technology, a seamless sealing structure is formed, and the hole is filled to form mechanical interlocking; one end of the conducting rod fixes a copper clamp to connect an external power supply line. A second mounting groove is formed in the bottom of the cross beam; the fixing assembly realizes detachable locking of the conducting rod and the cross beam through a rotating rod, a sliding plate and other parts; the rotating assembly adjusts the angle of the lifting lug through a rotating shaft, a rotating disc, a limiting rod and other structures. According to the invention, the crevice corrosion problem is completely eradicated, the conductive efficiency and the connection stability are improved, the installation and maintenance are convenient, and the applicability is high.

The invention relates to the technical field of ship environmental protection equipment, and discloses a ship modular oily water separation tank with a composite anti-corrosion structure, which comprises an oil-water separation tank body and a round seal head, and high-corrosion risk pipes are arranged on the oil-water separation tank body and the round seal head. The polytetrafluoroethylene coating is arranged to improve the high temperature resistance and oily water corrosion resistance of the oil-water separation tank body and the round sealing head, the hot galvanizing layer is arranged to enhance the atmosphere moisture corrosion resistance of the oil-water separation tank body and the round sealing head, the zinc alloy sacrificial anode block and the outer walls of the oil-water separation tank body and the round sealing head form a primary battery, and an oxidation reaction is preferentially carried out; the inner-layer polytetrafluoroethylene sealing tape, the outer-layer polytetrafluoroethylene sealing tape and the silicon rubber anti-corrosion sealant form physical sealing, oily water is prevented from permeating into welding gaps, crevice corrosion is avoided, and a double barrier is formed with electrochemical protection.

The invention discloses a steel rail foot friction corrosion behavior research method, and belongs to the technical field of railway steel rail service performance research and failure mechanism evaluation. The research method comprises the following steps: preparing a U75V steel rail and PA66 lining cylindrical sample, constructing a test platform consisting of a control motor and an electrochemical test system, carrying out reciprocating friction and potentiodynamic and constant potential corrosion loading in a 3.5% NaCl solution, collecting corresponding corrosion current data, and analyzing the surface failure behavior. The invention aims to provide the method for researching the friction corrosion behavior of the rail foot of the steel rail, which is characterized in that a repeatable, controllable and low-cost test platform is constructed by simplifying an experimental device and combining a control motor and an electrochemical system, and a cooperative acceleration failure mechanism between fretting wear and crevice corrosion is disclosed.

The application discloses a kind of based on the coupling of electrochemical parameter gap corrosion evaluation method and device, it is related to electrochemical corrosion evaluation technical field.Gap corrosion evaluation method includes the following steps: based on gap structure establishes oxygen concentration cell, determines anode, cathode and its surface area;In the oxygen-poor medium environment, the anodic polarization curve of target material is measured, the cathodic polarization curve of target material is measured in the oxygen-rich medium environment, obtains anode current density-potential relationship and cathode current density-potential relationship;According to the electrochemical balance formula that total cathode current is equal to total anode current, the coupling potential of oxygen concentration cell is calculated, and further the gap corrosion current density corresponding to coupling potential is obtained, and the gap corrosion rate is calculated according to gap corrosion current density.The gap corrosion evaluation method provided by the application is suitable for the rapid prediction of initial stage of gap corrosion, with the characteristics of convenient, high repeatability, the result is more accurate.

The purpose of the present invention is to provide a gasket that can prevent crevice corrosion while maintaining a sealing property, which is basic performance for a gasket. The gasket for electrolysis according to the present invention is frame-shaped and has a hollow part on an inner periphery thereof, and moreover: at least one protrusion having a peripherally continuous height of 1 mm or greater is provided on one surface thereof; at least one groove having a peripherally continuous depth of 0.1 mm or greater is provided to the other surface thereof; and L1 / L2≤3 is satisfied, where L1 is the distance from the inner peripheral end to the protrusion provided most on the inner peripheral side, and L2 is the distance from the inner peripheral end to the groove provided most on the inner peripheral side.

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.

The invention discloses a fine evaluation clamp for metal and alloy crevice corrosion, and belongs to the technical field of metal corrosion simulation. The clamp comprises a lower clamping block and an upper clamping block, and the lower clamping block and the upper clamping block are oppositely arranged on the two sides of the metal hanging piece and locked through a fastener. A penetrating central through hole is formed in the lower clamping block, a protruding part is formed around the central through hole, and the protruding part is attached to the metal hanging piece. The lower clamping block is embedded into a groove of a hanging piece rod of the reaction kettle to be positioned and used, the metal hanging piece is arranged above the protruding structure, then the upper clamping block covers the metal hanging piece, the clamp is fastened through the fastening piece, and a stable structure is formed. In the experiment process, the clamp can provide consistent gap size and position while ensuring the stability of the hanging piece, so that the repeatability, controllability and scientificity of a gap corrosion experiment are effectively improved. The device is compact in structure, convenient to operate, high in adaptability and widely applicable to application scenes such as metal material corrosion resistance evaluation, corrosion mechanism research and corrosion protection material performance test.

The invention discloses a crevice corrosion test device, and relates to the technical field of environmental tests.The crevice corrosion test device comprises a test bed, an upper sample assembly, a lower test assembly and a detection assembly, the test bed is provided with a test container, a displayer, a work station and an environmental liquid container, and the environmental liquid container is communicated with the test container through a pipeline; the upper sample assembly comprises an upper sample clamping piece with a function of moving along the direction perpendicular to the test bed and is used for clamping and fixing an upper sample, and the upper sample assembly comprises a lower sample clamping piece with a function of reciprocating along the direction parallel to the test bed and is used for clamping and fixing a lower sample; the detection assembly comprises a thermometer and a pressure meter which are electrically connected with the work station, and at least two acoustic emission sensors arranged on the peripheral side of the lower sample clamping piece, the crevice corrosion conditions under different conditions are accurately monitored, the test device is rich in function, and meanwhile, the simulation experiment result is stable and reliable.

To provide a fuel battery cell system capable of suppressing gap corrosion due to an aqueous liquid flow path in which all or a part is formed of a metal material, and a control method of the fuel battery cell system.SOLUTION: A fuel battery cell system includes: a fuel battery cell having therein an aqueous liquid flow path through which an aqueous liquid having a function of supplying a hydrogen-containing gas from a hydrogen supply source to a fuel electrode, introducing an oxygen-containing gas such as air from an oxidizer gas supply source to an oxidizer electrode to perform power generation and removing at least a part of heat generated by the power generation flows, in which all or a part of the aqueous liquid flow path is made of a metal material; an aqueous liquid circulation flow path connected to the aqueous liquid flow path and capable of circulating the aqueous liquid; an aqueous liquid feeding part configured to circulate the aqueous liquid in the aqueous liquid circulation flow path; and a control part configured to control the aqueous liquid feeding part, in which the control part causes the aqueous liquid feeding part to operate at predetermined time intervals for a predetermined time in a state in which the fuel battery cell does not generate power.SELECTED DRAWING: Figure 1

The invention discloses a crevice corrosion and flash corrosion resisting liquid medicine for an MSAP process and a using method of the crevice corrosion and flash corrosion resisting liquid medicine. The flash etching liquid medicine comprises 40-60 g / l of sulfuric acid, 20-30 g / l of hydrogen peroxide, 0.5-2.0 g / l of a stabilizer, 2.0-5.0 g / l of hyperbranched polyol, 0.1-0.5 g / l of tungstate, 0.02-0.04 g / l of a wetting agent and the balance of water. The number-average molecular weight of the hyperbranched polyol is 500 to 1200, and the hydroxyl value of the hyperbranched polyol is 500 to 700 mKOH / g. Through the synergistic effect of the hyperbranched polyol and the tungstate, the corrosion reaction in the included angle gap is effectively inhibited, the bottom lateral erosion amount can be controlled within 0.5 [mu] m, the problem of accelerated lateral erosion caused by the included angle gap in the IC carrier plate MSAP process is solved, and the processing requirement of a high-end IC carrier plate for a fine circuit is met.

The invention relates to the field of non-variable-capacity submersible electric pumps, in particular to a corrosion-resistant energy-saving submersible electric pump for a well. A corrosion-resistant well submersible energy-saving electric pump comprises a pump body, an insulating rubber seat is arranged on one side of the pump body, an insulating layer is arranged in the insulating rubber seat, a cable is attached to the insulating rubber seat, and the lower end of the cable is bent to enter the pump body. The pump body is connected with a cambered surface seat through two connecting columns, the bent position of the lower end of the cable is attached to the cambered surface seat, and a rubber cylinder is arranged at the position, entering the pump body, of the cable. The lower end of the pump body is slidably connected with a sliding ring, an arc-shaped pressing seat is fixed to the sliding ring, a groove corresponding to the bent position of the lower end of the cable is formed in the arc-shaped pressing seat, and the arc-shaped pressing seat is pressed at the bent position of the lower end of the cable through the groove. A vertical edge is arranged on the lower portion of the pump body, a sliding ring is connected to the vertical edge in a sliding mode, a second fastening screw is connected to the sliding ring through threads, and the second fastening screw is pressed on the vertical edge. The problem of pump body crevice corrosion caused by cable contact can be solved.

This invention relates to the field of rail vehicle technology, providing an online monitoring sensor and method for car body crevice corrosion. The online monitoring sensor includes a base, a substrate sample, a first gasket, a reference sample, a second gasket, and a cable. The substrate sample is mounted on the base. The corrosion sample is mounted on the base, with a first gap formed between the corrosion sample and the substrate sample via the first gasket. The reference sample is mounted on the base, with a second gap formed between the reference sample and the corrosion sample via the second gasket. The cable passes through the base, with one end electrically connected to the substrate sample, the corrosion sample, and the reference sample within the base. The other end of the cable exits the base and is connected to a current measuring unit. The current measuring unit measures a first current value between the corrosion sample and the reference sample, and a second current value between the corrosion sample and the substrate sample. This enables online monitoring of car body crevice corrosion.

The purpose of the present invention is to provide a high-strength seamless stainless steel pipe for oil wells, which has high strength, excellent low-temperature toughness, and excellent crevice corrosion resistance in an untreated seawater environment. A high-strength seamless stainless steel pipe for oil wells, which has a component composition that contains specific components and satisfies formula (1) and formula (2), with the remainder comprising Fe and unavoidable impurities, and which has a yield strength of 758 MPa or more, and an absorption energy vE-10 at-10 DEG C in a Charpy impact test of 40 J or more. Cr + 0.22 * Ni + 0.38 * (Mo + 0.5 * W) + 0.89 * Cu + 0.09 * Co > = 21.4 (1) In formula (1), Cr, Ni, Mo, W, Cu, and Co are the content (mass%) of each element, and the content of the elements not included is 0. Co-Nb > = 0.13 (2) In formula (2), Co and Nb are the contents (mass%) of the respective elements.

The application discloses a processing method of a high-entropy alloy, which comprises first laser action, second laser action, electric field action and He + ion irradiation, coupling of the three means, and can realize improvement of the corrosion resistance of the high-entropy alloy, and through accurate matching and regulation of multiple process parameters, a synergistic effect is realized. Specifically, a certain amount of He + ion irradiation can improve the residual stress distribution and mechanical properties of the surface layer of the high-entropy alloy, the electric field action can improve the diffusion of the composition of the high-entropy alloy, and the laser action can optimize the microstructure, so that the pitting corrosion resistance, the crevice corrosion resistance and the stress corrosion resistance of the high-entropy alloy can be significantly improved as a whole, the comprehensive corrosion resistance of the high-entropy alloy is significantly enhanced, and the market application value of the high-entropy alloy is increased, so as to meet the demand of nuclear power plants for corrosion-resistant materials.

The invention provides a stainless steel material, a product and a vehicle, and the stainless steel material comprises the following chemical components in percentage by mass: 18.2% < = Cr < = 21.2%, and 0.13% < N < = 0.18%. According to the stainless steel material disclosed by the invention, through the component design containing the TRIP effect, particularly, the content of the alloy element N is greatly improved, and the Cr element with the specific content is added, so that a passive film on the surface of the stainless steel material can be modified, the content of a Cr2O3 oxide film with protection is greatly improved due to N enrichment, and the crevice corrosion resistance of the material is greatly improved; by means of the method, complex deep drawing of a high-pressure oil tank of a new energy automobile can be met, crevice corrosion perforation oil leakage under the severe corrosion environment of the bottom of the automobile can be met, traditional 304 stainless steel is replaced, higher service safety is achieved, and driving and riding safety is improved.

The invention provides an end socket structure and a forming process. The sealing head structure comprises an inner container barrel body and a sealing head which is in butt joint with the end part of the inner container barrel body, the sealing head is a step-free straight-edge sealing head, and the inner container barrel body is communicated with a connecting pipe; the welding structure further comprises a hoop, and the hoop is arranged between the inner container barrel body and the straight edge section of the end socket and used for positioning and centering the end socket and the inner container barrel body before welding. According to the straight-edge end socket, the problems of crevice corrosion, short fatigue life, difficulty in assembly and the like of an end socket structure are solved, the straight-edge end socket is formed by stretching a blank to form an initial structure with a step, then the formed end socket with the step is stretched to form an end socket with a bevel edge, and then the bevel edge is cut off to form a step-free straight-edge structure, so that the straight-edge end socket is formed. Therefore, the stability of the stretching process is guaranteed, wrinkling and out-of-roundness are avoided, stress concentration is eliminated, and the fatigue life of the end socket is remarkably prolonged.

The invention discloses a full penetration welding method for assembling and welding a semicircular pipe jacket and a shell. Comprising the following steps: marking and blanking a half pipe, bending and forming the semicircular pipe, forming a groove of the half pipe, cleaning the groove of the semicircular pipe and a to-be-welded surface of a shell until the groove and the to-be-welded surface of the shell meet welding requirements, carrying out 100% PT on the surface of the groove of the semicircular pipe, assembling the semicircular pipe, welding the semicircular pipe and the shell, carrying out 100% PT detection on a connecting welding seam of the semicircular pipe and the shell, and the like. The method can solve the quality problems that when an existing semicircular pipe is welded to the outer groove of the shell, weld beading is likely to be generated at the root, welding dead corners are formed, and fusion is incomplete. The groove size and the assembly precision can be effectively improved by adopting auxiliary assembly tools for scribing, blanking and the like, and powerful guarantee is provided for welding of the semicircular pipe and the shell. The inner groove welding is adopted, so that smooth transition in a welding seam can be realized, and the incompletely filled inner side of a welding joint is reinforced by enlarging an outer side welding leg. The problems of stress concentration and crevice corrosion are avoided by adopting inner groove welding, and the strength of a welding joint can be ensured.

This invention relates to the field of submersible pump technology, specifically a corrosion-resistant submersible pump for wells. It includes a casing, a pump barrel fixedly connected to the top of the casing, a base at the bottom of the casing, a wound stator core inside the casing, and a rotor inside the casing. An end cover is located on the top of the pump barrel, and a cable for supplying power to the wound stator core is located on the side wall of the pump barrel. An insulation layer is provided between the cable and the pump barrel, with sealant applied to both sides of the insulation layer. A protective sleeve is wrapped around the side of the cable away from the insulation layer, and a pressure plate is located on the side of the protective sleeve away from the insulation layer. This invention, by providing an insulation layer between the cable and the pump barrel, filling both sides of the insulation layer with sealant, and then pressing the cable, sealant, insulation layer, and pump barrel together with a pressure plate, effectively avoids galvanic corrosion of the pump barrel caused by cable leakage current and crevice corrosion, thereby extending the service life of the submersible pump.

The invention relates to the technical field of microorganism crevice corrosion experiments, in particular to a microorganism crevice corrosion simulation experiment device with an adjustable opening degree and an operation method. The microorganism crevice corrosion simulation experiment device with the adjustable opening degree comprises a simulation experiment box, a metal sample and an adjusting mechanism, the metal sample is arranged between the inner walls of the two opposite sides of the simulation experiment box, and the adjusting mechanism is connected with the metal sample; the adjusting device is used for adjusting a gap between the metal sample and the inner wall of one end of the simulation experiment box. The device has the advantages that the growth conditions of microorganisms in anti-corrosion layer stripping environments with different opening degrees can be measured, characterization analysis of samples after crevice corrosion can be realized, and the device can accurately control the opening degree of the crevice, so that researchers are allowed to monitor microorganism activity and metal corrosion processes in different crevice environments. The technical support is provided for researching the growth rule of corrosion microorganisms in the anticorrosive coating stripping gap environment and the corrosion behavior of a metal sample in the gap environment.

The utility model relates to a steel rail crevice corrosion simulation device which comprises a corrosion solution container used for containing a corrosion solution; the multi-site integrated test block is arranged at the bottom of the corrosion solution container and is used for simulating a steel rail gap to form a working electrode; the auxiliary electrode is arranged on one side surface of the etchant solution container; the reference electrode is arranged on the other side surface of the etchant solution container; the working electrode, the auxiliary electrode and the reference electrode form a three-electrode system, and crevice corrosion behaviors of the steel rail under different corrosion conditions are analyzed by changing conditions of a corrosion solution. According to the utility model, by changing parameters such as components, concentration and temperature of the corrosion solution, factors influencing the corrosion of the steel rail crevice can be comprehensively researched under different corrosion conditions.

The invention relates to the technical field of submersible electric pumps, in particular to a corrosion-resistant well submersible electric pump which comprises a machine shell, a pump cylinder fixedly connected to the top of the machine shell, a base arranged at the bottom of the machine shell, a winding stator iron core arranged in the machine shell, a rotor further arranged in the machine shell and an end cover arranged at the top of the pump cylinder. The side wall of the pump cylinder is further provided with a cable used for supplying power to the stator iron core with the winding, an insulating layer is arranged between the cable and the pump cylinder, sealant is arranged on the two sides of the insulating layer, the side, away from the insulating layer, of the cable is wrapped with a protective sleeve, and the side, away from the insulating layer, of the protective sleeve is provided with a pressing plate. The insulating layer is arranged between the cable and the pump cylinder, the two sides of the insulating layer are filled with the sealant, then the cable, the sealant, the insulating layer and the pump cylinder are tightly pressed through the pressing block, and through superposition of double measures, galvanic corrosion, caused by cable leakage current, of the pump cylinder is effectively avoided, meanwhile crevice corrosion is avoided, and the service life of the pump cylinder is prolonged. And the service life of the submersible electric pump is prolonged.

The purpose of the present invention is to provide stainless steel and a seamless stainless steel pipe which exhibit a high yield strength of 448 MPa (65 ksi) or higher, excellent crevice corrosion resistance, and excellent low-temperature ductility.　The present invention provides stainless steel having a component composition containing, in terms of mass %, 0.002-0.040% C, 0.05-1.00% Si, 0.1-1.7% Mn, not more than 0.040% P, not more than 0.0200% S, 20.0-28.0% Cr, 4.0-10.0% Ni, 2.0-5.0% Mo, 0.001-0.050% Al, 0.06-0.35% N, 0.001-0.800% Pt, and not more than 0.0100% O, with the balance being Fe and unavoidable impurities, said stainless steel having a structure containing an austenitic phase at a volume ratio of 20-70% and a ferritic phase at a volume ratio of 30-80%, and exhibiting a yield strength of 448 MPa or greater.

The application discloses a die-casting energy-saving cathode plate and belongs to the technical field of electrochemical metallurgy equipment, which comprises a conductive rod, a main plate, anticorrosion wrapping material, a copper clamp, a crossbeam, a fixing assembly, a lifting lug and a rotating assembly; a first installation groove is formed in the bottom of the conductive rod, one end of the main plate with a hole is inserted into the groove and is pre-fixed through elastic sheets and clamping blocks, the two are integrally die-cast through a die-casting forming process, a seamless sealing structure is formed, and the hole is filled to form mechanical interlocking; the copper clamp is fixed at one end of the conductive rod to connect external power supply lines; a second installation groove is arranged at the bottom of the crossbeam, and the fixing assembly realizes detachable locking of the conductive rod and the crossbeam through a rotating rod, a sliding plate and other components; the lifting lug is installed at the top of the crossbeam, and the rotating assembly adjusts the angle of the lifting lug through a rotating shaft, a rotating disc and a limiting rod and other structures. The application eliminates the problem of crevice corrosion, improves the conductive efficiency and connection stability, and is convenient to install and maintain and high in applicability.

The invention discloses an experimental device capable of simulating crevice corrosion acceleration at a biological-metal interface caused by ion exchange in situ in real time. The experimental device comprises a corrosion crevice real-time control assembly and an array electrode electrochemical scanning system assembly, in addition, the invention further discloses a test method, data are obtained by filling electrolyte into the test device and carrying out ion exchange test, so that an in-situ real-time simulation result of crevice corrosion acceleration at a biological-metal interface caused by ion exchange is obtained. Through the corrosion gap real-time control assembly and the array electrode electrochemical scanning system assembly, the potential distribution condition of a biological-metal interface developing from inside to outside along the corrosion gap is recorded in real time, and the development condition of crevice corrosion is timely and accurately observed and recorded in situ; the rule of corrosion acceleration of crevices at the biological-metal interface caused by ion exchange is reflected in real time, and related research on corrosion acceleration caused by ion exchange in crevices at the biological-metal interface under actual working conditions is enriched and developed.

The utility model discloses a three-layer polyethylene anticorrosion stainless steel pipe, which comprises a stainless steel pipe, a bottom layer, a middle layer, an outer layer and an inner coating, the bottom layer is fixed on the surface of the stainless steel pipe, the middle layer is fixed on the surface of the bottom layer, the outer layer is fixed on the surface of the middle layer, and the inner coating is arranged inside the stainless steel pipe; the bottom layer is coated on the surface of the stainless steel pipe and is made of a polyethylene coating material. The corrosion-resistant stainless steel pipe has the advantage of being good in corrosion-resistant effect, and the problem that the stainless steel pipe still possibly has local corrosion phenomena such as pitting corrosion and crevice corrosion in some extreme environments such as high-salinity seawater and strong acid and alkali environments is solved.

The invention discloses a curing agent for underwater overweight anticorrosive paint and an underwater overweight anticorrosive paint composition containing the curing agent, the curing agent is formed by compounding a wetting heating curing component and an interface curing component according to a mass ratio of 5: 1 to 15: 1, and the two components cooperate to realize underwater wetting, heat release curing and strong interface bonding. The problems of easy shrinkage, poor adhesive force and slow curing during construction of traditional underwater coatings are solved, a coating composition using the curing agent is suitable for corrosion prevention of underwater metal structures, pitting corrosion, crevice corrosion and other problems can be effectively prevented, and the service life of the structures is prolonged.

A chromium-bearing, cobalt-based alloys amenable to wrought processing has improved resistance to both chloride-induced crevice corrosion and galling. The alloy contains up to 3.545 wt. % nickel, 0.242 to 0.298 wt. % nitrogen, and may contain 22.0 to 30.0 wt. % chromium, 3.0 to 10.0 wt. % molybdenum, up to 5.0 wt. % tungsten, up to 7 wt. % iron, 0.5 to 2.0 wt. % manganese, 0.5 to 2.0 wt. % silicon, 0.02 to 0.11 wt. % carbon, 0.005 to 0.205 wt. % aluminum, and the balance is cobalt plus impurities.

The invention belongs to the technical field of magnesium alloy and stress corrosion tests, and particularly relates to a test method suitable for a stress corrosion test of a magnesium alloy C-shaped ring sample. The test method comprises the following steps: S1, preparing a magnesium alloy C-shaped ring sample; s2, the radial compression amount is calculated through the following formula (1); s3, loading a magnesium alloy C-shaped ring sample; s4, corroding the magnesium alloy C-shaped ring sample by using a corrosive liquid; in the step S3, the bolt and the nut used for loading the magnesium alloy C-shaped ring sample are made of non-metal materials, especially PA66. The invention further provides a testing device for implementing the testing method. According to the test method, magnesium alloy characteristics are accurately matched, evaluation is more close to actual working conditions, crevice corrosion interference is eliminated, test accuracy is improved, data credibility is high, and a result can be verified through a slow strain rate tensile test.