CN-121994628-A - Hydrogen embrittlement test device and method for simulating underwater wave current scouring

CN121994628ACN 121994628 ACN121994628 ACN 121994628ACN-121994628-A

Abstract

The invention discloses a hydrogen embrittlement test device and method for simulating underwater wave current scouring. The device comprises a flushing system, a slow stretching system and an electrochemical system, wherein the flushing system comprises a box body, an upper fixing plate, a lower fixing plate, a vertical rod group, a fluid monitoring probe, a fluid data acquisition system, a medium mixing tank, a proportioning pump and a flowmeter, the slow stretching system comprises a slow stretching testing machine, and the electrochemical system comprises a graphite electrode, a salt bridge, a saturated calomel electrode and an electrochemical workstation. The using method comprises fixing the sample on a slow tensile testing machine, delivering seawater with target silt content at a certain flow rate, applying DC cathodic protection current to the electrochemical workstation to inhibit uniform corrosion of the sample, recording pure scouring loss Ww of the sample, pre-charging the sample with the same steel grade and the same specification, performing slow tensile test, recording total loss W of the sample, The contribution rate of scouring and hydrogen embrittlement was characterized, and the hydrogen embrittlement sensitivity was evaluated by area reduction.

Inventors

AI FANGFANG
CHEN YIQING
WANG JIAJI
LI LIN
GAO PENG
HU FENGYA
WANG CHU
ZHONG BIN

Assignees

鞍钢股份有限公司

Dates

Publication Date: 20260508
Application Date: 20250122

Claims (10)

1. A hydrogen embrittlement test device for simulating underwater wave current flushing is characterized by comprising a flushing system, a slow stretching system and an electrochemical system, wherein the flushing system simulates a wave current flushing environment of a marine platform riser system to construct horseshoe-shaped vortexes and denuded vortexes, the flushing system comprises a box body (1), an upper fixing plate (2), a lower fixing plate (3), a vertical rod (4) group, a fluid monitoring probe (11), a fluid data acquisition system (12), a medium mixing tank (15), a proportioning pump (13) and a flowmeter (14), the slow stretching system comprises a slow stretching test machine (6), the electrochemical system comprises an electrochemical workstation (10), a graphite electrode (7), a salt bridge (8) and a saturated calomel electrode (9), a space formed by the upper fixing plate (2) and the lower fixing plate (3) is a wave current flushing space, the upper fixing plate (2), the lower fixing plate (3) are symmetrically provided with a plurality of mounting holes, the vertical rod (4) is mounted between the upper fixing plate (2) and the lower fixing plate (3) through the mounting holes, the mixing tank (13), the fluid data acquisition system (12) is connected with the fluid flow meter (12) through the proportioning pump (13) in sequence, the vertical rod (4) is circumferentially and horizontally provided with a fluid monitoring probe (11), the fluid monitoring probe (11) is connected with a fluid data acquisition system (12), a sample (16) is connected to the slow tensile testing machine (6) through an upper end clamp (5) and a lower end clamp (5) of the slow tensile testing machine (6), an electrochemical workstation (10) applies cathode current to the sample (16), a three-electrode system is adopted, a working electrode is the sample (16), an auxiliary electrode is a graphite electrode (7), and a reference electrode is a saturated calomel electrode (9).
2. The hydrogen embrittlement test device for simulating underwater wave flow scouring according to claim 1 is characterized in that the number of the vertical rods (4) is not less than 14, the vertical and horizontal distances between the adjacent vertical rods (4) are equal, the vertical rods (4) are cylinders, polytetrafluoroethylene or organic glass materials are adopted, and the diameter of each vertical rod (4) is 1-3 times that of the clamping section of the sample (16).
3. The hydrogen embrittlement test device for simulating underwater wave flow washout according to claim 1, wherein the specimen (16) is a circular specimen having a surface roughness of less than 0.8 μm.
4. The hydrogen embrittlement test device for simulating underwater wave flow flushing according to claim 1, wherein the wave flow flushing space height in the flushing system box body (1) is larger than the sum of the lengths of the transition section and the parallel section of the tensile sample, and the distance between the outer vertical rod (4) and the box body wall is more than or equal to 0.7m.
5. The fatigue test device for simulating underwater wave flow flushing according to claim 1, wherein the horizontal position set by the fluid monitoring probes (11) is the midpoint position of the sample (16), and the number of the fluid monitoring probes (11) in the circumferential direction of the vertical rod (4) is more than or equal to 4.
6. A method for using a hydrogen embrittlement test device for simulating underwater wave current scouring according to any one of claims 1 to 5, characterized in that, Step one, determining two test parameters of the space between vertical rods (4) and the flow rate of fluid entering a box body (1); Fixing a sample (16) on the slow tensile testing machine (6) by using upper and lower end clamps (5) of the slow tensile testing machine (6), configuring seawater with target silt content by using a medium mixing tank (15), conveying a target simulated fluid medium into a box body (1) at the flow rate determined in the step one, externally adding direct-current cathodic protection current by using an electrochemical workstation (10), inhibiting uniform corrosion of the sample (16), removing corrosion products on the surface of the sample (16), drying by alcohol dehydration and cold air, weighing, and recording pure scouring loss Ww of the sample (16); step three, applying constant current through an electrochemical workstation (10) to precharge samples with uniform specification of the same steel grade; Step four, mounting a pre-charged sample (16) on a slow tensile testing machine (6), conveying the simulated fluid medium into a box body (1) at the flow rate determined in the step one, carrying out a slow tensile test on the pre-charged sample (16) at a target tensile rate, breaking the sample (16), stopping the test, removing corrosion products on the surface of the sample (16), drying alcohol, drying by using dehydrated cold air, weighing, and recording the total loss W of the sample (16); step five, obtaining an acceleration increment delta W of hydrogen embrittlement to flushing through W-Ww And (3) characterizing the contribution rate of the interaction of scouring and hydrogen embrittlement in the service process of the material, and evaluating the hydrogen embrittlement sensitivity through the area reduction rate.
7. The hydrogen embrittlement test method for simulating underwater wave flow flushing according to claim 6, wherein the determination method of the space between the vertical rods (4) and the flow rate test parameters of the fluid entering the box body (1) is that the uniformly mixed simulated fluid medium is conveyed into the box body (1) through the proportioning pump (13), the flow rate and the flow direction of the fluid are monitored by the fluid monitoring probe (11), data are collected every 15 minutes, a fluid waveform chart is obtained through the fluid data collecting system (12), whether the fluid forms horseshoe-shaped vortex and denuded vortex is judged, if not, the space between the vertical rods (4) and the flow rate of the fluid entering the box body (1) are continuously adjusted until the target wave flow form is formed.
8. The hydrogen embrittlement test method for simulating underwater wave current scouring according to claim 6, wherein direct-current cathodic protection current is externally applied to the electrochemical workstation (10), and uniform corrosion of the sample (16) is inhibited, and the cathodic protection current ranges from 0.002 to 0.01A/m 2 .
9. The hydrogen embrittlement test method for simulating underwater wave flow flushing according to claim 6, wherein cathodic current is applied to the sample (16) through the electrochemical workstation (10) to precharge, and specific process parameters are that a hydrogen charging solution is 0.1-0.5 mol/LNaOH and 0.5-2 g/L thiourea, the hydrogen charging current density is 0.05-10A/m 2 , and the hydrogen charging time is 0.5-100 h.
10. The method for simulating the hydrogen embrittlement test for underwater wave stream washout according to claim 6, wherein the slow tensile testing machine (6) has a tensile rate of 10 -5 ～10 -8 mm/s.

Description

Hydrogen embrittlement test device and method for simulating underwater wave current scouring Technical Field The invention relates to the field of metal materials, in particular to a hydrogen embrittlement test device and method for simulating underwater wave current scouring. Background Ocean platforms are the infrastructure for offshore oil and gas resource development. The ocean platform built at the ocean continental shelf can suffer from strong scouring of wave current and sediment, is easy to generate structural failure, and brings great hidden trouble to the stable and normal use of the platform structure. And once the ocean platform is in failure and destruction in the long-term service process, the life and property loss caused by the ocean platform is difficult to measure, and the environmental pollution is extremely serious. With the development of arc additive manufacturing technology, the application range of the arc additive manufacturing technology is wider and wider. The arc additive manufacturing has the advantages of high material utilization efficiency, low cost, high generation efficiency and the like, is particularly suitable for manufacturing the vertical pipe, the horizontal pipe and the supporting structure of the ocean platform, and has wide application prospect. For additive manufactured products to be used in marine industrial environments, it is desirable to have high corrosion resistance, such as seawater corrosion resistance, erosion resistance, and hydrogen embrittlement resistance. Through research, the original ocean current state of the area is changed by establishing the platform vertical pipe, so that the surrounding water flow condition is very complex. Secondary flow is formed in front of the pile and eddies are formed around it, resulting in a greater flush strength, causing the riser system to be subjected to a strong flush. And the scouring causes the stress state of the pile top to change, so that the length of the equivalent pile is increased, the lateral rigidity and the internal force of the structure are influenced, and the stability of the platform is further influenced. In addition, arc additive manufacturing techniques inevitably introduce some amount of hydrogen. Hydrogen ingress can degrade the performance of the steel, which reduces its plasticity when subjected to external loads, causing delayed fracture, resulting in hydrogen embrittlement. Therefore, the probability of corrosion failure of the marine platform riser system is dramatically increased under the combined action of wave current scouring and hydrogen embrittlement. The invention discloses a single tester and a testing method under the action of simulated fatigue load and dynamic water flushing (publication number CN 106644788B), which belong to the pavement material testing technology, and relate to dynamic water flushing, namely water film covering pavement and dissolution of deicing salt on pavement, and do not relate to the seawater wave flow flushing problem. The utility model discloses a concrete scouring test device under the coupling effect of load and environment (publication No. CN 216386650U), which relates to a scouring fatigue test of a concrete engineering structure in a simulated sea wave environment, and does not relate to the problems of wave flow scouring and hydrogen embrittlement sensitivity. In summary, the above-mentioned published patent does not address the problem of testing the performance of the marine platform riser system under the combined action of wave current flushing and hydrogen embrittlement, and cannot construct the marine platform riser environment wave current morphology. Therefore, the hydrogen embrittlement test device and the hydrogen embrittlement test method for simulating underwater wave flow scouring are established, have practical significance, are beneficial to checking potential safety hazards of the existing system, have important significance for reducing platform maintenance cost and guaranteeing life and property safety, and can provide technical information for further optimization of selected materials, so that the safety coefficient of ocean platform service is improved. Disclosure of Invention The invention aims to solve the technical problem of providing a hydrogen embrittlement test device and a hydrogen embrittlement test method for simulating underwater wave current scouring, which are used for testing and evaluating the corrosion resistance of a marine platform riser structural member material and providing a basis for safety evaluation and material selection optimization of a marine platform riser system. In order to achieve the above purpose, the invention adopts the following technical scheme: the hydrogen embrittlement test device for simulating underwater wave current scouring comprises a scouring system, a slow stretching system and an electrochemical system, wherein the scouring system comprises a box body, an upper fixing pl