17-4PH wear-resistant plate is composed of copper, niobium martensitic precipitation hardening wear-resistant plate, its low carbon content, high strength, corrosion resistance and weldability are better than the general Martensitic wear-resistant plate, similar to 18-8 wear-resistant plate, heat treatment process is simple, good workability, has good formability and good weldability, Alloy materials of different strength grades can be obtained through different heat treatment systems, which are usually used as ultra-high strength materials in the nuclear industry, aviation and aerospace industry, and have been widely promoted and used in high-strength parts with certain corrosion resistance requirements, such as valves, shafts, steam turbine parts, etc.
In the process of application, especially in the environment containing hydrogen, the high-strength wear-resistant plate structure is easy to occur because of its high hydrogen embrittlement sensitivity. In order to determine the hydrogen embrittlement safety of 17-4PH wear-resisting plate in service environment, the hydrogen evolution behavior and the change of hydrogen embrittlement sensitivity of 17-4PH wear-resisting plate under cathode polarization were studied by electrochemical test and slow strain rate test.
The test material was 17-4PH wear-resistant plate. The samples were smelted by non-vacuum electroslag remelting process, and different strength alloy materials were obtained by different heat treatment methods.
The cathodic polarization behavior of two 17-4PH wear-resistant plates in seawater was evaluated by electrochemical testing. The hydrogen content of 17-4PH wear-resistant plates with two kinds of strength was studied after cathodic polarization for 15d at -1.1V (SCE) potential by hydrogen charging test. The hydrogen embrittlement coefficients of two kinds of 17-4PH wear-resistant plates after hydrogen filling were studied by slow strain rate test.
The results show that the hydrogen evolution transition potential of 17-4PH wear-resisting plates with two strengths is about -0.90V in seawater. The hydrogen mass fraction of low-strength wear-resisting plate is about 2.55×10-4%, while the hydrogen mass fraction of high-strength wear-resisting plate is as high as 6.84×10-4%. After the sample is filled with hydrogen, the brittleness of the high-strength wear-resisting plate is significantly increased, while the brittleness of the low-strength wear-resisting plate is not significantly increased. The hydrogen brittleness coefficient of the high-strength wear-resisting plate is far more than 25%, and the material has the risk of hydrogen brittleness at this time, while the hydrogen brittleness coefficient of the low-strength wear-resisting plate is about 18%, which is still in the hydrogen brittleness safety zone.
