Method for predicting initiation life of stress corrosion crack
A technology for stress corrosion cracking and life prediction, applied in the direction of material electrochemical variables, etc., can solve the problems of not being able to prevent stress corrosion damage accidents, not being able to predict the life of austenitic stainless steel parts, and poor accuracy, so as to achieve low cost, The effect of high reuse rate and easy operation
Active Publication Date: 2018-12-25
GUANGDONG UNIV OF TECH
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Problems solved by technology
[0003] The purpose of the present invention is to solve the problem that the existing methods for predicting the life of stress corrosion crack initiation are relatively complicated and have poor accuracy, and cannot accurately predict the life of austenitic stainless steel parts, thereby failing to better prevent stress corrosion damage accidents. Provide a life prediction method for stress corrosion crack initiation with simple operation, high prediction accuracy and low hardware cost
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[0033] see Figure 1 to Figure 3 , the present embodiment relates to a stress corrosion crack initiation life prediction method, comprising the following steps:
[0034] Step 1. Make the stainless steel sample 1 into a U-shape; and the straight plate at both ends of the U-shaped stainless steel sample 1 needs to be polished to 800 mesh to 2000 mesh with SiC water-grinding paper, so as to avoid surface damage and damage other than bending during processing. additional processing stress.
[0035] Step 2, using an isolation layer to coat the non-working surface of the stainless steel sample 1, soak the stainless steel sample 1 in the NaCl solution, and the isolation layer isolates the solution from contacting the non-working surface of the stainless steel; the isolation layer is transparent resin or Silica gel. When studying the influence of residual tensile stress on pitting corrosion sensitivity, the working surface is tensile surface 2, which is the outer surface of U-shaped...
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The invention discloses a method for predicting initiation life of a stress corrosion crack. The method comprises the following steps of: 1) making a stainless steel sample into a U-shaped shape; 2) coating a non-working surface of the stainless steel sample by adopting an isolating layer, and soaking the stainless steel sample in a NaCl solution; 3) measuring electric potential and current of thestainless steel sample in an electrochemical reaction process by adopting a three-electrode system; 4) measuring passivation regions and steady state pitting potentials of different residual stress surfaces; obtaining incubation periods t1 under different residual stress conditions; 5) measuring a stress corrosion threshold value of the stainless steel by adopting a constant load or a constant strain method; 6) determining polarization time t2 for the etch pit to grow to rm. According to the method for predicting the initiation life of the stress corrosion crack, a critical etching pit depthof the stress corrosion crack initiation is predicted through a micro-nano-scale metastable pitting based on the relationship of the pitting and the stress corrosion crack, the initiation life of thestress corrosion crack of the stainless steel sample is accurately obtained, the method is simple and convenient, the prediction accuracy is high, and the cost is low.
Description
technical field [0001] The invention relates to a stress corrosion crack initiation life prediction method, in particular to a life prediction method for predicting stress corrosion by using a U-bend sample to simulate the influence of residual stress on stainless steel pitting sensitivity. Background technique [0002] 80% of stress corrosion failure accidents are caused by residual stress. So far, the stress corrosion damage process is difficult to monitor effectively during the service of equipment and components. However, due to the rapid growth rate of stress corrosion cracks, the crack initiation life accounts for 90% of the total life. Therefore, accurate prediction of the stress corrosion crack initiation life is particularly important for the reliable service of engineering equipment. As one of the biggest corrosion problems faced by austenitic stainless steel for a long time, pitting corrosion often becomes the main source of stress corrosion cracking. The intera...
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IPC IPC(8): G01N27/26
CPCG01N27/26
Inventor 关蕾李雨张永康王冠
Owner GUANGDONG UNIV OF TECH