Issues regarding HIC testing of hydrogen sulfide plates

Typically, the R-HIC test is conducted after heat treatment (except for PWHT types); in other words, specimens from head-shaped components should be taken for testing while the material is at a temperature below its phase transition point, so that no further heating can cause phase changes, and even subsequent processes such as stress relief or hydrogen removal through tempering take place at temperatures below the phase transition point. However, sometimes accidents occur while going upstairs. When such accidents happen, clearance is generally granted based on the following criteria: 1, check the final mechanical properties; furthermore, the HB value must not exceed the standard, as an increase in material hardness raises susceptibility to sulfide stress corrosion ； 2. Indicators of material homogeneity such as grain size uniformity, and the degree of sulfide inclusions ； 3. The most crucial factor is whether the sulfur content is less than 0.002% – the material’s resistance to hydrogen sulfide depends to a large extent on its sulfur content and the distribution of sulfur within it ； 4. Microstructure. The sensitivity of various microstructures to stress corrosion cracking increases in the following order: ferrite with spherical carbides → fully quenched and tempered structure → normalized and tempered structure → structure after normalization → untempered martensite structure after quenching. Martensite is highly sensitive to hydrogen sulfide stress corrosion cracking and hydrogen-induced cracking. Parts with excessive martensite cannot be released.

Given the conditions, it should be possible. The hot-rolled condition meets all the requirements; after normalizing, the microstructure becomes uniform and the hardness decreases. According to what was said above, it should meet the requirements even more. Under normal circumstances, (HIC) is primarily ensured by the P and S contents, rather than by the heat treatment condition.

Where does this information come from?

What is mentioned on the second floor is quite detailed; however, the original poster can refer to section 1.3 on sulfide stress cracking factors (SSC) in NACE MR0175 for more in-depth information. Please advise those who are more knowledgeable

Are there any further comments?

This post was last edited by fqhhg on 2016-12-26 at 15:00, based on my 30 years of work experience. I have been working in long-term collaboration with several universities, starting with 16Mn (R-HIC). Through years of collecting test data on HIC and SSCC, I have roughly summarized the following points. The test condition of the specimen is very important; we have conducted extensive analysis on the corrosion resistance of different microstructural configurations resulting from heat treatment, and the data show that the microstructure and the degree of homogenization are crucial.

I was wondering if there are any papers published on this topic, so that I can study it.