What does the T4 after 0Cr18Ni9-T4 mean?
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We encountered this while welding oil pipelines; I don’t know what it means What is the difference from 0Cr18Ni9? Can it be welded using TIG-308?
T4 represents a heat treatment (aging) process.
I just checked the world steel grade numbering system; there is only one type that includes the suffix T, which denotes Thomas steel, and this does not apply here. Therefore, it must refer to the wall thickness of the tube
I’m sorry, I agree with the person above: T4 represents a heat treatment (ageing) process.
T4 represents a heat treatment (aging) process.
I’ve learned it. Also, everyone else, please talk about the meanings of the codes for the other treatments
T1: Natural aging after cooling from high-temperature processing. T3: The purpose of cold working after solution treatment is to improve strength, flatness, and dimensional accuracy. T36: T3 that has undergone 6% cold working. T361: Higher cold working degree than T3. T4: Natural aging after solution treatment. T5: Rapid cooling after hot processing, followed by artificial aging treatment. T6: Artificial aging is applied after solution treatment. T61: After solution treatment, it is quenched in warm water followed by artificial aging; the purpose of quenching in warm water is to prevent deformation. T7: The temperature or time for stabilization treatment and artificial aging treatment after solution treatment is higher or longer than that of the T6 treatment. Its purpose is to improve resistance to hard corrosion cracking and prevent deformation during quenching. T7352: Remove residual stresses after solution treatment and then carry out over-aging treatment; apply compressive processing resulting in 1–5% permanent deformation after solution treatment to eliminate residual stresses. T8: After solution treatment, cold working is carried out followed by artificial aging; the reduction rates in cross-sectional area during cold working of 3% and 6% correspond to T83 and T86 respectively. T9: Artificial aging after solution treatment, followed by cold working.
Could you please tell me the standards or sources relied on? Thank you.
Reply to 9# nimoo: It’s not certain yet that this T4 refers to age treatment. The code mentioned is quite common in aluminum alloys; it’s also used in martensitic alloys. However, it hasn’t been seen in austenitic alloys.
It might represent a certain temperature rating!
T4: Heat treatment method – water cooling at 1080~1100℃