What are the grades of medium-alloy steel?
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What medium-alloy steels are commonly used in pressure vessels and pressure pipelines? Please provide the specific grade? Low-alloy and high-alloy steels need not be mentioned. :)
Such as 1Cr5Mo, 10Cr9Mo1VNb, 1Cr9Mo1
In the section on materials in the new GB150 standard, relating to pipes, steel forgings, and steel rods used for bolts and nuts, the grade 1Cr5Mo is mentioned; however, it is classified as a low-alloy steel. Moreover, the term \"medium-alloy steel\" does not appear at all in the new GB150 standard. But looking at the mass fraction of the alloying elements in 1Cr5Mo, it seems that it could be higher than 5%. This is confusing – is there actually a clear boundary between low-alloy steel and medium-alloy steel? :)
According to GBT13304.1-2008 \"Classification of Steels\", under Category 3, steels are classified into non-alloy steel, low-alloy steel, and alloy steel; there is no such category as medium-alloy steel.
The standard GBT13304.1-2008 \"Classification of Steels\" also does not mention the concept of high-alloy steel; however, the new standard GB150 refers to high-alloy steel plates, high-alloy steel pipes, high-alloy steel forgings, and high-alloy steel bars. So what exactly is meant by high-alloy steel in this context? Is it not very precise? Is it that high-alloy steel from the past whose alloy content exceeded 10%? :)
You can also find information on the concept of medium alloy steel on Baidu, but it is not used in pressure vessels and pressure pipelines
General material manuals use the terms low-alloy steel, medium-alloy steel, and high-alloy steel. According to Baidu Baike, they can be classified based on the total content of alloying elements as follows: low-alloy steel (5% or less), medium-alloy steel (5–10%), and high-alloy steel (over 10%). ”Many material manuals also use such a classification, but **this classification term is not included in the classification standards.