What is the boundary between carbon steel and low-alloy steel?
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Steel is an iron-carbon alloy with a carbon content ranging from 0.04% to 2.3%. To ensure its toughness and ductility, the carbon content generally does not exceed 1.7%. The main elements of steel, in addition to iron and carbon, include silicon, manganese, sulfur, phosphorus, etc. 1. Classification by quality (1) Ordinary steel (P≤0.045%, S≤0.050%) (2) High-quality steel (P and S both ≤0.035%) (3) Ultra-high-quality steel (P≤0.035%, S≤0.030%) 2. Classification by chemical composition (1) Carbon steel: a. Low-carbon steel (C≤0.25%) ； b. Medium carbon steel (C≤0.25~0.60%) ； c. High-carbon steel (C≤0.60%). (2) Alloy steel: a. Low-alloy steel (total alloy element content ≤ 5%) b. Medium-alloy steel (total alloy element content > 5–10%) c. High-alloy steel (total alloy element content > 10%). As can be seen from the above, low-alloy steel only specifies that the content of alloying elements shall be ≤5%, with no lower limit specified. So how is carbon steel distinguished from low-alloy steel? Let’s discuss! The focus is on participation! This post was last edited by zhanong on 2008-1-8 13:09.]
Alloys generally refer to manganese, silicon, chromium, etc. And the content of these alloys in carbon steel can be disregarded.
15Mn is a carbon steel, while 16Mn is a low-alloy steel; how can this be explained?
The main components of 15Mn are C, Si, Mn, P, S, along with small amounts of Cr, Ni, Cu, etc； The main components of 16Mn are C, Si, Mn, P, S, V, Ti, Nb, as well as small amounts of Al, etc ； Take a close look at the standards and it will be clear
Low-alloy steel contains higher levels of alloying elements than carbon steel, with these alloying element contents being 5% or less. Carbon steel contains small amounts of impurity elements such as manganese, silicon, sulfur, phosphorus, and oxygen, while low-alloy steel has a higher manganese content, in addition to other alloying elements as well
The alloying elements in carbon steel are not intentionally added; rather, they are \"impurities\" that failed to be removed during smelting. In contrast, the alloying elements in low-alloy steels are added to improve their properties.