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The steel chemical composition and heat treatment for the different property classes of nuts

The chemical composition of steel for nuts can vary depending on the specific grade or specification of steel being used. Steel is a versatile material, and its properties can be tailored to meet various requirements.
Common Elements in Carbon and Alloy Steels:
1.Iron (Fe): Iron is the primary element in steel, typically making up the majority of its composition.
2.Carbon (C): Carbon content varies depending on the grade of steel. Low carbon steels have carbon content usually below 0.30%, while medium and high carbon steels may have higher carbon content.
3.Manganese (Mn): Manganese is often added to improve the strength and hardenability of steel. It is commonly found in many steel alloys.
4.Sulfur (S) and Phosphorus (P): These elements are considered impurities and are typically controlled to very low levels in steel, as they can negatively impact the material’s properties. In general, lower levels of sulfur and phosphorus are desirable.
5.Silicon (Si): Silicon is sometimes added to steel for deoxidation and to improve its strength and toughness.
6.Other Alloying Elements: Depending on the specific grade, alloying elements such as chromium (Cr), molybdenum (Mo), vanadium (V), and nickel (Ni) may be added to enhance specific properties like corrosion resistance, high-temperature strength, or hardenability.
Material and heat treatmentChemical
composition limits
(cast analysis, %) a
C (max)Mn (min)P (max)S (max)
5Carbon steel0.58-0.060.15
6Carbon steel0.58-0.060.15
8 High nut (style 2)Carbon steel0.580.250.060.15
8 Regular nut (style 1) D ≤ M16Carbon steel0.580.250.060.15
8 Regular nut (style 1) D > M16Carbon steel (quenched and tempered)0.580.300.0480.058
10Carbon steel (quenched and tempered)0.580.300.0480.058
12Carbon steel (quenched and tempered)0.580.450.0480.058