What are the differences between the national standards for “special steel”, “superior steel” and “general steel”?

There are significant differences between national standard special steel,superior steel and general steel,which are mainly reflected in the composition,production process,performance and use.Here's a breakdown of the three:

1.Special steel

Definition:Special steel refers to steel products that have special physical and chemical properties or special uses due to their special composition,structure,and production process.

Composition and production process:Special steel usually has a special chemical composition,that is,one or several alloy elements are added to carbon steel in an appropriate amount and produced by a special process.

Performance:Special steel has special organization and properties,such as high strength and hardness,good plasticity and toughness,wear resistance,corrosion resistance,etc.

Use:Special steel is mainly used in high-end fields such as automobiles,machinery manufacturing,petrochemicals,and aerospace military industries.It can be divided into eight categories,including high-quality carbon structural steel,alloy structural steel,carbon tool steel,alloy tool(mold)steel,high-speed tool steel,bearing steel,spring steel(carbon spring steel and alloy spring steel),and stainless steel(heat-resistant and acid-resistant).Except for high-quality carbon structural steel,carbon tool steel,and carbon spring steel,the rest are alloy steels,and alloy steel accounts for about 70%of special steel.

2.Superior steel

Definition:Superior steel is between special steel and general carbon steel,generally does not contain alloy,but has excellent mechanical properties.

Composition and production process:Superior steel has fewer impurities,and the gold particles are relatively small and uniform.Its production process may be simpler than special steel,but more sophisticated than ordinary steel.

Performance:Superior steel has good tensile and compressive strength,toughness and mechanical properties,is easy to process,and the mechanical effect is significantly improved after heat treatment.

Use:Superior steel is widely used in the manufacture of parts for various machines,such as carbon steel(high-quality carbon structural steel)can be used for rolling thin plates,deep-drawing products,oil drums,high-grade enamel products,etc.;mold steel is used for forging,stamping,cutting,die-casting and other processes;spring steel is specifically used to manufacture springs and elastic elements;bearing steel is used to manufacture balls,rollers and bearing rings,etc.

3.General steel

Definition:Compared with special steel and superior steel,general steel has relatively ordinary composition,production process and performance.

Composition and production process:General steel usually contains no or little alloying elements and is mainly smelted by oxygen converter,open hearth or electric furnace.

Performance:The performance of ordinary steel is relatively average,and performance indicators such as strength and toughness may not be as good as special steel and superior steel.

Purpose:General steel is mainly used in infrastructure construction,real estate and other fields.General steel include carbon structural steel,which is mainly used to manufacture engineering structural parts and mechanical parts with low stress,such as factories,bridges,ships and other building structures.

To sum up,there are significant differences between national standard special steel,superior steel and general steel in terms of composition,production process,performance and use.These differences make them have unique advantages and applicability in different fields.