Twenty years ago, the concept of “superior steel” was rarely mentioned. At that time, when referring to “special steel”, it included “superior steel”. The typical description of what constituted “special steel” was that steel produced in converters was generally called “carbon steel” and that produced in electric furnaces was called “special steel.” Even in the 1990s, this was a common explanation in our industry.
In the past two decades, the rapid development of the steel industry has been overwhelming. In the mid-1990s, the special steel industry's ultra-high-power electric arc furnaces, combined with external refining and continuous smelting and rolling, represented the most advanced equipment technology. Even at that time, we were exploring the feasibility of using continuous casting and rolling techniques to produce bearing steel. Today, extremely high-power continuous rolling and casting technology equipment is almost a basic requirement.
An important fact that we should not forget is that in the late 1990s, it was Xingcheng Special Steel's adoption of ultra-high-power furnaces with external refining and continuous casting and rolling technology for bearing steel production that improved significantly improve production efficiency. Based on this, further attempts were made to produce bearing steel using converter furnaces with external refining. This solidified Xingcheng's leading position in bearing steel production and sales.
Consequently, more metallurgical companies began to use converter furnaces with external refining to produce GB 699 and 3077 standard carbon and special low-alloy steels, commonly called “higher steel” products. This has led to widespread recognition of the concept of “superior steel” in the industry.
Therefore, my subsequent references to “superior steel” refer primarily to products listed in GB 699 and 3077. This classification is not intended to delve into the categorization of “superior steel” and “special steel”, but rather serves as an explanation temporary. for further discussion. Industry leaders and experts will have more professional opinions on your specific classification.
I. Common Types of “Superior Steel”
“Superior steel” (positioned between special steel and simple carbon steel, generally unalloyed) is characterized by good mechanical properties, such as tensile and compressive strength, toughness, easy machinability and significant improvement in mechanical properties after heat treatment. In terms of composition, it has fewer impurities and finer, more uniform metallic grains.
Common types of superior steel include carbon structural steel, alloy structural steel, tool steel, spring steel, high-grade steel, high-speed steel, bearing steel, high-quality carbon steel, gear steel, carbon tools, alloy tool steel, carbon structural steel, billet steel, rolled steel, etc.
Carbon Structural Steel: Simply put, high-quality carbon structural steel is known as carbon structural steel. Specifically, its carbon content is less than 0.08%. Low carbon structural steel is used for rolling thin sheets and deep-drawn products; medium carbon structural steel is used for quenched and tempered smaller parts, including tie rods, bushings, gears, piston pins, fasteners, etc.; High-carbon structural steel is used for springs and wear-resistant parts.
Structural steel alloy: Used for mechanical parts and various engineering components, containing one or more specific quantities of alloying elements. It can be divided into ordinary alloy structural steel and special-purpose alloy structural steel, widely used in ships, vehicles, aircraft, missiles, weapons, railways, bridges, pressure vessels, machine tools and other structures.
Tool steel: Generally divided into cold work tool steel, hot work tool steel and plastic mold steel, used for forging, stamping, die cutting, pressure casting, etc.
Steel spring: Specifically designed for its elasticity in quenched and tempered states, used in the manufacture of springs and elastic components.
Bearing steel: Used to make bearing balls, rollers and rings. Bearing steel must have high and uniform hardness, wear resistance and a high elastic limit due to the immense pressure and friction it endures during operation.
Gear steel: Refers to steel materials suitable for manufacturing gears. It is a critical material in special steel alloys used in automobiles, railways, ships, construction machines and is an essential component to ensure safety.
II. Common Types of “Specialty Steel”
Special Steel: There is no unified definition or concept for special steels worldwide. Generally, they are considered to include steels with special chemical compositions (alloyed and with an appropriate quantity of one or more alloying elements), produced through special processes, having special structures and properties and meeting specific needs.
Compared with ordinary steel, special steel has higher strength and toughness, physical properties, chemical properties, biocompatibility and processability, such as high strength, hardness, good plasticity, toughness, wear resistance, corrosion resistance and many other excellent properties.
- Tungsten steel, manganese steel: Extremely hard, used in the manufacture of metallurgical tools, tractor tracks, axles, etc.
- Manganese-silicon steel: Exceptionally strong, used to make spring plates, coils, etc.
- Molybdenum steel: Resistant to high temperatures, used in the manufacture of aircraft crankshafts, especially hard tools, etc.
- Tungsten-chromium steel: Very hard and tough, used for machine tool cutters and molds, etc.
- Nickel-chromium steel (stainless steel): Strongly resistant to corrosion, not easily oxidized, used to make acid-resistant towers in chemical production, medical instruments and daily use items.
Special steel plays a crucial role in industries such as machinery, automotive, military, chemical, household appliances, navigation, transportation, railways and emerging industries. The specialty steel industry supports national defense, high-tech industries and key sectors such as machinery and automotive with essential varieties of specialty steel.
