I. Ferrous metals, steel and non-ferrous metals
Let's first briefly introduce the basic concepts of ferrous metals, steel and non-ferrous metals before delving into the classification of steel.
1. Ferrous metals refer to iron and its alloys, such as steel, pig iron, ferroalloys and cast iron. Both steel and pig iron are iron-based alloys with carbon as the main added element, known collectively as iron-carbon alloys.
Pig iron is a product obtained by smelting iron ore in a blast furnace, mainly used in steelmaking and foundry.
Melting molten pig iron in a melting furnace results in liquid molten iron, which is poured into molds to form castings, known as cast iron components.
Ferroalloys are alloys composed of iron and elements such as silicon, manganese, chromium and titanium. Ferroalloys are one of the raw materials for steelmaking, acting as deoxidizers and alloying element additives during the process.
2. When pig iron for steel production is smelted in a steel production furnace following a specific process, steel is produced. Steel products include steel ingots, continuous casting billets and various directly cast steel castings. The term “steel” generally refers to steel laminated into various steel materials. Steel belongs to ferrous metals, but it is not fully equivalent to ferrous metals.
3. Non-ferrous metals, also known as non-ferrous metals, refer to metals and alloys other than ferrous metals, such as copper, tin, lead, zinc, aluminum, as well as brass, bronze, aluminum alloys and bearing alloys . In addition, chromium, nickel, manganese, molybdenum, cobalt, vanadium, tungsten and titanium are used in industry. These metals mainly serve as alloying additives to improve metal properties, with tungsten, titanium, molybdenum and others often used to produce hard alloys for cutting tools.
All these non-ferrous metals are called industrial metals. In addition, there are precious metals such as platinum, gold, silver and rare metals, including radioactive ones such as uranium and radium.
II. Steel Classification
Steel is an iron-carbon alloy with carbon content ranging from 0.04% to 2.3%. To ensure its toughness and plasticity, the carbon content generally does not exceed 1.7%.
In addition to iron and carbon, the main elements in steel include silicon, manganese, sulfur and phosphorus. There are several methods for classifying steel, the following seven being the main ones:
1. Classification by quality:
(1) Common steel (P≤0.045%, S≤0.050%)
(2) High quality steel (P, S both ≤0.035%)
(3) High quality advanced steel (P≤0.035%, S≤0.030%)
2. Classification by chemical composition:
(1) Carbon steel:
- The. Low carbon steel (C≤0.25%);
- B. Medium carbon steel (C≤0.25~0.60%);
- w. High carbon steel (C≤0.60%).
(2) Alloy steel:
- The. Low alloy steel (total alloy content ≤5%)
- B. Medium alloy steel (total alloy content >5~10%)
- w. High alloy steel (total alloy content >10%).
3. Classification by training method:
(1) Forged steel;
(2) Cast steel;
(3) Hot rolled steel;
(4) Cold drawn steel.
4. Classification by metallographic structure:
(1) Annealed state:
- The. Hypoeutectoid steel (ferrite+pearlite);
- B. Eutectoid steel (perlite);
- w. Hypereutectoid steel (perlite+cementite);
- d. Ledeburite steel (perlite+cementite).
(2) Normalized state:
- The. Pearlite steel;
- B. Bainite steel;
- w. Martensitic steel;
- d. Austenite Steel.
(3) Non-transforming or partially transformed.
5. Classification by Use:
(1) Steel for construction and engineering:
- The. Common carbon structural steel;
- B. Low alloy structural steel; w. Reinforced steel.
(2) Structural steel:
The. Steel for mechanical manufacturing:
- The. Quenched and tempered structural steel;
- B. Surface-hardened structural steel, including carburized steel, nitrided steel, and surface-quenching steel;
- w. Free-cut structural steel;
- d. Cold formable steel, including cold punching and heading steel.
B. Steel spring
w. Bearing steel
(3) Tool steel:
- The. Carbon steel for tools;
- B. Alloy tool steel;
- w. High speed tool steel.
(4) Steel with special properties:
- The. Acid-resistant stainless steel;
- B. Heat-resistant steel, including oxidation-resistant steel, heat-resistant steel and valve steel;
- w. Alloy steel for electric heating;
- d. Wear-resistant steel;
- It is. Low temperature steel;
- f. Electrical steel.
(5) Professional steel: such as bridge steel, marine steel, boiler steel, pressure vessel steel, agricultural machinery steel, etc.
6. Comprehensive Classification:
(1) Common steel:
The. Carbon structural steel:
- The. Q195;
- B. Q215(A,B);
- w. Q235(A, B, C);
- d. Q255(A,B); It is. Q275.
B. Low Alloy Structural Steel
w. Common Structural Steel for Specific Purposes
(2) Quality steel (including high-quality steel)
The. Structural steel:
- The. High quality carbon structural steel;
- B. Structural alloy steel;
- w. Steel spring;
- d. Free cutting steel;
- It is. Bearing steel;
- f. Quality structural steel for specific purposes.
B. Tool steel:
- The. Carbon steel for tools;
- B. Alloy tool steel;
- w. High speed tool steel.
w. Special Performance Steel:
- The. Acid-resistant stainless steel;
- B. Heat resistant steel;
- w. Alloy steel for electric heating;
- d. Electrical steel;
- It is. Wear-resistant steel with high manganese content.
7. Classification by Casting Methods
(1) Categorized by oven types
The. Open fireplace steel:
- (a) Acidic open-hearth steel;
- (b) Open base steel.
B. Converter steel:
- (a) Acid Converter Steel;
- (b) Basic Converter Steel;
or
- (a) Bottom Converter Steel;
- (b) Side-blow converter steel;
- (c) Top blow converter steel.
w. Steel for Electric Furnace:
- (a) Steel for Electric Arc Furnace;
- (b) Electric slag furnace steel;
- (c) Steel for Induction Furnaces;
- (d) Steel for Self-Consuming Vacuum Furnace;
- (e) Electron beam furnace steel.
(2) Categorized by Degree of Deoxidation and Casting System
- The. Boiling steel;
- B. Semi-Wet Steel;
- w. Dead steel;
- d. Special Deadsteel.
Steel materials can be divided into four main categories based on shape: profiles, plates, tubes and metal products. To facilitate acquisition, ordering and management, China currently classifies steel into sixteen main types:
| Category | Product type | Declaration |
| Profiled bar | Heavy Rail | Steel rails weighing more than 30 kilograms per meter (including crane rails) |
| Light Rail | Steel rails weighing 30 kilograms per meter or less. | |
| Large Section Steel | Common steel includes round, square, flat, hexagonal, I-beam, channel, equal and unequal angle steel, as well as threaded steel. According to size, they can be categorized into large, medium and small. | |
| Medium Section Steel | ||
| Small Section Steel | ||
| Wire machine | Round steel and disc bars with diameters of 5 to 10 millimeters. | |
| Cold formed steel | Steel section formed by cold bending steel or steel strips. | |
| High quality profiles | High quality round steel, square steel, flat steel, hexagonal steel and more. | |
| Other steel materials | Including heavy rail components, axle blanks, tire rings, among others. | |
| Sheet metal | Thin Steel Sheet | Steel sheets with a thickness equal to or less than 4 millimeters. |
| Thick steel sheet | Steel sheets with a thickness greater than 4 millimeters. | |
| It can be classified into medium plates (thickness greater than 4mm and less than 20mm), thick plates (thickness greater than 20mm and less than 60mm) and extra-thick plates (thickness greater than 60mm). | ||
| steel strips | Also known as steel strip, it is actually a thin, long, narrow steel plate supplied in rolls. | |
| Electrical Silicon Steel Sheet | Also known as silicon steel sheet. | |
| Tube material | Seamless Steel Tubes | Seamless steel tubes produced by methods such as hot rolling, hot rolling and cold drawing or extrusion. |
| Welded Steel Pipes | Steel tubes are formed by rolling and shaping steel plates or strips and then welded together. | |
| Metal Products | metal products | This includes steel wires, steel cables and steel cords. |
III. Types of steel
1. Carbon steel
Carbon steel, also known as plain carbon steel, is a type of ferrocarbon alloy that contains less than 2% carbon (wc).
In addition to carbon, carbon steel often contains small amounts of silicon, manganese, sulfur and phosphorus.
Carbon steel can be classified into three types: carbon structural steel, carbon tool steel, and free-cutting structural steel.
Carbon structural steel can be divided into two categories: structural steel for construction and structural steel for machinery manufacturing.
Based on carbon content, carbon steel can be divided into low carbon steel (wc ≤ 0.25%), medium carbon steel (wc 0.25% ~ 0.6%) and high carbon steel (wc > 0.6%).
Furthermore, based on phosphorus and sulfur content, carbon steel can be categorized as ordinary carbon steel (with higher phosphorus and sulfur content), high-quality carbon steel (with lower phosphorus and sulfur content), and high-quality steel. quality. (with even lower phosphorus and sulfur content).
It is important to note that the higher the carbon content in carbon steel, the greater its hardness and resistance, but its plasticity will decrease.
2. Carbon structural steel
The mechanical properties of carbon steel are reflected mainly in its brand, which is represented by the letter “Q” followed by numbers. The letter “Q” refers to the yield limit, while the number represents the yield point value. For example, Q275 represents a yield strength of 275 MPa.
If the letters A, B, C and D are added after the grade, this indicates that the quality grade of the steel is different, with the sulfur (S) and phosphorus (P) content decreasing in turn, and the overall quality of steel increasing.
If the letter “F” is added after the grade, it indicates that the steel is rimmed, while “b” indicates that it is semi-dead. If neither “F” nor “b” are marked, it is considered dead steel. For example, Q235-A · F represents grade A edged steel with a yield strength of 235 MPa, and Q235-c represents grade C finished steel with a yield strength of 235 MPa.
Carbon structural steel is typically used in its supplied state, without heat treatment.
Low carbon steels such as Q195, Q215 and Q235 have good welding performance, plasticity, toughness and some strength. These steels are commonly used to manufacture thin plates, reinforcing bars, welded steel tubes, and other structures, as well as to manufacture common fasteners such as rivets, screws, and nuts.
Steels with higher carbon content, such as Q255 and Q275, have slightly higher strength, better plasticity and toughness, and are still capable of being welded. They are often used to manufacture structural members, connecting rods, gears, couplings and other parts for simple machines.
3. High quality structural steel
Carbon steel must meet the requirements for chemical composition and mechanical properties. The grade of carbon steel is expressed by two digits, representing 10,000 times the average mass fraction of carbon in steel (wc × 10,000). For example, 45 steel has an average carbon mass fraction of 0.45% and 08 steel has an average carbon mass fraction of 0.08%.
High-quality carbon structural steel is mainly used in the manufacture of machine parts and often requires heat treatment to improve its mechanical properties.
Different mass fractions of carbon have different uses.
Steels 08, 08F, 10, 10F, which have high plasticity and toughness, are known for their excellent cold forming and welding performance. They are commonly cold rolled into thin plates and used for cold stamping of parts in instruments, automobiles and tractors, such as automobile bodies and tractor cabs.
Steel 15, 20, 25 is used to manufacture small-sized, light-load carbureted parts, as well as those requiring wear-resistant surfaces and low core strength, such as piston pins and sample plates.
After heat treatment (high temperature quenching and tempering), steels 30, 35, 40, 45 and 50 have good comprehensive mechanical properties, including high strength, plasticity and toughness. They are often used to make shaft parts such as crankshafts, connecting rods, general machine tool spindles, and machine tool gears.
Steels 55, 60 and 65 have a high elastic limit after heat treatment (quenching and tempering at medium temperature). They are typically used to make springs with small loads and small sizes (section size less than 12~15mm), such as pressure regulating and speed regulating springs, plunger springs and cold coil springs.
4. Tool carbon steel
Carbon tool steel is a type of high-carbon steel that contains minimal alloying elements. Its carbon content varies from 0.65% to 1.35%.
Carbon tool steel is preferred for its low production cost, easy availability of raw material, good machinability, and high hardness and wear resistance after treatment. As a result, it is widely used in the manufacture of various cutting tools, molds and measuring tools.
Related Reading: Understanding Cutting Tools
However, carbon tool steel has the disadvantage of low red hardness. This means that when the working temperature exceeds 250°C, the hardness and wear resistance of the steel will decrease significantly and it will lose its ability to function properly.
Additionally, carbon tool steel is difficult to harden when used to make larger parts and is prone to warping and cracking.
5. Free cutting structural steel
Free-cutting structural steel is designed to be brittle by adding elements that make it easier to break chips during cutting, which improves cutting speed and extends tool life.
Sulfur is the main element that makes steel brittle. Lead, tellurium, and bismuth are used in common unalloyed and low-alloy cutting structural steels.
The sulfur content (wMn) of this steel is between 0.08% and 0.30%, while its manganese content (wMn) ranges from 0.60% to 1.55%. The sulfur and manganese in steel exist in the form of manganese sulfide, which is highly brittle and has lubricating properties, facilitating chip breaking and improving the quality of the machined surface.
6. Alloy steel
In addition to iron, carbon and small amounts of the inevitable elements silicon, manganese, phosphorus and sulfur, steel can also contain various alloying elements such as silicon, manganese, molybdenum, nickel, chromium, vanadium, titanium, niobium, boron , lead. and rare earths. This type of steel is called alloy steel.
Different countries have developed various alloy steel systems depending on their resources, production and usage conditions. For example, abroad, nickel and chromium steel systems have been developed, while in China the emphasis has been on developing alloy steel systems based on silicon, manganese, vanadium, titanium, niobium, boron and rare earths.
Alloy steel represents approximately 10% of total steel production.
Alloy steel produced in electric furnaces can be divided into 8 categories based on their use, including structural alloy steel, spring steel, bearing steel, alloy tool steel, high-speed tool steel, stainless steel, heat-resistant and non-peeling steel, and silicon steel for electrical engineering.
7. Common low-alloy steel
Common low-alloy steel is a type of alloy steel that contains a small amount of alloying elements, typically no more than 3% of the total composition.
This type of steel has high strength and good comprehensive properties, as well as resistance to corrosion, wear, low temperatures and good cutting and welding properties.
Under conditions that conserve valuable alloying elements such as nickel and chromium, 1 ton of common low-alloy steel can replace 1.2 to 1.3 tons of carbon steel and has a longer service life and wider range of use in compared to carbon steel.
Common low-alloy steel can be produced using the conventional open-hearth furnace or converter method, and its cost is similar to that of carbon steel.
8. Engineering structural steel
Refers to a variety of alloy steels used in engineering and construction structures, including high-strength weldable alloy structural steels, alloy reinforcing steels, alloy steels for railway use, alloy steels for drilling oil, alloy steels for pressure vessels, high manganese content. wear-resistant steels and others.
This type of steel is mainly used as structural members in engineering and construction projects.
Although the total amount of alloying elements in this type of alloy steel is relatively low, it is widely used due to its large production and use.
9. Mechanical structural steel
This type of steel refers to alloy steels suitable for manufacturing machines and machine parts.
Based on high-quality carbon swirl steel, one or several alloying elements are added to increase the strength, toughness and hardenability of the steel. This steel is typically used after undergoing heat treatment, such as quenching and tempering, or surface hardening.
There are two main categories of this steel: commonly used structural alloy steel and spring alloy steel. These include quenched and tempered alloy steel, surface-hardened alloy steel (such as carburized steel, nitrided steel, and high-frequency surface-hardened steel), and alloy steel for cold plastic forming (cold heading steel, cold extrusion, etc.).
The chemical composition series can be divided into several basic categories, including Mn series steel, SiMn series steel, Cr series steel, CrMo series steel, CrNiMo series steel, Nj series steel and B series steel.
10. Alloy structural steel
The carbon content (wc) of alloy structural steel is generally lower than that of carbon structural steel and varies between 0.15% to 0.50%. It contains one or more alloying elements, such as silicon, manganese, vanadium, titanium, boron, nickel, chromium and molybdenum, in addition to carbon.
Alloy structural steel is known for its hardenability and resistance to deformation or cracking, making it ideal for heat treatment to improve its performance. It is widely used in the production of various transmission components, fasteners for automobiles, tractors, ships, steam turbines and heavy machine tools.
Low-carbon alloy steel is typically case-hardened, while medium-carbon alloy steel is typically quenched and tempered.
11. Alloy tool steel
Alloy tool steels are medium to high carbon steels that contain various alloying elements such as silicon, chromium, tungsten, molybdenum and vanadium. These steels are known for their hardenability and resistance to deformation and cracking, making them suitable for the production of cutting tools, dies and large, complex measuring tools.
The carbon content of alloy tool steels varies depending on the intended use. Most alloy tool steels have a carbon content ranging from 0.5% to 1.5%. Hot deformation die steel has a lower carbon content, typically between 0.3% and 0.6%. Steel used for cutting tools generally contains about 1% carbon. The steel used for cold work dies, on the other hand, has a relatively high carbon content. For example, graphite die steel has a carbon content of 1.5%, while steel used for high-carbon, high-chromium cold work dies has a carbon content greater than 2%.
12. High Speed Tool Steel
High-speed tool steel is a type of high-carbon, high-alloy tool steel that contains a carbon content ranging from 0.7% to 1.4%. This steel is composed of alloying elements, including tungsten, molybdenum, chromium and vanadium, which form high hardness carbides.
One of the main characteristics of high-speed tool steel is its high red hardness, which allows it to maintain its hardness even at high temperatures such as 500-600℃ during high-speed cutting operations. This results in good cutting performance and makes high speed tool steel an ideal choice for high speed cutting applications.
13. Spring steel
Spring steel is used in applications that require resistance to impact, vibration or long-term alternating stress. To perform well under these conditions, spring steel must have high tensile strength, yield strength, and fatigue resistance.
From a technological point of view, spring steel must have good hardenability, be resistant to decarburization and have good surface quality.
Spring carbon steel is a high-quality carbon structural steel with carbon content ranging from 0.6% to 0.9%, including normal and high manganese content. On the other hand, spring alloy steel is mainly composed of silicon-manganese steel, with a slightly lower carbon content but higher silicon content (1.3% to 2.8%) for improved properties. There are also spring steel alloys that contain chromium, tungsten and vanadium.
With the resources available in our country and the requirements of new technologies for automobile and tractor projects, a new type of steel was developed that contains boron, niobium, molybdenum and other elements added to the base of silicon-manganese steel. This extends the life of the springs and improves their quality.
14. Bearing steel
Bearing steel is used to manufacture bearing balls, rollers and rings. Given the high pressure and friction that bearings must withstand during operation, bearing steel must have high and uniform hardness, wear resistance and a high elastic limit.
The requirements for the uniformity of chemical composition, the content and distribution of non-metallic inclusions and the distribution of carbides in bearing steel are very strict.
Bearing steel is also known as high carbon chromium steel, with a carbon content of about 1% and a chromium content of 0.5% to 1.65%. There are several different types of bearing steel, including high carbon and chromium bearing steel, chromium-free bearing steel, carbureted bearing steel, stainless bearing steel, medium and high temperature bearing steel, and antimagnetic bearing steel .
15. Electrical silicon steel
Silicon steel for the electrical industry is mainly used in the production of silicon steel sheets, which are widely used in the manufacture of motors and transformers.
Silicon steel can be classified into low silicon steel and high silicon steel based on its chemical composition. Low silicon steel has a silicon content ranging from 1.0% to 2.5% and is mainly used in engine manufacturing. High silicon steel, on the other hand, has a silicon content of 3.0% to 4.5% and is generally used in transformer manufacturing.
The carbon content of low-silicon steel and high-silicon steel is normally less than or equal to 0.06% to 0.08%.
16. Steel rail
The steel rail is mainly responsible for withstanding the pressure and impact load of the rolling stock, so it must have sufficient strength, hardness and toughness.
The steel commonly used for rails is dead carbon steel, which is smelted in an open furnace or converter and contains 0.6% to 0.8% carbon, making it a medium or high carbon steel. Steel also has a high manganese content, ranging from 0.6% to 1.1%.
In addition to carbon steel, various low-alloy steel rails have also been widely used, such as high silicon rails, medium manganese rails, copper rails, titanium rails and others. These low alloy rails are generally more resistant to wear and corrosion than carbon steel, leading to improved service life.
17. Steel for shipbuilding
Shipbuilding steel refers to steel used in the construction of seagoing ships and large river vessels. Since the hull structure is typically constructed through welding, shipbuilding steel must have good welding performance.
In addition to welding performance, shipbuilding steel must also have sufficient strength, toughness and resistance to low temperatures and corrosion.
In the past, low carbon steel was mainly used in shipbuilding. However, common low-alloy steel is now widely used, and available steel types include 12-manganese ship, 16-manganese ship, and 15-manganese vanadium ship, among others. These types of steel have high strength, good toughness, ease of processing and welding, resistance to seawater corrosion and other desirable characteristics, and can be effectively used to build 10,000-ton ocean-going ships.
18. Steel Bridge
Railway or road bridges must withstand the impact load of vehicles. Therefore, the bridge steel must have adequate strength, toughness and fatigue resistance, and must also have high standards of steel surface quality.
Basic open-sill dead steel is often used for bridge construction, as well as common low-alloy steels such as 16-manganese and 15-manganese nitrogen vanadium steel, which have proven successful.
19. Boiler steel
Boiler steel refers to the materials used in the production of superheaters, main steam tubes, and boiler fire chamber heating surfaces. The performance requirements of boiler steel include good welding performance, high temperature resistance, alkali corrosion resistance and oxidation resistance.
Commonly used boiler steels are low-carbon dead steels produced in an open hearth furnace or low-carbon steels produced in an electric furnace, with a carbon content ranging from 0.16% to 0.26% .
For high-pressure boilers, heat-resistant pearlitic steel or heat-resistant austenitic steel should be used. In addition, common low-alloy steels such as 12-manganese, 15-manganese-vanadium and 18-manganese-molybdenum-niobium are also used in boiler construction.
20. Welding Rod Steel
This type of steel is used specifically for the production of wires for electric arc welding and gas welding electrodes. The composition of steel varies depending on the material that needs to be welded.
As required, it can be classified into three categories: carbon steel, structural alloy steel and stainless steel. The sulfur and phosphorus content of these steels should not exceed 0.03%, which is stricter compared with normal steels.
These steels do not require specific mechanical properties and are tested only for their chemical composition.
21. Stainless steel
Stainless and acid-resistant steel, commonly referred to as stainless steel, is composed of stainless steel and acid-resistant steel. In simple terms, steel that can resist atmospheric corrosion is called stainless steel, and steel that can resist corrosion in chemical media (such as acid) is called acid-resistant steel.
Generally, steel with a chromium content greater than 12% is considered to have the properties of stainless steel.
Based on its microstructure after heat treatment, stainless steel can be divided into five categories: ferritic stainless steel, martensitic stainless steel, austenitic stainless steel, austenitic ferritic stainless steel and precipitation hardening stainless steel.
22. Heat resistant steel
Heat-resistant steel refers to steel that has good oxidation resistance, sufficient high temperature resistance and good heat resistance under high temperature conditions.
Heat-resistant steel can be divided into oxidation-resistant steel and heat-resistant steel. Oxidation-resistant steel is also known as non-peel steel.
Heat-resistant steel refers to steel that has good oxidation resistance and high resistance to high temperatures.
Heat-resistant steel is primarily used in parts that are subjected to high temperatures for long periods of time.
23. Superliga
Superalloy is a kind of high temperature resistant material that has adequate strength, creep resistance, thermal fatigue resistance, high temperature toughness and sufficient chemical stability at high temperatures.
It is used for thermal power components operating at temperatures above 600℃.
Based on its basic chemical composition, superalloy can be divided into nickel-based superalloys, iron-nickel-based superalloys and cobalt-based superalloys.
24. Precision Alloy
Precision alloy refers to alloys with unique physical properties. It is an essential material in electrical industry, electronic industry, precision instrument industry and automatic control system.
Based on their specific physical properties, precision alloys can be categorized into seven groups: soft magnetic alloys, deformed permanent magnetic alloys, elastic alloys, expansion alloys, thermal bimetals, resistance alloys, and thermocouple alloys.
Most precision alloys are based on ferrous metals, with only a few based on non-ferrous metals.
Note: Wc, Ws, Wmn and Wp represent the mass fraction of C, S, Mn and P, respectively.
Common questions
How to classify steels?
Steel is an iron-carbon alloy that has a carbon content ranging from 0.04% to 2.3%. To ensure its toughness and plasticity, the carbon content of steel normally does not exceed 1.7%.
The main components of steel are iron and carbon, along with other elements such as silicon, manganese, sulfur and phosphorus.
Steel classification is diverse and the main methods include:
Classification by quality .
- Common steel（P≤0.045%,S≤0.050%）
- High quality steel（P、S≤0.035%）
- High quality advanced steel（P≤0.035%,S≤0.030%）
Classification by chemical composition.
(1) Carbon steel
- Low carbon steel（C≤0.25%）
- Medium carbon steel（C≤0.25~0.60%）
- High carbon steel（C≤0.60%）
(2) Alloy steel
- Low alloy steel（Total amount of alloy element≤5%）
- Medium alloy steel（Total amount of alloying element >5~10%）
- High alloy steel（Total amount of alloy element.＞10%）
Classification by training method.
- Forged steel
- Cast steel
- Hot rolled steel
- Cold drawn steel
Classification by metallographic structure.
(1) Annealed
- Hyposteel (ferrite + pearlite)
- Eutectoid steel（pearlite）
- Hypereutectoid steel（pearlite + cementite）
- Ledeburitic Steel（pearlite + cementite）
(2) Standardized
- Pearlitic steel
- bainite steel
- martensitic steel
- Austenitic steel
(3) No phase change or partial phase change.
Classification by use.
(1) Steel for construction and engineering
- Common Carbon Structural Steel
- Low alloy structural steel.
- Reinforced steel
(2) Structural steel
The. Mechanical steel manufacturing
- Hardened structural steel
- Surface hardening structural steel: including carburized steel, carburized steel, surface hardened steel
- Free Cutting Structural Steel
- Cold plastic forming steel: Including cold stamping steel, cold heading steel.
B. Steel spring
w. Bearing steel
(3) Tool steel
- Carbon steel for tools.
- Alloy tool steel
- High speed tool steel
(4) Special performance steel
- Acid-resistant stainless steel
- Heat-resistant steel: including anti-oxidation steel, refractory steel, air valve steel;
- Electrothermal alloy steel.
- Wear-resistant steel
- Cryogenic steel
- Electrical steel
(5) Steel for dedicated use
Such as steel for bridges, ships, boilers, pressure vessels, agricultural machinery, etc.
Comprehensive classification
(1) Common steel
The. Carbon structural steel.
- Q195
- Q215 (A, B)
- Q235 (A, B, C)
- Q255 (A, B)
- Q275
B. Low alloy structural steel.
w. General structural steel for a specific purpose.
(2) Quality steel (including high-quality steel)
The. Structural steel
- Quality carbon structural steel
- Structural Alloy Steel
- Steel spring
- Free cutting steel
- Bearing steel
- High quality structural steel for a specific purpose.
B. Tool steel
- Carbon steel for tools.
- Alloy tool steel
- High speed tool steel
w. Special performance steel
- Acid-resistant stainless steel.
- Heat resistant steel
- Electrothermal alloy steel.
- Electrical steel
- Steel with high manganese content
Classification by casting method.
(1) Classification by oven types
The. Fireplace steel
- Acid Fireplace Steel
- Basic fireplace steel
B. Converter steel
- Acid Bessemer Steel
- Basic bessemer steel
OR
- Bottom blown converter steel
- Side-blown converter steel
- Blown converter steel
w. Arc Furnace Steel
- Electric oven steel
- Electroslag Furnace Steel
- Induction Furnace Steel
- Vacuum self-consumer steel furnace
- Electron Beam Furnace Steel
(2) Classification by degree of deoxidation and boiling system.
- Steel rim
- Half dead steel
- Dead steel
- Dead special steel
Related Reading: Metal Type
