Different Types of Structural Steel Profiles: Comprehensive Guide

1. Classification of steel sheets (including steel strips):

1. By thickness:

(1) Thin Plate
(2) Medium Plate
(3) Thick plate
(4) Extra thick board

2. By Production Method:

(1) Hot rolled steel plate
(2) Cold rolled steel plate

3. By surface features:

(1) Galvanized plate (hot-dip galvanized, electro-galvanized)
(2) Tin plated board
(3) Coated steel plate
(4) Color coated steel plate

4. By purpose:

(1) Bridge steel plate
(2) Boiler steel plate
(3) Shipbuilding Steel Plate
(4) Armored steel plate
(5) Automotive steel plate
(6) Roofing steel plate
(7) Structural Steel Plate
(8) Electrical steel plate (silicon steel plate)
(9) Spring steel plate (10) Others

2. Common Japanese steel grades used in general and mechanical structures

1. The designations of Japanese steel (JIS series) mainly consist of three parts:

• The first part means the material, e.g. 'S' for Steel, 'F' for Ferrum (Iron);
• The second part denotes various shapes, types and uses, e.g. 'P' for Plate, 'T' for Tube, 'K' for Kogu (Tool);
• The third part represents characteristic numbers, usually the minimum tensile strength.

For example, SS400 – the first 'S' stands for Steel, the second 'S' stands for 'Structure' and 400 is the lower limit tensile strength of 400MPa, collectively representing a common structural steel with a tensile strength of 400MPa.

2. SPHC — the initial 'S' stands for Steel, 'P' stands for Plate, 'H' stands for Heat and 'C' stands for Commercial, collectively indicating hot-rolled steel sheets and strips in general.

3. SPHD denotes hot-rolled steel plate and stamping steel strip.

4. SPHE designates hot rolled steel plate and deep drawing steel strip.

5. SPCC refers to general-purpose cold-rolled carbon steel sheets and strips, equivalent to China's Q195-215A grade.

The third letter C is an abbreviation for Cold. If tensile strength must be guaranteed during testing, the note is appended with a T, becoming SPCCT.

6. SPCD means cold-rolled carbon steel sheets and strips for stamping, equivalent to high-quality carbon structural steel 08Al (13237) from China.

7. SPCE stands for deep drawing cold-rolled carbon steel sheets and strips, equivalent to China's 08Al (5213) deep drawing steel. If you want to guarantee non-aging, the grade is increased by an N, becoming SPCEN.

Hardness codes for cold-rolled carbon steel sheets and strips: Annealed condition is A, standard temper is S, 1/8 hard is 8, 1/4 hard is 4, 1/2 hard is 2 and hard is 1 .

Surface finish codes: matte finish rolling is D, glossy finish rolling is B. For example, SPCC-SD represents cold rolled carbon steel sheet with standard tempering and matte finish rolling.

Likewise, SPCCT-SB denotes cold-rolled carbon steel sheet with standard tempering, bright finish and guaranteed mechanical properties.

8. The JIS (Japanese Industrial Standards) representation for mechanical structural steel grades is: S + Carbon content + Alphabetical code (C, CK), where carbon content is expressed as the median value × 100.

The letter 'C' denotes carbon and 'K' denotes carburizing steel. For example, S20C carbon wound plate has a carbon content of 0.18-0.23%.

3. Representation of silicon steel sheet grades in China and Japan

1. Chinese degree representation method:

(1) Cold rolled non-oriented silicon steel strip (sheet):

The representation is: DW + iron loss value (iron loss value at a frequency of 50HZ, with a sinusoidal magnetic peak value of 1.5T per unit weight) multiplied by 100 + thickness value multiplied by 100.

For example, DW470-50 represents cold-rolled non-oriented silicon steel with an iron loss value of 4.7w/kg and a thickness of 0.5mm. The new model is now represented as 50W470.

(2) Cold rolled grain oriented silicon steel strip (sheet):

The representation is: DQ + iron loss value (iron loss value at a frequency of 50 Hz, with a sinusoidal magnetic peak value of 1.7T per unit weight) multiplied by 100 + thickness value multiplied by 100 Sometimes 'G' is added after the iron loss value to indicate high magnetic induction.

For example, DQ133-30 represents cold-rolled grain-oriented silicon steel strips (sheets) with an iron loss value of 1.33 and a thickness of 0.3 mm. The new model is now represented as 30Q133.

(3) Hot rolled silicon steel sheet

Hot rolled silicon steel sheets are called DR, divided into low silicon steel (silicon content ≤ 2.8%) and high silicon steel (silicon content > 2.8%) based on the silicon content.

The representation is as follows: DR+100 times the value of iron loss (the value of iron loss per unit weight at maximum magnetic induction force of 1.5T with repeated magnetization of 50HZ and sinusoidal change) + 100 times the thickness value.

For example, DR510-50 represents a hot-rolled silicon steel sheet with an iron loss value of 5.1 and a thickness of 0.5 mm.

For hot-rolled silicon steel sheets used in household appliances, the grade is represented by JDR + iron loss value + thickness value, such as JDR540-50.

2. Representation method of Japanese banknotes:

(1) Cold rolled non-oriented silicon steel strip

This is represented by the nominal thickness (value multiplied by 100) + code A + iron loss guarantee value (iron loss value at a frequency of 50HZ, with a maximum magnetic flux density of 1.5T, multiplied by 100).

For example, 50A470 represents a cold-rolled non-oriented silicon steel strip with a thickness of 0.5 mm and a guaranteed iron loss value ≤4.7.

(2) Grain oriented cold rolled silicon steel strip

Consisting of nominal thickness (value enlarged by 100) + code G: indicating standard material, P: indicating high-grain material + iron loss guarantee value (the iron loss value at the frequency of 50 Hz and maximum flux density 1.7T magnet, multiplied by 100).

For example, 30G130 denotes a silicon steel strip with a thickness of 0.3 mm and iron loss guarantee value ≤1.3.

4. Electrolytic tinplate and hot-dip galvanized sheet:

1. Electrolytic Tinplate

Electrolytic tinplate and steel strip, also known as tinplate, are steel plates (strips) tinned on the surface, offering excellent corrosion resistance, non-toxicity and are suitable for packaging canned goods, as internal and external covering of cables, telecommunications parts, torches and other small hardware.

Classification Method	Category	Symbol
By the amount of tin	Uniform tin plating	E1, E2, E3, E4
	Differential Tin Coating	D1, D2, D3, D4, D5, D6, D7
By degree of hardness.		T50, T52, T57, T61, T65, T70
Based on surface conditions	Smooth surface	G
	Stone Pattern Surface	s
	Linen surface	M
Through passivation	Low chromium passivation	I
	Chemical Passivation	H
	Cathodic Electrochemical Passivation	s
By the amount of oil applied	Lightly oil	P
	Reapply the oil	Z
By surface quality	Group one	Ⅰ
	Group Two	Ⅱ

The stipulations for uniform tin plating thickness and differential tin plating thickness are as follows:

Symbol	Nominal weight of tin coating g/ m2	Minimum average weight of tin coating g/ m2
E1	5.6(2.8/2.8)	4.9
E2	11.2(5.6/5.6)	10.5
E3	16.8(8.4/8.4)	15.7
E4	22.4(11.2/11.2)	20.2
D1	5.6/2.8	5.05/2.25
D2	8.4/2.8	7.85/2.25
D3	8.4/5.6	7.85/5.05
D4	11.2/2.8	10.1/2.25
D5	11.2/5.6	10.1/5.05
D6	11.2/8.4	10.1/7.85
D7	15.1/5.6	13.4/5.05

2. Hot dip galvanized sheet

A continuous hot-dip process is used to galvanize the surfaces of thin sheets and strip steel, effectively preventing corrosion and rust.

Galvanized steel sheets and strips are widely used in various sectors, including mechanical engineering, light industry, construction, transportation, chemical industry and telecommunications.

5. Boiling steel plate and still steel plate

1. Boiling steel plate is a kind of steel plate hot-rolled from common carbon structural steel.

Boiling steel is a type of incompletely deoxidized steel, deoxidized with only a certain amount of weak deoxidizer, resulting in a high oxygen content in the molten steel.

When molten steel is poured into the ingot mold, the carbon-oxygen reaction produces a large amount of gas, causing the molten steel to boil, hence the name “boiling steel”.

Boiling steel has a low carbon content and, as it is not deoxidized with ferrosilicon, it also has a low silicon content (Si<0.07%).

The outer layer of boiling steel is crystallized under the conditions of intense agitation caused by boiling, so it has a pure and dense surface, high-quality exterior, excellent plasticity and stamping performance.

It does not have large centralized retraction cavities, few cut ends, high material yield and simple production process. It consumes less ferroalloy and costs less.

Boiling steel sheet is widely used in the manufacture of various stamped parts, construction and engineering structures and some less important mechanical structural components.

However, boiling steel has more impurities in the core, severe segregation, non-dense structure and uneven mechanical properties.

Due to the high gas content in steel, its tenacity is low, it presents greater fragility to cold and sensitivity to aging, in addition to lower weldability.

Therefore, boiling steel plate is not suitable for manufacturing structures that bear impact loads, operate in low temperature conditions, welded structures and other important structures.

2. Calm steel plate is a steel plate made by hot rolling of calm carbon structural steel.

Still steel is a fully deoxidized steel, where the steel liquid is fully deoxidized with ferromanganese, ferrosilicon and aluminum before smelting, hence its low oxygen content (generally 0.002-0.003%).

The steel liquid remains calm in the steel ingot mold and does not undergo a boiling phenomenon, hence the name calm steel. Under normal operating conditions, there are no bubbles in calm steel, and its structure is uniformly dense.

Due to the low oxygen content, the steel has fewer oxide inclusions and greater purity, resulting in less cold brittleness and aging tendencies.

At the same time, calm steel has minimal segregation, more uniform properties and superior quality. The disadvantage of calm steel is that it has concentrated shrinkage holes, lower yield and higher price.

Therefore, calm steel is mainly used for components that withstand impacts at low temperatures, welded structures and other components that require greater strength. All low alloy steel plates are still and semi-calm steel plates.

Due to their high strength and superior performance, they can save a lot of steel, reduce structural weight, and their use has become increasingly widespread.

6. High quality carbon structural steel plate

High-quality carbon structural steel is a type of carbon steel with less than 0.8% carbon content.

This steel contains less sulfur, phosphorus and non-metallic inclusions compared to normal carbon structural steel, resulting in superior mechanical properties.

High-quality carbon structural steel can be divided into three categories based on carbon content: low-carbon steel (C≤0.25%), medium-carbon steel (C is 0.25-0.6%) and high carbon steel (C>0.6%).

Based on manganese content, high-quality carbon structural steel is divided into two groups: normal manganese content (0.25%-0.8% manganese) and high manganese content (0.70%-1. 20% manganese).

The latter has better mechanical and processing properties.

1. Hot rolled thin steel sheet and steel strip of high quality carbon structural steel

Hot-rolled thin steel sheet and high-quality carbon structural steel strip are used in the automotive, aviation and other industries.

Steel grades are boiling steel: 08F, 10F, 15F; calm steel: 08, 08AL, 10, 15, 20, 25, 30, 35, 40, 45, 50. Those with 25 and below are low carbon steel plates, and 30 and above are medium carbon steel plates.

2. High quality carbon structural steel hot rolled thick plates and wide strips

Hot-rolled thick plates and wide strips of high-quality carbon structural steel are used in various mechanical components.

Steel grades include low carbon steels such as 05F, 08F, 08, 10F, 10, 15F, 15, 20F, 20, 25, 20Mn, 25Mn and more; medium carbon steels including 30, 35, 40, 45, 50, 55, 60, 30Mn, 40Mn, 50Mn, 60Mn and more; high carbon steels covering 65, 70, 65Mn and more.

7. Special structural steel plate

1. Steel plate for pressure vessels: End the note with a capital “R”. The class can be represented by the yield strength or by the carbon or alloy element content.

Examples include: Q345R, where Q345 is the yield point. Others like 20R, 16MnR, 15MnVR, 15MnVNR, 8MnMoNbR, MnNiMoNbR, 15CrMoR, etc. are represented by the carbon content or alloy elements.

2. Steel plate for welding gas cylinders: End the note with a capital “HP”. The class can be represented by the yield strength, such as: Q295HP, Q345HP; or can be represented by alloying elements such as: 16MnREHP.

3. Boiler steel plate: End the note with a lowercase “g”. The grade can be represented by the yield limit, for example: Q390g; or it can be represented by the content of carbon or alloy elements, such as 20g, 22Mng, 15CrMog, 16Mng, 19Mng, 13MnNiCrMoNbg, 12Cr1MoVg, etc.

4. Steel sheet for bridges: End the note with a lowercase “q”. Examples include: Q420q, 16Mnq, 14MnNbq, etc.

5. Steel sheet for car beams: End the note with a capital “L”. Examples include: 09MnREL, 06TiL, 08TiL, 10TiL, 09SiVL, 16MnL, 16MnREL, etc.

8. Color coated steel plate

Color-coated steel sheets and strips are products that use metal strips as a base and are coated on their surface with various organic coatings.

They are used in areas such as construction, household appliances, steel furniture and transportation equipment.

9. Structural Steel for Shipbuilding

Shipbuilding steel generally refers to structural steel for ship hulls, which is produced in accordance with the ship classification society's construction specifications for the manufacture of ship hull structures.

It is often ordered, scheduled and sold as special steel, including ship plates, profiles, etc.

At present, several large steel companies in our country produce it, and they can manufacture shipbuilding steel materials according to the specifications of different countries according to customer needs, such as the United States, Norway, Japan, Germany, France, etc. .

Its specifications are as follows:

Nationality	Standard
China	CCS
Germany	GL
UK	LR
Norway	DNV
U.S	abdomen
France	B.V.
Japan	KDK

(I) Types and Specifications

Structural steel used in ship hulls is classified into strength levels based on their minimum yield point: general strength structural steel and high strength structural steel.

According to the standards of the China Classification Society, general strength structural steel is divided into: A, B, D, E four quality grades; High-strength structural steel, in accordance with the standards of the China Classification Society, is divided into three strength levels and four quality grades.

(II) Considerations for delivery and acceptance of steel for shipbuilding:

1. Quality certification review:

The steel company must deliver according to the specifications agreed in the contract according to the customer's needs and provide the original quality certification.

The certificate must include the following content:

(1) Specification requirements;

(2) Quality registration number and certification number;

(3) Batch number, technical classification;

(4) Chemical composition and mechanical properties;

(5) Approval of the Classification Society and signature of the surveyor.

2. Physical Inspection:

For the delivery of naval steel, there must be manufacturing marks on the physical object. These specific brands include:

(1) Classification society approval mark;

(2) Technical parameters are marked with paint or stickers, including furnace batch numbers, standard classes, dimensions, etc.;

(3) The appearance should be smooth and clean, without defects.