1、Categories of steel plate (including steel strip):

1、Categorized according to the thickness:：
 （1）thin sheet （2）medium plate （3）thick plate （4）extra thick plate
2、Categorized according to the manufacturing methods：
 （1）hot rolled steel plate （2）cold rolled steel plate
3、Categorized according to surface characteristics：
（1）galvanized plate（hot galvanized plate, electro-galvanized plate） （2）tinning plate （3）composite steel plate （4）color-coated steel plate
4、Categorized according to usages：
 （1）bridge steel plate （2）boiler steel plate （3）ship steel plate （4）armor plate （5）automobile steel plate （6）roof steel plate （7）structural steel plate （8）electrical steel plate (silicon steel sheet）（9）spring steel plate （10）others

2、Common Japanese Steel numbers of ordinary and mechanic structural steel plates

　　 1、 Steel numbers of Japanese steel (JIS series) for ordinary structural steel are mainly composed of three parts. The first part stands for material, e.g., S（Steel） stands for steel material, F（Ferrum）stands for iron; The second part stands for different shapes, categories, and usages, e.g., P(Plate) stands for plate material, T（Tube） stands for tube, and K(Kogu) stands for tool; and the third part stands for representative numbers, usually the minimum tensile strength, e.g., SS400 — the first S stands for steel material (Steel)，the second S stands for “structural material”（Structure），400 means the minimum tensile strength is 400 MPa，it in whole represents an ordinary structural steel with a tensile strength of 400 MPa.

　　 2、 SPHC— S in the first place is the abbreviation of Steel，P is Plate，H is Heat，C is Commercial，the number in whole stands for hot rolled steel plate and strip for ordinary commercial use.

　　 3、 SPHD— stands for hot rolled steel plate and strip used for drawing.

　　 4、 SPHE— stands for hot rolled steel plate and strip used for deep drawing.

　　 5、SPCC— stands for cold rolled carbon steel thin sheet and strip for ordinary use, which corresponds to Chinese Q195-215A steel number, where the third place C means Cold. If a tensile test is required, add a T at the end of the number, which becomes: SPCCT.

　　 6、 SPCD—stands for cold rolled carbon steel thin sheet and strip for drawing use, which corresponds to Chinese 08AL（13237）quality carbon structural steel.

　　 7、 SPCE— stands for cold rolled carbon steel thin sheet and strip for deep drawing use, which corresponds to Chinese 08AL（5213）deep drawing steel. When non-aging is required, add an N at the end of the number which becomes to SPCEN. Cold rolled carbon steel thin sheet and strip code name: temper grade code name：annealing condition is represented by A，standard temper grade is S，1/8 hardness is8，1/4 hardness is 4，1/2 hardness is 2，full hardness is 1. Surface finishing code name: dark finish rolling is represented by D， brightened finish rolling is B。e.g., SPCC-SD stands for cold rolled carbon thin sheet for ordinary commercial use with standard temper grade, dark finish rolling. Another example is SPCCT-SB, which means cold rolled carbon thin sheet with standard temper grade and brightened finish, and mechanical performance should be guaranteed.

　　 8、 JIS steel numbers for mechanical structural steel are expressed as follows: S + carbon content + letter code name（C、CK），where carbon content is represented by the actual average value×100，the letter C means carbon, and K means steel used for cementite use. E.g., carbon steel roll sheet S20C is with a carbon content of 0.18-0.23%。

3、Steel number expression for silicon steel sheet in China and Japan

1、 Steel number expression in China:

　　 （1） Cold rolled non-oriented silicon steel strip (sheet)
Expression: DW + iron loss value（unit weight iron loss with a sine function wave form with a frequency of 50HZ and a magnetic induction peak value of 1.5T）×100 + thickness ×100, e.g., DW470-50 stands for cold rolled disoriented silicon steel with iron loss of 4.7 w/kg and thickness of 0.5 mm, new code name of which is 50W470。

　　 （2） Cold rolled oriented silicon steel strip (sheet)
Expression：DQ + iron loss value（unit weight iron loss with a sine function wave at frequency of 50 HZ and magnetic inductance peak value of 1.7 T.）×100 + thickness×100. Sometimes, a G is added after the iron loss value to represent a high magnetic inductance, e.g., DQ133-30 stands for cold rolled oriented silicon steel strip (sheet) with an iron loss of 1.33 and thickness of 0.3 mm, the new code name of which is 30Q133.

　　 （3） Hot rolled silicon steel plate
Hot rolled silicon steel plate is represented by DR, which is categorized according to silicon content into lowsilicon steel（silicon content ≤2.8%）, high silicon steel（silicon content ＞2.8%）. Expression: DR + iron loss value（iron lossfor unit weight with repeated magnetization of a sine function wave with frequency of 50HZ and magnetic inductance peak value of 1.5T）×100 + thickness×100, e.g., DR510-50 stands for a hot rolled silicon steel plate with an iron loss of 5.1 and thickness of 0.5 mm. Hot rolled silicon steel thin sheet for electrical appliance use is represented by JDR + iron loss value + thickness, e.g., JDR540-50.

2、 Expression of Japan steel number

　　 （1） Cold rolled non-oriented silicon steel strip
By nominal thickness（×100）+ code name A + iron loss guarantee value（100×iron loss when frequency = 50 HZ, and maximum magnetic flux density = 1.5 T）, e.g., 50A470 stands for cold rolled non-oriented silicon steel strip with a thickness of 0.5 mm and iron loss guarantee value ≤4.7.

　　 （2） Cold rolled oriented silicon steel strip
By nominal thickness (×100）+ code name G：stands for ordinary material, P：means highly oriented material + iron loss guarantee value（100 × iron loss value when frequency = 50HZ，and the maximum magnetic flux density = 1.7T）, e.g., 30G130 means cold rolled oriented silicon steel strip with a thickness of 0.3 mm and iron loss guarantee value ≤1.3.

4、Tinning plate and hot galvanized plate：

1、 Tinning plate
Tin galvanized thin sheet and strip, also known as “Ma Kou Tie” in China, the surface of which is plated with tin. Therefore, it has a good corrosion resistant property, and is poison-less, so that it can be used as small metal products such as packing material for can, interior/exterior sheath of the cable，parts for communication instruments, and flashlight, etc..

5、Rimmed steel sheet and killed steel sheet  

1、 Rimmed sheet is made by hot rolling ordinary carbon structural steel and rimmed steel, which is not completely deoxidized. Because only a certain amount of weak deoxidant is used to deoxidize the molten steel, the oxygen content is high in the molten steel. After the molten steel is filled into the ingot mold，the carbon oxygen reaction will result in a large amount of gas, which will make the molten steel boiling. The Chinese name of the rimmed steel is named after this. Rimmed steel has a low carbon content, and because silicon-iron deoxidant is not used, the silicon content in steel is also low（Si<0.07%）. The exterior layer of rimmed sheet is formed by crystallization under strong stirring caused by the boiling effect of the molten steel, therefore, the surface layer is pure and dense, with a good surface quality, and very good plasticity and drawing characteristics, without big concentrated shrinkage holes，with less waste heads and high success rates. Furthermore, the manufacturing technology of rimmed steel is simple, with low consumption of iron alloy, therefore, the cost of steel is low. Rimmed steel sheet is widely used for making all kinds of pressing parts，architecture and construction structures, and some less important parts or components for instruments. However, the interior part of rimmed steel has a lot of impurities, with serious segregation，and the structure is not densely organized. The mechanical property is not uniform. In the mean time, because air content in steel is high, the tenacity is low, and the cold short and aging sensitivity is high. The welding performance is also bad. Therefore, rimmed steel is not suitable for making welding structures which bear impact loads, or work under low temperatures, and other important structures.  

2、 Killed steel is made by hot rolling ordinary carbon structural steel and killed steel. Killed steel is completely deoxidized. Before the molten steel is filled, Mn-Fe, Si-Fe, and/or Al deoxidants are used to thoroughly deoxidize the molten steel, therefore, the oxygen content of the molten steel is low（usually 0.002-0.003%）. The molten steel in the ingot mold is “quiet” without boiling; therefore, the name is given after this. Under normal operation conditions, there is no air bubble in killed steel, as a result, the structure is uniformly and densely organized; Because oxygen content is low, the oxidized impurity in steel is also less and the steel is purer, with low cold short and aging tendency；in the mean time, the segregation in killed steel is less. The properties are uniform, and quality is high. The shortcomings of killed steel is that it’s with concentrated shrinkage holes， the success rate is low, and the price is higher. Therefore, killed steel is mainly used for structural components which bear impact under low temperatures, welding structures, and other structures with high strength requirements. Low alloy steel plates are either killed steel or semi killed steel. Because it’s with high strength and excellent properties, and its use can help save a lot of steel materials and decrease the weight of structures, killed steel is more and more widely used.

6、Quality carbon structural steel plate

Quality carbon structural steel is carbon steel with carbon content less than 0.8%. This type of steel has lower sulfur, phosphorus and non-metal impurities than carbon structural steel does, and the mechanical performance is good. Quality carbon structural steel can be divided into three categories according to carbon content: low carbon steel（C≤0.25%）, medium carbon steel（C为0.25-0.6%）, and high carbon steel（C＞0.6%）. Quality carbon structural steel can be categorized according to Mn content into normal Mn steel (Mn content 0.25%-0.8%）and high Mn steel (Mn content 0.70%-1.20%), the latter of which has better mechanical performance and machining performance.

　　 1、Quality carbon structural steel hot rolled thin sheet and strip
Quality carbon structural steel hot rolled thin sheets and strips are used in automobile industry, aviation industry, and other departments, the steel numbers for rimmed steel are: 08F, 10F, 15F；for killed steel are：08, 08AL, 10, 15, 20, 25, 30, 35, 40, 45, 50, and steels with numbers below 25 are low carbon steel plate, steels with numbers of 30 and above 30 are medium carbon steel plates.

　　 2、 Quality carbon structural steel hot rolled thick plate and wide strip 
Quality carbon structural steel hot rolled thick plates and wide strips are used for different kinds of mechanical structural components. The steel numbers for low carbon steel are: 05F, 08F, 08, 10F, 10, 15F, 15, 20F, 20, 25, 20Mn, 25Mn, etc.; for medium carbon steels are: 30, 35, 40, 45, 50, 55, 60, 30Mn, 40Mn, 50Mn, 60Mn, etc.; for high carbon content steel are: 65, 70, 65Mn, etc.

7、Special structural steel plate

1、 Steel plates for pressurized container: denoted by capitalized R at the end of its steel number. Its steel number can be denoted by either yielding point or carbon content or alloy element symbols, e.g., Q345R，Q345 are using yielding points. Another example is: 20R, 16MnR, 15MnVR, 15MnVNR, 8MnMoNbR, MnNiMoNbR, and 15CrMoR, etc., are using carbon content or alloy element symbols.

2、 Steel plates for welding gas tanks：denoted by capitalized HP at the end of its steel number. Its steel number can be denoted by either yielding point, e.g., Q295HP, Q345HP；or alloy element symbols, e.g., 16MnREHP.

3、 Steel plates for boilers：denoted by g in lower case at the end of its steel number. Its steel number can be denoted by either yielding point, e.g., Q390g；or carbon content or alloy elements, such as 20g, 22Mng, 15CrMog, 16Mng, 19Mng, 13MnNiCrMoNbg, and 12Cr1MoVg, etc.

4、 Steel plates for bridges: denoted by q in lower case at the end of its steel number, such as Q420q, 16Mnq, and 14MnNbq, etc.

5、 Steel plates for beams of automobile: denoted by capitalized L at the end of its steel number, such as 09MnREL, 06TiL, 08TiL, 10TiL, 09SiVL, 16MnL, and 16MnREL, etc.

8、Pre-painted steel plate

Color coated steel plate and strip is using metal strip as base, and its surface is painted with different kinds of organic paint, which is mainly used in the field of architecture, electrical appliance, steel furniture, and transportation vehicles, etc..

9、Structural steel for ship body

Steel for ship manufacturing is usually referred to steel for ship body structures. It is the ship body structural steel manufactured in accordance with the manufacturing specifications of ship classification society. It is often ordered, arranged for manufacturing, and sold as special steel, usually including ship deck, and section steel, etc. Nowadays, several major steel companies in China can manufacture this type of steel, furthermore, the manufacturing can be tailored to customer’s needs to produce ship steel complying with specifications of different countries, such as: USA, Norway, Japan, Germany, and France, etc., the specifications are as follows:  

 

Nationality	Specification
China	CCS
USA	ABS
Germany	GL
France	BV
UK	LR
Japan	KDK
Norway	DNV

(I) Categories and specifications

The strength grade of ship body structural steel can be categorized according to the minimum yielding point into: averaged strength structural steel and high strength structural steel. According to the ship classification society of China, the averaged strength structural steel can be categorized into four quality levels as A, B, D, and E；and the high strength structural steel can be categorized into three strength grades and four quality levels.

(II)Notes for checking and accepting the delivered ship steel：

1、 Checking the quality certificate：
In accordance with the requirement of the customer, steel factories must deliver productsaccording to the specifications as defined in the contract and provide original quality certificate, which shall bearing the following contents:

（1）required specifications；
（2）quality record number and certificate number;
（3）furnace batch number, technical level;
（4）chemical composition and mechanical property;
（5）authorization certificate from ship classification society and signature from the surveyor.

2、 Checking the products： 
During the delivery of ship steel, sings of the manufacturers should be marked on the product body. The following should also be checked:

（1）sign of authorization from the ship classification society；
（2）marking out or sticking the signs to show technical parameters such as: furnace batch number, levels as defined in the specifications and standards, and dimensions in length, width, etc..
（3）steel shall be smooth, clean, and flawless in appearance.

10、Method of denoting Baogang 1550 cold rolled products

(I)Method of denoting cold tandem rolled steel strips for drawing use
1.commercial drawing steel：BLCB— B—abbreviation of （BAO STEEL）；L-- Low Carbon）；C - (Commercial）
2.anti-aging low-yielding steel：BLDB—B –abbreviation of （BAOSTEEL）；L--（Low Carbon）；D - (Drawing)
3.Non-aging ultra deep drawing steel：BUFD（BUSD）B - abbreviation of (BAO STEEL)；U - (Ultra)；F - (Formability)；D - (Drawing)
4.Non-aging ultra super deep drawing steel：BSUFDB - B - abbreviation of （BAOSTEEL）；SU -（Ultra+Super）；F -（Formability）；D -（Drawing）

(II)Method for denoting high strength cold tandem rolled steel strips for cold forming use, B ×××××
B - abbreviation for（BAO STEEL）；×××- minimum yielding point value；×- usually represented in V, X, Y, and Z
V: high strength low alloy, Difference between yielding point and tensile strength: Not required
X: Difference between minimum yielding point and minimum tensile strength as defined in V: 70 MPa
Y: Difference between minimum yielding point and minimum tensile strength as defined in V: 100MPa
Z: Difference between minimum yielding point and minimum tensile strength as defined in V: 140MPa
×- oxide/sulfide impurity control（K：killed, tiny crystal grain；F：K + sulfide control；O：except K and F）
e.g., B240ZK、B340VK

(III)Method for denoting denting-resistant cold tandem rolled steel strip
B ×××××
B - abbreviation for （BAO STEEL）
×- strengthening mode（P：strengthened；H：bake-hardened）
×- denoted by 1 or 2（1：ultra low carbon；2：low carbon）
e.g., B210P1：deep drawing high strength steel；B250P2：high strength phosphorus steel for commercial processing use；B180H1：deep drawing bake-hardened steel.