I. Steel plates and strips
Steel plates are flat-section steel materials with a significantly greater width-to-thickness ratio that are widely used in industrial applications. Steel plates can be categorized into medium and thin based on their thickness.
Steel strips are long, thin, narrow-width plates, mainly supplied in rolls. Specifications for steel plates are expressed in thickness * width * length (or roll) in millimeters.
1. Steel plates
(1) Medium thickness steel sheets:
Steel sheets with a thickness of more than 4 mm are classified as medium-thickness steel sheets. Within this category, plates with a thickness of 4.5 to 25.0 mm are called medium thickness plates, those with a thickness of 25.0 to 100.0 mm are known as thick plates, and plates with a thickness greater than 100. .0 mm are called extra thick. dishes.
At present, most medium-thickness steel sheets are produced by hot rolling and can be divided into common and high-quality medium-thickness steel sheets.
(2) Medium thickness common steel plates:
These are hot-rolled steel plates made from ordinary carbon structural steel or low-alloy structural steel. They mainly include common carbon boiling steel plates, common carbon stilling steel plates, low alloy steel plates, bridge steel plates, shipbuilding steel plates, boiler steel plates, steel plates for pressure vessels, stamped steel plates, automobile beam steel plates.
(3) High quality medium thickness boards:
These are hot-rolled steel plates made from various high-quality steels. Based on material and application, they are divided into high quality carbon structural steel plates, carbon tool steel plates, alloy structural steel plates, alloy tool steel plates, spring steel plates , bearing steel plates, high speed tool steel plates, stainless steel plates, 90 series steel plates, bulletproof steel plates, pure iron plates, high pressure steel plates, steel plates weather resistant, pressure resistant steel plates, low magnetic steel plates.
The most commonly used are high-quality carbon structural steel plates and stainless steel plates. In addition, there are composite steel plates, such as stainless composite steel plates, plow steel plates, copper-steel composite steel plates, etc. High quality medium thickness boards are used for parts, components, tools, etc. in machines and vehicles. . Stainless steel plates are used in the aviation, petrochemical, textile, food and medical industries.
(4) Thin steel sheets:
Steel sheets with a thickness of no more than 4.0 mm are classified as thin steel sheets. Thin steel sheets are divided into ordinary thin steel sheets, high-quality thin negative sheets and coated thin steel sheets, again divided into hot-rolled and cold-rolled based on the rolling process.
(5) Hot-rolled common thin steel sheets:
These are produced by hot rolling of common carbon structural steel or low alloy structural steel, mainly including common steel plates, shipbuilding steel plates, low alloy steel plates, stamped steel plates, steel plates for oil barrels, liquefied gas bottle steel plates, automotive beams steel plates, steel templates, etc.
Ordinary steel plates have a wide range of uses, especially for components where surface requirements are not high and deep punching is not required, such as machine covers, ventilation ducts, split boxes and other plate materials. The uses of steel sheets for automotive beams, standard beams, shipbuilding beams and others are the same as medium thickness sheets.
Oil Barrel Steel Plates are hot rolled into 1.25, 1.50mm thick thin plates using high quality carbon structural steel Q215-A, Q235-A or 08, 10. The surfaces of the plates are specified as 660*1310 (1970) (for barrel lids), 930*1800 (for barrel bodies) based on requirements.
(6) Hot rolled high quality thin steel sheets:
They are made by hot rolling of various types of high quality steel. The main types include high quality carbon structural steel plates, carbon tool steel plates, alloy structural steel plates, alloy tool steel plates, spring steel plates, bearing steel plates, stainless steel plates, 90 series plates and bulletproof steel plates. Its applications and uses are similar to those of high-quality hot-rolled medium and thick steel sheets.
(7) Common cold-rolled thin steel sheets:
These are cold rolled from common carbon structural steel or low alloy structural steel. Cold-rolled sheets feature superior surface quality and excellent stamping performance. They must pass cold bending and cupping tests and are commonly used in the automotive industry and as a raw material for coated sheet metal.
(8) High quality cold rolled thin steel sheets:
These mainly include various high-quality steel cold-rolled thin plates, the most common being carbon structural steel plates, specifically deep-drawing cold-rolled thin steel plates. They are cold-rolled thin sheets of high-quality, low-carbon 08Al steel.
Steel plates are divided into three groups based on surface quality: Group I, Group II and Group III, representing high-grade, high-grade and relatively high-quality surfaces, respectively. They are divided into levels ZF, HF, F (representing parts with more complex, very complex and complex stretching) and, according to the allowable deviation in the thickness of the steel sheet, they are divided into two precision levels, A and B. They are widely used in the automotive and tractor industries.
(9) Coated thin plates:
They are steel plates with other metals or non-metallic coatings coated on their surfaces to improve their corrosion resistance. Examples include galvanized steel plates, lead-coated steel plates, tin-coated steel plates, and plastic composite steel plates, collectively called coated steel plates. Coated steel plates are all thin plates.
(10) Galvanized thin steel sheets:
Also known as galvanized iron sheets or white iron sheets, they are made by acid washing thin cold-rolled steel plates 0.25-2.50mm thick and then dipping them in molten zinc to create a thin layer of zinc. The surface of the steel plate has a distinct crystalline pattern that resembles fish scales or leaves.
The zinc layer protects the steel plate from rust caused by air and water. Galvanized sheets are widely used in construction, packaging and daily life, such as roofing, gutters, downpipes, ventilation pipes and household items. The main requirement for galvanized thin steel plates is a good quality zinc layer.
The zinc layer on one side must be ≥0.2mm thick, and there are requirements for the plasticity of the steel plate and the strength of the zinc layer. Galvanized thin plates are divided into hot-dip galvanizing and electro-galvanizing.
(11) Lead-coated thin steel sheets:
They are generally made of 08Al thin plates cold rolled through lead coating. Lead is actually a lead-antimony alloy. Because lead, especially in many media containing H2S, SO2 and other petroleum products, has excellent corrosion resistance. Therefore, thin lead-coated steel plates are often used to make automobile fuel tanks and oil storage containers. The common thickness for lead-coated thin steel plates is 0.5 to 1.8 mm. There are requirements to ensure surface quality and stamping performance.
(12) Tinned thin steel sheet:
Also known as “tinplate”, it is typically made from cold-rolled thin low-carbon steel sheets such as 08F through hot-dip tinning or electroplating to form thin steel sheets of 0. 15-0.50mm. Due to its high resistance to corrosion from air, especially from various foods, the tin layer is particularly non-toxic when tin compounds are formed with food, causing no harm to the human body.
The surface of tinplate is shiny, attractive and easy to paint and print, making it widely used in the manufacture of food, candy, tea, condiments and containers for paints, dyes and medicines. The method for calculating the thickness of tinplate differs from other thin plates, it is expressed in numbers, that is, the average thickness in millimeters within a given range multiplied by 100, for example, nº 40 represents a thickness in the range 0.36-0.44mm tinplate.
The standard tinplate size is generally 508 x 712 mm (equivalent to 20 inches x 38 inches), with 112 per box for Nos. 26, 28, 32 and 56 or 84 per box for Nos. 36, 45, 50. The main Requirement for tinplate is a uniform layer of tin and good stamping moldability. In addition to the coated plates mentioned above, there is also rapid development in aluminum, chrome and organic coated steel plates.
2. Steel strips
Also known as steel strips, they are actually thin, narrow and long steel sheets, usually supplied in rolls. Compared to steel plates, they offer greater dimensional accuracy, better surface quality and ease of use.
They are widely used for producing welded steel pipes, cold bent steel blanks, manufacturing bicycle frames, wheel rims, hose clamps, washers, spring sheets, cable armor, saw blades, blades knife, packing iron, etc. is similar to thin steel plates:
(1) Hot-rolled common steel strips:
Made of common carbon structural steel or low-alloy structural steel, mainly used for pipe welding, cold-bent steel blanks and cold-rolled steel strip raw materials. Subdivided into common carbon steel strip, low alloy steel strip, common carbon longitudinal shear steel strip and low alloy longitudinal shear steel strip. Longitudinal shear steel strips are made by cutting coil plates lengthwise or to a certain width.
(2) Cold-rolled common steel strips:
These are made from common steel through a cold rolling process. They include common carbon steel strips, low alloy steel strips, common bright carbon steel strips, common carbon steel strips cut lengthwise, lengthwise cut low alloy steel strips, wheelbarrow steel strips, steel strips for bundling, steel strips for lantern, steel strips for hoses and cables steel strips. They are mainly used in the production of various structural components and special products.
(3) Hot rolled high quality steel strips:
They are steel strips made from various high-quality steels through a hot rolling process. Common types include watch spring steel strips, watch case steel strips, and chrome-aluminum steel strips.
(4) Cold rolled high quality steel strips:
They are made from various high-quality steels through a cold rolling process. They include carbon structural steel strips, tape measure steel strips, mechanical chain steel strips, carbon tool steel strips, alloy structural steel strips, spring steel strips, alloy, ball bearing steel strips, stainless steel strips, high speed tool steel, pure iron steel strips, silicon steel strips, nickel-chromium steel strips, precision alloy steel strips and more . Its applications are similar to those of high-quality thin steel sheets.
(5) Coated steel strips:
This includes galvanized straps, tin coated straps, galvanized cable straps, tin coated cable straps and painted cable straps.
The sizes of the steel strips are indicated by thickness*width. Steel strip size accuracy requirements are higher, especially for cold-rolled steel strip. Depending on manufacturing accuracy, edge condition, surface condition, delivery condition, mechanical properties and surface color, they are classified into several categories. It is crucial to carefully review relevant regulations as necessary during use.
(6) Electrical silicon steel sheet:
Also known as silicon steel sheet or silicon steel plate, it is made of electrical steel with silicon content of 0.8-4.8% through hot or cold rolling. Cold-rolled silicon steel electrical sheets have a smooth surface, uniform thickness, high fill factor, lower losses than hot-rolled sheets, and high magnetic induction.
Especially, cold-rolled grain-oriented electrical silicon steel sheets have higher magnetic induction and lower iron losses. Therefore, the use of cold-rolled electrical silicon steel sheets for the manufacture of motors and transformers can reduce their weight and volume by 10-25% compared to hot-rolled ones.
(7) Hot rolled electrical silicon steel sheet:
This is divided into silicon steel sheets for motors and silicon steel sheets for transformers. The thicknesses of motor silicon steel sheets are 0.35, 0.50, 1.00mm and transformer silicon steel sheets have thicknesses of 0.10, 0.20, 0.35, 0.50mm. They are mainly supplied in rolls.
(8) Cold rolled electrical silicon steel sheet:
This is divided into grain-oriented silicon steel sheets, non-oriented silicon steel sheets and DW materials. Non-oriented silicon steel sheets for motors, commonly supplied in rolls, are generally 0.35 and 0.50mm thick and generally have a lower silicon content. Silicon steel sheets for transformers, commonly supplied in rolls, have thicknesses of 0.20, 0.30, 0.35, 0.50 mm and generally have a higher silicon content.
In addition to motors and transformers, silicon steel electrical sheets are indispensable magnetic materials in the electrical and telecommunications industries, electrical instruments and other electrical appliances.
II. Classification of steel plates (including steel strips):
1. By thickness:
- (1) Thin Plate
- (2) Medium Plate
- (3) Thick plate
- (4) Extra thick plate
2. By Production Method:
- (1) Hot rolled steel plate
- (2) Cold rolled steel plate
3. By surface features:
- (1) Galvanized plate (hot-dip galvanized plate, electro-galvanized plate)
- (2) Tin plate
- (3) Coated steel plate
- (4) Color coated steel plate
4. By use:
- (1) Bridge steel plate
- (2) Boiler steel plate
- (3) Shipbuilding Steel Plate
- (4) Armored steel plate
- (5) Automobile steel plate
- (6) Roofing steel plate
- (7) Structural Steel Plate
- (8) Electrical steel plate (silicon steel plate)
- (9) Spring steel plate
- (10) Others
III. Japanese grades often seen in general structural and mechanical steel plates
1. The designation of Japanese steel (JIS series) in general structural steel is mainly composed of three parts: the first part indicates the material, such as: S (Steel) represents steel, F (Ferrum) represents iron; the second part represents different shapes, types, uses, such as P (Plate) implies plate, T (Tube) indicates tube, K (Kogu) indicates tool; the third part represents the characteristic number, usually the minimum tensile strength. For example: SS400 – the first S stands for Steel, the second S stands for “Structure”, 400 is the lower limit tensile strength of 400MPa, representing general structural steel with a tensile strength of 400 MPa.
2. SPHC—The initial 'S' stands for Steel, 'P' for Plate, 'H' for Heat and 'C' for Commercial. In general, this means hot-rolled steel sheets and steel strips typically used in commercial applications.
3. SPHD—This denotes hot-rolled steel sheet and steel strip used for stamping.
4. SPHE – Represents hot-rolled steel sheets and steel strips designed specifically for deep drawing applications.
5. SPCC – Means cold-rolled carbon steel sheets and strips commonly used in commercial environments, equivalent to China grade Q195-215A. The third letter 'C' stands for Cold. To ensure tensile strength during testing, 'T' is added at the end of the grade, making it SPCCT.
6. SPCD – Means cold-rolled carbon steel sheets and strips used for stamping, equivalent to high-quality carbon structural steel 08AL (13237) from China.
7. SPCE—This denotes cold-rolled carbon steel sheets and strips for deep drawing, equivalent to 08AL (5213) deep drawing steel from China. To ensure non-aging, 'N' is added to the end of the note, making it SPCEN.
The temper designations for cold-rolled carbon steel sheets and strips are: Annealed state is 'A', Standard temper is 'S', 1/8 hard is '8', 1/4 hard is '4', 1/2 hard is '2', fully hard is '1'.
Surface Finish Designations: Matte finish is 'D', glossy finish is 'B'. For example, SPCC-SD means cold-rolled carbon steel sheet with matte finish and standard temper. SPCC-SB means cold-rolled carbon steel sheet with bright finish and standard tempering, where mechanical properties must be guaranteed.
8. The JIS method for denoting mechanical structural steel grades is 'S'+ Carbon Content + Letter Code (C, CK), where carbon content is represented by the median value ×100. Here, 'C' stands for Carbon and 'K' stands for Carburizing Steel. For example, the carbon content in S20C carbon steel rolled coil is 0.18-0.23%.
4. Grade Nomenclature of Silicon Steel Sheet in China and Japan
1. Chinese nomenclature:
(1) Cold rolled non-oriented silicon steel sheet
Identification: DW + Iron loss value (times 100) at 1.5T peak magnetic flux density in 50 Hz sine wave + Thickness (times 100)
For example, DW470-50 denotes a cold-rolled non-oriented silicon steel sheet with an iron loss value of 4.7 w/kg and a thickness of 0.5 mm. The new model is represented as 50W470.
(2) Cold rolled grain oriented silicon steel sheet
Identification: DQ + Iron loss value (times 100) at 1.7T peak magnetic flux density in 50Hz sine wave + Thickness (times 100). The letter G is sometimes added after the iron loss value to indicate high magnetic induction.
For example, DQ133-30 represents a cold-rolled grain-oriented silicon steel sheet with an iron loss value of 1.33 and a thickness of 0.3 mm. The new model is represented as 30Q133.
(3) Hot rolled silicon steel sheet
Hot-rolled silicon steel sheets are denoted by DR and are divided into low silicon steel (silicon content ≤2.8%) and high silicon steel (silicon content >2.8%).
Identification: DR + Iron loss value (times 100) at 1.5T peak magnetic flux density at 50Hz repetitive magnetization and sinusoidal variation + Thickness (times 100).
For example, DR510-50 denotes a hot-rolled silicon steel sheet with an iron loss value of 5.1 and a thickness of 0.5 mm.
The designation for hot-rolled silicon steel thin sheets used in household appliances is represented by JDR + Iron Loss Value + Thickness, such as JDR540-50.
2. Japanese nomenclature:
(1) Cold rolled non-oriented silicon steel sheet
Identification: Nominal thickness (100 times) + Code A + Guaranteed iron loss value (100 times after iron loss expansion at 50Hz, maximum magnetic flux density 1.5T).
For example, 50A470 denotes a cold-rolled non-oriented silicon steel sheet with a thickness of 0.5 mm and a guaranteed iron loss value of ≤4.7.
(2) Cold rolled grain oriented silicon steel sheet
Identification: Nominal thickness (100 times) + G code for regular material, P code for highly granular material + Guaranteed iron loss value (100 times after iron loss expansion at 50 Hz, maximum magnetic flux density 1.7T ).
For example, 30G130 represents a cold-rolled grain-oriented silicon steel sheet with a thickness of 0.3 mm and a guaranteed iron loss value of ≤1.3.
V. Electrolytic tin plate and hot dip galvanized plate
1. Electrolytic tin plate
Electrolytic tinplate and strip, also known as tinplate, are steel sheets and strips coated with tin on the surface. They have excellent corrosion resistance and are non-toxic. They can be used as packaging material for cans, as protective covers for cables, components for telecommunications, and in small hardware items such as torches.
2. Hot dip galvanized plate
The surface of thin steel sheets and strips is coated with zinc through a continuous hot-dipping process, which can prevent corrosion and rust on the steel surface. Galvanized steel sheets and strips are widely used in mechanical, light, construction, transportation, chemical, postal and other industries.
SAW. Boiling steel plate and calm steel plate
1. Boiling steel plate
The boiling steel plate is made of hot-rolled carbon structural steel. Boiling steel is a type of steel that is incompletely deoxidized. It is deoxidized with a certain amount of weak deoxidizer, resulting in steel with a high oxygen content. 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.
Boiling steel has a low carbon content and low silicon content (Si<0.07%) due to the lack of deoxidation of ferrosilicon. The outer layer of boiling steel is crystallized under the intense stirring of boiling molten steel, resulting in a pure and dense surface with good plasticity and stamping performance.
It does not have large concentrated shrinkage cavities, has fewer cut ends, a high yield rate and low steel cost due to its simple production process and low consumption of ferroalloys. Boiling steel plates are widely used in the manufacture of various stamped parts, architectural and engineering structures and some less important mechanical structural components.
However, boiling steel has more impurities in the core, serious segregation, non-dense structure and uneven mechanical properties. It also has low toughness, high cold brittleness, aging sensitivity and poor welding performance.
Therefore, boiling steel plates are not suitable for manufacturing structures that withstand impact loads, work at low temperatures or for other important structures.
2. Calm Steel Plate
Calm steel plate is made of hot-rolled carbon structural steel. Calm steel is completely deoxidized steel. Molten steel is fully deoxidized with ferromanganese, ferrosilicon and aluminum before casting, resulting in steel with a low oxygen content (generally 0.002-0.003%). The steel molten in the ingot mold is calm and does not boil, hence the name calm steel.
Under normal operating conditions, calm steel does not have bubbles and has a uniform, dense structure. Due to its low oxygen content, there are fewer oxide inclusions in the steel, in addition to having greater purity, less brittleness to cold and a tendency to aging.
At the same time, calm steel has less segregation, more uniform properties and higher quality. The disadvantage of calm steel is that it has concentrated shrinkage cavities, lower yield and higher price. Therefore, calm steel is mainly used for components that withstand impacts at low temperatures, welding structures and other components that require high strength.
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 application has become increasingly extensive.
VII. High Quality Carbon Structural Steel Plate
High-quality carbon structural steel is a type of carbon steel with a carbon content of less than 0.8%. This steel contains less sulfur, phosphorus and non-metallic impurities than normal carbon structural steel, resulting in superior mechanical properties.
High-quality carbon structural steel can be categorized into three types based on carbon content: low carbon steel (C≤0.25%), medium carbon steel (C=0.25-0.6%) and high carbon steel (C>0.6). %).
Depending on the 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 last group presents superior mechanical and processing properties.
1. Hot rolled thin plates and strips of high quality carbon structural steel
Hot-rolled thin sheets and strips of high-quality carbon structural steel are used in the automotive, aerospace and other industries. Steel types include boiling steel: 08F, 10F, 15F; and calming steel: 08, 08AL, 10, 15, 20, 25, 30, 35, 40, 45, 50.
Grades 25 and below are classified as low carbon steel plates, while grades 30 and above are classified as medium carbon steel plates.
2. Hot rolled thick plates and wide strips of high quality carbon structural steel
Hot-rolled thick sheets and wide strips of high-quality carbon structural steel are used in various mechanical structural components.
Steel types include low carbon steel: 05F, 08F, 08, 10F, 10, 15F, 15, 20F, 20, 25, 20Mn, 25Mn, etc.; medium carbon steel: 30, 35, 40, 45, 50, 55, 60, 30Mn, 40Mn, 50Mn, 60Mn, etc.; and high carbon steel: 65, 70, 65Mn and so on.
VIII. Specialized Structural Steel Plates
1. Pressure vessel steel plates:
Identified by a capital 'R' at the end of the designation. The designation may represent yield point or carbon/alloy content. For example: Q345R, where Q345 refers to the yield strength. Similarly, designations such as 20R, 16MnR, 15MnVR, 15MnVNR, 8MnMoNbR, MnNiMoNbR, 15CrMoR, etc., represent carbon content or alloying elements.
2. Gas Cylinder Welding Steel Plates:
Identified by 'HP' at the end of the designation. The designation may represent the yield point, such as Q295HP, Q345HP; or alloying elements such as 16MnREHP.
3. Boiler steel sheets:
Identified by a lowercase 'g' at the end of the designation. The designation may represent the yield strength, such as Q390g; or carbon content/alloying elements, such as 20g, 22Mng, 15CrMog, 16Mng, 19Mng, 13MnNiCrMoNbg, 12Cr1MoVg, etc.
4. Bridge Steel Plates:
Identified by a lowercase 'q' at the end of the designation, such as Q420q, 16Mnq, 14MnNbq, etc.
5. Steel Sheets for Automotive Beams:
Identified by a capital 'L' at the end of the designation, such as 09MnREL, 06TiL, 08TiL, 10TiL, 09SiVL, 16MnL, 16MnREL, etc.
IX. Color Coated Steel Plates
Color-coated steel sheets and strips are products based on metal strips coated with various organic paints, used in areas such as construction, household appliances, steel furniture, transport vehicles and much more.
X. Structural Steel for Ship Hulls
Shipbuilding steel generally refers to steel used in the structural framework of the ship's hull, manufactured specifically in accordance with production standards established by classification societies. It is typically ordered, scheduled and sold as specialty steel and includes ship plates and steel profiles.
Currently, the main steel manufacturers in our country produce this type of steel, being able to manufacture steel for shipbuilding according to the standards of different countries according to the needs of customers, such as those in the United States, Norway, Japan, Germany, France, etc.
(1) Variety and Specifications
Structural steel for ship hulls is categorized by its minimum yield point into two strength grades: general strength structural steel and high strength structural steel.
In the standards set by the China Classification Society, general strength structural steel is divided into four quality grades: A, B, D, E; high-strength structural steel is divided into three strength grades and four quality grades.
(2) Important Points for the Delivery and Acceptance of Steel for Shipbuilding:
1. Quality Certification Review:
Upon delivery, the steel company must provide the original quality certification in accordance with the customer's needs and the contract.
This certification must include the following information:
(1) Standard requirements;
(2) Quality registration number and certification number;
(3) Furnace batch number and technical classification;
(4) Chemical composition and mechanical properties;
(5) Certification of approval from the classification society and signature from the ship's surveyor.
2. Physical Inspection:
The marine steel delivered must have the manufacturer's mark on the physical object. Specifically:
(1) Classification society approval mark;
(2) Use of paint boxes or adhesive labels indicating technical parameters such as: oven batch number, standard class, dimensions, etc.;
(3) The appearance is smooth and perfect.
XI. Naming method for Baosteel 1550 cold-rolled product classes
(1) Naming method for grades of cold-rolled steel strip for stamping
1. General stamping steel: BLC
B–Abbreviation for Baosteel; L–Low Carbon; C – Commercial Use
2. Aging-resistant low-yield steel: BLD
B–Abbreviation for Baosteel; L–Low Carbon; D – Use of stamping
3. Non-aging super deep drawing steel: BUFD (BUSD)
B–Abbreviation for Baosteel; U-Ultra; F–Formability; D – Stamping
4. Aging-free ultra-deep drawing steel: BSUFD
B–Abbreviation for Baosteel; SU–Ultra+Super; F–Formability; D – Stamping
(2) Naming method for grades of high-strength cold-rolled steel strip for cold forming
B ××× × ×
B–Abbreviation for Baosteel; ×××–Minimum yield point value;
× – General use of V, X, Y, Z
V: High strength and low alloy, no specified difference between yield strength and tensile strength
X: A minimum difference of 70 MPa between the yield strength and the V-tensile strength
Y: A minimum difference of 100 MPa between the yield strength and the V-tensile strength
Z: A minimum difference of 140 MPa between the yield strength and the V-tensile strength
×–Control of oxide/sulfide inclusions (K: Dead, Fine Grain; F: K + Sulfide Control; O: Other than K, F)
Example: B240ZK, B340VK
(3) Class naming method of dent-resistant continuous cold rolling steel strip
B ××× × ×
B – Acronym for Baosteel
×××–Minimum yield point value
×–Strengthening method (P: Strengthening; H: Baking hardening)
×–Indicated by 1 or 2 (1: Ultra-low carbon; 2: Low carbon)
For example, B210P1: High strength steel for deep drawing; B250P2: Phosphorus-rich high-strength steel for general processing; B180H1: Hardened steel for deep drawing.
