What is stainless steel plate?

What is stainless steel plate?

Stainless steel plate is the general term of stainless steel plate and acid resistant steel plate. Stainless steel plate refers to the steel plate which is resistant to the corrosion of weak medium such as atmosphere, steam and water, while the acid resistant steel plate refers to the steel plate which is resistant to the corrosion of chemical etching medium such as acid, alkali, salt, etc. The stainless steel plate has smooth surface, high plasticity, toughness and mechanical strength, and is resistant to corrosion of acid, alkaline gas, solution and other media. It is not easy to rust alloy steel, but not absolutely rust free.

Classification of stainless steel plate

By thickness

• (1) Thin plate (0.2mm-4mm)
• (2) Medium plate (4mm-20mm)
• (3) Tthick plate (20mm-60mm)
• (4) Extra thick plate (60-115mm)

According to production method

Hot rolled steel plate

After the straight hair coil is processed by the finishing line of cutting head, tail, edge and straightening and leveling for many times, then the plate is cut or rewound, and the products such as hot-rolled steel plate, flat hot-rolled coil and longitudinal strip are formed. If the oxide scale is removed by pickling and oiling, the hot-rolled pickling coil is formed. The product has the tendency of partial substitution of cold-rolled sheet, the price is moderate, and it is loved by the majority of users.

Cold rolled steel plate

Cold rolling is made of hot rolled coil under recrystallization temperature at room temperature. Cold rolled steel sheet is produced by cold rolling process, which is called cold plate. The thickness of cold rolled sheet is generally between 0.1 mm and 8.0 mm. The thickness and width of cold rolled sheet produced by most factories are less than 4.5 mm. The thickness and width of cold rolled sheet are determined according to the equipment capacity and market demand of each factory.

By surface features

Surface	Features	Summary of manufacturing law	Purpose
NO.1	Silvery white without luster	Hot rolled to specified thickness	There is no need for glossy applications
NO.2D	Silvery white	Heat treatment and pickling after cold rolling	General material, deep drawing material
NO.2B	The luster is stronger than No.2D	After No. 2D treatment, the final pass of light cold rolling is carried out by polishing roller	General materials
BA	Bright as a mirror	There is no standard, but usually bright annealing surface processing, the surface reflection is very high.	Building materials, Kitchenware
NO.3	Rough grinding	Grind with 100 ~ 200 mm abrasive belt	Building materials, Kitchenware
NO.4	Intermediate grinding	The polished surface obtained by grinding with 150 ~ 180 abrasive abrasive abrasive belt	Ditto
NO.240	Fine grinding	Grinding with 240# abrasive beltKitchenware	Kitchenware
NO.320	Very fine grinding	Grinding with 320# abrasive belt	Ditto
NO.400	The luster is close to BA	Grind with a 400# polishing wheel	General materials, building materials, kitchen utensils
HL	Hair line grinding	There are a lot of grinding grains when the material with proper particles is used to grind hair lines (150 ~ 240#)	Building materials
NO.7	Close to mirror grinding	Grind with 600# rotary polishing wheelFor art and decoration
NO.8	Mirror grinding	Mirrors are ground with polishing wheels	Reflector, decorative

By use

(1) bridge steel plate

(2) boiler steel plate

(3) shipbuilding steel plate

(4) armored steel 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) solar energy special plate (Hai Ruite steel)

(11) other

Structure according to steel grade

• (1) Austenite
• (2) austenite ferrite
• (3) ferrite
• (4) martensite

JIS
In the grades of Japanese steel (JIS Series), the common structural steel mainly consists of three parts: the first part represents the material, for example, s (steel) represents steel, f (ferrum) represents iron; the second part represents different shapes, types and uses, such as P (plate) for plate, T (tube) is tube, K (kogu) is tool; the third part is characteristic number, generally 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, and the whole represents ordinary structural steel with tensile strength of 400MPa.
SPHC
SPHC — the first s is the abbreviation of steel steel, P is the abbreviation of plate, h is the abbreviation of hot heat, and C is the abbreviation of commercial commercial. Generally speaking, hot rolled steel plate and strip are used.
SPHD
SPHD — hot rolled steel plate and strip for stamping.
SPHE
Sphe — hot rolled steel plate and strip for deep drawing.
SPCC
SPCC – cold rolled carbon steel sheet and strip, equivalent to q195a. The third letter C stands for cold cold. To ensure the tensile test, add t at the end of the grade to spcct.
SPCD
SPCD – cold rolled carbon steel sheet and strip for stamping, equivalent to China 08Al (13237) high quality carbon structural steel.
SPCE
Spce – cold rolled carbon steel sheet and strip for deep drawing, equivalent to China 08Al (5213) deep drawing steel. When non timeliness is required, add n at the end of the grade to be spcen. Quenching and tempering code of cold rolled carbon steel sheet and strip: annealing state is a, standard quenching and tempering is s, 1/8 hard is 8, 1/4 hard is 4, 1/2 hard is 2, hard is 1. Surface processing code: D for matte finish rolling and B for bright finishing rolling. Spcc-sd stands for standard quenched and tempered, matt finish rolled carbon sheet for general use. Another example is spcct-sb stands for standard quenching and tempering, bright processing, which requires to ensure the mechanical properties of cold-rolled carbon sheet.
The steel grade of JIS mechanical structure is expressed as: S + carbon content + letter code (C, CK), in which the carbon content is expressed by the middle value × 100, and the letter C: represents carbon and K: represents the steel for carburizing. For example, the carbon content of s20c is 0.18-0.23%. 

The designation of silicon steel sheet in China and Japan.

Chinese brand

• (1) Cold rolled non oriented silicon steel strip (sheet): DW + iron loss value (at frequency of 50 Hz, sinusoidal magnetic induction peak value is 1.5T unit weight iron loss value.) 100 times the thickness value. For example, DW470-50 represents the cold-rolled non oriented silicon steel with core loss of 4.7w/kg and thickness of 0.5mm, and the new model is 50W470.
• (2) Expression method of cold rolled oriented silicon steel strip (sheet): DQ + iron loss value (core loss value per unit weight of magnetic induction peak value of 1.7t at frequency of 50 Hz and sinusoidal waveform) 100 times the thickness value. Sometimes G is added after the core loss to indicate high magnetic induction. For example, DQ133 stands for cold rolled grain oriented silicon steel strip (sheet) with iron loss of 1.33 and thickness of 0.3mm, and the new model is 30q133.
• (3) Hot rolled silicon steel plate hot rolled silicon steel plate is represented by Dr, which is divided into low silicon steel (silicon content ≤ 2.8%) and high silicon steel (silicon content > 2.8%). Expression method: 100 times of Dr + iron loss value (core loss per unit weight when the maximum value of magnetic induction intensity is 1.5T after repeated magnetization with 50 Hz and sinusoidal variation) + 100 times of thickness value. For example, DR510-50 represents hot-rolled silicon steel plate with iron loss of 5.1 and thickness of 0.5mm. The grade of hot-rolled silicon steel sheet for household appliances is expressed by JDR + iron loss + thickness value, such as JDR540-50.

Japanese brand

• (1) The cold rolled non oriented silicon steel strip is composed of nominal thickness (increased by 100 times) + code a + guaranteed value of core loss (the value of core loss increased by 100 times when the frequency is 50 Hz and the maximum flux density is 1.5 T). For example, 50a470 refers to the cold-rolled non oriented silicon steel strip with thickness of 0.5mm and iron loss guarantee value of ≤ 4.7.
• (2) Cold rolled grain oriented silicon steel strip is composed of nominal thickness (increased by 100 times) + code G: common material, P: high oriented material + guaranteed value of core loss (the value of core loss increased by 100 times when the frequency is 50 Hz and the maximum flux density is 1.7 T). For example, 30g130 means cold-rolled oriented silicon steel strip with thickness of 0.3mm and core loss guarantee value of ≤ 1.3.

Properties of stainless steel plate

Corrosion resistance

The stainless steel plate has similar resistance to general corrosion as the unstable NiCr 304. Long time heating in the temperature range of the degree of chromium carbide may affect the corrosion resistance of alloys 321 and 347 in harsh corrosive media. It is mainly used in high temperature applications. High temperature applications require strong sensitization resistance to prevent intergranular corrosion at lower temperatures.

High temperature oxidation resistance

All stainless steel plates have high temperature oxidation resistance, but the oxidation rate is affected by inherent factors such as exposure environment and product morphology.

Physical property 

The total heat transfer coefficient of metal depends not only on the thermal conductivity of metal, but also on other factors. In most cases, the heat dissipation coefficient of the film, rust scale and surface condition of the metal. Stainless steel keeps the surface clean, so it has better heat transfer than other metals with higher thermal conductivity.

Thickness standard of stainless steel plate

Comparison of common thickness tolerance standards of stainless steel in related countries
Allowable deviation of steel strip thickness

Chinese national standard (GB) unit: mm

Width Thickness	Allowable deviation of thickness
	High precision（A）		General accuracy（B）
	>600~1000	>1000~1250	>600~1250
0.05~0.10	—-	—-	—-
>0.10~0.15	—-	—-	—-
>0.15~0.25	—-	—-	—-
>0.25~0.45	±0.040	±0.040	±0.040
>0.45~0.65	±0.040	±0.040	±0.050
>0.65~0.90	±0.050	±0.050	±0.060
>0.90~1.20	±0.050	±0.060	±0.080
>1.20~1.50	±0.060	±0.070	±0.110
>1.50~1.80	±0.070	±0.080	±0.120
>1.80~2.00	±0.090	±0.100	±0.130
>2.00~2.30	±0.100	±0.110	±0.140
>2.30~2.50	±0.100	±0.110	±0.140
>2.50~3.10	±0.110	±0.120	±0.160
>3.10~<4.00	±0.120	±0.130	±0.180

Japanese industrial standard unit: mm

Thickness	Width
	<1250	≥1250~<1600
≥0.30~<0.60	±0.05	±0.06
≥0.60~<0.80	±0.07	±0.09
≥0.80~<1.00	±0.09	±0.10
≥1.00~<1.25	±0.10	±0.12
≥1.25~<1.60	±0.12	±0.15
≥1.60~<2.00	±0.15	±0.17
≥2.00~<2.50	±0.17	±0.20
≥2.50~<3.15	±0.22	±0.25
≥3.15~<4.00	±0.25	±0.30
≥4.00~<5.00	±0.35	±0.40
≥5.00~<6.00	±0.40	±0.45
≥6.00~<7.00	±0.50	±0.50

American Society for materials (ASTM) standard unit: mm

Thickness	Allowable deviation		Width
	Upper	Lower	≤1000	>1000~≤1300
0.10	0.03	0.03
0.15	0.04	0.04
0.20	0.05	0.05
0.25	0.05	0.05
0.30			0.03	—
0.40			0.04	0.04
0.50	0.08	0.08
0.50			0.045	0.05
0.60			0.05	0.05
0.75	0.10	0.10
0.80			0.05	0.05
1.00	0.13	0.13
1.00			0.055	0.06
1.20			0.08	0.08
1.25	0.13	0.13
1.50			0.08	0.08
1.75	0.15	0.15
2.00	0.18	0.18
2.00			0.10	0.10
2.25	0.20	0.20
2.50	0.23	0.23
2.50			0.10	0.11
2.75	0.25	0.25
3.00	0.25	0.25
3.00			0.13	0.13
3.25	0.30	0.30
3.50	0.30	0.30
3.75	0.36	0.36
4.00	0.36	0.36
4.00			0.17	0.17
4.99	0.36	0.36
5.00			0.17	0.17
6.00			0.17	0.20
8.00			0.17	0.22

Element action of stainless steel plate

• Carbon (C): 1. Improve the deformation resistance and tensile strength of the cutting edge; 2. Enhance the hardness and improve the wear resistance.
• Chromium (CR): 1. Enhance hardness, tensile strength and toughness; 2. Wear and corrosion resistance.
• Cobalt (CO): 1. Increase hardness and strength so that it can withstand high temperature quenching; 2. Used to strengthen some individual properties of other elements in more complex alloys.
• Copper (Cu): 1. Enhance corrosion resistance; 2. Enhance wear resistance.
• Manganese (MN): 1. Increase hardenability, wear resistance and tensile strength; 2. Remove oxygen from molten metal by separation oxidation and separation vaporization; 3. Increase hardness but increase brittleness when adding a large amount.
• Molybdenum (MO): 1. Strengthening strength, hardness, hardenability and toughness; 2. Improving machinability and corrosion resistance.
• Nickel (Ni): 1. Strength, hardness and corrosion resistance.
• Phosphorus (P): 1. Strength, machinability and hardness; 2. If the concentration is too high, it is easy to crack.
• Silicon (SI): 1. Increase ductility; 2. Increase tensile strength; 3. Remove oxygen from molten metal by separation oxidation and separation vaporization.
• Sulfur (S): small amounts of sulfur can improve machinability.
• Tungsten (W): increase strength, hardness and toughness.
• Vanadium (V): increase strength, hardness and seismic resistance.

Corrosion conditions of stainless steel plate

• 1. There are dust containing other metal elements or attachments of different metal particles on the surface of stainless steel. In humid air, the condensation water between the attachment and the stainless steel connects them to form a micro cell, which causes electrochemical reaction and damages the protective film, which is called electrochemical corrosion.
• 2. The surface of stainless steel adheres organic juice (such as melon and vegetable, noodle soup, phlegm, etc.) to form organic acid in the presence of water and oxygen, which will corrode the metal surface for a long time.
• 3. The adhesion of stainless steel surface contains acid, alkali and salt substances (such as alkali water and lime water splashing on the decoration wall), causing local corrosion.
• 4. In the polluted air (such as the atmosphere containing a large amount of sulfide, carbon oxide and nitrogen oxide), sulfuric acid, nitric acid and acetic acid liquid spots will be formed when meeting condensate water, which will cause chemical corrosion. The above situations can cause the damage of the protective film on the surface of stainless steel and cause corrosion.

Corrosion resistance

The corrosion resistance of stainless steel plate mainly depends on its alloy composition (chromium, nickel, titanium, silicon, aluminum, manganese, etc.) and its internal structure, and chromium plays a major role. Chromium has high chemical stability, can form a passivation film on the surface of steel to isolate the metal from the outside, protect the steel plate from oxidation and increase the corrosion resistance of the steel plate. After the passivation film was destroyed, the corrosion resistance decreased.

Identification method of stainless steel plate

Number and indication of stainless steel plate

• ① The chemical composition is represented by international chemical element symbols and national symbols, and the content is represented by Arabic letters, such as China and Russia 12CrNi3A
• ② Steel series or numbers are represented by fixed digit numbers, such as USA, Japan, 300 series, 400 series and 200 series.
• ③ The serial number is composed of Latin letters and sequence, which only indicates the purpose.

International stainless steel marking method

AIS uses three digits to indicate various standard grades of malleable stainless steel. Among them:

• ① Austenitic stainless steel is indicated by numbers of 200 and 300 series, for example:
  

  SS 316L stainless steel plate 2B Finish.
  

• ② Ferritic and martensitic stainless steels are represented by 400 series numbers. For example, some of the more common austenitic stainless steels are marked with 201, 304, 316, and 310.
• ③ Ferritic stainless steel is marked with 430 and 446, while martensitic stainless steel is marked with 410, 420 and 440C, with two phases (austenite ferrite).
• ④ Stainless steel, precipitation hardening stainless steel and high alloy with iron content less than 50% are usually named by patent name or trademark.

Selection essentials of stainless steel plate

The selection of stainless steel plate should consider the use of operating conditions, such as manual operation or automatic operation, the performance and type of hot press, and the quality requirements of pressed materials, such as hardness and luster. Economic accounting should also be considered. Each time the steel plate is polished, it is required to produce a low quality decorative plate.
In addition, when selecting the most reasonable thickness of the steel plate, the service time, quality and stiffness should be considered. At the same time, the strength requirements of the plate under compression, the heat conduction performance, the pressure distribution, and the sheet size should be considered.
If the thickness of steel plate is not enough, it is easy to bend, which will affect the production of decorative plate. If the thickness is too large and the steel plate is too heavy, it will not only increase the cost of steel plate, but also bring difficulties in operation. At the same time, the allowance should be considered when the stainless steel plate is processed or used. The thickness of copper plate is not absolutely consistent, but the thickness of the same steel plate should be as consistent as possible. Generally, the thickness tolerance of medium size saw plate is 0.05-0.15mm. If the requirements are too strict, the grinding cost will also increase. Generally, steel plates with large tensile strength and hardness have higher mechanical damage resistance and longer service life, but the grinding cost is also higher.

Source: Stainless Steel Plate Supplier: www.epowermetals.com

(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)

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