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Views:2     Author:Site Editor     Publish Time: 2019-05-06      Origin:Site

Stainless steel is a kind of corrosion resistant high alloy steel. Because the surface is beautiful, does not need plating or paint and other surface treatment, so many machinery plants to show that they are stainless steel, often do not do any paint treatment, black material (so-called black material is ordinary steel) is to use rust treatment.

A simple classification of stainless steel

Stainless steel can be roughly divided into 200 series, 300 series and 400 series, of which 300 series is the most commonly used, 200 series and 400 series are to some extent the replacement of 300 series. Strictly speaking, 400 series is not called stainless steel, called stainless steel, because there is no nickel in it, so it is acted on by magnets. The 200 and 300 series are nickel, so without magnetism, the magnet will not be charged.

304 is the most common variety in the 300 series, so the general price change starting from 304 can judge the price trend of the entire stainless steel. The 200 series contains less nickel, the 400 series does not contain nickel, and the 300 series contains the most nickel. Therefore, the 300 series that is most affected by the nickel price is the 300 series.

The series can be divided into 304304L, 316316L, 321309S, 310S, etc., according to the content of different metal elements, the content of different stainless steel is also different, the difference between 304L and 304L lies in the content of carbon (C), L is low carbon, also known as low carbon, The same is true of 316 and 316L

Morphological classification of stainless steel.

Stainless steel can be divided into rolling plates, plates, profiles, steel pipes and five major types of parts, the most important being rolling and sheeting. The profiles are made of materials of various shapes and are made of angle steel, flat steel, I-BEAM, channel steel. Steel pipe refers to the seamless steel pipe, and seamless steel pipe is the opposite of welded pipe, the difference is whether it is formed. Parts mainly refer to small things such as elbows and flanges.

Coils and boards are actually the same, and the production forms are different. The coil is one coil at a time, and the board is one at a time. If the coil is a plate, it is also called the original plate, generally speaking, it is a thicker plate because if it is very thick, it can not generally roll more than 16 mm cannot be rolled.

There are rolls, there are plates, and they have been boarded many times. The price of rolls and plates is not the same. In the case of a purchase volume, the price is higher by real weight, the price of the plate is theoretical and the price is lower, because if the thickness of 10 mm is actually 9.6 mm, there is a difference, that is, there is a price difference.

According to the rolling process, the stainless steel plate can be divided into two categories: hot rolling and cold rolling. Hot rolling is usually marked No. 1. Cold rolling is marked 2B or BA (BA is better, brighter, closer to the mirror, the best in the mirror, there is no inventory in the mirror, all need to be processed), for example, 304times is the purchasing board, This means that the coil must be rolled by a machine called a leveling machine, which is called a straightener. Through the bottle opener, you can open different lengths, if not the traditional length is called fixed, which means opening the size, because the customer often puts forward different length requirements according to the actual needs, this time, The important thing is to roll a normal board that doesn't do the trick.

Domestic cold rolling is generally less than 3 mm, hot rolling is generally more than 3 mm, the thickness of 3 mm is both hot rolled and cold rolled, but the thickness of imported cold rolled steel plate can reach 4 mm or even 6 mm. The hot rolled steel plate from 3 mm to 12 mm is called steel plate, and the steel plate above 12 mm is called thick plate. It can be said that the hot rolled steel plate is more than 120 mm thick, and the cold rolled steel plate is cold rolled sheet.

A simple method for calculating the theoretical weight of stainless steel plates

Specific Thickness (m) Width (m) Length (m) (mm in M m, min meter)

In the field of construction machinery, due to the emphasis on precision dimensions, the units used in the world are 1000mm 1 meter and 1mm 100 lines.

According to this formula, the weight in kilos of (KG) should be accurate to two decimal places, because the price of stainless steel, trading volume is very large, after the decimal point number is also very important, so the money should be accurate to two decimal places.

The specific gravity of stainless steel (KG)

Different stainless steels have different weights:

The proportion of A 400 series is 7.75.

B, 304.31.304301 is 7.93

C, 310 seconds. 309S.316.316 liters are equal to 7.98 liters.

Use the Steel Reference List

Different countries in the world have different terms for stainless steel, and the market is often in contact with China and the United States, known as the GB and the American Standard. The 200Series300S400series mentioned above are American standards because they are easy to understand. So they usually call it the American standard.

The element content in the national standard refers to the intermediate value of the content, which is the theoretical value and can be large or small.

WHAT‘S A business trip

This is an important term, and tolerances are generally considered to be allowable length or thickness deviations. Because in the production process of a metal sheet, it is difficult to do it for various reasons. The actual thickness is often less than the theoretical thickness, such as 6 mm steel plate, only 5.6 mm, which is the tolerance, domestic tolerance is often negative tolerance, of course, there are positive tolerances, but very few. In buying and selling, it is usually calculated according to the theoretical thickness, which is why the theoretical price is lower than the weighing price, the tolerance and size are larger, the price is different, and the price tolerance is cheaper. For example, if less than 5.5, 6mm is a large tolerance.

1.304 / 2B tolerances are shown in the table below(for reference only)

two. The tolerance range of the hot-rolled sheet is shown in the table below (for reference only)

Features and uses of major stainless steel types

304: As a widely used steel, it has good corrosion resistance, heat resistance, low-temperature strength, and mechanical properties, hot workability such as stamping and bending, no heat treatment hardening, no magnetism, use temperature minus 193 degrees plus 800 degrees.

Use tableware, kitchenware, water heater, boiler, auto parts, medical equipment, food machinery, wine storage, pressure vessels (chemical machinery, chemical equipment).

As a low-carbon 304 steel, the corrosion resistance of 304l is similar to that of 304l under normal conditions, but after welding and stress removal, it has good corrosion resistance between crystals, and it can maintain good corrosion resistance even without heat treatment. Usually used at 400 °C

Uses petrochemical, building materials.

321 add Ti to 304steel to prevent intergranular corrosion, suitable for positive 430C to 900C, non-magnetic;

The use of automotive exhaust, heat exchangers, containers and other products without heat treatment after welding, due to the addition of TI elements, is not suitable for the production of food processing equipment.

316 is low carbon, adding molybdenum, so it has excellent corrosion resistance, atmospheric corrosion resistance, and high-temperature resistance. It can be used under harsh conditions, suitable for below 900 degrees, non-magnetic.

Uses: There are special requirements for seawater, chemicals, dyes, papermaking, acetic acid, fertilizer and other production equipment, food industry and coastal facilities, anti-grain-corrosion products, etc..

The content of nickel and chromium in 309S/310S is high, and the content of SI is increased, which makes it resistant to high temperature and corrosion. 309S can withstand 980 times of repeated heating, 310S can be used at 1200 °C, and the continuous service temperature can reach 1150 °C.

Application: suitable for high-temperature electric furnace equipment, drying equipment, and other key components, charge, aviation, petrochemical, electric power and so on.

The 200 series is similar in price and economy to 304.

Use food processing equipment, kitchen equipment, food processing equipment, filters, milk cans, durable consumer goods, washing machine accessories, water heaters, steel furniture, architectural decoration, decoration. Fatigue resistance, 201 hardness, toughness is not as good as 304, or 304 fatigue performance is better.

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