201 stainless steel pipe is an international stainless steel marking method

201 Stainless Steel Pipe - S20100 (AISI. ASTM)

The American Iron and Steel Institute uses three digits to indicate various standard grades of malleable stainless steel. Among them:

① Austenitic stainless steel is labeled with numbers from the 200 and 300 series,

② Ferritic and martensitic stainless steels are represented by 400 series numbers. For example, some more common austenitic stainless steels

It is 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

Note that dual phase (austenite ferrite),

④ Stainless steel, precipitation hardened stainless steel, and high alloys with iron content less than 50% are usually referred to by patent or trademark names

The production process of seamless stainless steel pipes

a. Preparation of round steel; b. Heating; c. Hot rolled perforation; d. Cutting the head; e. Acid washing; f. Grinding and polishing; g. Lubrication; h. Cold rolling processing; i. Degreasing; j. Solid solution heat treatment; k. Straightening; l. Cutting pipes; m. Acid washing; n. Finished product inspection.

Formula for weight of 201 stainless steel pipe: [(outer diameter wall thickness) * wall thickness] * 0.02491=kg/meter (weight per meter)

Application and Performance of 201 Stainless Steel Pipe

201 stainless steel tube has the characteristics of acid and alkali resistance, high density without pinholes, etc., and is a high-quality material for producing various watch cases, watch strap covers, etc. 201 stainless steel pipes can be used in decorative pipes, industrial pipes, and some shallow stretched products. The use of 201 stainless steel pipes for physical properties

1. Elongation rate: 60 to 80%

2. Tensile stiffness: 100000 to 180000 psi

3. Elastic modulus: 29000000 psi

4. Yield stiffness: 50000 to 150000 psi

Formula for weight of 201 stainless steel pipe: [(outer diameter wall thickness) * wall thickness] * 0.02491=kg/meter (weight per meter).

201 stainless steel pipe is an international stainless steel marking method

　　

brand 201, 202, 301(1Cr17Ni17) , 304(0Cr18Ni9) ,304L(00Cr19Ni10) ,321(1Cr18Ni9Ti), TP316l(0Cr17Ni12Mo2) ,316L(00Cr17Ni14Mo2),310S(0Cr25Ni20) ,317L(00Cr19Ni13Mo3)

Execution standards GB/T14976-2002 、 GB13296-91 、 GB9948-88 ， Reaching the United States ASTM/ASME A213/SA213 、 ASTM/ASME A312/SA312 、 ASTM/ASME A269/SA269 、 DIN 17458-85 、 DIN 17456-85 、 JIS G 3459 、 JIS G 3463 、 JIS G 3448 JIS G 3446 Standard.

Extension and Development of 201 Stainless Steel Pipe

1、 From 201 to 201A

At present, 201, which is used to produce stainless steel welded pipes in the market, is not 201 in the American ASTM standard, nor SUS201 in the Japanese JIS standard. Its nickel content does not reach the American 201 or Japanese 201 standard, and we call it 201A. It is a nickel saving stainless steel material introduced from India, which uses manganese instead of nickel and contains about 1% nickel. It is called J4 in India, 202A in Taiwan, China, and 1Cr15Mn8Ni1N in Chinese Mainland.

Since the late 1980s when stainless steel entered the decoration market, the main decorative material for stainless steel has been 304. Although it has developed rapidly, it has always been sold in large and medium-sized cities. As a high-end decorative material, it is mainly used for the decoration of doors, windows, and stair handrails in high-end hotels and restaurants. In the mid-1990s, the author went on a business trip to Urumqi, Xinjiang and found that only the top pipe of the staircase handrails in star rated hotels was made of stainless steel, while other pillars were supported by wood and other materials. Moreover, except for the developed Pearl River Delta and Yangtze River Delta regions, there were almost no handrails in small and medium-sized cities and rural areas in mainland China. The high price of 304 stainless steel pipes seriously affects their application in the decoration industry.

In the late 1990s, India's Jindalai Company introduced a stainless steel material called J4 to China (referred to as 201A in this article), and its low price immediately attracted many stainless steel welded pipe enterprises and decoration manufacturers to produce and sell. At that time, there were few manufacturers providing this material, and Jindalai Company can be said to have dominated the world, and its business in China has developed rapidly. Afterwards, some private enterprises in China quickly discovered this business opportunity and quickly invested funds to start producing this stainless steel material. Around 2006, Jindalai Company temporarily ceased sales in China and now only provides a small portion. The domestic welded pipe industry almost no longer uses Jindalai Company's sheet metal.

2、 201A's share in the stainless steel decorative pipe market

Due to the fact that stainless steel strips made of 201A material are only slightly harder and have lower elongation than 304, they may crack during deep drawing and drawing. However, in the decorative welded pipe industry, these do not affect their use. After polishing, they will not rust indoors in a short period of time. Like 304, they are non-magnetic and cannot be distinguished by observing the surface alone. This has led to the rapid development of this inexpensive stainless steel.

As of 2008, there were nearly 200 manufacturers in Foshan, Guangdong Province that mainly produce decorative pipes, with a production capacity of about 1 million tons. Except for a few enterprises such as Lanshi Yuhangxing, most companies do not produce stainless steel pipes made of 304 pipe material, and the ratio of 304 and 201A production is about 1:9.

In terms of sales volume, except for Fujian, Shanghai, Guangdong, Jiangsu and Zhejiang, which are still selling some 304 stainless steel decorative pipes, almost all stainless steel decorative pipes sold in other parts of the country are 201A or worse "nickel free and non-magnetic" so-called stainless steel welded pipes.

Mr. Li Jinlong, a stainless steel analyst at Pohang in South Korea, believes in his article "Outlook on the Development and Circulation Structure Changes of China's Stainless Steel Industry" that in 2006, the proportion of 200 series (mainly 201A) stainless steel in stainless steel sales was 23.9%. However, from the perspective of decorative stainless steel welded pipes, except for a few coastal provinces that still use some 304 stainless steel welded pipes as decorative materials, other provinces and cities almost do not use 304 as decorative materials, and use 201A in large quantities, including plates and pipes, accounting for more than 80% of the sales volume of stainless steel decorative pipes in the market.

　　

Identification of Authenticity of 201 Stainless Steel

Currently, internationally, the corrosion resistance of materials is divided into three categories based on annual corrosion rate. The first category is complete corrosion resistance, with a corrosion rate of less than 0.1mm/year, and high-quality stainless steel belongs to this type of material; The second type is still corrosion-resistant, with a corrosion rate of 0.1-1.0mm/year, belonging to general stainless steel; The third type is non corrosion resistant, with a corrosion rate greater than 1.0mm per year. The counterfeit stainless steel products discovered this time have a corrosion rate of up to 9.67mm/year, indicating severe corrosion resistance. When further analyzing the composition of the product, it was found that the chromium content, which represents an important indicator of stainless steel, was only 10.03% and 7.1%, respectively, far below the minimum requirement of 10.5% for chromium in stainless steel.

Generally speaking, iron-based alloys with chromium content greater than 10.5% are referred to as stainless steel, but these two products have chromium content far below this lower limit, and the product is not stainless steel at all.

The reason why this product appears in the market is mainly due to the producer's greed for profit, taking advantage of the loophole of the public's insufficient understanding of stainless steel to carry out fraud. It is widely believed that stainless steel does not have magnetism, and counterfeiters have achieved high profits by extensively using manganese instead of nickel to alter the product composition, resulting in a material that is both non-magnetic and extremely low-cost.

The appearance of this product is difficult to distinguish from typical stainless steel in the market circulation. At the same time, due to the lack of magnetism and the use of adulteration and mixing tactics by illegal distributors, it poses great difficulties for consumers to distinguish authenticity, and can cause unforeseeable consequences after use. In addition, a small amount of nickel is used in this material, but it cannot play the role that nickel should play, which is a waste of precious metals and causes a certain amount of resource waste.