The method to distinguish between 304 and 304l

The method to distinguish between 304 and 304l
304 is equivalent to 0Cr18Ni9 stainless steel in China [which has now been changed to 06Cr19Ni10 according to GB/T 20878-2007].
304 stainless steel is a very common type of stainless steel and is also known in the industry as 18/8 stainless steel. Its corrosion resistance is superior to that of 430 stainless iron. It is resistant to corrosion and high corrosion, and has good processing performance. Therefore, it is widely used in the industrial and furniture decoration industries as well as the food and medical industries, such as some high-end stainless steel tableware, bathroom and kitchen utensils.
Although this type of stainless steel is very common in China, the term "304 stainless steel" originated from the United States. Many people think that 304 stainless steel is a type name in Japan, but strictly speaking, the official name for 304 stainless steel in Japan is "SUS304". Among the common marking methods in the market, there are three types: 06Cr19Ni10, 304, and SUS304. Generally, 06Cr19Ni10 indicates production in accordance with national standards, 304 indicates production in accordance with ASTM standards, and SUS304 indicates production in accordance with Japanese standards.
304 is a general-purpose stainless steel that is widely used in the manufacture of equipment and components that require good comprehensive performance (corrosion resistance and formability). To maintain the inherent corrosion resistance of stainless steel, the steel must contain more than 16% chromium and more than 8% nickel. 304 stainless steel is a grade of stainless steel produced in accordance with the American ASTM standard.
304 and 304L are commonly used stainless steel materials. They have certain differences in chemical composition, so they need to be distinguished in some specific applications. The following will introduce in detail the differences between 304 and 304L from four aspects: chemical composition, corrosion resistance, weldability and application fields.
I. Chemical Composition
The main components of 304 and 304L are iron, 18% to 20% chromium, 8% to 10.5% nickel, as well as small amounts of carbon, manganese and silicon, etc. Here, "L" stands for low carbon, meaning that the carbon content in 304L is lower than that in 304. The carbon content of 304L is below 0.03%, while that of 304 is around 0.08%. The low carbon content makes 304L have better corrosion resistance and welding performance.
Ii. Corrosion resistance
Both 304 and 304L have excellent corrosion resistance and can resist the erosion of most acidic media and some alkaline media. However, due to the low carbon content of 304L, it has better intergranular corrosion performance during the welding process and can avoid corrosion problems at the weld seam. Therefore, 304L is often used in situations where the corrosion resistance of welds is highly demanded, such as in chemical equipment and food processing equipment.
Iii. Weldability
Both 304 and 304L have good weldability and can be joined by conventional welding methods. However, due to the low carbon content of 304L, there is less carbon precipitation in its heat-affected zone, which reduces the tendency of intergranular corrosion and enhances the corrosion resistance of the welded joint.
Iv. Application Fields
Because 304 and 304L have similar chemical compositions and properties, they can be used interchangeably in many fields. They are widely used in industries such as construction, chemical engineering, food processing, and medical equipment. However, it should be noted that in applications such as welding equipment and chemical equipment where there are high requirements for the corrosiveness of weld seams, 304L material should be given priority.
The differences between 304 and 304L mainly lie in aspects such as chemical composition, corrosion resistance, weldability and application fields. Although they have similar performance in many aspects, choosing the appropriate material according to specific application requirements can enhance the performance and service life of the product. During the usage process, it is also necessary to maintain and care for the materials according to specific circumstances to ensure their good corrosion resistance and durability. www.boismarinecreation.com

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