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During the manufacturing and selection process of valves, we often encounter various material codes. For example, common material codes such as 304 and 316 stainless steel are usually easy to understand. However, codes like CF8, CF8M, CF3, and CF3M might not be as familiar. These codes also represent specific material properties. This article aims to delve into the differences between CF8 materials, CF8M materials, CF3 materials, and CF3M material, and their suitability for different working conditions. The goal is to provide a strong reference for users, agents, design institutes, and owners in selecting valve materials suitable for their specific working conditions.
CF8, CF8M, CF3, and CF3M are stainless steel castings under the American Standard ASTM A351:
CF8 is equivalent to 304
CF3 is equivalent to 304L
CF8M is equivalent to 316
CF3M is equivalent to 316L
(304, 304L, 316, 316L are bars or forgings)
In the field of casting valves, stainless steel materials are often represented by the CF series codes, where CF8, CF8M, CF3, and CF3M correspond to the casting standards of 316, 316L, 304, and 304L, respectively. Next, we will mainly explore the differences between these different materials and the media environments they are suitable for.
CF8 material is a pressure casting austenitic material under the American ANSI standard, partially following the ASTM A351 specification. Its chemical composition includes: carbon (max 0.08%), manganese (max 1.5%), sulfur (max 0.04%), silicon (max 1.5%), nickel (8.0 to 10.0%), and chromium (17.0% to 19.0%). In terms of physical properties, CF8 shows a tensile strength of 485MPa, a yield strength of 205MPa, and an elongation of 30%. Although CF8 is chemically almost equivalent to the domestic 304 steel grade, it is not completely identical. In practical applications, once CF8 material is specified, it is usually converted to the corresponding 304 material domestically for supply.
CF8M material is a pressure casting austenitic material in the American ANSI standard that conforms to the ASTM A351 specification. Its chemical composition includes carbon (max 0.08%), manganese (max 1.5%), sulfur (max 0.04%), silicon (max 1.5%), nickel (9.0 to 12.0%), chromium (18.0% to 21.0%), and molybdenum (2.0% to 3.0%). In terms of physical properties, CF8M material exhibits a tensile strength of 485MPa, a yield strength of 205MPa, and an elongation of 30%. CF8M material corresponds to the standard steel grade, with its chemical composition being almost equivalent to the domestic 316 steel grade, albeit with some differences. In practical applications, CF8M material and 316 material can be considered similar in most cases, but specific selection should be based on specific working conditions and requirements.
CF3M material is a specific material widely used in valve manufacturing. It is essentially the cast version of 316L stainless steel, and 316L is the low-carbon version of 316 stainless steel. CF3M, being an equivalent material, is highly favored for its superior corrosion resistance, especially performing excellently in environments sensitive to intergranular corrosion. Valves made from CF3M stainless steel, such as 6-inch and 10-inch globe valves, are often used in situations handling corrosive fluids like acids, chemicals, and seawater. Additionally, CF3M material has excellent mechanical properties, including high strength and good weldability, making it an ideal choice in the field of valve manufacturing.
