Mayers Martenistic Chromium Stainless Steel 7Cr17(440A), 8Cr17 (440B), 11Cr17(440C)
Mayer’s Martensitic Chromium Stainless Steels are a family of steels designed to provide improved free-machining performance, as well as superior corrosion and mechanical properties. They are used in numerous industrial applications and are highly valued due to their remarkable resistance to corrosion and ease of working with.
The Mayer’s Martensite family includes three stainless steel grades - 7Cr17 (440A), 8Cr17 (440B) and 11Cr17 (440C). All steels are standardized according to ASTM, AISI, DIN, and other standards to ensure product quality, uniformity and minimal product variations.
7Cr17 (440A)
The 7Cr17 martensitic stainless steel (440A) is a lower-carbon, moderate chromium steel with corrosion resistance similar to a stainless steel such as 430 but with higher hardness in the range of 440-480 HV (HRC 45 to 50). It is a relatively low-cost steel which can be hardened to various levels with heat treatment. The steel can be tempered to ReL 50 to 60 range, and polishable to a glossy finish.
This grade is often used in items such as cutlery, ball bearings, valves, and plumbing fittings. 440A is also widely used for surgical tools and medical implants, due to its good temperature and corrosion resistance, low cost and easy machinability.
8Cr17 (440B)
The 8Cr17 martensitic stainless steel (440B) is a medium-carbon, moderate chromium steel with corrosion resistance similar to a stainless steel such as 412 but with higher hardness in the range of 440-480 HV (HRC 50 to 55). It is a relatively low-cost steel which can be hardened to various levels with heat treatment. The steel can be tempered to ReL 50 to 60 range, and polishable to a glossy finish.
This grade is often used in items such as gun barrels, knives, and various hand tools. It is also used in aerospace, marine and automotive industries, especially those that require corrosion resistance and mechanical strength.
11Cr17 (440C)
The 11Cr17 martensitic stainless steel (440C) is a high-carbon, moderate chromium steel with corrosion resistance similar to a stainless steel such as 420 but with much higher hardness in the range of 450-530 HV (HRC 56 to 60). It is a relatively expensive steel which can be hardened to various levels with heat treatment. The steel can be tempered to ReL 50 to 60 range, and polishable to a glossy finish.
This grade is often used for blades such as pocket knives and cutlery. It is also used for measuring tools and axle parts due to its excellent wear resistance. Additionally, it is commonly used for medical applications such as surgical implements, orthodontic braces, dental cutting devices and implants.
Overall, Mayer’s Martensite family of stainless steels includes three unique grades which provide different characteristics based on the needs of the application. 7Cr17 (440A) is the lowest-cost member and has good corrosion resistance and machinability, while 8Cr17 (440B) offers better hardness and corrosion resistance and is suitable for more demanding applications. On the other hand, 11Cr17 (440C) provides the highest corrosion resistance, hardness and wear resistance, making it the most expensive member of the family.
