The annealing temperature for 440 stainless steel balls is low. For heat treatment as cutting tools and bearings, the recommended hardness is HRC57-59. If deep cryogenic treatment is applied, the hardness can reach HRC60.

440 Stainless Steel BallStainless steel is a high-carbon, high-chromium martensitic stainless steel. Carbon content is 1.0%, and chromium content is 17%. Applications include:

主要用于 manufacturing bearing components that operate in corrosive environments and under non-lubricated, strongly oxidizing atmospheres. The 440 stainless steel balls offer excellent high-temperature dimensional stability, making them suitable for use as corrosion-resistant high-temperature bearing steel as well. Additionally, they are employed in the production of high-quality tools, such as surgical knives, scissors, nozzles, and bearings. However, the 440 stainless steel balls have a lower capacity to withstand dynamic loads.

The SUS440 stainless steel ball is a martensitic stainless steel with a higher carbon content than 3Cr13 steel, thus offering higher strength and hardness. Its other properties are similar to those of 3Cr13 steel, but it has poor weldability and is generally not used as welding material. It is used in the production of surgical medical instruments. Imported from Japan, this stainless steel is suitable for manufacturing bearing components that operate in corrosive environments and under strong oxidation without lubrication. The steel also boasts good high-temperature dimensional stability, allowing for the production of corrosion-resistant high-temperature bearings and tools with temperatures not exceeding 250°C.
Hardness: Annealed, ≤269HB; Quenched and tempered, ≥55HRC

Heat Treatment Specifications: 1) Annealing, slow cooling at 800～900℃; 2) Quenching, oil cooling at 1000～1050℃; 3) Tempering, air cooling at 200～300℃.