What is the fine-grained topic of the following text: Qualities and standards carbon steel Technical data Nearest equivalent qualities and standards ... RSt 37.2 A181-Class 60 C22.3 1503-221-410 St 52.3 A694-F52 StE 355 1503-221-510 St E 355 A694-F52 St 52.3 1503-221-510 C21 ... Only return the topic.
Technical specifications and equivalencies of different types of carbon steel