What is the difference between 15CrMoR steel and 15CrMo material

What is the difference between 15CrMoR steel and 15CrMo material?
15CrMoR steel generally refers to steel plate, the material is 15CrMo material, the following R is the abbreviation of the word "capacity" for container plate, and the one without letter after 15CrMo material only refers to the alloy structural plate made of 15CrMo material.

15CrMoR steel plate is used for medium temperature pressure vessel. There are also 15CrMoR steel plate in the presence of hydrogen. It is mainly used on petrochemical equipment. When implementing the standard GB713, the corresponding American grade is SA387gr12 series, which is delivered in the normalized + tempered state. The flaw detection standard is implemented according to JB / T4730.3. The sulfur (S) and phosphorus (P) contents can also be controlled according to the customer's needs, and the high temperature tensile test can be carried out.

After normalizing and tempering, 15CrMo material can be used to manufacture boiler superheater, medium and high pressure steam pipes and headers with steam temperature up to 510℃, and main steam pipes with steam temperature up to 510℃. After quenching and tempering, 15CrMo material can be used to manufacture various important parts working at normal temperature.