石油和天然气工业机械加工服务供应商资格（第一版

This standard specifies requirements for the qualification of suppliers of machining services where API product standards require such services or are otherwise specified as a requirement for conformance. Conformance with this standard is not required to demonstrate conformance with any other API standard or specification. This API standard establishes the requirements for three machining qualification levels (MQL 1, MQL 2, and MQL 3). These three MQL designations define different levels of quality and qualification requirements. These MQLs are numbered in increasing levels of requirements to reflect increasing quality and qualification criteria. Final assembly, component testing (e.g., nondestructive examination, pressure testing) or a broker of machining services are outside the scope of this standard. This standard applies when specified by the customer or voluntarily followed by the machining services supplier.