API SPEC 20F:2018

This standard specifies requirements for the qualification, production, and documentation of corrosion-resistant bolting used in the petroleum and natural gas industries.
This standard applies when referenced by an applicable API equipment standard or otherwise specified as a requirement for compliance.
This standard establishes requirements for two bolting specification levels (BSL). These two BSL designations define different levels of technical, quality, and qualification requirements: BSL-2 and BSL-3. The BSLs are numbered in increasing levels of requirements in order to reflect increasing technical, quality, and qualification criteria. BSL-2 and BSL-3 are intended to be comparable to BSL-2 and BSL-3 as found in API 20E. BSL-1 is omitted from this standard.
This standard covers the following product forms, processes, and sizes:
a) machined studs;
b) machined bolts, screws, and nuts;
c) cold-formed bolts, screws, and nuts with cut or cold-formed threads;
d) hot-formed bolts and screws <1.5 in. (38.1 mm) nominal diameter;
e) hot-formed bolts and screws =1.5 in. (38.1 mm) nominal diameter;
f) roll threaded studs, bolts, and screws <1.5 in. (38.1 mm) diameter;
g) roll threaded studs, bolts, and screws =1.5 in. (38.1 mm) diameter;
h) hot-formed nuts <1.5 in. (38.1 mm) nominal diameter;
i) hot-formed nuts =1.5 in. (38.1 mm) nominal diameter.