The ASME Construction Codes normally do not identify, and provide stress values for, nut material for bolting. This is because the design of bolted connections is based on the strength and stress values provided for the bolt or stud material. The bolt or stud material specification usually references the associated nut material specification (e.g., SA-193 references SA-194). Even though the hardness or proof load test requirements for nut materials may change, there is no effect on design unless the associated bolting specification is revised as well. Use Table 3 or 4 of Section II Part D Bolting for appropriate bolting stress values.
Alos note the applicable Construction Code Paragraphs for specific details of design such as UCS-11 of VIII-1, AM-511 of VIII-2(prior to 2007 re-write).... Similar paragrpahs exist in Section III and the other ASME Construction Codes. For ASME Section I Boilers, bolting and nuts for bolts are not provided for specifically. However, SA-193 Bolting and SA-194 Nuts meet the intent of Section I wherein it is provided in the Preamble that where complete details are not given, it is intended that the Manufacturer, subject to the approval of the Authorized Inspector, shall provide details of design and construction which will be as safe as otherwise rovided by the rules in the Code.
Carbon or alloy steel nuts approximately the same hardness as the nuts may be used with alloy steel bolts or studs for metal temperatures not exceeding 900°F (482°C). Alloy steel nuts shall be used with alloy steel studs or bolts for metal temperatures exceeding 900°F (482°C).
