Tiêu chuẩn quốc tế

• Số hiệu / Standard Number: AASHTO M 291:2009
• Năm ban hành / Publication date: 2009
• Tình trạng / Status: W - Hết hiệu lực
• Tên tiếng Anh / Title in English: Standard Specification for Carbon and Alloy Steel Nuts
• Thay thế cho / Replace: AASHTO M 291:2006
• Số trang / Page: 10

Phạm vi áp dụng / Scope of standard

This specification² covers chemical and mechanical
requirements for eight grades of carbon and alloy steel nuts for
general structural and mechanical uses on bolts, studs, and other
externally threaded parts.

NOTE 1-See Appendix X1 for guidance on suitable application of
nut grades.

The requirements for any grade of nut may, at the supplier's
option, and with notice to the purchaser, be fulfilled by
furnishing nuts of one of the stronger grades specified herein
unless such substitution is barred in the inquiry and purchase
order.

Grades C3 and DH3 nuts have atmospheric corrosion resistance and
weathering characteristics comparable to that of the steels covered
in Specifications A 242/A 242M, A 588/ A 588M, and A 709/A 709M.
The atmospheric corrosion resistance of these steels is
substantially better than that of carbon steel with or without
copper addition (see 5.2). When properly exposed to the atmosphere,
these steels can be used bare (uncoated) for many applications.

NOTE 2-A complete metric companion to Specification A 563 has
been developed-A 563M; therefore, no metric equivalents are
presented in this specification.

Terms used in this specification are defined in Terminology F
1789 unless otherwise defined herein.

² For ASME Boiler and Pressure Vessel Code
applications see related Specification SA - 563 in Section II of
that Code.