A194

Scope
This specification2 covers a variety of carbon, alloy, and martensitic stainless steel nuts in the size range 1⁄4″ through 4″ nominal. It also covers austenitic stainless steel nuts in the size range 1⁄4″ nominal and above. These nuts are intended for high-pressure or high-temperature service, or both. Other grades of A194 nuts exist but are not listed on this page.

Ferritic Grades – 2H & 6
Austenitic Grades – 8 & 8M

Table 1: Chemical Requirements

Table 2: Hardness Requirements

Table 3: Proof Load Using Threaded Mandrel

NOTE 1 – Proof Loads ARE NOT design loads
A – See limit for proof load test in 8.2.2.1. The proof load for jam nuts shall be 46 % of the tabulated load.
B – Based on proof stress of 130 000 psi.
C – Based on proof stress of 120 000 psi.
D – Based on proof stress of 150 000 psi.
E – Based on proof stress of 135 000 psi.
F – Based on proof stress of 175 000 psi.
G – Based on proof stress of 150 000 psi.
H – Based on proof stress of 80 000 psi.
I – Based on proof stress of 75 000 psi.

Table 8: Proof Load Testing of Strain Hardened Nuts Using Threaded Mandrel

Note 1 – Proof Loads are not Design Loads
B – Based on proof stress of 110 000 psi up to 3⁄4 in.; 100 000 psi 7⁄8 to 1 in.; 95 000 psi 11⁄8 to 11⁄4 in.; 90 000 psi 13⁄8 to 11⁄2 in.
C – Based on proof stress of 100 000 psi up to 3⁄4 in.; 90 000 psi 7⁄8 to 1 in.; 85 000 psi 11⁄8 to 11⁄4 in.; 80 000 psi 13⁄8 to 11⁄2 in.
D – Based on proof stress of 125 000 psi up to 3⁄4 in.; 115 000 psi 7⁄8 to 1 in.; 105 000 psi 11⁄8 to 11⁄4 in.; 100 000 psi 13⁄8 to 11⁄2 in.

Table 10: Proof Load for Large Heavy Hex Nuts

A – ASME B 18.2.2 in the size range over 11⁄2 in. provides dimensions only for heavy hex nuts. Refer to 8.3.1.
B – Proof loads for nuts of larger dimensions or other thread series may be calculated by multiplying the thread stress area times the proof stress in the notes to Table 3 or Table 8. The proof load for jam nuts shall be 46 % of the tabulated load.</span>