A194-11

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

Grade 2H688M
MaterialCarbonType 410Type 304Type 316
UNS #-S4100S30400S31600
Carbon %0.40 min0.150.080.08
Magnanese %1.001.002.002.00
Phosphorus %0.0400.0400.0450.045
Sulfur ᴱ0.0500.0300.0300.030
Silicon %0.401.001.001.00
Chromium %-11.5-13.518.0-20.016.0-18.0
Nickel %--8.0-11.010.0-14.0
Molybedenum %---2.00-3.00
Titanium %----
Columbium & Tantaium----
Nitrogen %----
Other %----
Source: ASTM A194-11
A – The intentional addition of Bi, Se, Te, and Pb is not permitted except for Grades 6F, 8F, and 8FA, in which Se is specified and required.
B – Total aluminum, soluble and insoluble.
C – Maximum, unless minimum or range is indicated.
E – Because of the degree to which sulfur segregates, product analysis for sulfur over 0.060 % max is not technologically appropriate.
If no value present then there is no requirement

Table 2: Hardness Requirements

Grade & TypeCompleted NutsSample Nut After Treatment as in 8.1.5
Brinell HardnessRockwell CRockwell BBrinell Harness minRockwell Hardness B min
2H up to 1-1/2" Inclusive248 to 32724 to 35-17989
2H over 1-1/2212 to 32735 max95 min14779
6228 to 27120 to 28---
8 & 8M126 to 30032 max60 min--
Source: ASTM A194-11
If no value present then there is no requirement

Table 3: Proof Load Using Threaded Mandrel

NominalThreadsStress Area Proof Load lbf ᴬ For Grade 2H
Proof Load lbf ᴬ For Grade 6
Proof Load lbf ᴬ For All Grade 8s
Size ᴰPer InchIn ²Heavy Hex ᶠHex ᴳHeavy Hex ᴰHex ᴱHeavy Hex ᴴHex ᴵ
1/4200.0316557047704770430025402380
5/16180.0524917078607860707041903930
3/8160.07741356011620116201046062005810
7/16140.106318600159401594014350850007970
1/2130.1419248302128021280191601135010640
9/16120.182318502730027300245701456013650
5/8110.226395503390033900305101808016950
3/4100.334584505010050100450902672025050
7/890.462808506930069300623703696034650
180.6061060009090090900818104848045450
1-1/880.791382001185001185001067006320059250
1-1/4811750001500001500001350008000075000
1-3/881.2332158001850001850001665009864092450
1-1/281.492261100223800223800201400119360111900
Source: ASTM A194-11

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

Nominal SizeThreads per InchStressArea In ²Grade 8M Strain Hardened Heavy Hex ᴮGrade 8M Strain Hardened Hex ᶜAll Other Grade 8 Strain Hardened Heavy Hex ᴰAll Other Grade 8 Strain Hardened Hex ᴮ
1/4200.03163480316039503480
5/16180.05235760524065505760
3/8160.07748510774096758510
7/16140.106311690106301329011690
1/2130.14191561014190174015610
9/16120.18220020182002275020020
5/8110.22624860226002825024860
3/4100.33436740334004175036740
7/890.46246200415805313046200
180.60660600545406969060600
1-1/880.70975050671508295075050
1-1/481950008500010500095000
1-3/881.23311097098640123300110970
1-1/281.492134280119360149200134280
Source: ASTM A194-11

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

Nominal SizeThreads per IncStress Area in ²Proof Load lbf ᴮ for 2H Heavy HexProof Load lbfᴮ Grade 6 Heavy Hex
1-5/881.78311500267000
1-3/482.08364000312000
1-7/882.41421800361500
282.77484800415500
2-1/483.56623000534000
2-1/284.44777000666000
2-3/485.43950250814500
Source: ASTM A194-11

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>

 

ASTM A194-11 approved Nov. 1, 2011.

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