ASTM F593 Type 321 - Grade Specification for Stainless Steel 321 Hex Bolts, Hex Cap Screws & Stud Bolts

This type covers grade specification requirements for Cold-Worked 321 Stainless Steel Hex Bolts, Hex Cap Screws, Countersunk Screws, Stud Bolts, Threaded Rods, etc. Please find below chemical, mechanical, supply condition, heat treatment, marking and other requirements on 321 Stainless Steel Bolts. These F593 Type 321 Bolt Fasteners carry EN 10204 Type 3.1Inspection Certificate.

ASTM F593 Alloy Categories

Group AlloyA ConditionB
3 321, 347 (CW) Cold WorkedC

A Unless otherwise specified on the inquiry and order, the choice of an alloy from within a group shall be at the discretion of the fastener manufacturer
B See section 4.2 of F593 for options
C Sizes 0.75 inch and larger may be hot worked and solutoon annealed.
D When approved by the purchaser, alloys 303, 303Se, or XM1 may be furnished.
E When approved by the purchaser, alloy 430F may be furnished.
F When approved by the purchaser, alloys 416 or 416Se may be furnished.

ASTM F593 Bolts Supply Conditions

Alloy Group Condition Furnished Unless Otherwise Specified Optional Conditions (must be specified)
1, 2, 3 CW AF, A, SH

A - Machined from annealed or solution annealed stock thus retaining the properties of the original material; or hot formed and solution annealed.
AF - Headed and rolled from annealed stock and then reannealed
AH - Solution annealed and age hardened after forming.
CW - Headed and rolled from annealed stock thus acquiring a degree of cold work. Sizes 0.75inch and larger may be hot worked and solution annealed.
H - Hardened and tempered at 1050°F (565°C) minimum.
HT - Hardened and tempered at 525°F (274°C) minimum.
SH - Machined from strain hardened stock or cold worked to develop the specific properties.

Heat Treatments for 321 Austenitic Alloy

Condition A - When Condition A is specified, the austenitic alloys shall be heated to 1900+/- 50°F ( 1038 +/- 28°C), at which time the chromium carbide will go into the solution, be held for a sufficient time, and then be cooled at a rate sufficient to prevent precipitation of the carbide and to provide the specified properties.

Condition CW - When Condition CW is specified, the austenitic alloys shall be annealed in accordance with Condition A, generally by the raw material manufacturer and thenc old worked to develop the specified properties.

Condition AF - When Condition AF is specified, the austenitic alloys shall be annealed in accordance to Condition A after all cold working (including heading and threading) has been completed.

ASTM F593 Type 321 Chemical Requirements

Composition, %, maximum except as shown
UNS Designation Alloy Group Alloy Carbon Manganese Phosphorus Sulfur Silicon Chromium Nickel Copper Molybdenum Others
Austenitic Alloys
S32100 3 321 0.08 2.00 0.045 0.030 1 17.0 - 19.0 9.0 - 12.0 -- -- Ti 5 x C min

A At manufacturer's options, determined only when intentionally added.

ASTM F593 Mechanical Properties

Stainless Steel Alloys ConditionB Alloy Mechanical Property Marking Nominal Diameter, inch Full Size Tests Machined Specimen Tests
Tensile Strength, ksiC Yield Strength, ksiDC Rockwell Hardness Tensile Strength, ksiC Yield Strength, ksiDC Elongation in 4D, %
Austenitic Alloys
3 (321, 347) AF F593J 1/4 to 1-1/2, incl. 65 - 85 20 B85 max 60 20 40
3 (321, 347) A F593K 1/4 to 1-1/2, incl. 75 - 100 30 B65 to 95 70 30 30
3 (321, 347) CW1 F593L 1/4 to 5/8, incl. 100 - 150 65 B95 to C322 95 60 20
3 (321, 347) CW2 F593M 3/4 to 1-1/2, incl. 85 - 140 45 B80 to C32 80 40 25
3 (321, 347) SH1 F593J 1/4 to 5/8, incl. 120 - 160 95 C24 to C36 115 90 12
3 (321, 347) SH2 F593K 3/4 to 1, incl. 110 - 150 75 C20 to C32 105 70 15
3 (321, 347) SH3 F593L 1-1/8 to 1-1/4, incl. 100 - 140 60 B95 to C30 95 55 20
3 (321, 347) SH4 F593M 1-3/8 to 1-1/2, incl. 95 - 130 45 B90 to C28 90 40 28

A Minimum values except where shown as maximum or as a range.
B legend of conditions:
AF - Headed and rolled from annealed stock and then reannealed
AH - Solution annealed and age hardened after forming
CW - Headed and rolled from annealed stock thus acquiring a degree of cold work. Sizes 0.75inch and larger may be hot worked and solution annealed.
H - Hardened and tempered at 1050°F (565°C) minimum.
HT - Hardened and tempered at 525°F (274°C) minimum.
SH - Machined from strain hardened stock or cold worked to develop the specific properties.
C The yield and tensile strength values for full size products shall be computed by dividing the yield and maximum tensile load value by the stress area for the product size and thread sizes determined in accordance with Test Methods F606.
D Yield strength is the stress at which an offset of 0.2 & gauge length occurs.

Mechanical Test Requirements for Bolts and StudsA

Item Nominal Length Tensile Load, lbf Full Size Tests Machined Specimen Tests
Diameters 3/4 inch and Less Diameters Over 3/4 inch. Wedge Tensile Strength Axial Tensile Strength Yield Strength Rockwell Hardness Tensile Strength Yield Strength Elongation
Hex head, square head and hex socket cap screws Less than 2-1/4 D Less than 3D all Option A Option B B Option C B B B
2-1/4 D and longer 3D and longer 120 000 max Mandatory B Mandatory B B B B
2-1/4 D and longer 3D and longer over 120 000 Option A B Option A B Option B Option B Option B
Stud bolts and other bolts Less than 2-1/4 D Less than 3D all B Option A B Option B B B B
2-1/4 D and longer 3D and longer 120 000 max B Mandatory Mandatory B B B B
2-1/4 D and longer 3D and longer over 120 000 B Option A Option A B Option B Option B Option B
SpecialsC all all all B B Mandatory B B B B

A Where options are given, all the tests under an option shall be performed. Option A, Option B and Option C indicates manufacturer may perform all Option A (full-size), all Option B (machined specimen), or all Option C tests whichever is preferred. Option A tests should be made whenever feasible.
B Tests that are not mandatory
C Special fasteners are those fasteners with special configurations including drilled heads, reduced body, etc., that are weaker than the threaded section. Special fasteners have full size heads shall be tested as specified for stud bolts and other bolts.

Tensile Stress Areas and Threads per Inch

Nominal Size, inch. Coarse Threads - UNC Fine Threads - UNF Thread Series - 8UN
Threads / inch Stress AreaA, in2 Threads / inch Stress AreaA, in2 Threads / inch Stress AreaA, in2
1/4 20 0.0318 28 0.0364 -- --
5/16 18 0.0524 24 0.0580 -- --
3/18 16 0.0775 24 0.0878 -- --
7/16 14 0.1063 20 0.1187
1/2 13 0.1419 20 0.1599
9/16 12 0.1820 18 0.2030
5/8 11 0.2260 18 0.2560
3/4 10 0.3340 16 0.3730
7/8 9 0.4620 14 0.5090
1 8 0.6060 12 0.6630
1 1/8 7 0.7630 12 0.8560 8 0.790
1 1/4 7 0.9690 12 1.0730 8 1.000
1 3/8 6 1.1550 12 1.3150 8 1.233
1 1/2 6 1.4050 12 1.5810 8 1.492

A Tensile stress areas are computed using the following formula: AB = 0.7854 [D- (0.9743/n)]2
Where:
AB = Tensile stress area, inch2,
D = Nominal size (basic major diameter), in., and,
n = number of threads per inch.