ASTM F594 Specification

Specifications

At Adfast Components, ASTM F594 covers the specification for stainless steel hex nuts in imperial sizes ranging from 1/4 inch to 1-1/2 inch. These nuts are manufactured for applications requiring reliable general corrosion resistance. The standard includes seven groups of stainless steel alloys—comprising austenitic, ferritic, martensitic, and precipitation hardening grades. We manufacture and supply hex nuts in various F594 designations such as F594A, F594C, F594D, F594F, F594G, and F594H. All products are rigorously tested and provided with EN 10204 Type 3.1 certification for assured quality and traceability.

Alloy Categories

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 When approved by the purchaser, alloys 303, 303Se, or XM1 may be furnished.
D Sizes 0.75 inch and larger may be hot worked and solutoon annealed.
E When approved by the purchaser, alloy 430F may be furnished.
F When approved by the purchaser, alloys 416 or 416Se may be furnished.

Bolts Supply Conditions

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

Heat Treatments for Austenitic Alloys

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.

Heat Treatments for Ferritic Alloys

Condition A – The ferritic alloys shall be heated to a temperature of 145 +/- 50°F (788 +/- 28°C), held for an appropriate time, and then air cooled to procide the specified properties.

Condition CW – When Condition CW is specified, the ferritic alloys shall be annealed in accordance to above condition A for ferritic alloys, generally by the raw material manufacturer and then cold worked to develop the specified properties.

Condition AF – When Condition AF is specified, the ferritic alloys shall be annealed in accordance to same above condition A (Ferritic Alloys) after all cold working (including heading and threading) has been completed.

Heat Treatments for Martensitic Alloys (SS Alloy 410, 416 & 416Se)

Condition H – When Condition H is specified, the martensitic alloys 410, 416 and 416Se shall be hardened and tempered by heating to 1850 +/- 50°F (1010 +/- 28°C) sufficient for austenitization, held for atleast 1/2 hour and rapid air or oil quenched, and then reheating to 1050°F (565°C) minimum for atleast 1 hour and air cooled to develop the specified properties.

Condition HT – When Condition HT is specified, the martensitic alloys 410, 416 and 416Se shall be hardened and tempered by heating to 1850 +/- 50°F (1010 +/- 28°C) sufficient for austenitization, held for atleast 1/2 hour and rapid air or oil quenched, and then reheating to 525°F (272°C) minimum for atleast 1 hour and air cooled to develop the specified properties.

Heat Treatments for Martensitic Alloys ( SS Alloy 431)

Condition H and HT – Martensitic Alloy 431 shall be hardened and tempered in accordance with above condition H or HT (Martensitic 410, 416 and 416Se) as applicable.

Heat Treatments for Precipitation Hardening Alloy 630

Conditon AH – Precipitation Hardening Alloy 630 shall be solution annealed and aged by heating to 1900 +/- 25°F (1038 +/- 14°C) for atleast 1/2 hour and rapid air or oil quenched to 80°F (27*C) maximum, then reheating to a temperature of 1150 +/- 15°F (621 +/- 8°C) for 4 hour and air cooled to develop the specified properties.

Chemical Composition

At manufacturer’s options, determined only when intentionally added.

Mechanical Properties

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

Tensile Stress Areas and Threads per Inch

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.