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ASTM F593

Scope

ASTM F593 covers the chemical and mechanical requirements for stainless steel bolts, hex cap screws and studs in diameters ranging from 1/4" to 1-1/2" inclusive. These fasteners are for general purpose usage, and are available in seven alloy groups. Below is a basic summary of the common grades within the ASTM F593 specification. A number of other less common grades of ASTM F593 exist, but are not detailed in the description below. The Mechanical table here is limited to Alloy groups 1 and 2, as those are the most common and the Chemical table is only showing the most common alloy grades used for their respective alloy groups . More detailed information can be found in the ASTM F593 standard on the ASTM website.

Alloy Groups

Alloy GroupAlloy DesignationAlloy Type
1 303, 304, 304L, 305, 384, XM1, 18-9LW, 302HQ, 303Se Austenitic
2 316, 316L Austenitic
3 321, 347 Austenitic
4 430, 430F Ferritic
5 410, 416, 416Se Martensitic
6 431 Martensitic
7 630 (17-4) Precipitation Hardening

*The selection of an alloy within each group is at the discretion of the manufacturer unless the purchaser requests a specific alloy.

Mechanical Properties / Condition

Alloy GroupConditionMarkingDiameter RangeTensile, ksiYield, ksi minRockwell Hardness
1 AF F593A 1/4 to 1-1/2 65 to 85 20 B85 max
A F593B 1/4 to 1-1/2 75 to 100 30 B65 to 95
CW1 F593C 1/4 to 5/8 100 to 150 65 B95 to C32
CW2 F593D 3/4 to 1-1/2 85 to 140 45 B80 to C32
2 AF F593E 1/4 to 1-1/2 65 to 85 20 B85 max
A F593F 1/4 to 1-1/2 75 to 100 30 B65 to 95
CW1 F593G 1/4 to 5/8 100 to 150 65 B95 to C32
CW2 F593H 3/4 to 1-1/2 85 to 140 45 B80 to C32

Chemical Requirements

Element, max except as shownAlloy Group 1, Type 304Alloy Group 2, Type 316
Carbon 0.08% 0.08%
Manganese 2.00% 2.00%
Phosphorus 0.045% 0.045%
Sulfur 0.030% 0.030%
Silicon 1.00% 1.00%
Chromium 18.0 to 20.0% 16.0 to 18.0%
Nickel 8.0 to 10.5% 10.0 to 14.0%
Copper 1.00%  
Molybdenum   2.00 to 3.00%

Recommended Nuts and Washers

NutsWashers
F594 SS304 or SS316