ASTM F593

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.

F593 Alloy Groups

Alloy Group Alloy Designation Alloy 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.

F593 Mechanical Properties / Condition

Alloy Group Condition Marking Diameter Range Tensile, ksi Yield, ksi min Rockwell 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

F593 Chemical Requirements

Element, max except as shown Alloy Group 1, Type 304 Alloy 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%

F593 Recommended Hardware

Nuts Washers
F594 SS304 or SS316