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.
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 |