18-8 SS Socket Head Cap Screw
18-8 SS Socket Head Cap Screw
Manufacturers:
ASTM F837 stainless steel socket head cap screws (also known as Allen head screws) have a cylindrical head with a flat chamfered top surface, knurled cylindrical sides and hexagonal recess. The ASTM F837 specification covers the chemical and mechanical requirements for stainless steel inch socket head cap screws. Dimensional specifications are governed by ASME B18.3. Socket Head Cap screws require less surface area to counterbore.These fasteners are commonly used in applications in which it is necessary to recess the head of the fastener, as well as applications where space limits the size of the head, and the tool that drives the fastener. Stainless steel fasteners are commonly used in applications that require general atmospheric corrosion resistance, such as chemical and food processing equipment. Stainless steel has a higher corrosion resistance than carbon steel.Thread lengths listed are minimum thread lengths, actual thread length may be longer. Please note that in some cases for smaller diameters, mechanical testing may not be performed and thus will not meet ASTM F837.
Products
Governing Standards
| ASTM F837 | This specification covers the chemical and mechanical requirements for stainless steel inch socket head cap screw (SHCS) with nominal thread 0.060 through 1.500 in. and intended for use in applications requiring general corrosion resistance. |
| ASME B18.3 | Covers the complete general and dimensional data for various types of hexagon socket cap screws, shoulder screws, set screws, and hexagon keys recognized as an American National Standard. |
| ASME B1.1 UNC & UNF Class 2A | Specifies the thread form, series, class, allowance, tolerance, and designation for unified screw threads. |
Stainless Steel Socket Head Cap Screw requires no material marking
Mechanical Properties
| Austenitic Stainless Steel | Per ASTM F837-13 | |||||||
| Alloy Group 1, Condition CW |
Nominal Thread Diameter (1) |
Full-Size Product | Machine Specimen | Core Hardness (2) | ||||
| Tensile Strength |
Minimum Extension (3) |
Tensile Strength |
Yield Strength |
Minimum Elongation |
Vickers | Rockwell | ||
| ksi | ksi | ksi | % | |||||
| 0.60-0.750 | 80 min | 0.4D | 80 min | 40 min | 25 | 150 min | 50 HRA min | |
- 1. For fasteners with nominal thread diameter larger than 0.750 in., the mechanical properties and marking shall be agreed upon between the user and manufacturer.
- 2. Core hardness is only required when full-size product tensile testing cannot be accomplished.
- 3. D denotes nominal thread size.
Dimensional Specifications
| Per ASME B18.3-2012 | ||||||||||||
| Size | Nominal | UNC | UNF | D | A | H | J | LT | ||||
| Body Diameter | Head Diameter | Head Height | Hex Socket Size | Thread Length |
||||||||
| Max | Min | Max | Min | Max | Min | Fraction Nominal |
Decimal Nominal |
Min | ||||
| #0 | 0.0600 | 80 | 0.0600 | 0.0568 | 0.0960 | 0.0910 | 0.0600 | 0.0570 | …. | 0.0500 | 0.5000 | |
| #1 | 0.0730 | 64 | 72 | 0.0730 | 0.0695 | 0.1180 | 0.1120 | 0.0730 | 0.0700 | 1/16 | 0.0620 | 0.6625 |
| #2 | 0.0860 | 56 | 64 | 0.0860 | 0.0822 | 0.1400 | 0.1340 | 0.0860 | 0.0830 | 5/64 | 0.0780 | 0.6250 |
| #3 | 0.0990 | 48 | 56 | 0.0990 | 0.0949 | 0.1610 | 0.1540 | 0.0990 | 0.0950 | 5/64 | 0.0780 | 0.6250 |
| #4 | 0.1120 | 40 | 48 | 0.1120 | 0.1075 | 0.1830 | 0.1760 | 0.1120 | 0.1080 | 3/32 | 0.0940 | 0.7500 |
| #5 | 0.1250 | 40 | 44 | 0.1250 | 0.1202 | 0.2050 | 0.1980 | 0.1250 | 0.1210 | 3/32 | 0.0940 | 0.7500 |
| #6 | 0.1380 | 32 | 40 | 0.1380 | 0.1329 | 0.2260 | 2.1800 | 0.1380 | 0.1340 | 7/64 | 0.1090 | 0.7500 |
| #8 | 0.1640 | 32 | 36 | 0.1640 | 0.1585 | 0.2700 | 2.6200 | 0.1640 | 0.1590 | 9/64 | 0.1410 | 0.8750 |
| #10 | 0.1900 | 24 | 32 | 0.1900 | 0.1840 | 0.3120 | 0.3030 | 0.1900 | 0.1850 | 5/32 | 0.1560 | 0.8750 |
| #12 | 0.2120 | 24 | 28 | 0.2160 | 0.2095 | 0.3240 | 0.3140 | 0.2160 | 0.2100 | 5/32 | 0.1560 | 0.8750 |
| 1/4 | 0.2500 | 20 | 28 | 0.2500 | 0.2435 | 0.3750 | 0.3650 | 0.2500 | 0.2440 | 3/16 | 0.1880 | 1.0000 |
| 5/16 | 0.3125 | 18 | 24 | 0.3125 | 0.3053 | 0.4690 | 0.4570 | 0.3120 | 0.3060 | 1/4 | 0.2500 | 1.1250 |
| 3/8 | 0.3750 | 16 | 24 | 0.3750 | 0.3678 | 0.5620 | 0.5500 | 0.3750 | 0.3680 | 5/16 | 0.3120 | 1.2500 |
| 7/16 | 0.4375 | 14 | 20 | 0.4375 | 0.4294 | 0.6560 | 0.6420 | 0.4380 | 0.4300 | 3/8 | 0.3750 | 1.3750 |
| 1/2 | 0.5000 | 13 | 20 | 0.5000 | 0.4919 | 0.7500 | 0.7350 | 0.5000 | 0.4920 | 3/8 | 0.3750 | 1.5000 |
| 5/8 | 0.6250 | 11 | 18 | 0.6250 | 0.6163 | 0.9380 | 0.9210 | 0.6250 | 0.6160 | 1/2 | 0.5000 | 1.7500 |
| 3/4 | 0.7500 | 10 | 16 | 0.7500 | 0.7406 | 1.1250 | 1.1070 | 0.7500 | 0.7400 | 5/8 | 0.6250 | 2.0000 |
| 7/8 | 0.8750 | 9 | 14 | 0.8750 | 0.8647 | 1.3120 | 1.2930 | 0.8750 | 0.8640 | 3/4 | 0.7500 | 2.2500 |
| 1 | 1.0000 | 8 | 14 | 1.0000 | 0.9886 | 1.5000 | 1.4790 | 1.0000 | 0.9880 | 3/4 | 0.7500 | 2.5000 |
| 1 1/8 | 1.1250 | 7 | 12 | 1.1250 | 1.1086 | 1.6880 | 1.6650 | 1.1250 | 1.1110 | 7/8 | 0.8750 | 2.7500 |
| 1 1/4 | 1.2500 | 7 | 12 | 1.2500 | 1.2336 | 1.8750 | 1.8520 | 1.2500 | 1.2360 | 7/8 | 0.8750 | 3.0000 |
| 1 3/8 | 1.3750 | 7 | 12 | 1.3750 | 1.3568 | 2.0620 | 2.0380 | 1.3750 | 1.3600 | 1 | 1.0000 | 3.2500 |
| 1 1/2 | 1.5000 | 6 | 12 | 1.5000 | 1.4818 | 2.2500 | 2.2240 | 1.5000 | 1.4850 | 1 | 1.0000 | 3.5000 |
| 1 3/4 | 1.7500 | 5 | 12 | 1.7500 | 1.7295 | 2.6250 | 2.5970 | 1.7500 | 1.7340 | 1 1/4 | 1.2500 | 4.3800 |
| 2 | 2.0000 | 4 | 12 | 2.0000 | 1.9780 | 3.0000 | 2.9700 | 2.0000 | 1.9830 | 1 1/2 | 1.5000 | 5.0000 |
| 2 1/4 | 2.2500 | 4 | 12 | 2.2500 | 2.2280 | 3.3750 | 3.3440 | 2.2500 | 2.2320 | 1 3/4 | 1.7500 | 5.6200 |
| 2 1/2 | 2.5000 | 4 | 12 | 2.5000 | 2.4762 | 3.7500 | 3.7170 | 2.5000 | 2.4810 | 1 3/4 | 1.7500 | 6.2500 |
| 2 3/4 | 2.7500 | 4 | 12 | 2.7500 | 2.7262 | 4.1250 | 4.0900 | 2.7500 | 2.7300 | 2 | 2.0000 | 6.8800 |
| 3 | 3.0000 | 4 | 12 | 3.0000 | 2.9762 | 4.5000 | 4.4640 | 3.0000 | 3.9790 | 2 1/4 | 2.2500 | 7.5000 |
| 3 1/4 | 3.2500 | 4 | 12 | 3.2500 | 3.2262 | 4.8750 | 4.8300 | 3.2500 | 3.2280 | 2 1/4 | 2.2500 | 8.1200 |
| 3 1/2 | 3.5000 | 4 | 12 | 3.5000 | 3.4762 | 5.2500 | 5.2110 | 3.5000 | 3.4780 | 2 3/4 | 2.7500 | 8.7500 |
| 3 3/4 | 3.7500 | 4 | 12 | 3.7500 | 3.7262 | 5.6250 | 5.5840 | 3.7500 | 3.7270 | 2 3/4 | 2.7500 | 9.3800 |
| 4 | 4.0000 | 4 | 12 | 4.0000 | 3.9762 | 6.0000 | 5.9580 | 4.0000 | 3.9760 | 3 | 3.0000 | 10.0000 |
- All dimensions are in inches.
Chemical Properties
| Per ASTM F837-13 | ||||||||
| Material | Carbon | Manganese | Phosphorus | Sulfur | Silicon | Chromium | Nickel | Copper |
| % by weight | % by weight | % by weight | % by weight | % by weight | % by weight | % by weight | % by weight | |
| Alloy Group 1, UNS S30400 |
0.08 | 2.00 | 0.045 | 0.030 | 1.00 | 18.0 to 20.0 | 8.0 to 10.5 | 1.00 |