SAE J429 Mechanical Properties of Fasteners
SAE J429 specifies the mechanical and material requirements for carbon steel and alloy steel mechanical fasteners used in automotive, machinery, construction and general industrial applications. The standard establishes requirements for commonly used inch-series fastener grades, including Grade 2, Grade 5, Grade 5.1, Grade 7 and Grade 8, with the required mechanical properties varying according to the grade and applicable diameter range.
The requirements of SAE J429 cover important mechanical characteristics such as tensile strength, yield strength, proof load and hardness, together with material and heat treatment requirements for applicable grades. These requirements provide a consistent basis for selecting and verifying high-strength bolts, screws and other mechanical fasteners for applications where defined strength and hardness are required. The tables on this page provide reference information for the principal SAE J429 grades, including their mechanical properties, material requirements and hardness ranges.
We manufacture SAE J429 fasteners in commonly specified grades and sizes, with options for different head styles, thread configurations, surface finishes and dimensional standards. SAE J429 mechanical requirements can be applied to a range of products, including hex bolts, flange bolts and other inch-series fasteners, according to the applicable product specification.
| GRADE | Nominal Size, inches | Full Size Proofload, psi | Yield Strength, min, psi | Tensile Strength, min, psi | Elong, min, % | RA, min, % | Core Hardness, Rockwell | Tempering Temperature, min |
|---|---|---|---|---|---|---|---|---|
| 2 | 1/4 thru 3/4 | 55000 | 57000 | 74000 | 18 | 35 | B80-B100 | N/A |
| Over 3/4 thru 1-1/2 | 33,000 | 36,000 | 60,000 | 18 | 35 | B70 to B100 | ||
| 5 | 1/4 thru 1 | 85,000 | 92,000 | 120,000 | 14 | 35 | C25 to C34 | 800F |
| Over 1 thru 1-1/2 | 74,000 | 81,000 | 105,000 | 14 | 35 | C19 to C30 | ||
| 8 | 1/4 thru 1-1/2 | 120,000 | 130,000 | 150,000 | 12 | 35 | C33 to C39 | 800F |
| Grade 2 requirements for sizes 1/4" thru 3/4" apply only to bolts 6" and shorter, and to studs of all lengths. For bolts longer than 6", Grade 1 requirements shall apply. | ||||||||
Material Chemical Composition:
SAE J429 specifies material and chemical composition requirements for the applicable carbon steel and alloy steel fastener grades. The required composition varies according to the grade, with elements such as carbon, manganese, phosphorus, sulfur and, for certain alloy steel grades, chromium, molybdenum and other alloying elements contributing to the required mechanical performance and heat-treatment response.
The following table summarizes the applicable chemical composition requirements for the principal SAE J429 fastener grades. The specified limits help ensure that the material can achieve the required tensile strength, yield strength, hardness and other mechanical properties after the applicable manufacturing and heat-treatment processes. Chemical composition should be evaluated together with the grade, diameter range and mechanical requirements specified by SAE J429.
| Thread Size | Stress Area, | Material | Heat Treament | C(min) | C(max) | P(max) | S(max) | B(max) | Tempering temperature(℃） |
|---|---|---|---|---|---|---|---|---|---|
| 2 | 1/4"-1-1/2" | Low or Medium Carbon Steel | - | 0.15 | 0.55 | 0.025 | 0.025 | ||
| 5 | 1/4"-1-1/2" | Medium Carbon Steel | Quenched&Tempered | 0.25 | 0.55 | 0.025 | 0.025 | 425℃（800℉） | |
| Carbon Steel with additives(Boron or Cr,or Mn) | Quenched&Tempered | 0.15 | 0.4 | 0.025 | 0.025 | 0.003 | 425℃（800℉） | ||
| 8 | 1/4"-1-1/2" | Carbon Steel with additives(Boron or Cr,or Mn) | Quenched&Tempered | 0.25 | 0.55 | 0.025 | 0.025 | 0.003 | 425℃（800℉） |
| Medium Carbon Steel | Quenched&Tempered | 0.25 | 0.55 | 0.025 | 0.025 | 425℃（800℉） | |||
| Alloy Steel | Quenched&Tempered | 0.25 | 0.55 | 0.025 | 0.025 | 425℃（800℉） |
Proof Load and Tensile Strength:
SAE J429 defines the mechanical performance requirements for carbon steel and alloy steel fasteners according to their specified grade and diameter range. Key requirements include minimum tensile strength and proof load, which are used to evaluate the load-carrying capability and resistance to permanent deformation of the fastener. The required values vary with the SAE J429 grade and nominal diameter.
The table below summarizes the minimum tensile strength and proof load requirements for commonly specified SAE J429 fastener grades. These values provide a useful reference when selecting Grade 2, Grade 5 and Grade 8 fasteners for applications requiring defined mechanical performance.
| Thread Size | Stress Area,in² | Grade2 Proof Load(lbf) | Grade2 Proof Load(lbf) | Grade5 Proof Load(lbf) | Grade 5Tensile Load(min)lbf | Grade8 Proof Load(lbf) | Grade 8Tensile Load(min)lbf |
|---|---|---|---|---|---|---|---|
| 6-32 | 0.00909 | - | - | - | - | - | - |
| 8-32 | 0.0140 | - | - | - | - | - | - |
| 10-24 | 0.0175 | - | - | - | - | - | - |
| 12-24 | 0.0242 | - | - | - | - | - | - |
| 1/4"-20 | 0.0318 | 1750 | 2350 | 2700 | 3800 | 3800 | 4750 |
| 5/16"-18 | 0.0524 | 2900 | 3900 | 4450 | 6300 | 6300 | 7850 |
| 3/8"-16 | 0.0775 | 4250 | 5750 | 6600 | 9300 | 9300 | 11600 |
| 7/16"-14 | 0.1063 | 5850 | 7850 | 9050 | 12800 | 12800 | 15900 |
| 1/2"-13 | 0.1419 | 7800 | 10500 | 12100 | 17000 | 17000 | 21300 |
| 9/16"-12 | 0.182 | 10000 | 13500 | 15500 | 21800 | 21800 | 27300 |
| 5/8"-11 | 0.226 | 12400 | 16700 | 19200 | 27100 | 27100 | 33900 |
| 3/4"-10 | 0.334 | 18400 | 24700 | 28400 | 40100 | 40100 | 50100 |
| 7/8"-9 | 0.462 | 15200 | 27700 | 39300 | 55400 | 55400 | 69300 |
| 1"-8 | 0.606 | 20000 | 36400 | 51500 | 72700 | 72700 | 90900 |
| 1-7/1"-7 | 0.763 | 25200 | 45800 | 56500 | 80100 | 91600 | 114400 |
| 1-1/4"-7 | 0.969 | 32000 | 58100 | 71700 | 101700 | 116300 | 145400 |
| 1-3/8"-6 | 1.155 | 38100 | 69300 | 85500 | 121300 | 138600 | 173200 |
| 1-1/2"-6 | 1.405 | 46400 | 84300 | 104000 | 147500 | 168600 | 210800 |
Products Covered by SAE J 429:
When sourcing inch-series bolts,screws,stud bolts, SAE J429 can be referenced for the material and mechanical requirements of many commonly used fastener types. The standard provides requirements for different strength grades, including Grade 2, Grade 5, and Grade 8, covering properties such as tensile strength, yield strength, hardness, and other mechanical characteristics. We supply a variety of inch-series externally threaded fasteners for industrial, mechanical, automotive, and equipment applications, including hex bolts, heavy hex bolts, flange bolts, T-bolts, carriage bolts, square head bolts, anchor bolts, threaded rods, and stud bolts. Depending on the product, the dimensional requirements are specified by separate ASME standards. The following fastener types are commonly associated with these requirements, and we can manufacture them according to SAE J429 together with the applicable dimensional standards, or to customer drawings and specifications.