ASTM A325 and SAE J429 grade 8 are not the same fastener. As a matter of fact, they couldn’t be more different. SAE (Society of Automotive Engineers) establishes specifications covering fasteners intended for use in automotive, OEM, and equipment applications, while ASTM (American Society for Testing and Materials) provides specifications for construction fasteners. There are several differences between these two bolts, including chemistry, strength, application, and dimensional tolerances.
Strength Differences
A325 bolts are typically manufactured from a medium carbon steel (although they can be made from an alloy) while SAE grade 8 bolts are made from a medium carbon alloy steel. Grade 8 bolts are significantly stronger than an A325. An ASTM specification with similar strength properties to grade 8 is ASTM A490.
| Grade | Nominal Size | Proof Load Min (ksi) | Yield Strength Min (ksi) | Tensile Strength Min (ksi) | Rockwell Hardness Min | Rockwell Hardness Max |
|---|---|---|---|---|---|---|
| ASTM A325-1 | 1/2" - 1" | 85 | 92 | 120 | C24 | C35 |
| 1-1/8" - 1-1/2" | 74 | 81 | 105 | C19 | C31 | |
| SAE J429 Grade 8 | 1/4" - 1-1/2" | 120 | 130 | 150 | C33 | C39 |
Compare more strengths with our strength by grade chart.
Configuration Differences
ASTM A325 bolts are heavy hex structural bolts and used in structural steel connections, while SAE grade 8 bolts are finished hex bolts and typically used in automotive and equipment applications. By nature, an SAE bolt is also a more precision fastener with tighter tolerances than an ASTM bolt.
Mechanical properties for A325 bolts under the new F3125 specification are the same for all diameters. Under the original A325 specification, mechanical requirements change for diameters above 1″.
whats is the torque value for this bolt
@Arun- We have estimated general purpose torque values on our website under “technical information”.
Pls quote me on 2000 a325 hex bolts sizes as follows:
3/4x 2″
3/4×21/2″
3/4×3″
Reply to michelle.ramnarine@gmail.com
Must be mill tested and galvanised coarse thread.
@Michelle- One of our salespeople will be contacting you shortly.
Is ASTM A 325 Bolt and 8.8 Bolt same.
@Bhavin- There some chemical and mechanical similarities between the two, but they are not identical bolts. Additionally, A325 bolts are for steel to steel structural connections, whereas 8.8 bolts are more for general purpose applications.
do you folks carry inch and a half by seven grade eight bolts and if so ,how much apiece/ if you do please give me a call. thanks jeff darr @darr scrapers… 618 535 3718
@Darr- Apologies for the delay, one of our sales people will be contacting you shortly.
I am looking for A325 structural bolts. We have consistent requirement of this in different sizes. We are managing a fleet or more than 30 rigs.
But every time I face challenge in sourcing this grade of steel. Is there any equivalent grade which I can use? These bolts will be used on Derrick of rigs. So I need to be 100% sure if mechanical properties of equivalent grade is similar or higher.
@Ravi- I would need to know a bit more about why you are running into trouble with sourcing. A325 bolts are widely available in the marketplace, and should be off the shelf at just about any fastener supplier. If there is something about your needs, whether size, configuration, etc, that is causing you trouble, then I might be able to offer some guidance.