- How many bolts does a flange have?
- ASME B16.5 flanges always got a bolt count that's a multiple of four, from 4 bolts on dem small sizes clear up to 20 or more on the large diameters. The exact count, bolt size, and bolt circle all depend on the nominal size and pressure class; just use the chart up above to look up yours, I tell you what.
- What's the difference 'tween a stud bolt and a machine bolt?
- A stud bolt is a fully threaded rod y'all tighten down with two heavy hex nuts, and it's the standard for most flange connections, 'specially for dem higher-pressure and critical jobs. Now, a machine bolt's got a fixed hex head and just one nut, and folks mostly use it for lower-pressure work where things ain't so critical.
- What material are dem flange bolts made from?
- The most common combination for carbon and alloy steel flanges is ASTM A193 Grade B7 stud bolts with ASTM A194 Grade 2H heavy hex nuts. Now, stainless and special-service applications use grades like B8 or B8M. We can sure enough supply the boltin' to match your flange and service.
- What length stud bolt do I need for a flange, reckon?
- Stud length is driven by the combined thickness of the two flanges, the gasket, and the facin', plus enough thread to engage both nuts. The chart up above lists standard stud lengths by size and class; tell us your gasket and facin' and we'll confirm it right quick.
- What bolt size does a Class 150 flange use?
- Class 150 bolt diameters run from 1/2" on small sizes up to 1-1/4" on a 24" flange. Dat chart above gives the exact diameter, count, and bolt circle for every size.
- What's dat correct bolt torque for a flange?
- Now, flange bolt torque depends on your bolt diameter, bolt material, gasket type, and that target bolt stress, so there ain't no single value per flange size, I tell you what. Torque is calculated for the joint rather than just readin' it from the flange class alone. ASME PCC-1 is the standard that covers bolted flange joint assembly, includin' how assembly torque is figured out and what tightening sequence y'all need to use. Start with this here bolt chart to confirm your bolt count, diameter and stud length, since those are the inputs any torque calculation needs, then go on and see our flange bolt torque values reference for worked figures by pressure class. For torque on a specific gasket and bolt grade, just follow the bolting or gasket manufacturer's published procedure, yessir.
- What's dat bolt circle diameter on an ASME B16.5 flange?
- The bolt circle diameter is the diameter of dat imaginary circle passin' right through the centers of the bolt holes. It's fixed by nominal pipe size and pressure class under ASME B16.5, and it's what determines whether two flanges are gonna mate up. This here chart covers bolt count, bolt diameter and stud length; for bolt circle diameter by size, y'all can see the ASME B16.5 dimension tables class by class, startin' with the Class 150 dimension table.
- Do Class 150 and Class 300 flanges use the same bolts?
- No sir. Class 300 flanges use a larger bolt circle than Class 150 at every size, and in most sizes larger diameter bolts, a higher bolt count, or both. At 1/2" and 5" the bolt count and diameter are the same, but dem bolt circles still differ. A Class 150 and a Class 300 flange of the same nominal pipe size ain't gonna bolt together. Check the bolt count and diameter in the chart on this page, and the bolt circle in the Class 150 and Class 300 dimension tables, before y'all go orderin'.
