Class 2 · Grade B7
Stud Bolt
Threaded stud bolts for flange bolting, supplied plain or as a kit with two nuts.
About the Stud Bolt
Stud bolts are threaded along their length and used with two nuts to bolt pipe flanges together, on oil, gas, mining, water and process plant. They come as ASTM A193 grade B7 alloy steel studs (alone or as a kit with two A194 2H heavy hex nuts) and B8 class 2 (304) and B8M class 2 (316) stainless studs, from 1/2 to 2 inch (UNC to 1 inch, 8 UN from 1-1/8 inch) and 40 to 600mm long, plain, Xylan blue, hot dip galvanised, zinc, zinc yellow, cadmium or Esso spec. Choose the grade, size, length and coating above; the guide below covers grades and temperatures, studs for 150 and 300 lb flanges, and torque.
Also called threaded studs, flange studs or B7 studs.
Features
- Full-length thread, tensioned both ends
- Plain or kit with two nuts
- B7 alloy and stainless
- ASTM A193 / A320
Applications
- Bolting pipe flanges together
- Oil, gas, mining and process plant
- High temperature service (B7)
What a stud bolt is
A stud bolt is a headless stud threaded along its length, with a nut run onto each end. Hobson's torque sheet notes they are most widely used for flange bolting on piping that carries fluids over a range of temperatures and pressures, and its petrochemical range offers a wide range of coatings for oil, gas and mining.
Ours are imperial: UNC thread from 1/2 to 1 inch and 8 UN (eight threads per inch, written UN8 by Hobson) from 1-1/8 to 2 inch, with lengths in mm. A few Xylan blue B7 studs in 1-1/8, 1-1/4 and 1-1/2 inch are UNC (Hobson marks them UNC*). Buy them as a stud only, or for B7 as a kit with two 2H heavy hex nuts.
B7, B8 or B8M: stud bolt grades
From Hobson's petrochemical bolt and nut property sheets. Service temperatures are actual metal temperatures. Select a row to open that grade.
- Check the nut and coating too. Hobson's sheet gives -100 to 400°C for B7 and L7 together; L7 is the low-temperature grade, impact tested at -101°C, so for sub-zero service specify L7 (ask us). The 2H nuts in the B7 kits are rated 0 to 450°C, which limits a kit to 0°C and above, and Hobson gives the Xylan coating an operating temperature of -40 to 205°C.
- Hobson also lists ASTM A320 L7 and ASTM A193 B16 bolting, and can source duplex stainless and nickel alloys on request. Call us if your spec calls for those; other nut grades are on our heavy hex nut page.
Material, service temperature and minimum strength from Hobson's petrochemical chemical and mechanical property sheets. Stainless Class 2 strengths fall as the diameter grows: the first figure is for 3/4 inch and under, the second for over 1-1/4 to 1-1/2 inch. Tap a number to show it in the selector above.
| Grade | Material | Service temperature (Hobson) | Min tensile strength | Min yield strength |
|---|---|---|---|---|
| B7, ASTM A193 | AISI 4140 chrome-moly alloy steel | Up to 400°C (Hobson gives -100 to 400°C for B7 and L7 together; L7 is the low-temperature grade) | 860 MPa (2-1/2 inch and under) | 720 MPa |
| B8 Class 2, ASTM A193 | AISI type 304 stainless | -250 to 575°C | 860 down to 690 MPa | 690 down to 345 MPa |
| B8M Class 2, ASTM A193 | AISI type 316 stainless | -250 to 600°C | 760 down to 620 MPa | 665 down to 345 MPa |
| 2H nut, ASTM A194 (in the B7 kits) | Carbon steel | 0 to 450°C | Hardness 248 to 327 HB (212 to 327 HB over 1-1/2 inch) | Not listed |
Stud bolt sizes, coatings and lengths we carry
Every grade and size, with the coatings and length range available in each. Select a row to open that grade and size, then pick the coating and length.
From our product data. Thread is size-TPI and series. Lengths in mm (mostly in 5mm steps). Min order is the pack quantity, which varies by size and length. Tap a number to show it in the selector above.
| Type | Size | Thread | Coatings | Lengths (mm) | Min order |
|---|---|---|---|---|---|
| B7 kit, stud with two 2H nuts | |||||
| B7 kit, stud with two 2H nuts | 1/2 inch | 1/2-13 UNC | plain, Xylan blue, hot dip galvanised, zinc yellow | 50 to 350 | 16 |
| B7 kit, stud with two 2H nuts | 5/8 inch | 5/8-11 UNC | plain, Xylan blue, hot dip galvanised, zinc yellow | 50 to 380 | 16 |
| B7 kit, stud with two 2H nuts | 3/4 inch | 3/4-10 UNC | plain, Xylan blue, hot dip galvanised, zinc yellow | 50 to 510 | 8 |
| B7 kit, stud with two 2H nuts | 7/8 inch | 7/8-9 UNC | plain, Xylan blue, hot dip galvanised, zinc yellow | 75 to 510 | 4 |
| B7 kit, stud with two 2H nuts | 1 inch | 1-8 UNC | plain, Xylan blue, hot dip galvanised, zinc yellow | 75 to 510 | 4 |
| B7 kit, stud with two 2H nuts | 1-1/8 inch | 1-1/8-8 UN8 | plain, Xylan blue, hot dip galvanised, zinc yellow | 75 to 510 | 4 |
| B7 kit, stud with two 2H nuts | 1-1/4 inch | 1-1/4-8 UN8 | plain, Xylan blue, hot dip galvanised, zinc yellow | 75 to 510 | 4 |
| B7 kit, stud with two 2H nuts | 1-3/8 inch | 1-3/8-8 UN8 | plain, Xylan blue, hot dip galvanised | 75 to 510 | 4 |
| B7 kit, stud with two 2H nuts | 1-1/2 inch | 1-1/2-8 UN8 | plain, Xylan blue, hot dip galvanised | 100 to 510 | 2 |
| B7 kit, stud with two 2H nuts | 1-5/8 inch | 1-5/8-8 UN8 | plain | 285 to 305 | 2 |
| B7 stud only | |||||
| B7 stud only | 1/2 inch | 1/2-13 UNC | plain, Xylan blue, hot dip galvanised, zinc yellow, zinc plated, cadmium, Esso spec | 45 to 350 | 16 |
| B7 stud only | 5/8 inch | 5/8-11 UNC | plain, Xylan blue, hot dip galvanised, zinc yellow, zinc plated, cadmium, Esso spec, zinc plated and Xylan green | 50 to 350 | 16 or 96 |
| B7 stud only | 3/4 inch | 3/4-10 UNC | plain, Xylan blue, hot dip galvanised, zinc yellow, zinc plated, cadmium, Esso spec, zinc plated and Xylan green | 50 to 510 | 1 or 8 |
| B7 stud only | 7/8 inch | 7/8-9 UNC | plain, Xylan blue, hot dip galvanised, zinc yellow, zinc plated, cadmium, Esso spec, zinc plated and Xylan green | 75 to 510 | 1 or 4 |
| B7 stud only | 1 inch | 1-8 UNC | plain, Xylan blue, hot dip galvanised, zinc yellow, zinc plated, cadmium, Esso spec | 75 to 510 | 1 or 4 |
| B7 stud only | 1-1/8 inch | 1-1/8-8 UN8 (some Xylan blue in UNC, 7 or 6 TPI) | plain, Xylan blue, hot dip galvanised, zinc yellow, zinc plated, cadmium, Esso spec | 75 to 600 | 1 or 4 |
| B7 stud only | 1-1/4 inch | 1-1/4-8 UN8 (some Xylan blue in UNC, 7 or 6 TPI) | plain, Xylan blue, hot dip galvanised, zinc yellow, zinc plated, cadmium, Esso spec | 75 to 510 | 1 |
| B7 stud only | 1-3/8 inch | 1-3/8-8 UN8 | plain, Xylan blue, hot dip galvanised, zinc yellow, cadmium, Esso spec | 75 to 510 | 1 |
| B7 stud only | 1-1/2 inch | 1-1/2-8 UN8 (some Xylan blue in UNC, 7 or 6 TPI) | plain, Xylan blue, hot dip galvanised, cadmium, Esso spec | 100 to 510 | 1 |
| B7 stud only | 1-5/8 inch | 1-5/8-8 UN8 | plain, Xylan blue, zinc yellow, cadmium, Esso spec | 150 to 510 | 1 |
| B7 stud only | 1-3/4 inch | 1-3/4-8 UN8 | plain | 150 to 510 | 1 |
| B7 stud only | 1-7/8 inch | 1-7/8-8 UN8 | plain, zinc yellow, Esso spec | 330 to 510 | 1 |
| B7 stud only | 2 inch | 2-8 UN8 | plain | 355 to 510 | 1 |
| B8 Class 2, 304 stainless stud | |||||
| B8 Class 2, 304 stainless stud | 1/2 inch | 1/2-13 UNC | 304 stainless | 40 to 350 | 1 or 16 |
| B8 Class 2, 304 stainless stud | 5/8 inch | 5/8-11 UNC | 304 stainless | 50 to 350 | 16 |
| B8 Class 2, 304 stainless stud | 3/4 inch | 3/4-10 UNC | 304 stainless | 50 to 510 | 1 or 8 |
| B8 Class 2, 304 stainless stud | 7/8 inch | 7/8-9 UNC | 304 stainless | 75 to 510 | 1 or 4 |
| B8 Class 2, 304 stainless stud | 1 inch | 1-8 UNC | 304 stainless | 75 to 510 | 1 or 4 |
| B8 Class 2, 304 stainless stud | 1-1/8 inch | 1-1/8-8 UN8 | 304 stainless | 75 to 510 | 1 |
| B8 Class 2, 304 stainless stud | 1-1/4 inch | 1-1/4-8 UN8 | 304 stainless | 75 to 510 | 1 |
| B8 Class 2, 304 stainless stud | 1-3/8 inch | 1-3/8-8 UN8 | 304 stainless | 75 to 510 | 1 |
| B8 Class 2, 304 stainless stud | 1-1/2 inch | 1-1/2-8 UN8 | 304 stainless | 100 to 510 | 1 |
| B8M Class 2, 316 stainless stud | |||||
| B8M Class 2, 316 stainless stud | 1/2 inch | 1/2-13 UNC | 316 stainless | 50 to 510 | 1 or 16 |
| B8M Class 2, 316 stainless stud | 5/8 inch | 5/8-11 UNC | 316 stainless | 50 to 510 | 1 or 16 |
| B8M Class 2, 316 stainless stud | 3/4 inch | 3/4-10 UNC | 316 stainless | 50 to 510 | 1 or 8 |
| B8M Class 2, 316 stainless stud | 7/8 inch | 7/8-9 UNC | 316 stainless | 75 to 510 | 1 or 4 |
| B8M Class 2, 316 stainless stud | 1 inch | 1-8 UNC | 316 stainless | 75 to 510 | 1 or 4 |
| B8M Class 2, 316 stainless stud | 1-1/8 inch | 1-1/8-8 UN8 | 316 stainless | 75 to 510 | 1 |
| B8M Class 2, 316 stainless stud | 1-1/4 inch | 1-1/4-8 UN8 | 316 stainless | 75 to 510 | 1 |
| B8M Class 2, 316 stainless stud | 1-3/8 inch | 1-3/8-8 UN8 | 316 stainless | 75 to 510 | 1 |
| B8M Class 2, 316 stainless stud | 1-1/2 inch | 1-1/2-8 UN8 | 316 stainless | 100 to 510 | 1 |
Stud bolts for 150 and 300 lb flanges
Hobson's table for bolting BS and ASA pipe flanges gives the number, diameter and length of stud bolts per flange. Our lengths are in mm, so the mm column is a straight conversion of Hobson's inch length: pick the listed length your drawing, spec or engineer calls for. Select a row to open that stud diameter.
Number, diameter and length of stud bolts per flange from Hobson's petrochemical flange bolting table (150 and 300 lb, 1/16 inch raised face). The mm column is the inch length x 25.4, rounded. Hobson's table also covers 400, 600, 900, 1500 and 2500 lb flanges: ask us. Tap a number to show it in the selector above.
| Flange size | Class | Studs | Stud diameter | Stud length | Length in mm |
|---|---|---|---|---|---|
| Class 150 lb flange (1/16 inch raised face) | |||||
| 1/2 inch (15mm) | Class 150 lb flange (1/16 inch raised face) | 4 | 1/2 inch | 2-1/4 inch | about 57mm |
| 3/4 inch (20mm) | Class 150 lb flange (1/16 inch raised face) | 4 | 1/2 inch | 2-1/4 inch | about 57mm |
| 1 inch (25mm) | Class 150 lb flange (1/16 inch raised face) | 4 | 1/2 inch | 2-1/4 inch | about 57mm |
| 1-1/4 inch (32mm) | Class 150 lb flange (1/16 inch raised face) | 4 | 1/2 inch | 2-1/2 inch | about 64mm |
| 1-1/2 inch (40mm) | Class 150 lb flange (1/16 inch raised face) | 4 | 1/2 inch | 2-3/4 inch | about 70mm |
| 2 inch (50mm) | Class 150 lb flange (1/16 inch raised face) | 4 | 5/8 inch | 3 inch | about 76mm |
| 2-1/2 inch (65mm) | Class 150 lb flange (1/16 inch raised face) | 4 | 5/8 inch | 3-1/4 inch | about 83mm |
| 3 inch (80mm) | Class 150 lb flange (1/16 inch raised face) | 4 | 5/8 inch | 3-1/2 inch | about 89mm |
| 3-1/2 inch (90mm) | Class 150 lb flange (1/16 inch raised face) | 8 | 5/8 inch | 3-1/2 inch | about 89mm |
| 4 inch (100mm) | Class 150 lb flange (1/16 inch raised face) | 8 | 5/8 inch | 3-1/2 inch | about 89mm |
| 5 inch (125mm) | Class 150 lb flange (1/16 inch raised face) | 8 | 3/4 inch | 3-3/4 inch | about 95mm |
| 6 inch (150mm) | Class 150 lb flange (1/16 inch raised face) | 8 | 3/4 inch | 3-3/4 inch | about 95mm |
| 8 inch (200mm) | Class 150 lb flange (1/16 inch raised face) | 8 | 3/4 inch | 4 inch | about 102mm |
| 10 inch (250mm) | Class 150 lb flange (1/16 inch raised face) | 12 | 7/8 inch | 4-1/2 inch | about 114mm |
| 12 inch (300mm) | Class 150 lb flange (1/16 inch raised face) | 12 | 7/8 inch | 4-1/2 inch | about 114mm |
| 14 inch (350mm) | Class 150 lb flange (1/16 inch raised face) | 12 | 1 inch | 5 inch | about 127mm |
| 16 inch (400mm) | Class 150 lb flange (1/16 inch raised face) | 16 | 1 inch | 5-1/4 inch | about 133mm |
| 18 inch (450mm) | Class 150 lb flange (1/16 inch raised face) | 16 | 1-1/8 inch | 5-3/4 inch | about 146mm |
| 20 inch (500mm) | Class 150 lb flange (1/16 inch raised face) | 20 | 1-1/8 inch | 6 inch | about 152mm |
| 24 inch (600mm) | Class 150 lb flange (1/16 inch raised face) | 20 | 1-1/4 inch | 6-3/4 inch | about 171mm |
| 30 inch (750mm) | Class 150 lb flange (1/16 inch raised face) | 28 | 1-1/4 inch | 7-1/2 inch | about 190mm |
| 36 inch (900mm) | Class 150 lb flange (1/16 inch raised face) | 32 | 1-1/2 inch | 8-1/2 inch | about 216mm |
| Class 300 lb flange (1/16 inch raised face) | |||||
| 1/2 inch (15mm) | Class 300 lb flange (1/16 inch raised face) | 4 | 1/2 inch | 2-1/2 inch | about 64mm |
| 3/4 inch (20mm) | Class 300 lb flange (1/16 inch raised face) | 4 | 5/8 inch | 2-3/4 inch | about 70mm |
| 1 inch (25mm) | Class 300 lb flange (1/16 inch raised face) | 4 | 5/8 inch | 3 inch | about 76mm |
| 1-1/4 inch (32mm) | Class 300 lb flange (1/16 inch raised face) | 4 | 5/8 inch | 3 inch | about 76mm |
| 1-1/2 inch (40mm) | Class 300 lb flange (1/16 inch raised face) | 4 | 3/4 inch | 3-1/2 inch | about 89mm |
| 2 inch (50mm) | Class 300 lb flange (1/16 inch raised face) | 8 | 5/8 inch | 3-1/4 inch | about 83mm |
| 2-1/2 inch (65mm) | Class 300 lb flange (1/16 inch raised face) | 8 | 3/4 inch | 3-3/4 inch | about 95mm |
| 3 inch (80mm) | Class 300 lb flange (1/16 inch raised face) | 8 | 3/4 inch | 4 inch | about 102mm |
| 3-1/2 inch (90mm) | Class 300 lb flange (1/16 inch raised face) | 8 | 3/4 inch | 4-1/4 inch | about 108mm |
| 4 inch (100mm) | Class 300 lb flange (1/16 inch raised face) | 8 | 3/4 inch | 4-1/4 inch | about 108mm |
| 5 inch (125mm) | Class 300 lb flange (1/16 inch raised face) | 8 | 3/4 inch | 4-1/2 inch | about 114mm |
| 6 inch (150mm) | Class 300 lb flange (1/16 inch raised face) | 12 | 3/4 inch | 4-3/4 inch | about 121mm |
| 8 inch (200mm) | Class 300 lb flange (1/16 inch raised face) | 12 | 7/8 inch | 5-1/4 inch | about 133mm |
| 10 inch (250mm) | Class 300 lb flange (1/16 inch raised face) | 16 | 1 inch | 6 inch | about 152mm |
| 12 inch (300mm) | Class 300 lb flange (1/16 inch raised face) | 16 | 1-1/8 inch | 6-1/2 inch | about 165mm |
| 14 inch (350mm) | Class 300 lb flange (1/16 inch raised face) | 20 | 1-1/8 inch | 6-3/4 inch | about 171mm |
| 16 inch (400mm) | Class 300 lb flange (1/16 inch raised face) | 20 | 1-1/4 inch | 7-1/4 inch | about 184mm |
| 18 inch (450mm) | Class 300 lb flange (1/16 inch raised face) | 24 | 1-1/4 inch | 7-1/2 inch | about 190mm |
| 20 inch (500mm) | Class 300 lb flange (1/16 inch raised face) | 24 | 1-1/4 inch | 8 inch | about 203mm |
| 24 inch (600mm) | Class 300 lb flange (1/16 inch raised face) | 24 | 1-1/2 inch | 9 inch | about 229mm |
| 30 inch (750mm) | Class 300 lb flange (1/16 inch raised face) | 28 | 1-3/4 inch | 11-1/2 inch | about 292mm |
| 36 inch (900mm) | Class 300 lb flange (1/16 inch raised face) | 32 | 2 inch | 12-3/4 inch | about 324mm |
Stud bolt coatings: Xylan, galvanised, cadmium and more
From Hobson's petrochemical coating table and coating benefits sheet. Select a row to open that coating.
- Xylan blue: Hobson lists the thread lubricant as part of the fastener, greatly reduced friction for evenly tensioned studs, less than 15% red rust after 1,488 hours salt spray, easy nut removal in maintenance, make-up torque reduced by as much as 70%, hydrogen embrittlement avoided, and nuts coated internally.
- Hobson recommends hot dip galvanising for long-term outdoor use, and zinc plated and zinc yellow for indoor and non-corrosive environments only.
Coating, description and corrosion resistance rating from Hobson's petrochemical coatings table and Xylan 1424 sheet. Stainless B8 and B8M studs are uncoated. Tap a number to show it in the selector above.
| Coating | What Hobson says | Corrosion resistance | Available on |
|---|---|---|---|
| Plain | No coating, supplied lightly oiled to inhibit rust in the packaging and help installation | Not rated | B7 studs and kits |
| Xylan blue | Proprietary coating, 25 micron, high corrosion resistance; low friction for evenly tensioned studs; nuts coated internally; operating temperature -40 to 205°C | High | B7 studs and kits |
| Hot dip galvanised | ASTM A153/M, 53 micron, recommended for long-term outdoor use | High | B7 studs and kits |
| Cadmium | ASTM B766, 12 micron; Hobson lists it for high-temperature and marine use and as a bonding surface for paint | Moderate | B7 studs |
| Zinc yellow passivate | ISO 4042, 5 micron, recommended for indoor and non-corrosive environments | Low | B7 studs and kits |
| Zinc plated | ISO 4042, 5 micron, recommended for indoor and non-corrosive environments | Low | B7 studs |
| Zinc plated and Xylan green | Xylan 1424 series green over zinc; Hobson gives the same Xylan benefits for blue and green | Not listed | A few B7 studs, 5/8 to 7/8 inch |
| Esso spec (IZSC) | Hobson code IZSC; Hobson publishes no description of this coating, so check it against your project spec | Not listed | B7 studs |
Stud bolt proof load and tensile load
Hobson's studbolt property sheet gives minimum proof loads and minimum ultimate tensile loads in lbf, worked from the stress area and the grade's minimum stresses. These are test values for the stud material, not working loads or a rating for a flanged joint. The joint design, gasket and bolt load come from the engineer.
Minimum loads in lbf from Hobson's petrochemical studbolt properties sheet, with kN in brackets (lbf x 0.00445). Sizes 1-1/8 inch and over are for 8 UN thread; Hobson gives no figures for the few UNC studs in those sizes, and none for B8 or B8M over 1-1/2 inch. Tap a number to show it in the selector above.
| Size | Thread | Stress area (sq in) | B7 proof load | B7 min tensile load | B8 Class 2 proof load | B8M Class 2 proof load |
|---|---|---|---|---|---|---|
| 1/2 inch | 1/2-13 UNC | 0.142 | 14,900 (66.3) | 17,738 (78.9) | 14,190 (63.1) | 13,622 (60.6) |
| 5/8 inch | 5/8-11 UNC | 0.226 | 23,730 (105.6) | 28,250 (125.7) | 22,600 (100.5) | 21,696 (96.5) |
| 3/4 inch | 3/4-10 UNC | 0.334 | 35,070 (156.0) | 41,750 (185.7) | 33,400 (148.6) | 32,064 (142.6) |
| 7/8 inch | 7/8-9 UNC | 0.462 | 48,510 (215.8) | 57,750 (256.9) | 36,960 (164.4) | 36,960 (164.4) |
| 1 inch | 1-8 UNC | 0.606 | 63,630 (283.0) | 75,750 (337.0) | 48,480 (215.6) | 48,480 (215.6) |
| 1-1/8 inch | 1-1/8-8 UN8 | 0.790 | 82,950 (369.0) | 98,750 (439.3) | 51,350 (228.4) | 51,350 (228.4) |
| 1-1/4 inch | 1-1/4-8 UN8 | 1.000 | 105,000 (467.1) | 125,000 (556.0) | 65,000 (289.1) | 65,000 (289.1) |
| 1-3/8 inch | 1-3/8-8 UN8 | 1.233 | 129,465 (575.9) | 154,125 (685.6) | 61,650 (274.2) | 61,650 (274.2) |
| 1-1/2 inch | 1-1/2-8 UN8 | 1.492 | 156,660 (696.9) | 186,500 (829.6) | 74,600 (331.8) | 74,600 (331.8) |
| 1-5/8 inch | 1-5/8-8 UN8 | 1.780 | 186,900 (831.4) | 222,500 (989.7) | Not listed | Not listed |
| 1-3/4 inch | 1-3/4-8 UN8 | 2.080 | 218,400 (971.5) | 260,000 (1156.5) | Not listed | Not listed |
| 1-7/8 inch | 1-7/8-8 UN8 | 2.410 | 253,050 (1125.6) | 301,250 (1340.0) | Not listed | Not listed |
| 2 inch | 2-8 UN8 | 2.770 | 290,850 (1293.8) | 346,250 (1540.2) | Not listed | Not listed |
Stud bolt tightening torque (a guide only)
Hobson's petrochemical torque guide is worked with a k factor of 0.2 (burr-free threads with a light oil coating) and an induced load of 65% of yield stress. Hobson states that flange stud tightening can really only be specified by engineers in the industry, because flange types, gaskets and temperatures vary; the table is only a guide where studs clamp metal faces directly together, like normal high tensile bolting.
It does not fit coated or dry stainless studs as written: Xylan reduces make-up torque by as much as 70%, and Hobson notes stainless that is not lubricated or coated often seizes and can show k factors over 0.35.
Tightening torque in lbf.ft from Hobson's petrochemical stud bolt tightening guide (k = 0.2, 65% of yield), Nm in brackets (lbf.ft x 1.356). For lightly oiled B7, B8 Class 2 and B8M Class 2 studs clamping metal to metal, not for gasketed flanges. Tap a number to show it in the selector above.
| Size | Thread | B7 | B8 Class 2 | B8M Class 2 |
|---|---|---|---|---|
| 1/2 inch | 1/2-13 UNC | 81 (110) | 77 (104) | 74 (100) |
| 5/8 inch | 5/8-11 UNC | 161 (218) | 153 (207) | 147 (199) |
| 3/4 inch | 3/4-10 UNC | 285 (386) | 271 (367) | 261 (354) |
| 7/8 inch | 7/8-9 UNC | 460 (624) | 350 (475) | 350 (475) |
| 1 inch | 1-8 UNC | 689 (934) | 525 (712) | 525 (712) |
| 1-1/8 inch | 1-1/8-8 UN8 | 1,011 (1,371) | 626 (849) | 626 (849) |
| 1-1/4 inch | 1-1/4-8 UN8 | 1,422 (1,928) | 880 (1,193) | 880 (1,193) |
| 1-3/8 inch | 1-3/8-8 UN8 | 1,928 (2,614) | 918 (1,245) | 918 (1,245) |
| 1-1/2 inch | 1-1/2-8 UN8 | 2,546 (3,452) | 1,212 (1,643) | 1,212 (1,643) |
| 1-5/8 inch | 1-5/8-8 UN8 | 3,290 (4,461) | Not listed | Not listed |
| 1-3/4 inch | 1-3/4-8 UN8 | 4,141 (5,614) | Not listed | Not listed |
| 1-7/8 inch | 1-7/8-8 UN8 | 5,140 (6,969) | Not listed | Not listed |
| 2 inch | 2-8 UN8 | 6,302 (8,544) | Not listed | Not listed |
Stud and nut kits
A B7 stud and nut kit is a Grade B7 stud with two ASTM A194 Grade 2H heavy hex nuts, in the same coating: plain, Xylan blue, hot dip galvanised or zinc yellow, from 1/2 to 1-5/8 inch. For stainless studs, or a different nut grade or coating, add nuts from our heavy hex nut range.
Stud bolts in Adelaide
Allmat supplies stud bolts, stud and nut kits and heavy hex nuts to maintenance crews, fabricators, pipe fitters and process plant across Adelaide and South Australia. Send us the grade, size, length, coating and quantity for each flange and we will price the lot.
Stud bolts and nuts for the flange job
B7 stud bolts, stud and nut kits, B8 and B8M stainless studs and ASTM A194 heavy hex nuts are available to order from Allmat for maintenance crews, fabricators, pipe fitters, mining and process plant across Adelaide and South Australia. Order through Allmat, we pick and pack it, then click and collect from the Allmat yard or have it delivered to site.
Goes with
Questions
What is a stud bolt?
A headless stud threaded along its length with a nut on each end. Hobson notes stud bolts are most widely used for flange bolting on piping carrying fluids over a range of temperatures and pressures.
What is the difference between B7 and B8M stud bolts?
B7 is AISI 4140 chrome-moly alloy steel (minimum tensile 860 MPa). Hobson's sheet gives -100 to 400°C for B7 and L7 together; L7 is the low-temperature grade, impact tested at -101°C, so for sub-zero service specify L7 (ask us). The B7 kits' 2H nuts are rated 0 to 450°C, so a kit is limited to 0°C and above. B8M Class 2 is 316 stainless (minimum tensile 760 down to 620 MPa as the size grows, -250 to 600°C). B8 Class 2 is the 304 stainless equivalent.
What nuts go on B7 stud bolts?
ASTM A194 Grade 2H heavy hex nuts. Our B7 kits come with two 2H nuts in the same coating. Other nut grades are on our heavy hex nut page.
What stud bolts does a 4 inch 150 lb flange take?
Hobson's flange table gives 8 studs of 5/8 inch diameter, 3-1/2 inches long (about 89mm), for a 4 inch (100mm) 150 lb flange with a 1/16 inch raised face. A 4 inch 300 lb flange takes 8 studs of 3/4 inch, 4-1/4 inches long. Pick the listed mm length your drawing or spec calls for.
What is Xylan coating on stud bolts?
A proprietary low friction coating (Hobson lists the Xylan 1424 series in blue and green): 25 micron, high corrosion resistance, under 15% red rust after 1,488 hours salt spray, make-up torque reduced by as much as 70%, nuts coated internally, operating temperature -40 to 205°C.
What is the difference between UNC and 8 UN stud bolts?
UNC is the coarse series (13 threads per inch at 1/2 inch down to 8 at 1 inch). From 1-1/8 inch up, flange studs use 8 UN: eight threads per inch at every size (a few Xylan blue studs are UNC: check the thread before ordering nuts). Match the nuts to the same thread.
What torque for B7 stud bolts?
Hobson's guide gives, for example, 161 lbf.ft (about 218 Nm) for a 5/8 inch B7 stud at k = 0.2 and 65% of yield, but states it is only a guide for metal to metal joints: flange stud tightening must be specified by the engineer. Xylan coated studs need much less (Hobson: up to 70% less make-up torque). For other coatings the guide figures do not apply as written; the engineer sets the torque.
Where can I buy stud bolts in Adelaide?
Order through Allmat. Order ahead by phone on 1300 03 03 63 or send your list for a quote, then click and collect from 25 Kapara Road, Gillman, or have them delivered to site.
Stud Bolt: sizes and finishes we supply
6,065 lines by finish. Pick one above for its product code, pack sizes and dimensions.
| Finish | Sizes | Lengths | Lines |
|---|---|---|---|
| Steel | 1/2, 5/8, 3/4, 7/8, 1, 1-1/8, 1-1/4, 1-3/8, 1-1/2, 1-5/8, 1-3/4, 1-7/8, 2 | 50 to 600mm (94 lengths) | 1553 |
| Xylan Blue | 1/2, 5/8, 3/4, 7/8, 1, 1-1/8, 1-1/4, 1-3/8, 1-1/2, 1-5/8 | 45 to 510mm (87 lengths) | 1156 |
| Galvanised | 1/2, 5/8, 3/4, 7/8, 1, 1-1/8, 1-1/4, 1-3/8, 1-1/2 | 50 to 440mm (65 lengths) | 901 |
| 316 Stainless | 1/2, 5/8, 3/4, 7/8, 1, 1-1/8, 1-1/4, 1-3/8, 1-1/2 | 50 to 510mm (93 lengths) | 802 |
| 304 Stainless | 1/2, 5/8, 3/4, 7/8, 1, 1-1/8, 1-1/4, 1-3/8, 1-1/2 | 40 to 510mm (94 lengths) | 739 |
| Zinc Yellow Passivate | 1/2, 5/8, 3/4, 7/8, 1, 1-1/8, 1-1/4, 1-3/8, 1-5/8, 1-7/8 | 50 to 385mm (61 lengths) | 339 |
| Cadmium | 1/2, 5/8, 3/4, 7/8, 1, 1-1/8, 1-1/4, 1-3/8, 1-1/2, 1-5/8 | 45 to 350mm (61 lengths) | 257 |
| Zinc Plated | 1/2, 5/8, 3/4, 7/8, 1, 1-1/8, 1-1/4 | 50 to 350mm (55 lengths) | 196 |
| Esso Spec | 1/2, 5/8, 3/4, 7/8, 1, 1-1/8, 1-1/4, 1-3/8, 1-1/2, 1-5/8, 1-7/8 | 65 to 350mm (47 lengths) | 117 |
| Zinc Plated & Xylan Green | 5/8, 3/4, 7/8 | 90, 100, 110, 115, 160mm | 5 |
Data sheets and documents
The documents for the product you choose are listed with the selector above. Here is every Stud Bolt document from Hobson Engineering.
All Stud Bolt documents (11)
Data sheets and technical data (8)
- Product Finish Comparison
- Petrochemical - Coating Application and Benefits
- Petrochemical - Chemical and Mechanical Properties Bolts
- Petrochemical - Chemical and Mechanical Properties Nuts
- Petrochemical Details for Bolting BS and ASA Pipe Flanges Technical Data
- Petrochemical Studbolt Loads
- Petrochemical Studbolt Properties
- Petrochemical Tightening Torque - Guide to Tightening
Did You Know flyers (1)
Guides and articles (2)
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