U-Bolts
U-bolts for pipe support and clamping, sized to the pipe OD, in carbon and stainless grades with coatings.
Technical specification
| Parameter | Specification |
|---|---|
| Product | Bolting & fasteners (stud bolts, hex bolts, nuts, washers, anchor & U-bolts) |
| Dimensional standard | ASME B18.2.1 (bolts) · B18.2.2 (nuts) · B18.22.1 (washers) |
| Threads | UNC / 8-UN (ASME B1.1) · metric ISO 261 · NPT B1.20.1 |
| Class / grade | A193 B7/B16 · A320 L7 · A194 2H/7/8 · A2/A4 |
| Size range | M6 – M64 · 1/4" – 4" |
| Material specifications | ASTM A193, A194, A320, A307, A563, F593, F594 |
| Coatings | PTFE / xylan · hot-dip galvanised · zinc · cadmium |
| Documentation | EN 10204 3.1 / 3.2, PMI, TPI |
How it is made
Bolting is hot- or cold-forged and thread-rolled from bar, then heat treated to the grade — alloy grades (B7, L7, B16) quenched & tempered; austenitic stainless (B8/B8M) solution treated (Class 1) or strain-hardened (Class 2). Nuts are hot-forged or machined and heat treated/hardness-controlled to A194. Threads are cut or rolled to ASME B1.1 (UN) or ISO 261 (metric). Bolt and nut grades are matched for strength and hardness, and coatings (PTFE, hot-dip galvanising, zinc) are applied with the friction factor stated where torque control matters.
Grades & materials
All grades supplied for this product family, with representative chemistry. Exact grade, class and condition are confirmed per order.
| Material family | Grades | UNS | Standard | Service |
|---|---|---|---|---|
| Alloy bolting | A193 B7 / B7M / B16 | — | ASTM A193 | General / high-temp |
| Low-temp bolting | A320 L7 / L7M / L43 | — | ASTM A320 | Low temperature |
| Austenitic stainless | A193 B8 / B8M Cl.1 & Cl.2 (304/316) | — | ASTM A193 | Corrosion |
| Carbon bolting | A307 Gr.A / Gr.B | — | ASTM A307 | General fixing |
| Nuts | A194 2H / 2HM / 4 / 7 / 7M / 8 / 8M | — | ASTM A194 | Matched to bolt |
| Stainless fasteners | F593 / F594 Group 1–3 (A2/A4) | — | ASTM F593 / F594 | Corrosion |
| Nickel alloys | B564 / B637 (Monel, 625, 718) | — | ASTM | Severe corrosion |
Chemical composition (representative)
| Grade | C | Mn | Cr | Ni | Mo | Other |
|---|---|---|---|---|---|---|
| A193 B7 (AISI 4140) | 0.37–0.49 | 0.65–1.10 | 0.75–1.20 | — | 0.15–0.25 | — |
| A193 B16 | 0.36–0.47 | 0.45–0.70 | 0.80–1.15 | — | 0.50–0.65 | V 0.25–0.35 |
| A320 L7 (AISI 4140) | 0.37–0.49 | 0.65–1.10 | 0.75–1.20 | — | 0.15–0.25 | Charpy −101 °C |
| A193 B8 (304) | 0.08 max | 2.00 max | 18.0–20.0 | 8.0–11.0 | — | — |
| A193 B8M (316) | 0.08 max | 2.00 max | 16.0–18.0 | 10.0–14.0 | 2.0–3.0 | — |
Standards & specifications
Dimensional & thread
- ASME B18.2.1 / B18.2.2 hex bolts & nuts
- ASME B1.1 UN / 8-UN threads; ISO 261 metric
- ASME B18.22.1 washers
- Metric DIN 931/934, ISO 4014/4032
Product & service
- ASTM A193/A194 bolting & nuts
- ASTM A320 low-temperature bolting
- ASTM A307/A563/F593/F594
- NACE MR0175 / ISO 15156 sour service
Mechanical properties (representative grades)
Representative grades — full MTC values on request. Values are ASTM/ASME specification minima or ranges at room temperature.
| Grade / class | Type | Tensile min (MPa) | Yield min (MPa) | Elong min (%) | Hardness |
|---|---|---|---|---|---|
| A193 B7 (≤2½") | Alloy stud/bolt | 860 | 720 | 16 | ≤ 35 HRC |
| A193 B7 (2⅝–4") | Alloy stud/bolt | 795 | 655 | 16 | ≤ 35 HRC |
| A193 B7M | Alloy (sour) | 690 | 550 | 18 | ≤ 235 HBW |
| A193 B16 (≤2½") | Alloy high-temp | 860 | 725 | 18 | ≤ 35 HRC |
| A320 L7 (≤2½") | Low-temp alloy | 860 | 720 | 16 | ≤ 35 HRC |
| A320 L7M | Low-temp (sour) | 690 | 550 | 18 | ≤ 235 HBW |
| A320 L43 | Low-temp alloy | 860 | 720 | 16 | ≤ 35 HRC |
| A193 B8 Cl.1 (304 ST) | Austenitic SS | 515 | 205 | 30 | ≤ 223 HBW |
| A193 B8 Cl.2 (304 SH, ≤¾") | Austenitic SS | 860 | 690 | 12 | — |
| A193 B8M Cl.1 (316 ST) | Austenitic SS | 515 | 205 | 30 | ≤ 223 HBW |
| A193 B8M Cl.2 (316 SH, ≤¾") | Austenitic SS | 655 | 450 | 15 | — |
| A307 Gr.A / B | Carbon | 414 / 414–690 | — | — | — |
| A194 2H (nut) | Carbon/alloy nut | — | — | — | 24–38 HRC |
| A194 2HM (nut) | Alloy nut (sour) | — | — | — | ≥ 159 HBW, ≤ 235 HBW |
| A194 7 / 7M (nut) | Alloy nut | — | — | — | ≥ 159 HBW |
| A194 8 / 8M (nut) | Austenitic nut | — | — | — | ≤ 223 HBW |
Testing, inspection & documentation
| Test / document | Detail |
|---|---|
| Chemical / PMI | Composition to the ASTM spec; PMI on alloy/stainless grades |
| Tensile / proof load | Tensile, yield/proof load and elongation per grade |
| Hardness | Rockwell/Brinell; NACE MR0175 hardness for sour service (B7M/L7M ≤ 235 HBW) |
| Impact (Charpy) | A320 L7/L43 at −101 °C (and as specified) |
| Coating | Coating thickness & adhesion; friction factor where torque-controlled |
| Certification | EN 10204 3.1 as standard; 3.2 with third-party endorsement |
Applications & industries served
Available forms, sizes & range
Provide with your enquiry
- Type, size (metric/imperial) and length.
- Material grade and nut/washer pairing.
- Coating and thread form.
And the commercial detail
- Standard and edition.
- Required tests (PMI, hardness, Charpy, NACE).
- Quantity and any drawing or BOQ.
Frequently asked questions
How is a U-bolt sized?
By the pipe outside diameter (not NPS alone) and the required thread length — give the pipe OD and grade and we supply the correct U-bolt with nuts.
What materials are available?
Carbon steel (zinc or hot-dip galvanised) and stainless (304/316), with rubber-lined options where needed.
Do they come with nuts?
Yes — U-bolts are supplied with matched nuts and washers.
Request a quote
Send your requirement to Sagiant Piping Industries and our team responds with grade, material selection, availability and pricing for u-bolts. Attach a BOQ, line list or drawing for a faster, more accurate quotation.
- Fast RFQ response with grade & material-selection support
- EN 10204 3.1 / 3.2 certification, PMI & third-party inspection
- BOQ & line-list project supply — India & export
Mechanical & chemical values shown are ASTM/ASME specification figures; certified heat-specific values appear on the MTC. Availability is confirmed with the quotation.
