ASTM A193 A194 Alloy Steel Stud Bolts for High-Temperature Pressure Vessel & Piping Flanges
Full-thread and double-end stud bolts with mating heavy hex nuts, manufactured for high-temperature, high-pressure, and cryogenic service in oil & gas, petrochemical, power generation, and industrial plant applications. Material traceability guaranteed with Mill Test Reports per EN 10204 Type 3.1.
Applications
- Pressure vessel & heat exchanger flange bolting (ASME VIII / EN 13445)
- Piping system flanges (ASME B16.5 / B16.47)
- Refinery process units (hydrocracking, catalytic reforming)
- LNG & cryogenic storage tank connections
- Valve bonnet bolting
- Marine tank & piping systems
- Power plant boiler & steam line flanges
Product Range
| Stud Grade | Mating Nut | Material | Temp Range | Size | Key Use |
|---|---|---|---|---|---|
| A193 B7 | A194 2H | Cr-Mo alloy steel | –45°C to +538°C | M12 – M100 (½"–4") | General high-temp service |
| A193 B7M | A194 2HM | Cr-Mo (hardness limited) | –45°C to +538°C | M12 – M100 | NACE sour service (H₂S) |
| A193 B16 | A194 4 / 7 | Cr-Mo-V alloy | –45°C to +595°C | M12 – M100 | Extended high-temp |
| A193 B8 CL2 | A194 8 | AISI 304 SS | –200°C to +815°C | M12 – M76 (½"–3") | Corrosive + high temp |
| A193 B8M CL2 | A194 8M | AISI 316 SS | –200°C to +815°C | M12 – M76 | Chloride / marine corrosion |
| A320 L7 | A194 4 / 7L | Cr-Mo (impact tested) | –101°C to +345°C | M12 – M76 | Cryogenic / low-temp |
Mechanical Properties (Key Grades)
| Grade | UTS min (MPa) | Yield min (MPa) | Elongation min (%) | Hardness (HRC) |
|---|---|---|---|---|
| B7 (≤M25 / 1") | 860 | 725 | 16 | 25–32 |
| B7 (>M25 / 1"–2½") | 825 | 655 | 16 | 22–30 |
| B7M | 690 | 550 | 16 | Max 22 |
| B16 | 760 | 585 | 16 | 25–32 |
| B8 CL2 | 860 | 690 | 12 | — |
| A320 L7 | 860 | 725 | 16 | 25–32 |
Values per ASTM A193 / A194 (latest edition). Always verify against project specification.
Standards Coverage
| Standard | Scope |
|---|---|
| ASTM A193 | Alloy-steel and stainless steel bolting for high-temperature service |
| ASTM A194 | Carbon & alloy steel nuts for high-pressure/high-temp service |
| ASTM A320 | Alloy-steel bolting for low-temperature service |
| ASME B16.5 | Pipe flanges and flanged fittings (NPS ½"–24") |
| ASME B16.47 | Large diameter steel flanges (NPS 26"–60") |
| GB/T 901 | Double-end stud bolts (Chinese national standard) |
| NACE MR0175 / ISO 15156 | Sour service — H₂S resistance requirements |
Coating Options
- PTFE (Xylan 1014 / 1052) — standard for offshore & chemical plant, low friction coefficient
- Hot-dip galvanized (ASTM A153) — for non-critical temp applications
- Zinc-nickel plating — superior corrosion resistance, 1000H+ salt spray
- Cadmium plated — aerospace/marine (restricted due to environmental regulations)
- Plain (oiled) — for stainless steel or customer-painted application
Quality Assurance
- Heat chemistry & mechanical testing — MTC per EN 10204 Type 3.1
- Hardness testing per lot (Brinell / Rockwell per ASTM A193)
- Impact testing per heat (Charpy V-notch for A320, B7M at –46°C)
- NACE MR0175 compliance verification for sour service grades
- Thread inspection: GO/NO-GO gauge, pitch diameter tolerance per ASME B1.13M
- Surface & coating inspection
- Third-party witness testing: SGS / BV / TÜV / LRS surveyor
Why Source From SINOFASTENER
SINOFASTENER is an integrated manufacturer and trader. Our capability is not limited to this catalog — exotic alloys, non-standard lengths, special thread forms, project-specific drawings: if your project requires it, we manufacture and supply it.
- In-house laboratory — spectrometry, 600 kN tensile machine, Charpy impact, hardness — full ASTM testing capability
- Full material traceability — heat number stamped on each stud, MTC with heat chemistry + mechanicals
- M12–M100 range — complete coverage from instrument bolts to large vessel flanges
- Custom lengths — cut to your flange dimension, thread both ends or full-thread
- Own packaging factory — bundled by size/grade, tagged with heat number, crate/pallet per spec
- EU trade advantage:
- Anti-dumping duty: 39.6% (TARIC C824) vs. 86.5% (C999)
- CBAM measured carbon: 1.698 tCO₂/t vs. EU default 7.013 — 93.5% lower
Packaging & Delivery
- Studs bundled by size & grade, heat number tagged
- Nuts & washers in cartons, matched to stud lots
- Anti-rust: VCI paper + PE bag or oil coating
- Export carton + pallet, or fumigated wooden crate (ISPM-15)
- Lead time: 15–25 days for standard grades (B7/2H), 25–35 days for special alloys
Request a Quote
Send your flange schedule or stud bolt list. We return pricing with MTC scope, lead time, and coating options within 24 hours.
Email:sales@sinofastener.com
Frequently Asked Questions
Q1: What is the difference between ASTM A193 B7 and B7M stud bolts?
B7 is the standard Cr-Mo alloy steel grade for high-temperature service up to 538°C. B7M has restricted hardness (max 22 HRC vs. 25–32 HRC for B7) and is specifically designed for NACE sour service environments containing H₂S. B7M also requires Charpy impact testing at –46°C. Both grades use mating nuts A194 2H (B7) or 2HM (B7M). For sour service applications (refineries, gas processing), B7M is mandatory per NACE MR0175 / ISO 15156.
Q2: Do you provide Mill Test Certificates with stud bolts?
Yes. Every stud bolt shipment includes Mill Test Certificate (MTC) per EN 10204 Type 3.1, showing: heat chemistry (C, Mn, Si, P, S, Cr, Mo), mechanical properties (UTS, yield, elongation, reduction of area), hardness test results, and impact test data (for B7M, B16, B8, A320 grades). Each stud is stamped with heat number for full traceability. Third-party witness testing (SGS / BV / TÜV / LRS) is available upon request.
Q3: Can you supply stud bolts for cryogenic LNG applications?
Yes. We supply A320 L7 stud bolts with A194 4 or 7L nuts for cryogenic service down to –101°C. A320 L7 is Cr-Mo alloy steel with mandatory Charpy impact testing at the specified low temperature. We also supply austenitic stainless steel grades (B8/B8M CL2) for temperatures down to –200°C. All cryogenic stud bolts undergo impact testing per heat, with test results included in MTC.
Q4: What coating options are available for stud bolts?
Standard coatings include: PTFE (Xylan 1014/1052) — preferred for offshore and chemical plants, low friction coefficient, excellent corrosion resistance; Hot-dip galvanized (ASTM A153) — for non-critical temperature applications; Zinc-nickel plating — superior corrosion resistance (1000H+ salt spray); Plain (oiled) — for stainless steel or customer-painted applications. Coating selection depends on service environment, temperature, and flange gasket compatibility.
Q5: What size range can you supply?
We manufacture stud bolts from M12 to M100 (½"to 4"). For sizes beyond M100 or special thread forms (ACME, buttress), contact us with your specification. We can supply full-thread studs or double-end studs (GB/T 901) with custom lengths cut to your flange dimensions. Mating nuts and washers are supplied as matched sets, tagged with corresponding heat numbers.
For complete product catalog and company information, visit www.sinofastener.com
