Question 1

What ASTM grades do LOKRON stud bolts cover?

Accepted Answer

LOKRON stocks ASTM A193 B7, B7M, B16, B8 Class 1 & 2, B8M Class 1 & 2; ASTM A320 L7 and L7M for cryogenic service; and ASTM A194 2H, 2HM, 7, 8, 8M heavy hex nuts. All PED-scope grades are covered under our CE certificate (No. MUE-008-002-2026).

Question 2

Are LOKRON fasteners PED 2014/68/EU certified?

Accepted Answer

Yes. LOKRON holds PED 2014/68/EU Certificate No. MUE-008-002-2026, issued by C&P srl (EU Notified Body 0681), covering ASTM A193/A320/A194 grades for pressure equipment applications. Certificate valid to February 2029.

Question 3

What documentation is included with each shipment?

Accepted Answer

Every LOKRON shipment includes an EN 10204 Type 3.1 Material Test Report (MTR), dimensional inspection certificate, and — for EU-bound shipments — a PED Declaration of Conformity. NACE MR0175/ISO 15156 compliance letters are available for sour-service grades (B7M, L7M).

Question 4

Can LOKRON supply special alloys and non-standard thread forms?

Accepted Answer

Yes. Our custom manufacturing covers Duplex 2205, Super-Duplex 2507, Inconel 625/718, Hastelloy C276, and Monel K-500. Thread forms including UNF, BSPP, API, Acme, and metric fine threads are produced to drawing with ±0.01mm CNC tolerance.

Question 5

What is the difference between ASTM A193 B7 and B7M?

Accepted Answer

B7 and B7M are the same chromium-molybdenum alloy (4140/4142) but with different heat treatment. B7M is tempered to a reduced maximum hardness of 22 HRC (237 HB) to comply with NACE MR0175/ISO 15156 sour-service requirements where hydrogen sulfide (H₂S) is present.

Question 6

What is the minimum order quantity for standard stud bolts?

Accepted Answer

There is no minimum order quantity for standard ASTM A193 B7/B8 and A194 2H stud bolt sets — we supply from single-flange emergency quantities to full-container volume. Custom alloy or non-standard items have a minimum of 1 piece for prototypes. Contact us with your quantity and we will confirm lead time and pricing within 24 hours.

Question 7

What is the lead time for ASTM A193 B7 stud bolts?

Accepted Answer

Standard ASTM A193 B7 stud bolts in common sizes (M16–M36) are typically available ex-stock or within 5–10 working days with 3.1 MTR. Special sizes, exotic grades (B16, B8M Class 2), or large-volume orders require 3–6 weeks. Custom alloy items (Inconel, Duplex) require 4–8 weeks from material procurement.

Question 8

Can LOKRON supply complete flange bolt sets with nuts and washers?

Accepted Answer

Yes. LOKRON supplies complete flange bolt packages: stud bolts + matched heavy hex nuts (e.g., A193 B7 + A194 2H) for ASME B16.5 Class 150 through 2500 flanges. Sets are supplied per ASME PCC-1 guidelines with a single 3.1 MTR covering both studs and nuts. Flat washers and spring washers can be added on request.

Question 9

Does LOKRON supply EN 10204 Type 3.2 material test reports?

Accepted Answer

Yes. EN 10204 Type 3.2 (dual-witnessed, third-party inspector) MTRs are available on request for critical applications requiring independent verification. Type 3.1 is standard on all LOKRON shipments. Third-party inspection by SGS, Bureau Veritas, or Intertek can be arranged for any order.

Question 10

What surface treatments are available for stud bolts used in offshore or subsea applications?

Accepted Answer

For offshore and subsea applications, LOKRON offers hot-dip galvanising to ASTM A153 (85–100 μm zinc coating), PTFE/Xylan fluoropolymer coating (reduces galling, K-factor 0.10–0.12), Dacromet (zinc-aluminium flake coating, no hydrogen embrittlement risk), and electroless nickel plating. For subsea connectors, we recommend Xylan 1424 or Molykote-based coatings — contact our technical team for application-specific selection.

Question 11

Are ASTM A193 B7 stud bolts suitable for sour gas (H₂S) service?

Accepted Answer

No — standard B7 (maximum 35 HRC hardness) is not approved for sour service. Where hydrogen sulfide partial pressure exceeds 0.0003 MPa (0.05 psia) per NACE MR0175/ISO 15156, B7M must be specified instead. B7M is the same 4140/4142 Cr-Mo alloy but heat-treated to a maximum of 22 HRC (237 HB), satisfying NACE requirements. LOKRON supplies B7M with full NACE compliance documentation.

Question 12

What is the difference between ASTM A194 Grade 2H and Grade 7 heavy hex nuts?

Accepted Answer

ASTM A194 2H nuts (carbon steel, quenched and tempered, 248–327 HB hardness) are the standard pairing for A193 B7 stud bolts in high-temperature service. Grade 7 nuts (same Cr-Mo alloy as B7, minimum 255 HB) are specified for elevated-temperature applications and are the correct pairing for A193 B16 stud bolts above 400°C. Mixing grade pairings — for example, using A563 nuts with B7 studs — risks thread stripping under full preload.

Question 13

Does LOKRON ship internationally and what are the typical shipping terms?

Accepted Answer

Yes — LOKRON ships to Europe, the Middle East, Southeast Asia, Australia, and North America. Standard shipping terms are FOB Suzhou or CIF destination port. All export orders include commercial invoice, packing list, certificate of origin (Form E for ASEAN, EUR.1 for EU), and EN 10204 3.1 MTRs. Dangerous goods classification does not apply to standard fasteners. Typical ocean freight transit: UK/Europe 25–35 days, Middle East 20–28 days, Australia 18–25 days.

Question 14

Can LOKRON supply API 20E or API 20F compliant bolting?

Accepted Answer

Yes. LOKRON supplies bolting compliant with API 20E (alloy and carbon steel) and API 20F (corrosion-resistant alloys) at BSL-1 through BSL-3 qualification levels. For oil and gas wellhead, BOP, and subsea applications, we can provide full heat treatment records, piece-level serialisation, Charpy impact certificates, and third-party inspection witness by SGS or Bureau Veritas. Contact our technical team with BSL level, grade (B7M, Duplex 2205, Alloy 718, etc.), and project specification for a formal compliance statement and quotation.

Question 15

What are the torque values for ASTM A193 B7 stud bolts on ASME B16.5 flanges?

Accepted Answer

Torque values depend on flange pressure class, bolt size, and lubrication condition. For a 4" Class 600 flange (⅞" B7 studs, 8 bolts) with light oil (K=0.17), the target torque at 50% SMYS is approximately 230 N·m per bolt. For a 6" Class 900 flange (1¼" B7 studs, 12 bolts), target torque is approximately 680 N·m per bolt. Always apply the ASME PCC-1 cross-bolt tightening sequence (snug tight → 50% → 100% → clockwise verification), and conduct a hot retorque after the first thermal cycle to compensate for gasket relaxation. See our stud bolt torque chart guide for the full ASME B16.5 Class 150–2500 reference table.

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