API 20E / API 20F Bolting Supplier
MT.BOLTS manufactures and supplies API 20E and API 20F bolting for critical applications in the petroleum and natural gas industries. API 20E covers alloy and carbon steel bolting, while API 20F covers corrosion-resistant bolting used where reliable mechanical performance and corrosion resistance are required.
Our API 20E / API 20F bolting is available for demanding applications including wellheads, valves, blowout preventers (BOPs), manifolds, drilling equipment, risers, connectors, trees, and other oil and gas pressure-control equipment.
We support customized sizes, thread configurations, materials, heat treatment, coatings, inspection requirements, and documentation according to customer specifications and applicable API requirements.
Our API 20E / API 20F bolting is available in the following specifications:
- Product Types: Stud Bolts, Studs, Bolts, Screws, Nuts
- Diameter: M3 to M64 | #4 to 2.5″
- Length: 6 mm to 500 mm | 0.25″ to 20″
- Threads: UNC / UNF / 8UN | Metric Coarse / Fine
- Standards: API 20E | API 20F | ASME B18.2.1 | ASME B18.2.2 | ASME B18.3 and applicable customer specifications
- API 20E: Alloy Steel and Carbon Steel Bolting
- API 20F: Corrosion-Resistant Bolting
- Bolting Specification Levels: BSL-1 / BSL-2 / BSL-3 where applicable
- Inspection: Chemical Analysis, Mechanical Testing, Hardness Testing, PMI, NDE and Dimensional Inspection according to applicable requirements
- Documentation: Material Test Certificate, Heat Treatment Records, Inspection Reports and other quality documents as specified
API 20E / API 20F Bolting – Standards, Materials & BSL Requirements
API Specification 20E establishes requirements for the qualification, production and documentation of alloy and carbon steel bolting used in the petroleum and natural gas industries. API Specification 20F establishes requirements for corrosion-resistant bolting used in the same industry.
The standards define different Bolting Specification Levels (BSL), with requirements increasing according to the applicable level and service requirements.
| Standard | Bolting Category | Typical Application |
| API 20E | Carbon & Alloy Steel Bolting | Wellheads, valves, BOPs, manifolds and drilling equipment |
| API 20F | Corrosion-Resistant Bolting | Offshore, subsea and corrosive oil & gas applications |
| BSL-1 | Applicable API 20E bolting level | Standard critical applications where specified |
| BSL-2 | Higher technical and quality requirements | More demanding pressure-control applications |
| BSL-3 | Enhanced qualification and quality requirements | Highly critical applications |
API’s published information confirms that API 20E covers alloy and carbon steel bolting, while API 20F covers corrosion-resistant bolting. API 20F uses BSL-2 and BSL-3; BSL-1 is omitted from API 20F.
API 20E Bolting – Material Grades
API 20E covers alloy and carbon steel bolting used in the petroleum and natural gas industries. The standard includes specified ASTM bolting grades and equipment manufacturer’s proprietary bolting material specifications.
| Standard | Grades |
| ASTM A193 | B7, B7M |
| ASTM A194 | 2H, 4, 7, 2HM, 7M |
| ASTM A320 | L7, L7M, L43 |
| ASTM A540 | B22, B23 |
| Proprietary Materials | Equipment Manufacturer’s Proprietary Bolting Specification |
All referenced ASTM or proprietary material requirements shall be met unless modified by API 20E. In case of conflict, API 20E requirements take precedence.
API 20E also prohibits oversizing of nut threads, undersizing of bolt threads, and welding for bolting covered by the applicable requirements.
API 20F Bolting – Materials & Grade Identification
API 20F corrosion-resistant bolting includes specific corrosion-resistant alloy grades and strength levels qualified according to the applicable API requirements. The applicable material designation, strength level, BSL and marking shall be confirmed according to the applicable API 20F edition and purchase specification.
| Material Designation | Strength Level | Grade Identification Marking |
| N07716 | 120K | N1A |
| N07716 | 140K | N1B |
| N07718 | 120K | N2A |
| N07718 | 140K | N2B |
| N07725 | 120K | N3A |
| N09925 | 110K | N4A |
| N09935 | 110K | N5A |
| N09945 | 125K | N6A |
| N09946 | 140K | N7A |
| N09946 | 150K | N7B |
| N09946 | 160K | N7C |
| UNS R30035 | Work Strengthened Only | R3A |
| UNS R30035 | Work Strengthened + Aged 1300°F | R3B |
| UNS R30035 | Work Strengthened + Aged 1350°F | R3C |
| UNS R30035 | Work Strengthened + Aged 1425°F | R3D |
| UNS R30035 | Work Strengthened + Aged 1450°F | R3E |
| UNS R30035 | Work Strengthened + Aged 1475°F | R3F |
| UNS R30035 | Work Strengthened + Aged 1500°F | R3G |
API 20E / API 20F Bolting Types
MT.BOLTS supplies a wide range of bolting configurations for oil and gas equipment:
API 20E / API 20F Hex Head Lag Screws
API 20E / API 20F Curved Washers
API 20E / API 20F Wave Washers
API 20E / API 20F Belleville Washers
Why Choose MT.BOLTS
- Material Diversity
- Standardized Production
- Ample Inventory
- Competitive Pricing
- Low-MOQ Customization
API 20E / API 20F Bolting Manufacturing & Inspection
For critical oil and gas applications, bolting quality depends on controlled manufacturing, material traceability and inspection.
Our inspection and quality documentation can include:
- Chemical Composition Analysis
- Mechanical Properties Testing
- Tensile Testing
- Yield Strength Testing
- Elongation Testing
- Hardness Testing
- Heat Treatment Records
- PMI – Positive Material Identification
- Magnetic Particle Testing
- Liquid Penetrant Testing
- Ultrasonic Testing where specified
- Dimensional Inspection
- Thread Inspection
- Surface Inspection
- Coating / Plating Inspection where applicable
- Material Test Certificates
- Heat Number Traceability
- Final Inspection Reports
Specific inspection requirements are confirmed according to the applicable API specification, BSL, material specification and customer purchase order.
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API 20E / API 20F Bolting – Threads & Dimensions
We manufacture and supply API bolting in both imperial and metric configurations.
| Item | Available Options |
| Thread System | UNC / UNF / 8UN / Metric |
| Diameter | M3–M64 / #4–2.5″ |
| Length | 6–500 mm / 0.25–20″ |
| Thread Form | Fully Threaded / Partial Thread / Customer Drawing |
| Nut Type | Heavy Hex / Hex / Customer Specification |
| Surface | Plain / Coated / Plated as specified |
| Marking | Grade / Manufacturer Identification / Heat or Traceability Marking as applicable |
For API 20E and API 20F products, marking and identification requirements must follow the applicable specification and purchase requirements.
Applications of API 20E / API 20F Bolting
API 20E and API 20F bolting is used in a wide range of petroleum and natural gas equipment and systems, including:
- Oil & Gas Wellheads
- Christmas Trees
- Blowout Preventers (BOPs)
- API 6A Valves
- API 6D Valves
- Manifolds
- Drilling Equipment
- Risers
- Connectors
- Pressure-Control Equipment
- Subsea Equipment
- Offshore Oil & Gas Equipment
- High-Pressure / High-Temperature Equipment
- Petroleum Processing Equipment
API documents reference API 20E and API 20F bolting in applications such as pressure-boundary bolting for API equipment, with the applicable BSL depending on the equipment specification and bolting material.
API 20E / API 20F Bolting FAQ
API 20E is an API specification covering alloy and carbon steel bolting used in the petroleum and natural gas industries. It establishes requirements related to qualification, production and documentation.
API 20F covers corrosion-resistant bolting used in the petroleum and natural gas industries. It establishes requirements for qualification, production and documentation of CRA bolting.
API 20E is for alloy and carbon steel bolting, while API 20F is for corrosion-resistant bolting. The applicable standard should be selected according to the equipment specification, material and service requirements.
BSL means Bolting Specification Level. The BSL designation defines different levels of technical, quality and qualification requirements. API 20F uses BSL-2 and BSL-3, while API 20E includes BSL requirements applicable to its scope.
Yes. We can manufacture and supply bolting according to the applicable API 20E requirements, BSL level, material specification, dimensions, thread configuration and inspection requirements.
Yes. We can supply corrosion-resistant bolting in stainless steel, duplex, super duplex and nickel-alloy materials subject to the applicable API 20F requirements and customer specification.
PMI can be provided where specified by the purchase order, inspection plan or applicable material requirements. PMI records can be included in the quality documentation package.
Yes. Documentation can include material certificates, heat treatment records, mechanical test reports, PMI reports, dimensional inspection reports and third-party inspection documentation according to the agreed specification.
Yes. Custom stud bolts, bolts, screws and nuts can be manufactured according to customer drawings, dimensions, thread specifications and applicable API requirements.
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