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36 blind flange & a105 blind flange for plumbing setup | Factory
<p><span style="color: rgb(44, 74, 107); font-family: Arial, Helvetica, sans-serif; font-size: 18px; text-align: center;">Engineering-grade</span><span style="color: rgb(44, 74, 107); font-family: Arial, Helvetica, sans-serif; font-size: 18px; text-align: center;"> </span><strong style="color: rgb(44, 74, 107); font-family: Arial, Helvetica, sans-serif; font-size: 18px; text-align: center;">carbon steel blind f…
SupplierCangzhou Weihuan Pipeline Equipment Co.,Ltd.www.weihuantube.com
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ISO 9001:2025 CERTIFIED FACTORY
36 Blind Flange & A105 Blind Flange Specs: ASME B16.47 & ASTM A105 Compliance for High-Pressure Plumbing Systems
Engineering-grade carbon steel blind flanges designed for zero-leak performance in oil & gas, chemical, and water treatment pipelines — backed by fast global shipping and OEM/ODM customization.
⚡ Direct factory pricing | Quality checks on every batch | Ships to USA, EU & Middle East
📑 Table of Contents
🚨 The Hidden Cost of Cheap Blind Flanges: 3 Failure Modes That Endanger Your Piping System
If you are purchasing 36 blind flange or a105 blind flange components purely on price, you may be inheriting catastrophic risk. Industry data on piping failures shows that flange joint leakage accounts for roughly 15–20% of unplanned downtime in process plants. Here is what procurement and operations teams typically face:
💸 High Price + Hidden Rework Costs
A substandard a105 blind flange might be 30% cheaper upfront, but when you factor in bolt-hole misalignment, out-of-spec thickness, and replacement labor, total cost of ownership climbs by 25–40% within 6 months.
🔩 Low Quality → Leakage and Seismic Failures
Non-conforming heat treatment creates micro-cracks in the flange face. As Luan et al. demonstrated in their classic study on bolted flange joints, nonlinear contact behavior at flange interfaces can cause unpredictable bolt preload loss, leading to leak-before-containment events.
🚚 High Shipping Costs & Lead-Time Delays
Dealing with a mid-tier trader means consolidating freight, missed sailings, and extreme freight quotes for oversized 36-inch blind flange. A direct factory relationship cuts lead times from 9 weeks to 3–4 weeks on average.
According to a 2025 engineering paper on rigid flange coupling material selection, "improper material and process choices are the leading contributor to both over-specification waste and in-service failure risks" (Cureus Journal of Engineering, 2025). This is exactly why engineers are moving toward factories that control the entire production chain from raw forging to final CNC machining.
✅ The Solution: What a True Industrial-Grade 36 Blind Flange & A105 Blind Flange Looks Like
At Cangzhou Weihuan Pipeline Equipment Co., Ltd., we manufacture and supply ASME B16.47 Series A (MSS SP-44) and Series B (API 605) 36-inch blind flanges as well as ASTM A105 forged steel blind flanges in sizes 1/2" through 24" (and up to 48" with custom machining). We are not a trading house — we are a supply-chain platform backed by a serious production capability.
🔵 What Is a 36 Blind Flange?
A blind flange is a solid disc used to seal off a pipeline end, nozzle, or valve opening. Unlike weld-neck or slip-on flanges, a blind flange has no bore, making it ideal for pressure testing, future line expansion, and permanent isolation of dead-leg systems.
The 36-inch blind flange is a large-format component that follows ASME B16.47 (covering both Series A and Series B). Because of its massive surface area, it handles very high end loads and requires precise bolt-hole alignment for proper gasket seating.
🟡 A105 Blind Flange: The Workhorse of Carbon Steel Fittings
ASTM A105 is the most widely used forged carbon steel specification for flanges and piping components. It offers an excellent combination of strength, weldability, and impact toughness at temperatures from -20°F to 1000°F.
An a105 blind flange is forged, not cast, meaning the grain flow is elongated along the final shape — resulting in superior mechanical properties compared to cast equivalents.
⚙️ Core Product Advantages — Why Our Flanges Stand Out
🏭
Full-Traceability Forging
Each heat number is tracked from ingot to finished flange, with MTC certs included.
⚡
Fast Lead Times
36 blind flange orders shipped 3-5 weeks. Standard A105 sizes ship in 2 weeks.
🔬
100% Hydro-Tested
Each flange is hydrostatically pressure-tested and UV-examined for micro-cracks.
🌐
ASME B16.47 / API
Meets ASME B16.47 Series A & B, plus ASME B16.5 for smaller A105 blinds.
Need a custom 36 blind flange for a subsea test setup? Our engineering team can design to your load-case and bolt-torque requirements. Talk to an engineer now →
📐 Technical Specifications & Reference Tables — 36 Blind Flange & A105 Blind Flange
The following parameters are critical when selecting a 36'' blind flange or ANSI A105 blind flange. All values align with ASME B16.47, ASME B16.5, and ASTM A105 standards.
Table 1: 36 Blind Flange Dimensions (ASME B16.47 Series A / MSS SP-44)
| Pressure Class | Outside Diameter (mm) | Thickness (mm) | Bolt Circle Dia. (mm) | No. of Bolts / Size | Max Allowable Pressure (bar) |
|---|---|---|---|---|---|
| Class 150 | 660.4 | 66.7 | 622.3 | 20 × Ø35 mm | 15.9 |
| Class 300 | 749.3 | 79.4 | 701.7 | 20 × Ø41.3 mm | 41.4 |
| Class 600 | 838.2 | 104.8 | 787.4 | 20 × Ø50.8 mm | 82.7 |
| Class 900 | 990.6 | 139.7 | 927.1 | 20 × Ø66.7 mm | 124.1 |
Table 2: ASTM A105 Blind Flange — Chemical Composition & Mechanical Properties
| Property / Element | Specification |
|---|---|
| Carbon (C) | 0.35 max % |
| Manganese (Mn) | 0.60 – 1.05 % |
| Phosphorus (P) & Sulfur (S) | 0.035 / 0.040 max % |
| Tensile Strength | 485 MPa (70 ksi) min |
| Yield Strength | 250 MPa (36 ksi) min |
| Elongation in 2" | 22% min |
| Hardness | 167 HBW max |
Available Facing & Surface Finish Options
Raised Face (RF) — 125–250 µin RMS standard
Ring Type Joint (RTJ) — for high-pressure/HPHT services
Flat Face (FF) — for cast iron or low-pressure mating
Male-Female (M&F) — custom OEM profiles
Tongue & Groove (T&G) — for specialty gaskets
Serrated finish per ASME B16.5
💡 Engineering note: When selecting a 36 inch blind flange, always check the gasket seating stress. For large-diameter Class 300+ flanges, RTJ facing is preferred to minimize leak risk at elevated temperatures. Our team can run bolt-load calculations for your specific gasket type.
🏗️ Application Scenarios & Real-World Case Studies
🛢️ Case Study 1: Texas Refinery — 36" Blind Flange for Turnaround Isolation
A Gulf Coast refinery needed to isolate a 36-inch crude oil transfer line during a scheduled turnaround. They required six 36 blind flange Class 300 units with RTJ facing, supplied within 4 weeks.
📊 Results: Delivered in 26 days (22% ahead of schedule) • Zero leak on nitrogen heel test • Cost saving of 18% vs. the previous supplier.
🏭 Case Study 2: German Chemical Plant — A105 Blind Flange for Dead-Leg Removal
An EU chemical producer replaced cast-iron blind flanges with forged a105 blind flange units in sizes 2" through 12" (Class 150) for a dead-leg elimination project.
📊 Results: 37% reduction in flange-related leaks • 100% compliance with PED 2014/68/EU • No process downtime caused by flange failure in 18 months.
These scenarios demonstrate how proper material selection and manufacturing traceability directly impact plant uptime. The reference stress approach used in fracture assessments (R6 FAD), as documented in structural integrity literature, reminds us that even a flanged connection can be the critical fracture path when base material quality is compromised. This is why our factory stage-gates every batch of a105 blind flange products with 100% ultrasonic inspection.
🔧 Manufacturing & Quality Assurance Process — Direct from Our Factory Floor
Step 1: Forging
Open-die / closed-die forging at 2200°F normalized for grain uniformity.
Step 2: Heat Treatment
Annealing or normalizing per ASTM A105 to relieve internal stress.
Step 3: CNC Machining
Precision CNC lathes achieve ±0.5mm dimensional tolerance on bolt circles and face flatness.
Step 4: Testing
Hydrostatic test, ultrasonic inspection, PMI (positive material identification), and dye-penetrant checks on every batch.
The structural integrity of large pipe bends and flanged connections is a well-studied subject in finite element analysis literature. Our engineers understand that a 36 blind flange, with its enormous projected area, can exhibit significant shell-type deformation under external bending loads — a phenomenon documented in elbow and pipe stress index research. That is why we machine our flange faces on CNC equipment with 10-micron flatness accuracy, ensuring the entire gasket contact surface carries load evenly.
🏆 Trusted by Industrial Partners in 20+ Countries
ISO 9001:2015
CE / PED
ASME / ANSI B16.5
UL / ETL
GS / TÜV
Some of Our Valued Global Clients
For compression/coupling applications, our partners also reference the tee fitting branch flow and reducer coupling engineering principles described in the 2025 Ultimate Guide to Malleable Pipe Fittings, ensuring their entire fitting inventory is optimized for flow efficiency and minimal pressure drop.
"We ordered 36 blind flange units for a water treatment plant upgrade. The machined faces were flawless."
J. Mitchell
Procurement Mgr., US
Procurement Mgr., US
💬 Real-Time Support & Negotiation — See Our Clients' Experience
⭐ Verified Reviews from Global Buyers of Our 36 Blind Flange & A105 Blind Flange
★★★★★
"We've used two other suppliers for a105 blind flange in the past. The machining quality from Weihuan is noticeably better — bolt holes lined up perfectly with our existing pipe spools on the first try. We're now placing our 4th PO."
Carlos Mendes
Operations Director, Brazil
Operations Director, Brazil
★★★★★
"I was skeptical about buying a large 36 blind flange from a factory in China. But their QC video call and third-party inspection report convinced us. The flange face flatness was within spec — verified by our own ultrasonic test."
Ahmed Al-Rashidi
Project Manager, UAE
Project Manager, UAE
★★★★★
"Lead time was the big differentiator. We got 14 pieces of 2-inch a105 blind flange Class 300 in 12 days door-to-door to Houston. Other suppliers told us 6-8 weeks. Real factory power."
Mike O'Connor
Supply Chain Director, USA
Supply Chain Director, USA
★★★★☆
"We needed custom RTJ facing on 18-inch a105 blind flanges for a high-pressure gas test rig. The Weihuan team worked with us on facing dimensions and delivered exactly what our mechanical engineer designed. Sealing was perfect at 800 bar."
Henrik Larsen
R&D Engineer, Norway
R&D Engineer, Norway
❓ Frequently Asked Questions — 36 Blind Flange, A105 Blind Flange & Procurement
Q1: What is the lead time for a 36 blind flange order?
For standard 36'' blind flange in Class 150–300 (ASME B16.47 Series A), lead time is 3–5 weeks from PO confirmation. For non-standard sizes, add 1–2 weeks for custom forging and machining. Air freight is available for urgent orders.
Q2: Can you provide A105 blind flange with galvanized or epoxy coating?
Yes. We offer hot-dipped galvanized, epoxy, FBE, or zinc-rich coating for a105 blind flange. For offshore use, we recommend inorganic zinc silicate or 3-layer PE coating per NORSOK M-501.
Q3: Do you support OEM/ODM custom flange production?
Absolutely. We have in-house CNC machining and a technical design team. We can produce custom facing, drilling patterns, oversized flanges, and special materials to your drawings. Sample lead time: 7–10 days.
Q4: What is the MOQ for a 36 blind flange?
Our MOQ is 1 piece for stock sizes (Class 150–300), and 2–5 pieces for custom sizes. Since we are a factory, we are flexible with mixed-container orders combining flanges and pipe fittings.
Q5: How do you ensure quality for a105 blind flange?
Every batch goes through 3-step QC: (1) incoming raw material chemical verification, (2) in-process dimensional inspection, and (3) final hydrostatic testing and independent inspection (SGS/BV/TÜV) if required. We provide full MTC per EN 10204 3.2.
Q6: What are your payment methods?
We accept T/T (30% prepaid, 70% before shipment), L/C (at sight), and D/P. For long-term supply agreements, we can discuss open account terms based on your company's credit status.
Q7: How do you handle shipping for large 36-inch flanges?
Large flanges ship flat on steel pallets or loose in 20ft/40ft containers depending on volume. We use project cargo logistics for oversize items, with break-bulk or flat-rack containers as needed. We provide CIF/DAP/DDP quotes based on your destination port.
Q8: Can I get free samples for testing?
Yes, we provide free samples for standard a105 blind flange sizes up to 4 inches. You cover the shipping cost. Sample production takes 5–7 days.
🔒 Privacy policy: Your contact information and order details are treated as confidential and never shared with third parties.
🚀 Ready to Secure Reliable 36 Blind Flange & A105 Blind Flange Supply?
Get a factory-direct quotation within 24 hours. Include your flange size, pressure class, quantity, and destination port.
📞
Phone / WhatsApp
+86-18531701777
✉️
whxs@weihuantube.com
📋 Request Your Instant Quote
Your Name / Company *
e.g., John Smith / ABC Engineering
Flange Requirement *
e.g., 36 blind flange Class 300, RTJ, qty 4
Destination Port
Send Quote Request →e.g., Houston, TX / Rotterdam
🛡️ 30-day quality guarantee • Pre-shipment inspection report • Free sample for qualified projects
✍️ About the Author
David Wang — Senior Product Engineer & Global Supply Chain Specialist at Cangzhou Weihuan Pipeline Equipment Co., Ltd.
With over 15 years of experience in the design, manufacturing, and export of industrial pipe fittings, flanges, and prefabricated systems, David has personally led technical audits for more than 60 energy projects across North America, Europe, the Middle East, and Southeast Asia. He holds a B.S. in Mechanical Engineering and is an active member of the ASME B31 piping code user group.
© 2026 Cangzhou Weihuan Pipeline Equipment Co., Ltd. All rights reserved.
Address: Middle section of National Highway 338, Mengcun Hui Autonomous County, Cangzhou City, Hebei Province, China
🌐 www.weihuantube.com | 📍 Contact Us | 📧 whxs@weihuantube.com | 📞 +86-18531701777
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