Carbon Steel Long Weld Neck Flange
Carbon steel flanges are engineered to provide reliable bolted connections in piping systems, ensuring leak-proof sealing and stable support under various pressure and temperature conditions.
They combine robust strength, durability, and cost-efficiency, making them the preferred choice for oil, gas, chemical, power generation, and construction applications.
Material Grades & Mechanical Properties
Available Sizes & Dimensions
Q1: What are the main products you can supply?
A: We are a professional manufacturer and supplier in China for steel pipe and pipe fittings, including carbon steel flanges, elbows, pipes, bolts, nuts, and other piping products. Our product range covers both standard and custom solutions for industrial piping and structural applications.
Q2: What types of flanges do you offer?
A: We supply a full range of carbon steel flanges, including:
Weld Neck Flange (WN) – for high-pressure, high-temperature applications
Slip-On Flange (SO) – for general low-pressure systems, easy to install
Blind Flange (BL) – for sealing pipe ends or pressure testing
Socket Weld Flange (SW) – for small-diameter, high-pressure systems
Threaded Flange (TH) – for non-welded, low-pressure connections
Lap Joint Flange (LJ) – with stub end, for easy alignment and dismantling
Please contact us with your specific requirements for recommendations.
Q3: What is the difference between Weld Neck and Slip-On flanges?
A: Weld Neck Flanges (WN) have a long tapered hub that provides reinforcement and stress distribution, making them suitable for high-pressure, high-temperature, and critical applications. Slip-On Flanges (SO) are slid over the pipe and welded both inside and outside, offering easier alignment and lower cost, but they are generally used for low-pressure, less critical systems.
Q4: What is your minimum order quantity (MOQ)?
A: For trial orders, our MOQ is 10 pcs per size. For bulk orders, MOQ is flexible — please contact us with your target quantity for a competitive quote. Volume discounts are available for large orders.
Q5: How long is the delivery time?
A: 7-15 days for standard sizes in stock after payment confirmation. For custom orders (non-standard sizes, special grades, or large quantities), delivery time is typically 20-30 days, depending on specifications. We will confirm the exact timeline upon order confirmation.
Q6: How do you control quality?
A: We implement strict 3-stage quality control:
Raw material – chemical composition verified by spectrometer per ASTM A105 / A350 / A694 requirements
Production – dimensional checks during forging, machining, and heat treatment
Final – dimensional inspection (OD, ID, thickness, bolt hole alignment, facing), hardness testing, and PMI (positive material identification) per ASME B16.5 / B16.47
A Mill Test Certificate (EN 10204 Type 3.1) is provided with every shipment, including chemical analysis and mechanical test results.
Q7: Which material grade should I choose for my application?
A:
For general industrial service up to 425°C, we recommend ASTM A105 (carbon steel flange).
For low-temperature service down to -46°C, we recommend ASTM A350 LF2 (low-temperature carbon steel).
For high-strength and low-temperature service, ASTM A694 F52 / F60 / F65 are available for high-yield pipeline applications.
For high-temperature, high-pressure service requiring alloy steel, we recommend ASTM A182 F11 / F22.
Please contact us with your specific service conditions for a material recommendation.
Q8: What pressure ratings do your flanges cover?
A: Our carbon steel flanges are available in:
Class 150 / 300 / 600 / 900 / 1500 / 2500 (per ASME B16.5, for NPS 1/2" to 24")
Class 150 / 300 / 600 / 900 / 1500 (per ASME B16.47 Series A / B, for NPS 26" to 60")
PN6 / PN10 / PN16 / PN25 / PN40 / PN63 / PN100 (per EN 1092-1, metric)
Q9: What sealing faces do you offer?
A: We offer all standard facing types:
Flat Face (FF) – for low-pressure systems
Raised Face (RF) – standard for most industrial applications
Ring Type Joint (RTJ) – for high-pressure, high-temperature service
Tongue & Groove (T&G) – for critical sealing applications
Male & Female (M&F) – for precise alignment and sealing
Q10: Can I get samples before ordering?
A: Yes. Stock samples are free of charge – you only pay the shipping cost. Custom samples require a small production fee, which will be deducted from your first bulk order.
Q11: Do you accept OEM or custom orders?
A: Yes, we accept custom orders based on your drawings, specifications, or samples. We can also apply your logo on products and packaging. Our engineering team will review your requirements and provide a solution within 24 hours.
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