ASME SB111 UNS C68700 Seamless Tube

ASME SB111 UNS C68700 seamless tube is an aluminium brass tube manufactured for high-pressure and high-temperature applications. C68700 (aluminium brass) combines high strength with general corrosion resistance and has low susceptibility to stress corrosion cracking. These tubes can be heat treated and used in hard drawing conditions while remaining stress corrosion fracture free.

GNEE offers a comprehensive range of SB111 UNS C68700 SMLS tubes manufactured using high-quality raw materials. These tubes are developed using advanced technology and offered at competitive prices. They are available in different sizes, grades, shapes, and specifications per client requirements. You can also order small quantities. GNEE is happy to quote the best price for small and large quantities.

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Aluminium brass tubes (UNS C68700) have a combination of high strength and general corrosion resistance, as well as low susceptibility to stress corrosion cracking, making them a preferred choice for a variety of applications. The tubes may be heat treated and utilized in hard drawing circumstances, ensuring they are stress corrosion fracture free.

ASME SB111 UNS C68700 tubes are used in various industries including:

Petroleum

Chemical

Power

Gas

Water

Metallurgy

Shipbuilding

Construction

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Q1: What is the MOQ for ASME SB111 UNS C68700 seamless tube?

A: The MOQ is 500 kg for standard sizes. Small quantities down to 200 kg are accepted for common dimensions like OD 19mm or 25mm with 1.2mm wall thickness. Contact supplier for small order pricing.

Q2: What is the lead time for C68700 seamless tubes?

A: Standard sizes: 20-30 days. Special sizes: 35-45 days. Common sizes (OD 19mm, 25.4mm, 31.8mm; WT 1.2mm, 1.5mm, 2.0mm) are often in stock for immediate shipment.

Q3: How does C68700 compare to C70600 for seawater service?

A: C70600 (90-10 cupronickel) has better corrosion resistance but costs about 40% more. C68700 is preferred for high-velocity seawater (>2m/s). C70600 is better for very aggressive seawater or when service life exceeds 20 years.

Q4: Can C68700 tube be bent without cracking?

A: Yes, use annealed (O61) temper with minimum bend radius of 2 x OD. For 0.5mm thin wall tubes, use a mandrel during bending to prevent collapse. Never bend hard temper C68700.

Q5: What welding filler metal works for C68700?

A: Use ERCuAl-A1 (CuAl8) aluminum bronze filler metal. Welding method: TIG. Parameters: 80-120A, argon purity ≥99.99%, preheat to 150°C. Skipping preheat causes arsenic porosity.

Q6: How many years does C68700 last in seawater?

A: Design life is greater than 15 years. Per ASTM G48, dezincification depth is less than 200μm per year. Actual life depends on water temperature, flow velocity, and sand content. Condenser tubes typically last 15-20 years.

Q7: What is the difference between seamless and welded C68700 tube?

A: Seamless (SMLS) has no longitudinal weld seam and handles higher pressure. For ASME SB111 condenser applications, always specify seamless. Welded tubes have a seam that can corrode in seawater.

Q8: What test reports are provided for ASME SB111 C68700 tubes?

A: EN 10204 3.1 mill test certificates are standard. Third-party inspection is optional. Reports include chemical composition, tensile strength, yield strength, elongation, flaring test, flattening test, and eddy current test. SGS, BV, or TUV inspection available at extra cost.

Q9: What surface finishes are available for C68700 seamless tubes?

A: Bright, mirror, brushed, oiled, and pickled finishes are available. Bright finish is standard for condensers. Mirror finish suits special cleaning requirements. Brushed finish is for anti-slip surfaces.

Q10: What is the maximum operating temperature for C68700?

A: Continuous service up to 300°C. Above this temperature, dezincification accelerates and strength decreases. For applications above 300°C, use C70600 cupronickel or stainless steel.

Q11: What is the Werkstoff Nr. for UNS C68700?

A: Werkstoff Nr. 2.0460 (also listed as 1785). This German designation corresponds to CuZn22Al2. When ordering in Europe, specify either UNS C68700 or Werkstoff 2.0460 – both refer to the same alloy.

Q12: What is the hardness of annealed C68700?

A: Annealed (O61) C68700 has HRB 55-65. Hard temper (H04) has HRB 170-180. For tube bending and expansion, always use annealed. For straight tubes with no forming, hard temper is acceptable.

Every tube in this lot has passed third-party witnessed inspection per ASTM B111 standard for C68700 alloy. Below are actual photos from customer-onsite inspection, including eddy current testing and dimensional verification.

Inspection items verified:
• Eddy current testing (ECT) – no through-wall defects
• Outer diameter & wall thickness – within ±0.02mm tolerance
• Surface finish & temper (O61) – conforms to ASTM
• Hardness & chemical composition – certified.

After passing inspection, all tubes are packed according to export standards and customer-specific requirements. The packing process is documented below to ensure traceability and damage-free delivery.

Packing steps shown in video & images:
1. Tube cleaning & drying
2. Plastic end caps on both ends
3. VCI anti-rust paper wrapping
4. Bundle strapping with moisture barrier film
5. Plywood wooden case (ISPM-15 compliant) with foam padding
6. Labeling with ASTM grade, lot number, and inspection stamp

All ASTM C68700 tubes are produced and inspected on our in-house equipment, allowing full process control from billet casting to final packing.

Key equipment used for this lot:
• Induction melting furnace – precise alloying (Cu + Zn + Al + As)
• Horizontal continuous casting – uniform billet structure
• Extrusion press (800T / 1630T) – seamless tube forming
• Cold drawing bench (5–40m) – dimensional accuracy to ±0.02mm
• Online eddy current tester (FOERSTER / MAC) – 100% NDT
• Ultrasonic wall thickness gauge – real-time monitoring
• Annealing furnace (controlled atmosphere) – temper O61

In-house metrology: Micrometers, pin gauges, optical comparator, hardness tester (HV/HRB)

All equipment is calibrated quarterly. Production records are traceable by lot number.

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