Designed for fusion orbital welding, the AMI 9 Series weld heads deliver exceptional precision and reliability. Ideal for welding tubes, pipes, fittings, and other cylindrical components, the 9 Series offers a weld head suited for virtually any application. Available in eight sizes and three configurations, the series accommodates tube and pipe diameters ranging from 3/32″ to 7.5″ OD.
Each weld head accommodates a wide range of tube sizes through easily interchangeable, size-specific clamps. The standard Model 9 features a dual-sided clamping mechanism that securely holds components in alignment and concentric position, eliminating the need for tack welding. Select models also include a flip-up viewing window, allowing operators to quickly verify proper fit-up before welding. Most Model 9 weld heads are equipped with integrated water cooling for both the cables and internal components, enabling higher duty cycles and improved performance during extended operation.
AMI 9 Series weld heads
Model 9-250
The 9-250 weld head is a compact, high-precision weld head designed for applications with extremely tight radial clearances. Engineered for fusion butt welding, mini-fittings, and valve bodies, it accommodates OD tubing sizes from 3/32″ to 1/4″.
A visual sight window allows operators to easily verify proper fit-up before welding, while two sets of hardened clamp plates securely grip the workpieces to maintain precise alignment throughout the welding process.
Model 9-500 & 9-500C
The 9-500 and 9-500C weld heads are designed specifically for welding components. They can weld parts with a stick-out as short as 1/4″ and support diameters ranging from 3/32″ to 1/2″. The 9-500C features water-cooling, enabling it to handle high duty-cycle applications.
The 9-500C includes the Quick Release Kit (optional for the 9-500), which provides a 360° view of the weld joint and allows operators to use multiple clamp assemblies to further increase duty cycle when needed. A wide variety of tooling options are available for the 9-500 and 9-500C, including clamp assemblies, tube clamp inserts, and more.
Model 9-750
The most popular weld head in the 9 series, the 9-750 weld head is commonly used in ultra-high purity applications where consistent, repeatable welds are critical. Designed for smaller-diameter tubing, it accommodates outside diameters from 1/8″ to 3/4″, making it ideal for precision tube welding.
The 9-750 features a dual-clamp alignment system that securely holds workpieces together to ensure proper fit-up during welding. A flip-up viewing window allows operators to visually confirm alignment and fit-up prior to starting the weld.
model 9-1500
The 9-1500 weld head is a mid-small orbital weld head designed for tube diameters ranging from 1/4″ to 1.5″. Ideal for instrument tubing and stainless process lines, it is one of the most commonly used weld heads in process piping applications.
A dual-side clamping system securely holds the workpiece in position, removing the need for tack welds. Built for applications that demand high-purity and repeatable welds, the 9-1500 is widely used in semiconductor gas systems, pharmaceutical processing, aerospace tubing, and other high-precision industries.
model 9-2500
The 9-2500 weld head is designed for tube-to-tube and tube-to-fitting fusion welding, supporting tube outer diameters from 3/4″ to 2.5″.
Like other weld heads in the 9 Series, the 9-2500 features a double-clamp alignment system that securely holds and precisely aligns both workpieces throughout the welding process.
This weld head is commonly used in applications where larger process tubing requires high-quality orbital welds, including pharmaceutical process piping, semiconductor gas delivery systems, and similar high-purity environments.
model 9-3500
With an outside diameter (OD) range of 1″ to 3.5″, the AMI 9-3500 is a mid-to-large orbital weld head designed for industries such as aerospace, semiconductor manufacturing, pharmaceuticals, and high-purity piping systems.
The 9-3500 is commonly used for tube-to-tube butt welds, pipe fittings, cylindrical components, and other applications that demand high-quality, repeatable welds with minimal contamination.
model 9-4500
The 9-4500 is a large-diameter weld head designed to weld pipe and tube with an outside diameter range of 2 in. to 4.5 in. The 9-4500 is available in three variants: 9-4500, 9E-4500, and 9ER-4500.
The standard 9-4500 features a dual-clamp system that securely holds the work pieces. The 9E-4500 features a single clamp design with an offset tungsten electrode, allowing the weld head to be used in restricted or tight-clearance environments where a full dual-clamp head may not fit. The 9ER-4500 incorporates a modified rotor design intended for specialized welding applications that require different torch positioning or arc characteristics. The 9-4500 series is the only weld head family that includes the ER variation.
model 9-7500
The AMI 9-7500, the largest weld head in the Model 9 series, supports pipe and tube outside diameters from 2.875″ to 7.5″, making it well suited for large process piping systems. Water-cooled components allow for higher duty cycles and improved thermal stability during extended welding operations.
Interchangeable clamp inserts enable the weld head to accommodate multiple tube sizes within its range, while the enclosed welding chamber maintains controlled shielding gas coverage to protect the weld pool from contamination. These features help ensure consistent, high-quality welds on materials such as stainless steel, nickel alloys, and titanium.
With a wide range of sizes, configurations, and specialized features, the AMI 9 Series weld heads provide a versatile solution for precision orbital fusion welding across many industries. From compact heads designed for tight-clearance applications to large-capacity models capable of handling heavy process piping, the 9 Series delivers consistent alignment, controlled welding environments, and reliable performance. Whether used in semiconductor manufacturing, pharmaceutical processing, aerospace systems, or high-purity piping installations, AMI 9 Series weld heads help ensure repeatable, high-quality welds while maximizing productivity and operational efficiency.
