Model 52 NGT Heavy-Duty Precision Pipe Weld Head

The Model 52 is intended for field or heavy duty shop use in the nuclear, shipbuilding, chemical, petrochemical and construction industries where weld quality requirements are stringent and the use of the GTAW process is beneficial.

The Model 52 is a "full function" welding head, meaning that it provides all functions necessary for true automated welding including Arc Rotation, Arc Voltage Control (AVC) for arc gap control, Wire Feed (weld filler) and Torch Oscillation (weave). The Model 52 also features range expandability of most of these functions as well as providing other standard features that are options on most other weld heads.

The Model 52 weld head provides a durable, extremely versatile, heavy-duty platform for using a variety of torch options. These torch options range from a "standard" head using a single-entry torch and a single wire feeder to more complex torches for Narrow Groove Welding, Remote Welding with Vision and Hot Wire Welding. It can be ordered or retrofitted with numerous application-specific accessories, customizing the head for a user’s needs.

Narrow-Gap Torch

The Arc Machines' type NGT-B narrow-gap torch was designed to promote positive fusion of weld-joint side walls in heavy-wall pipe and vessel welds, with less heat input and quicker weld times than conventional narrow gap equipment. This torch uses a rotating tungsten, which provides mechanical manipulation of the arc and wire feed within the groove. The integral gas cup provides direct gas shielding of the tungsten and the weld metal. This combination, in conjunction with the rotating electrode and narrow preps, allows deposition rates that are higher than conventional cold-wire GTAW. Current weld preps being used are appoximately 0.5" wide (12,70 mm), in the root area, with a 3-9° included angle for welds up to 12" thick (304,80 mm). The clean, compact torch design simplifies process operation so that no special training is required for operators familiar with AMI orbital pipe welding equipment.

Features & Benefits 

  • 350 A torch
  • Wire size range: 0.030" - 0.045" (0,762 mm - 1,143 mm)
  • Standard accessories included to weld up to 6" wall thicknesses (152,40 mm)
  • 2 video cameras
  • Torch set-up in 2" (50,80 mm) increments to minimize radial clearance
  • Water-cooling
  • Reduced weld time
  • Reduced component distortion


0.375" wide (9,525 mm) gas cups for special applications are available

  • Arc Voltage Control
  • Oscillation
  • Travel Speed
  • Vision System
  • Wire Feed
  • Wire Manipulator

Quick Specs

Torch AVC Stroke 4" standard (position encoder)
(101,6 mm)
Travel Speed 0.2 to 20 IPM
(position encoder)
Wire Feed Speed 5 to 200 lPM
Torch Water-cooled 300 ADC, 100% Duty Cycle (typical)
Torch Adjustments Torch specific
Tungsten Size 3/32", 1/8" or 5/32" (torch specific)
(2,4 mm, 3,2 mm or 4 mm)
Torch Cross-seam Steering Range 4" standard (position encoder)
(101,6 mm)
Maximum Wall Thickness Depends on torch type, options and accessories
Torch Oscillation Amplitude, max.  4" standard (up to 16" optional)
(101,6 mm - 406,4 mm)
Wire Manipulator Vertical, horizontal and angular (manual adj.)
Filler Wire Size: 0.020" - 0.045"
(0,508 mm - 1,143 mm)
Wire Spool Size 10 lbs., 8" spool (standard)
(4,5 kg, 203 mm spool)
Radial Clearance Range Depends on pipe diameter, torch type and configuration
6.56" minimum (166,6 mm)
Axial Clearance Range Depends on torch type and options; 15.75" minimum (400 mm)