Internal Welding Machine

The CRC-Evans Internal Welding Machine (IWM) is a combination internal clamp and automatic multi head internal root pass welding system. This machine is available in two variations; one for barge or offshore applications and one for land or standard pipeline right of way.

A self contained low voltage electrical source provides power for the shielding gas, air control valves, ring drive and wire feed motors. The pneumatic system, also self contained, operates the travel motors, brakes, drive wheels, aligners, and front and rear clamping shoes. Manipulation of the internal welder is controlled by an operator at the end of a 40’/80’ Reach Rod by a control box or by the master control box located on the nose cone. The lightweight tubular Reach Rod contains the control cable, all welding leads, air line, gas charge hose, and battery charge cable.

The welding heads are located symmetrically around the rotating ring and perform the root pass welding from the inside. The number of welding heads on the IWM varies between four and eight depending on the machine’s size (most machines have six or eight).

The CRC-Evans IWM is the most productive system for pipeline root pass welding. On a 36” pipeline, the root pass welding arc time less than one minute. The internal root pass technique is also more tolerable to pipe mismatch (high/low) than any other external root pass technique.

Features & Benefits


  • Multi-welding heads
  • Internal root pass
  • No root gap
  • Fully automatic welding


  • High production rates
  • More tolerance to high/low
  • Quick, accurate alignment
  • No copper contamination
Operational Specifications

Ring Drive Travel Speed

0-50 IPM

Wire Travel Speed

100-500 IPM

Shield Gas Flow

50-100 CFM

Shield Gas Pressure

Min 500 PSI Max 2,000 PSI

Air System Pressure

Min 170 PSI Max 210 PSI