RMD root pass has been accepted by Chinese Owners andContractors

Welding plays a key role in the completion of deadline-driven construction projects in the energy engineering industry. More and more contractors and fabricators are looking for successful methods to meet owner's demands. Changing welding processes is one of the option that can help improve productivity and efficiency, to maximize the available skilled operators and complete jobs on time.


In refinery, petrochemical or power plant project, there's a lot of C.S pipe spool fabrication job. Conventional welding process, TIG root pass and SAW fill and cap pass is agreed by ownersand contractors. Now more and more famous contractors and fabricators are converting to Regulated Metal Deposition (RMD ) for root pass, SAW or GMAW for fill and cap pass.


Regulated Metal Deposition, or RMD Welding Process, is a modified short circuit transfer GMAW (MIG welding) technology. Miller Electric Mfg. Co. developed the RMD Process to reduce heat input and increase control of the metal transfer process (compared to short circuit transfer). Inpipe welding applications, the RMD Process provides the following benefits:

  • Easy learn and use. Reduce training time.

  • Faster travel speed thanTIG. For example, generally for CS pipe, TIG root pass speed is 110 to140mm/min, while RMD root pass speed is 170 to 200mm/min.

  • Potential to eliminate the hot pass.

  • Minimize clean-up time,as the process creates no slag and little or no spatter.

  • Create the ability to bridge wide gaps and compensate for less-than-optimal fit-up.

  • Enable using the same wire and shielding gas for subsequent passes with other GMAW processes.


NAEC R&D team integrate multi-processes, RMD, SAW, TIG into one station for automatic pipe welding by utilizing Miller Power Source. We programmed 40sets of WPS into our pipe welding station. It is suitable for different pipe material and can also utilizing different welding processes due to it flexibility.


Now combination of welding processes RMD+SAW+SAW or RMD+GMAW+GMAW for CS pipe spool fabrication have been widely agreed and accepted by most Chinese contractors and owners, such as BOMESC or SCCCNCEC, CNCEC 7, SINOPEC Nanjing Engineering Co., Ltd, SINOPEC Fifth ConstructionCo., Ltd.


Such welding processes are also used in South Pars Gas Field project and Saudi Jazan Integrated Gasification Combined Cycle Project because of stable welding quality and high welding efficiency.


NAEC will develop more solutions to adapt to challenges in fabrication and construction.

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