Cutting and welding pipe is an everyday occurrence in the O&G world, including new builds, MRO operations and turnarounds.
Yet when it comes to cutting and beveling pipe prior to welding, there are many different competing technologies to consider. We believe a solid case can be made that using cold cutting technology — machining the work — is the hot setup.
What does cold cutting equipment do? How does it work? Basically, it consists of industrial machine tools that are designed specifically for pipe, either OD mounted on the pipe circumference or ID mounted bevel tools that chuck into open ended pipe. OD mounted machines, popularly known as "split frames" or "clamshells," are designed to split in half at their frame to fit around inline pipe. They utilize two rings, one fixed and one stationary, that rotate tooling around the pipe to cut and bevel simultaneously.
Cold cutting offers major advantages. To name just a few: cold cutting, or machining, produces the most accurate cuts and bevels, it can perform complex bevels such as J preps and it does not use any open flames or produce any appreciable sparks. Sparks can be hazardous in any area where volatile hydrocarbons are, or were present, so open flames are not the hot ticket for these applications.
We believe a solid case can be made that using cold cutting technology — machining the work — is the hot setup.
Other benefits are that cold cutting does not produce a heat-affected zone that materially damages the structural integrity of the pipe. It does not require additional work like grinding after the machining process, so there is no potential for inhalation of dangerous hexavalent chromium particles. Cold cutting does not require a fire watch, and it can handle all metal types including high alloy and heavy wall. Additionally, split frames serve as the rotating platform for modules that perform many other common field machining projects, such as counterboring, flange facing and weld crown removal. One machine that serves as the centerpiece of the portable pipe machining world is the hot setup.
While other technologies have their place, they come with significant drawbacks in the in situ workplace conditions found in the O&G industry. Examples of these technologies include water jet, porta-band cutters and hot torch cutting and grinding. Water jets have an initial high-cost outlay and can create significant by-products from the high-pressure water spray and abrasive media used. Porta-band cutting is labor intensive and introduces a large amount of grinding dust, while torch cutting and grinding, though common, is the least safe alternative.
Using any technology that is not cold — in other words that uses or produces heat — or grinding that generates heat and sparks, completely changes the workplace dynamic. Any pipe or assembly that previously contained hydrocarbons presents an inherent risk of explosion when coupled with heat and sparks. While steps have been introduced to minimize these risks, such as plugs and gas inerting, anything less than perfection in these steps can lead to a catastrophic outcome.
What none of these other technologies offer is the precision and versatility of cold cutting machine tools. This includes their ability to deliver the complex bevel profiles required in modern welding procedures or in semi-automated welding. Nor can they produce the cut-line precision that cold cutting equipment can, down to within thousandths of an inch or to within a fraction of a degree in a miter-cut situation. This precision becomes of paramount importance onsite when fitting up large assemblies built offsite.
Additionally, non-cold cutting pipe technologies tend to be singular, where they perform one single task. By way of contrast, Wachs split frames can be equipped for parting, beveling, squaring, facing flanges, counterboring, external and internal casing cutting, tapering, transitions, out-of-round beveling and removing weld crowns to name just a few of their applications.
For more information, visit ehwachs.com or email sales@ehwachs.com.
