Any workshop has a plethora of machines for cutting metal pipes - a good portion of the floor space of any self-respecting shop is taken up by chop saws, cold saws, band saws and other large and heavy cutting devices.
However, if you're doing maintenance on existing objects, pipe will often need to be cut in situ. Anyone who's working on maintaining, fixing or upgrading an industrial facility such as a chemical factory or a refinery needs portable solutions for industrial pipe cutting, and this article is meant as a quick overview of such methods.
Cutting pipe in situ includes various operations that require varying levels of precision. These include such as cutting pipe lengths and prepping them for welding; cutting down pipes as part of demolition or equipment removal; excavating faulty welds for repair; cutting out valves for replacement; cutting and replacing pipe casing and so on.
Cutting lengths of pipe on site presents its own challenges; to do this, a tool needs to be portable, light, powerful and accurate all at the same time.
Some of the equipment designed for in situ pipe cutting and related operations includes portable hack saws and reciprocating saws. Many portable saws are pneumatic driven, because this reduces the weight of the tool by eliminating the need for an electric motor assembly - all the kinetic power is delivered via compressed air, making the tool, pound for pound, much more powerful than its electric counterpart.
When using hand-held tools like portable band saws, it's important to secure them to the work material using pipe clamps and to make the cut using guides for precision.
For cutting especially large pipes - such as oil pipelines - specialized orbital tube cutting machines exist. They are shaped like a ring that clamps onto the pipe, and have cutting elements that travel around the pipe in a loop. These machines can feature both mechanical cutters and torch cutters, and can bevel or process edges as well as cut them.
Torches are also well suited for cutting pipe - the acetylene torch is the reliable standby of a metal worker. Cold cutting is preferred whenever possible, because heat can alter the structural integrity of the material and weaken it; however, when it comes to speed and the ability to cut extremely hard metal, heat can be invaluable. Plasma torches are some of the few tools that can cut hardened high-carbon steel - most metal blades can't handle that material. (Though carbon steel is also one of the materials that lose their hardness under high temperatures.)
Unfortunately, unlike guided saws and abrasive cutters, hand-held torches don't leave very clean cuts; after cutting a pipe with a torch, the cut usually needs to be ground or abraded.
When it comes to welding in a new pipe segment, the existing sections need to be prepared by measuring and cutting pipe to length and forming "weld preps" that will make sure the weld holds solidly. Weld prep is done by grinding the pipe ends and smoothing them out, removing rust, corrosion, burrs, paint and slag. Grinding wheels of various diameters and coarseness are used for various stages of this process, from heavy stock removal to fine work. For prepping welds on smaller pipes, abrasive grinders are best - wire wheels aren't very effective for material removal. For prepping large-diameter pipes with precision, specialized weld prep machines are available - they can deburr, cut, bevel, flange and counterbore pipe.
These are just some of the types of on-site pipe cutting tools that you may use when doing maintenance on an industrial plant. Every day, the market sees new tools and methods that allow workers to cut, process and weld pipe more efficiently; keeping up with the new technology is a never-ending process of learning and improvement.
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