PRODUCTS & EQUIPMENT


Saddle cut bevelling tool from Protem saves time and improves weld quality


A


s any pipefitter knows, joining a new branch pipe to an existing main line involves a


saddle cut, which is sometimes referred to as a fish mouth because the shape of the cut resembles the open mouth of a fish. The saddle cut is created to


produce a T-shaped joint to join the branch pipe to the main pipe. Once the saddle has been cut and properly fit, the field weld can be executed. The traditional method for making the saddle cut, however, is easier said than done. Back at the shop, pipefitters mathematically lay out the saddle on the pipe or use a paper template, a method of trial and error. For the latter, the paper template is wrapped around the pipe and traced with chalk. They then take a hand-cutting plasma torch or oxyfuel torch and slowly rotate the pipe, following the chalk line they created. For the latter, the paper template


is wrapped around the pipe and traced with chalk. They then take a hand-cutting plasma torch or oxyfuel torch and slowly rotate the pipe, following the chalk line they created. The process sounds simple, but


because it’s cut by hand, it’s not always consistent, which requires a lot of grinding to make sure that the profile fits good enough to weld. Typically, though, one pass of grinding and fitting isn’t sufficient. And that’s where regrinding and


refitting – and sometimes guessing – comes into play. Pipefitters will grind on the cut, hold it up to the main pipe and look for gaps and high spots, trying their best to make a tight fit while keeping the angle of the branch and length of the branch per print.


Depending on the skill of the 14 IMT April 2019


welder and the pipe sizes, the process can take from 20 minutes to an hour and a half When cutting is carried out by a thermal process, such as oxy-fuel, plasma, or laser, the cut quality may prove to be satisfactory when made by an experienced operator or with the help of an automated system. However, in most cases, these


techniques create a heat-affected zone (HAZ) close to the cutting point. Significant heat input changes the material’s physical characteristics, which causes significant changes in a weld’s strength. The area in question


requires another step, machining, to eliminate the HAZ. Using a tool designed for a specific purpose—in this case, for beveling saddles—helps to ensure consistency in bevel angles and dimensions, which assists in making welds that are robust and durable. Fortunately, in recent years, a


new tool has been developed by PROTEM that will enable the pipe fitters to simply insert the machine, expand the mandrel, and complete the correct and accurate profile in minutes. The advantages are quite


obvious, the cold cutting function www.internationalmetaltube.com


removes the danger of heat changing the metal’s properties…….. the debris, sparks, fumes, and physical dangers to workers are eliminated…


And the time to prepare (which


can take up to one hour using conventional techniques), is now reduced to minutes.


More information PROTEM USA : contact@ protemusa.com PROTEM FRANCE : contact@ protem.fr PROTEM GERMANY : info@ protem-gmbh.de


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