This petroleum industry remanufacturer uses Tungaloy's robust 10-sided inserts, which can reduce the number of inserts used in intermittent turning operations. #case analysis

The remanufactured blowout preventer (BOP) is made of 4140 steel, and the surface is welded with Inconel. In order to process the seams to specifications, NOV uses TurnTen-Feed inserts in the intermittent turning operations.

In the intermittent turning process, the cutting tool will be subjected to huge strains due to the continuous separation and rejoining of the weld. This shortens tool life, increases costs and makes planning more difficult.

The sturdy double-sided TurnTen-Feed blade has rounded edges with MNW-style chip-breaking protrusions. In addition, a flat wiper edge along each cutting edge improves surface quality, even at higher feed rates.

After the Deepwater Horizon oil rig disaster in 2010, the United States implemented many new regulations for deep-sea drilling, requiring regular replacement of blowout preventers (BOP), which are designed to prevent future leaks. In order to reduce costs, oil companies turned to remanufacturers to restore the used BOP to specifications. One such remanufacturer is National Oilwell Varco (NOV), an international manufacturing company dedicated to the petroleum industry.

In order to restore the BOP to specification, the company welded it with Inconel and then processed the seam back to its original position. In order to process the excess material, the company performed intermittent turning operations, slowly lowering the tool onto the workpiece and cutting off irregular Inconel joints.

Unfortunately, when the cutting tool is engaged with the seam, it is subjected to tremendous pressure due to the continuous separation and re-engagement of the seam. The most laborious part of a cutting tool machining operation is the moment it comes into contact with the part, which makes intermittent turning particularly harmful to the cutting tool. For NOV, this actually means a large number of damaged blades.

According to the company, the variability of the seam and the interrupted passage means that each workpiece will chew 5 to 10 blades, which increases cost and processing time. In addition, the variability in the use of inserts makes planning more difficult. NOV needed a way to extend the life of its blades, so it eventually turned to Tungaloy.

Tungaloy has developed a 10-blade tungsten carbide insert called TurnTen-Feed, designed to improve durability and depth of cut in medium to heavy turning and roughing operations. The double-sided pentagonal inserts have rounded edges with MNW-type chip-breaking protrusions and flat wipers along each cutting edge to improve surface quality, even at higher feed rates. It also uses dovetail clips to improve stability and rigidity.

According to Tungaloy’s sales engineer Greg Davis, the characteristics of the tool allow it to perform deep cuts on strong materials without sacrificing durability or accuracy. "The blade has the strength of a round cutter, and 10 cutting edges can extend the tool life," he said. In addition, the tool uses its entire edge, not just a corner. This function distributes the cutting force to the insert instead of concentrating it on one point, thereby improving durability and increasing the potential feed rate.

The company sells two different blade holders. One is a high-feed (HF) tool holder with a high feed rate and a 22.5 degree approach angle. The feed rate can be as high as 0.079 inches per revolution. The other has an approach angle of 48.5 degrees, which increases the depth of cut per pass to 0.276 inches (7 mm).

Due to its special thickness and dovetail clamping, the blade has high durability, which has attracted the attention of NOV. This combination of elasticity and rigidity jointly increases the service life of the blade.

According to NOV, the company reduced the number of inserts on a single BOP from 5 to 10 per part, with only one or two per part. This resulted in a 70% savings in the cost of inserts alone. By reducing the time saved by the number of tool changes, the company saves even more.

The new blade also improves the processing technology. Before switching to TurnTen-Feed, NOV was able to reach a feed rate of 0.014 inches per revolution, but with the new blade, it was able to reach 0.03 inches per revolution. In addition, the company was able to more than double its feed rate while maintaining accuracy of 0.200 inches.

This simple conversion to a stronger blade has a huge impact on BOP remanufacturing operations. NOV not only saves time and money by reducing tool changes and increasing feed rates; it can also improve its order planning due to the reduced range of tools passed. Increasing productivity on the shop floor usually means making simple process changes where they are most needed.

To transition to hard turning, you need to switch from carbide inserts to CBN inserts, but this is easier (and more economical) than you think. It is jumping to a higher surface speed, which may scare you. It does not need. why is that.

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