Bandsaw cuts wrought supperalloys quickly

Saw News

	'We consider that in the KASTOtec A7, we have acquired a premium product without having to pay over the top for it.' Simon Marshall, Managing Director, Special Quality Alloys
An Inconel 718 step forging being lowered onto the powered input conveyor of the KASTOtec A7 bandsaw at Special Quality Alloys, Sheffield.

Wrought nickel-based superalloys are high strength, corrosion resistant metals, used widely for safety-critical applications in the offshore and aerospace industries. A problem with these materials, however, is that they can be extremely difficult to saw.

One superalloy stockholder, Sheffield-based Special Quality Alloys (SQA), has identified what it believes to be the best bandsaw for cutting high-nickel-content alloy bars, billets and forgings, especially those of large cross section. After reviewing machines from three suppliers, at the end of 2006 it bought a KASTOtec A7 CNC bandsaw with a cutting capacity of 730 mm. The machine uses carbide-tipped blades almost all of the time, although bimetal blades are used occasionally for cutting softer alloys.

Commented Managing Director, Simon Marshall, “It is important to cut straight through these wrought alloys quickly without backing off the blade during the cycle, otherwise the material hardens at the point of contact, making it even more difficult to saw.

“The KASTO machine has proved to be ideal for these applications, reliably cutting some of the world’s toughest materials to one millimetre accuracy on length and squareness, despite working 24 hours a day.”

“Blade deflection monitoring, with automatic machine shutdown if the cut drifts out of tolerance, gives us peace of mind for ‘lights out’ cutting of materials typically worth over £20 per kilogram. The last thing we want is a piece of scrap costing thousands of pounds.”

“Moreover, the new A7 costs us less on maintenance than some other manufacturers’ bandsaws we use, which are more temperamental and constantly need money spending on them.”

It was the good performance of a 360 mm capacity KASTO bandsaw bought by SQA in the early 1990s, which is still operational today, that persuaded Mr Marshall and works manager, Jonathan Gillott, to return to the same supplier for the larger KASTOtec A7.

The Inconel 718 forging being prepared for carbide cutting on the KASTOtec A7 at SQA.  Works manager, Jonathan Gillott, is pictured right.

Its purchase reflects a steady increase over the years in both the size and volume of materials stocked.  As larger material is heavy to handle (a four-metre length of 660 mm diameter bar weighs in excess of ten tonnes), the machine has been supplied with a powered roller conveyor to facilitate material infeed to the saw blade.

There is another KASTO machine that is over 15 years old working every day at the stockholder’s US subsidiary in Houston, Texas, which was opened in 1999.  Staff there are said to be delighted with the performance of this older bandsaw and have subsequently purchased two newer machines, the latest, a KASTOtec A4, installed during 2007.

SQA is part of the Special Steel Group of companies, founded in 1925 by Bennett Beardshaw and currently run by his grandson, group chairman Alan Beardshaw.  The company moved to its present site in 1994.  Expansion in 2007 saw the firm’s stockholding capacity more than double to 4,000 tonnes, due to increasing demand from the oil, gas and power generation markets for its technically driven products and expert processing capabilities.

North Sea operations consume a large proportion of output after the sawn material has been heat treated, machined and tested in the group’s extensive range of facilities.

Overseas customers are many, with deliveries regularly made to Continental Europe, South America, Scandinavia, the Middle East and Asia. Batch size varies dramatically due to the customised nature of the products, so sawing machine qualities such as speed of set up, ease of operation, and safety in use are all-important areas of consideration.

Continued Mr Marshall, “Unlike some businesses which are looking to maximise short-term profits, perhaps at the expense of mid or long term growth and sustainability, our family-run company is 83 years old and here for the long term. We buy equipment accordingly, always looking to source top quality machines, as we feel that buying second-best plant is a false economy.

“We consider that in the KASTOtec A7, we have acquired a premium product without having to pay over the top for it. The machine has impressive capabilities for cutting a broad range of materials, as the operating parameters are wide and can be adjusted to within fine limits to optimise the cutting conditions.”

It is surprising how much faster the latest KASTO bandsaw is compared with the one dating back to the early 90s. Mr Gillott says that it is at least one third quicker at cutting tough materials.  They include Inconel 718 up to 635 mm diameter and high strength steels such as F6NM, Super Duplex and 17-4 stainless varieties up to 660 mm diameter, which is SQA’s other speciality.

Even compared with other makes of bandsaw on the Sheffield site that are only three to five years old, productivity is appreciably higher on the KASTOtec A7.