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A Real Heavy Hitter

A Real Heavy Hitter

Precision heat treatment with BALITHERM IONIT for components under massive pressure

Scot Forge and BALITHERM IONIT

16’500 US tons or nearly 15’000 metric tonnes: this is the almost unbelievable force generated by the new forging press from Scot Forge, a specialist in the area of heavy-duty open-die forging. It is one of the biggest presses in the world and didn’t only present the developers at Scot Forge with a number of challenges, but also the heat treatment experts from Oerlikon Balzers. This is because the press’s four main cylinder rods alone each weigh 25 US tons (22 tonnes) and thereby count amongst the biggest parts ever treated by Oerlikon Balzers.

The largest press Scot Forge has manufactured to date generates a pressing force of 6’300 US tons (5’700 metric tonnes). Quite an amount – yet still not enough for the increased demands the industry is placing on Scot Forge’s heavy-duty presses. “We wanted a press allowing us to process much more complex parts than in the past. Anyone who played with modelling clay as a child will easily know what we are talking about: it’s really easy to form modelling clay into a simple shape such as a cube; the more complex a shape is, however, the more force one must apply,” says Laura Diedrich, Scot Forge’s Marketing Specialist, explaining the demands.

Scot Forge’s expectations regarding the performance of its new heavy-duty forging press were soon clearly defined; however, no provider seemed able to fulfil them. “We therefore decided to develop our new press on our own, as we do for most of our machines,” says Laura Diedrich. The new press generates a force of 16’500 US tons (15’000 metric tonnes), making it one of the biggest open die presses in the world.

A jointly developed one-stop solution

In order to achieve the required level of precision and other attributes – maximum wear resistance and shape accuracy with minimal distortion – the engineers from Scot Forge spent a long time tinkering about to find the right coating for the press. Nitriding was soon discussed as a possibility, but the press parts were so big that the use of conventional methods had to be ruled out. “We joined the project very early in the planning process, when the new press was still only on the drawing board. The engineers from Scot Forge were just starting to look around for ways to manufacture these enormous parts,” explains Craig Reuter, Oerlikon Balzers Account Manager in the USA. Under the joint direction of Roman Gaida, Global Business Development Manager for Components Nitriding at Oerlikon Balzers in Liechtenstein, and the engineers at Scot Forge, a solution was developed which allowed even parts such as the four 25-tons (22 tonnes) main cylinder rods and the 8.4-metre return cylinder rods, each weighing 8.5 tons (7.7 tonnes), to be treated. In the end we were able to offer Scot Forge a one-stop solution, obviating the need to involve other providers,” explains Roman Gaida.

BALITHERM IONIT, a process for the plasma nitriding of steels, was developed by Oerlikon Balzers especially for the surface treatment of large components. To guarantee their safety throughout the entire process, a high-frequency plasma generator was combined with an automatic control system. The INAURA coating system in which this process takes place can accommodate components up to 10 metres long, 3 metres in diameter and weighing up to 40 tonnes – enough space for the different parts of the new Scot Forge press.

»The enormous parts of the Scot Forge press count amongst the biggest components Oerlikon Balzers has ever treated with BALITHERM IONIT. This presented us with a new challenge: the standard fasteners were unsuitable for the accommodation of the parts in our INAURA. So we worked closely with Scot Forge developers to also make the appropriate holders,” says Craig Reuter, illustrating the joint work involved.

Facts & Figures

Company: Scot Forge, www.scotforge.com
Challenge: One of the largest forging presses under construction in the northern hemisphere will experience galling and wear of chrome plating on huge pistons and connector rods. Thermal surface treatments have been proven to prevent galling, but the mammoth size of the parts took this option from the design table.

Objectives:

  • A nitriding vessel of sufficient size had to be be used.
  • Experts in the field of large component surface treatment had to be engaged to lock in design specifications for these unusual components.
  • Demonstration of prior success in the handling and treatment of massive and expensive parts was a key selection criteria.
  • Timely and safe turnaround required close logistical coordination with the supplier.

Solution: BALITHERM IONIT
Location: Spring Grove, Illinois, USA
Date of project: 2015/2016

Unique precision for maximum efficiency

The Scot Forge press is unique – not just in terms of size, but also because of the precision with which it creates near-net shaped parts. This means that extremely detailed parts can be formed, which, in turn, greatly reduces the amount of hard machining work needed to finalize a given part. The result: both Scot Forge and its customers save valuable time during machining.

Scot Forge is targeting customers from a wide range of sectors with the new press: aerospace, ship building, energy, defence, oil and gas, and mining, to name just a few. “For us, the new press does more than simply allow us to forge new and more complex structures than we could before. It also means that the parts we have been forging on our existing machines can now be produced much more efficiently,” says Laura Diedrich.

BALITHERM IONIT

BALITHERM IONIT and IONIT OX processes are the nitriding diffusion and nitrocarburizing brands for all types of steel and non-ferrous metals.

Plasma nitriding is an industrial surface hardening process in which molecular nitrogen and hydrogen are ionized under vacuum and react with an iron substrate.

The addition of carbon to the nitriding process and the subsequent oxidization lead to plasma nitrocarburizing, which creates an especially hard, wear resistant compound layer. Nitrocarburizing moreover significantly reduces the tendency of iron to react with other materials in the environment, for example lubricants.

  • Very good wear resistance
  • Extended service life
  • Improved corrosion resistance
  • Increased surface hardness
  • Environmentally friendly technology, as no harmful chemicals or gases are used in the process

Find more information at:
www.oerlikon.com/balzers/balitherm-ionit

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