ADI DAYS - Simone Ricca

Austempering, A Technology for Substitution

ADI DAYS 2016 6th – 7th October Minerbe

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Replacement of a welding structure with an Austempered Ductile Iron (ADI) one

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Cometto Industries Activities



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Cometto Industries s.p.a is leader in design, production and selling of trailers, semi trailers and self propelled vehicles for heavy transportation.

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MSPE vehicles



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This type of vehicles, especially addressed to heavy lifting and transportation companies and to big steel and manufacturing

industries, allows the realization of movable lifting transportation of any dimension and load capacity until several thousands tons.

Electronic steering system that allows a very high handling in small areas, makes this product line really adapted for the transportation of very big and heavy loads for chemical plants, sea platforms and

wind turbine components.

MSPE vehicles are self prolpelled modular means that can be assembled side by side or back to back. In this way, they can compose a transportation mean with a

theorically unlimited number of axles.

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MSPE vehicles



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MSPE vehicles are equipped with «compass» hydraulic suspensions that allow to change the height of loading deck of 700 mm.

In this way it is possible to lift the payload without the use of special cranes.

Launching of the frigate of Marina Militare Italiana “Carlo Bergamini”. Tonnage: 7000 ton. Work done with 240 MSPE axle’s lines

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MSPE vehicles: improvement required



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MSPE 4/4/2.43 MSPE 6/4/2.43

Axle load 40 ton 40 ton

Dead weight 16.5 ton 24 ton

Gross weight 160 ton 240 ton

Payload 143.5 ton 216 ton

Technical data of MSPE Objective

of 50 ton/axle line

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MSPE vehicles: initial situation



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Lower part of suspension was electro welded structure Material: S690QL + S355JR Load capacity: 20 ton Weight: 99 kg

S690QLRp0.2 Rm A %

700 MPa 780-930 MPa 14

S355JRRp0.2 Rm A %

315 MPa 470-630 MPa 20

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MSPE vehicles: analysis of possible solutions



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Initial structure did not allow the increasing of load capacity. Increasing of thickness of metal plates was not possible because of the constrains due to cynematisms . 1 -‐ Possible solution: materials with higher admittable stress as S890QL

S890QLRp0.2 Rm A %

900 MPa 940-1100 MPa 12Stress distribution with 40 ton/axle line

Weak points: • More complex welding process(pre-‐heating,

interpass temperatures…) • Stress concentrations due to geometry (notch

effects) that can generate early fatigue phenomena. Hard points: • Low investments in production and assembly tools

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2 -‐ Possible solution: design of a new structure produced by casting.

Weak points: • Tooling

Hard points: • Increase of load capacity of 25 % with an

increase of 2 % of weight • Part more accurateand repeatable • Increasing of fatigue life due to reduction

of notch effects • Shape with less constrains • Reduction of components

Stress distribution with 50 ton/axle

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MSPE vehicles: choice of material



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Why using Austempered Ductile Iron JS/800-10?

Rp0.2 Rm A %

500 MPa1 800 MPa1 101

574 MPa2 847 MPa2 132

Rp0.2 Rm A %

700 MPa 780-930 MPa 14

rif. Weldox 700 by SSAB

1ref. ISO 17804 2ref. Infosheet Zandardi fonderie

Principal technical properties

JS/800-10 thickness < 30 mm

S690QL thickness < 30 mm

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Axle oscillating structure

New cast structure Material: JS/800-‐10 Load capacity: 25 ton Weight: 101 kg

Old electro welding structure Material: S690QL + S355JR Load capacity: 20 ton Weight: 99 kg

Conclusions…

Comparable production

costs

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Application of new structure



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Suspens ions w i th the s t ruc tu re i n austempered ductile iron are used on AIT 250 self propelled vehicle. This vehicle works in the Centre Spatial Guyanais to transport of sectors of rocket with solid fuel for vectors Ariane 5 and Vega.

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Application of new structure



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Cast structure Material: GJS 450-‐15 Load capacity : 20 ton Weight : 101 kg

Electro welding structure Material: S690QL + S355JR Load capacity: 20 ton Weight: 99 kg

Reduction of production costs:

20%

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Further application of ADI material on Cometto vehicles



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Reduction of

production costs: 35%

Existing solution

Cast structure Material: GJS 450-‐15 Load capacity : 25 ton Weight : 80 kg

Electro welding structure Material: S690QL + S355JR Load capacity: 20 ton Weight: 62kg

New solution

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Application of ADI material in Cometto EMT vehicle



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The Electrical Modular self propelled Transporter (EMT) is a vehicle for inside a n d o u t s i d e t r a n s po r t a t i o n s , c o n f i g u r a b l e , u s i n g L i F e P O 4 accumulators with all electrical functions (lifting, steering, travelling).

The axles of its suspension groups are produced by casting in JS800/10.

When the vehicle must comply ATEX requirements, the axle, thanks to its peculiar shape, in addition to resist to standard stresses of a steering and driving suspension, must contain an eventual inner explosion that increase an overpressure 27 times the nominal value.

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Application of ADI material in Cometto EMT vehicle



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EMT in steel industry



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Thank you for attention

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Engineering

ADI DAYS - Simone Ricca