ASP08/E

Perucchini moulding process successfully solves the problems related to the drops of the material resilience at low temperatures. The strong development of the mining and mineral explorations in polar areas has involved the set up of new products and solutions able to work at temperatures lower than 40 degrees below zero (Fig. 1). These temperatures are not compliant with the traditional components made with standard commercial cast irons and steels, as, under a certain critical temperature, many kinds of steels lose their natural ductility and become extremely fragile and subject to breakdown. These “fragile” fractures are sudden and unpredictable, unlike the typical “ductile” breakings, that are preceded and accompanied by plastic deformations of the metallic structure, easily verifiable on the project (Fig. 2).

Perucchini castings are the ideal solution for low temperatures applications (<-40°C), such as refrigeration processes, storage and transport of oil or liquid gas, as well as military field; they are made in special austenitic steels with FCC crystal (face-centered-cubic) structure, capable to dissipate the energy introduced with the tensile strains (Fig.3) by plastic deformation of the crystal structure also at very low temperatures.

The special “full shell moulding” process of Perucchini also allows to obtain:• steel and cast iron castings, with absence of carbides and porosities• complex shapes and thin walls• close dimensional tolerance ranges (CT6-CT7 as per UNI ISO 8062 normative)• reduced draft angle (0°30’-1°)• low surface roughness (Ra 6,3 μm)• drastic reduction of the high machining operations costs

A successful example of these innovative developments is represented by the new inoxidizable hydraulic valves of Atos spa, on/off and proportional, with Atex, UL and Rostechnadzor certification (Fig. 4), that definitively solve the problems of reliability of the electrohydraulic plants in polar applications.

For further information look at www.perucchini.com

solubilizedstainless

hardenedstainless

carbon

Test Temperature °C

Abs

orbe

d en

ergy

J

200

160

120

80

40

0-200 -140 -80 -20 40 100

Fig. 3 - Steels ductility to T° change

Fig. 4 - Inoxidizable ex-proof valves

Full Shell Moulding for low temperatures (< -40°C )Stainless steel castings - high resilience

Fig. 2 - Fragile and ductile breakings

Fragile breaking

Ductile breaking

Fig. 1 - Oil pumps operating in Siberia

Perucchini has developed innovative castings that successfully solve the problems related to the drops of the material resilience at temperatures lower than 40 degrees below zero.

These special castings are manufactured in austenitic steels capable to avoid the risk of “fragile” fracture also at very low temperatures.

The special “full shell moulding” process of Perucchini also allows to obtain:• absence of carbides and porosities• complex shapes and thin walls• close dimensional tolerance ranges (CT6-CT7 as per UNI ISO 8062 normative)• reduced draft angle (0°30’-1°)• low surface roughness (Ra 6,3 μm)• drastic reduction of the high machining operations costs

This innovative development has made possible to realize a line of special stainless steel electrohydraulic valves specifically developed for military and oil fields polar plants.

For further information look at www.perucchini.com

Full Shell Moulding for low temperatures (< -40°C)

Inoxidizable ex-proof valves

ASP08/Esynthetic version