Fastener now comes in stainless steel

The process-free "Automatic" fastener is now being produced by Item in stainless steel, following higher than expected sales of other stainless steel components such as T-slot nuts.

Suitable even where vibration is present, automatic fasteners require only socket wrenches to fit (no drilling or tapping required), and are typically used as corner joints to build or modify aluminium frames where machining facilities are not readily to hand.

Automatic fasteners are a particular favourite of commissioning engineers who must work on site, but up until now could not be used in hostile or wet environments because even though zinc-plated, they would eventually corrode.

Silos Cordoba reaps benefits of strong steel

Without compromising on strength, the weight of the finished products has been cut.
This has resulted in reduced transport costs, lower fuel consumption and quicker erection.

As a result, one third of the transport costs has been eliminated and erection has been speeded up by around 20 per cent.

The designs are the result of determined work to put high-strength steels to optimum use.

Jose Cabrera Cuevas, technical executive at Silos Cordoba, said: 'Less material is needed than in the past for an equally strong or even stronger product.
'Some time ago, a delivery of new silos to Slovakia weighed 1,200 tonnes and needed more than 30 trucks.

'In the past, a similar delivery would have weighed 1,500 tonnes and would have needed 42 trucks.

'So we saved more than 12m3 of diesel oil by switching to high-strength steels.
'In addition to the cut in costs, the emissions also decreased,' he added.
High-strength steel strips are roll-formed at the factory directly from coils and are punched and cut into finished cover sheets of exactly the right shape.
The factory also includes production lines for roof parts, load-bearing structures and other parts needed for every silo.

The thicknesses of the high-strength cover sheets vary depending on their locations on the silo.

The higher up, the thinner the sheets.
Every silo is 'tailored' to the order.

The span of the silos produced ranges from small silo buildings measuring only a few metres up to the largest units that are more than 30m high and upward of 20m in diameter.

The volume of the largest silo is about 20,000m3.

Around 1,200 to 1,300 cover sheets are needed for the biggest silo, in addition to several load-bearing structural parts.

Silos Cordoba uses high-strength, hot-dip galvanized sheet steel with minimum yield strengths of between 460MPa and 500MPa for the cover sheets.
Untreated, hot-rolled steel with a minimum yield strength of 600MPa is used for the load-bearing structural parts.

Plans are afoot to use steels of even higher strength and the company is studying the possibility of going up to 700MPa.