Xylem Water Solutions - High-strength pumps for high-grade steel in the french alps.

High-strength pumps for high-grade steel in the french alps.

In 1908, French ironmaster Paul Giraud founded the Ironworks and Electric Steelworks at Ugine, a town located just a stone's throw away from Alberville, next to the Arly River. In 1910, this lovely valley in the French Alps witnessed the first steel casting in an electric furnace. With a hydropower plant in the area, electricity is in abundance for this type of production.

Today, the company is known as Ugine Savoie. Together with its sister company, Ugine S.A., Ugine Savoie is a world-class manufacturer of flat stainless-steel bars and a major European supplier of stainless-steel lengths of bars and wires. More than 270 grades of stainless steel are supplied to customers in the form of raw or semifinished products. About 70 percent of production is exported and sold globally through more than 50 agencies and representatives.

Stainless steel bars ready for final inspection and shipping.
Ugine Savoie is also ISO 9002-certified, testifying to its commitment to having a total quality approach to production.

The company's manufacturing base is in Ugine, where Ugine Savoie has its steelworks, rolling mill, drawing and finishing installations, research laboratory and commercial services employing a total of 1,200 persons.

The plant has been modernized since 1980. A Basic Oxygen Furnace (BOF) converter has been installed, as well as a continuous casting machine. As part of a recent modernization program, two ITT Flygt slurry pumps, model HP 5560, were installed to recycle water containing highly abrasive particles from the continuous casting process. The pumps were chosen for their high operating reliability, low maintenance requirements and ability to handle abrasive liquids.

Production and casting of stainless steel
"We produce about 130,000 tons of stainless steel by melting scrap and metal alloys," says Olivier Bletton, manager of the Ugine Savoie steelworks. "The alloy is then refined in the BOF converter."

In Ugine Savoie's continuous casting plant, a ladle containing molten steel (1700'C) is positioned more than 20 meters in the air and pours the molten metal to feed a distributor. With the continuous casting technique, 50 tons of stainless steel can be produced in 50 minutes in the form of blooms measuring 205 x 205 mm, with a length of 3 m.

The molten metal is distributed along three casting strands formed by the ingot mold. After cooling gradually, the metal is cut with the flame of a blow torch and the blooms are tilted onto a run-out table.

The casting speed is one meter per minute per strand. Thus, every three minutes, three blooms measuring three meters in length exit the continuous casting installation incandescently.

Continuous casting and water
Water is used to cool the steel and to drain the waste produced from flame cutting.

According to Albert Carron, the engineer responsible for continuous casting, each ton of steel requires as much as 10 m3 of water. A recycling system for the water is therefore required to minimize water consumption and waste.

The water circuit includes a Hydroclone H centrifuge, which allows the water to return to a wet well via an overflow (see diagram). From the well, the P6 pumps feed the water via an F filter and cooling tower to a gravity feed tank.

From the tank, the P8 surface pumps feed water to the steel cooling system and the P 11 pumps deliver water for the flame cutting process. Water supplied during flame cutting of the strands causes the residue to granulate and form balls, which are easy to recycle.

Since the installation of the well, the P5 pumps supply the bottom of the casting strands in a sequential manner to "expel" the residue. Taking into account the different circuits in a cooling bed, the water in the well stabilizes at a temperature of around 60'C.

Modernization of the flame cabin and HP 5560 pumps for reciculating water
The entire continuous casting plant was improved in 1992 to boost production to a design capacity of 160,000 tons per year.

Among other measures, the cooling process was enhanced and the protection for the walls of the flame cutting cabin was improved.

When a steel bar is cut by the oxyacetylene torch, about 1 cm of metal is destroyed. Despite the granulation device described above, the large flames quickly destroyed the rear wall of the flame cutting cabins. When the plant was modernized, stainless steel walls were installed which are permanently cooled by water supplied by the P12 pumps, representing two ITT Flygt heavy-duty HP 5560 slurry pumps.

According to R. Monvignier of the Department for Research and New Works, Ugine Savoie selected the HP 5560 submersible pumps in chromium-alloy cast-iron because of their high operating reliability and minimum maintenance needs. The HP 5560s were also installed instead of long-shaft pumps to avoid the type of frequent repair work that was normally required on the long-shaft pumps on shaft lines P5 and P6 in the same well.

Due to the abrasive power of the suspended particles - even after decanting- the ITT Flygt pumps are equipped with an impeller and internal lining made of cast iron with a high chromium content (hardness: 55 HRC). The mechanical seals, made of solid tungsten carbide, have been specially developed for hard-wearing applications. To further prolong the life of the seals, a flushing system is employed in this application. Despite their elaborate design, these submersible pumps were delivered in six weeks after they were ordered.

When maintenance is required, the pumps are simply hoisted out of the pit and serviced on the plant floor. A new volute liner can be installed in just a few hours.

Operation of the HP 5560 pumps
The two HP 5560 MT 630 (44 kW) pumps were installed and commissioned in August 1992. According to plant engineer Laurent Carcey, the pumps have operated trouble-free ever since the installation.

The first maintenance inspection will take place after two years. After more than 10,000 hours of operation, the delivery pressure of the water-service pump is about the same as the pressure of the emergency pump, indicating that wear and tear of the hydraulic components has been relatively minimal, despite the abrasive nature of the water.

The pumps are also equipped with ITT Flygt's HP stand and guide bar system. The pumps can be lifted for inspection and maintenance in a matter of minutes, without having to disconnect the pipelines or empty the well, which would bring production to a halt.

HP 5560, 44 kW Slurry Pumps at Ugine Savoie

Applications and operating conditions:

Recovery of cooling water from the cooling circuit of the oxyacetylene cabins (30 g/l of fine metallic oxides and metals).

Operating temperature: 60 degrees Celsius

24-hour operation with one pump, with one backup unit for emergencies.

Output: 175 m3/h

HmT: 35 m

Pumping of clarified water for secondary washing circuit.

Technical specifications:
The lower sealing of the pumps is designed as a "monobloc" casting to allow complete coverage of all components coming in contact with the pumped liquid. The seal supporting the seal rings is protected by a metallic casing to prevent it from becoming blocked by solid particles, string, cloth or similar material.
The pumps are of chromium alloyed cast iron (impeller, lining, wear cover and suction cover).
The horizontally split pump housing is made of grey cast iron covered in resin.