Manufacturing process

Last updated on Fri, 02/04/2011 - 18:43

Hot blast cupola

The metallurgical furnace used at the SAINT-GOBAIN PAM plant of Bayard for smelting to produce its cast iron, is a hot blast cupola. The loads made of metal scrap and other components are continuously supplied through the top of the furnace, while air is blown, so that so that chemical reactions take place.

The blast furnace produces molten metal and slag.
The molten metal is continuously tapping and feeding the fore-hearth; the slag is rejected, whilst in the upper part of the cupola, the gas and dust are collected and sent to a combustion chamber. Permanent pre-heating is provided and speeds up the melting rate.
This is the principle of the hot blast cupola. This process enables the feeding with low quality scrap metal, which is particularly important in times of scarcity.

Spinning process

Ladles of melted iron are taken from the fore-hearth and supply the pouring boots, reservoirs at the head of the spinning machines, which contain enough to make several pipes depending on the diameters to be spun.

The pouring boot is equipped with an electric jack, lifting one sector for each spinning and releasing the quantity of melted metal required for a pipe.

Sand cores of Crowning sand are used to form pipe sockets. This sand has the property of hardening in contact with heat. It is burnt during the translation; the remainder is broken off by the operator before it moves on to the heat treatment.

Before each pouring, the chute and the trough are being blacked to avoid thermal shocks.

In this process, a constant flow of molten metal at perfectly controlled temperature and composition is gradually input into a steel mould rotating at high speed. The mould external wall is cooled by circulating water and the evenly distributed molten metal cools on contact with the wall before extraction.

The process is characterised by its quick cooling that gives a finer solidification matrix and thus a more homogeneous metallurgical structure.

The process is completed with a heat treatment of utmost importance for the mechanical properties of the finished pipes.