Reinforced boiler steel is obtained by rolling the material from slabs, which means a reinforced boiler plate is compressed by rolling. The quality of plates depends on the degree of compression, which should be at least twenty times. At the same time, the cast structure is being destroyed, the metal becomes denser, bubbles (in boiling steel) are completely welded. In plates, rolled from slabs, the degree of compression is higher than in plates, rolled from ingots.
A reinforced boiler steel sheet shows a tendency to aging in the hardened state (after rolling, bending or other cold plastic deformation operations). When staying at room temperature, the hardness and strength increase, and the ductility and toughness decrease. This process lasts for many months and is called natural aging. Heating the metal to 250–300 ° C accelerates the process. In this case, the impact strength can be reduced to a value of 5–10% of the initial one. Especially steel, deformed by 3-10% is prone to aging. In terms of technical conditions for the supply of steel plates, requirements for production methods, chemical composition, mechanical properties, volumes and methods of defectoscopic control are controlled by standard requirements. However, in advanced capitalist countries, nickel and molybdenum alloyed steels are more widely used, as well as steels that have undergone thermal hardening at the sheet manufacturer.
What are the ways of improving the process of making?
When developing new technical specifications for boiler steel plates, it is advisable to include tests on sharp-cut samples. This will help improve the quality of the plate and improve operational reliability during hydraulic testing, emergency situations and under extreme circumstances.
How are they made?
Boiler plates are made by rolling, pressing or traction. A reinforced boiler steel plate is produced by rolling. As a result of the pressure treatment, not only the shape changes, but also the structure and properties of the metal are significant. The enclosing panels of the main part are provided by a boiler plate steel, which is insulated for the machinery room and cold for boiler rooms.
The choice of configuration of the economizer when producing a boiler plate steel should be made while considering the requirements of manufacturability of the design, technical aesthetics and ease of economizer layout in boiler silt and outside the main part. Apparently, a more technological cylindrical design that requires a smaller number of technological operations and the number of welds is preferable. It is sometimes preferable to have a rectangular cross section configuration. The thickness of the steel sheet from which the economizer body is made does not usually exceed 4-5 mm. In EC-BMM economizers, it is basically 3 mm. To increase the rigidity of the structure we use strip steel, angles, channels.
Some USA companies produce steel plates with titanium by explosion method. The maximum dimensions of the cladding sheets are 2.5 m, the thickness of the base metal is from 5 to 30 mm, and the claddings themselves are 2-3 mm. The shear resistance of the clad layer is about 250 MN / m (140 MN / m minimal). Boiler steel is used as the base material, and cladding is made with pure titanium or titanium doped with palladium.