In order to reduce the wear on the surface of the plant components, which are submitted to considerable mechanical and chemical degradation at high temperatures, we recommend that our clients use MARINI ENDURANCE special anti-wear sheet-plating. The result is longer lasting plants, with consequent reductions in the costs of maintenance and repairs.
What does wear mean?
We know that wear is a phenomenon which results in damage to the surface of two solid bodies which are in contact and in relative motion. There are various kinds of mechanisms involved in this phenomenology, but the one which effects the production of our plants most is one of the quickest and severest forms of wear and tear – abrasion.
By abrasion we mean the damage caused to a plate by the passage of particles of a material which are as hard as / harder than the plate surface itself, and this can have several results, each with its own characteristics.
The aggregates /RAP (abrasive material) are free flowing and through asperity they cut the surface of the plate which is less hard, constantly remove material and therefore reduce the thickness of the plate.
The aggregates hit the surfaces from several angles, resulting in micro-cracking and deformation, therefore weakening the surface through fatigue.
The two phenomena have a simultaneous effect and, in order to prevent them resulting in considerable reduction in thickness, the plates must be made from material which is harder than the aggregates. The harder the plates, the more difficulty the abrasive material has in cutting the surface, and so the amount of wear and tear is reduced.
Another factor which influences abrasion is the angle of incidence of the material i.e. the angle between the direction of movement of the abrasive body and the surface level of the plate. The inclination of the MARINI chutes have been designed for optimum material flow, avoiding the built up of deposits and limiting the phenomenon of wear.
Plant parts subject to wear
Thanks to 30 years experience and constant dialogue with our clients, MARINI technicians are aware that the parts which are most frequently subject to abrasion and require greater intervention and maintenance are the material discharge chutes, in addition to the central core element of the plant – the mixer. These plant parts are generally lined with HARDOX. However, when conditions deteriorate, we advise our clients to use MARINI ENDURANCE.
What is ENDURANCE MARINI ?
MARINI ENDURANCE consists of carbon sheet plates soldered with a high-density chromium carbide alloy lining, which increases resistance to abrasion, even at high temperatures, without effecting the flow of materials and the costs.
The thickness is optimum , and can vary between 6 and 12 mm, in order to guarantee the life-span required of the plant. The steel base guarantees the mechanical features required by the plant parts to satisfy job requirements.
This investment translates into savings in maintenance costs, which can be as much as 6 times higher that with the classic anti-wear materials (HARDOX or similar), when compared under similar working conditions.
The hardness of HARDOX used on standard plates on MARINI plants is however relatively high and, in any case, higher than construction steels. MARINI chutes are protected with HARDOX plates which are at least 400 HV. The MARINI ENDURANCE solution has a hardness value which is as high as 600 HV, which is maintained at high temperatures, unlike HARDOX and construction materials.
This solution is an advantage for all plants and becomes an absolute must for the entrepreneur who wants to avoid down-time and damage to his plant and who needs to work under the following conditions:
- with hard materials with a shape that can cause high levels of wear and tear (e.g. basalt materials),
- with RAP, especially when the exact nature and shape of the material is not known and which could be highly abrasive. In order to encourage the flow of the material, the chutes are usually heated, and it is known that high temperatures can have a negative effect on the hardness of the material. For this reason if RAP is used in the recycling ring, MARINI fits out the plant with a complete kit of resistances to heat the discharge chutes, together with MARINI ENDURANCE plates.
The plates have holes for quick and easy assembly and replacement with bolts. It is therefore possible to purchase the kit right at the beginning of the plant’s life, or it can be installed at a later date during retrofitting procedures.