Materials

From our long experience in heat treatments comes our “know-how”.

BSA has developed and tested several different steel grades, various chemical compositions and heat treatment methods allowing to develop a more efficient roll manufacturing technology and an advanced quality of production. This leads to recommend to customers selected special materials in order increase output tonnage and life time of rolls, through improved hardness, wear resistance, toughness and compressive strength.

BSA has only selected European raw material suppliers for forging blanks.

All materials are produced and heat treated according to our own technical specifications in order to achieve the best microstructure and mechanical properties of leveler rolls. The best combination of alloy elements, carbides distribution and mechanical properties are essential to perform during production.

All the materials are passed through quality inspection to guarantee the best workability properties.

All BSA work rolls are made of Chromium, Molybdenum and Vanadium steel grades to match all the customers requests for hot and cold working application and for all the different configuration of leveling equipment.

The availability of raw materials it is guaranteed from our stock of forged bars that consists of over 2000 tons of steel. A material stock range from diameter 10 mm up to diameter 410 mm in maximum length of 8 meters to satisfy customer requests. Our stock guarantees stability in quality and constant manufacturing capacity so to feed the mechanical operations with speed, consistency and flexibility.

There is no standard rule to fix which is the grade that can guarantee the best working performance. The choice depends on several production conditions, among which: nature of the rolled material (carbon steel, stainless steel, aluminium, copper, …) and relevant hardness (tensile strength), type of rolling conditions like speed, plasticization rate, presence/absence of vibrations or impacts and the surface condition of the strip (cold rolled / hot rolled / pickled …).

MATERIAL PROPERTIES

Influence of elements in steel chemistry

C:

Carbon is the most relevant element to control hardness charateristics, it is necessary to guarantee the correct martensitic tansformation.

Caution:

High C rate can lead to reduced toughness and is the principal cause of brittleness.
High C rate can give final undesired metallic structures leading to lack of wear resistance
High C rate is responsible of thermal shock sensibility and heating cracks propagation.

Cr:

Chromium carbides increase wear resistance, evenly increase the hardenability, break corrosion phenomena at high temperature, decarburization and oxides, increase mechanical characteristics at high temperature conditions, improve polishability.

Mo:

Molybdenum is responsible for steel hardenability, increases surface hardening depth because it decreases the critical cooling rate, guarantees uniformity for cross-section hardness, helps to keep small the austenitic grain during heating leading to fine martensitic structure.

V:

Vanadium is responsible for high yield strength and elongation and increases compressive strength, giving steel the best toughness and shock resistance cababilities; further increases wear resistance and helps to guarantee low grain size after hardening.

Ni:

Nickel increases the mechanical characteristic leading to high tensile strength meterials, slightly helps hardenability and increases impact strength.

CHROMIUM:

FOR BETTER WEAR RESISTANCE

MOLYBDENUM:

IMPROVE SURFACE HARDNESS

VANADIUM:

INCREASE TOUGHNESS AND FLEXIBILITY