Hot Rolling mill work rolls.
In hot rolling mills, a work roll is a critical component that plays a vital role in the metal forming process. It is a cylindrical shape roll that is used to deform the metal and reduce its thickness. The work roll is positioned between the backup roll and the metal material being rolled. It exerts pressure and applies force on the metal, causing it to undergo plastic deformation. This deformation helps in shaping and reducing the thickness of the metal, ultimately achieving the desired dimensions and surface finish. The work roll is typically made of a high-quality steel material that can withstand the high temperatures and pressures involved in the hot rolling process. Its durability and precision are crucial for maintaining the quality and efficiency of the rolling mill operation. There are many types of work rolls available, you can choose according to your requirements. Let’s understand the basic of rolls types and their compositions.
SG Iron Roll…
SG iron roll, also known as spheroidal graphite iron roll, is a type of roll used in hot rolling mills. It is highly durable and has excellent heat resistance properties, making it suitable for the demanding conditions of hot rolling processes. SG iron roll is made from spheroidal graphite iron, which is a type of cast iron that contains graphite in the form of small spheroids. The chemical composition of SG iron roll typically consists of a high percentage of carbon, along with elements such as silicon, manganese, and small amounts of other alloying elements. This composition gives SG iron roll its superior strength and wear resistance, enabling it to withstand the high pressures and temperatures involved in the hot rolling of metals.
Spheroidal Graphite Cast Iron (S G Iron) or Ductile Iron is considered as one of the most versatile roll materials now a days. It is produced by a small proportion of magnesium added to the melt as nickel-magnesium or alternative alloy, or as pure magnesium. In S G Iron Roll, the free carbon takes the shape of spheroidal or nodules, thereby eliminating the notch effect of flake graphite and improving upon the mechanical properties of the cast iron. Bainitic Acicular is more alloyed with very higher percentage of Nickel and Molybdenum than the S.G.I. Pearlitic and as a result, the Acicular roll material has a Bainitic matrix with increased carbide.
S.G Iron Rolls are so superior in wear resistance to that of Cast Steel Rolls that they are specially adapted for rough and intermediate plate mills and rod , bar mill rough. As a result of the spheroidal form of the graphite, S G Iron Rolls are much strong than rolls of the clear-chill type and the gradual fall in hardness is an added advantage. As such, these rolls are particularly suitable for Skelp and Strip Mills, also Bar Billet Mills, and are being increasingly used for other applications.
| Symbol | Hardness (ShC) | C. | Mn. | Si. | Cr. | Ni. | Mo. |
| SGP45 | 45-50 | 2.80-3.40 | 0.30-1.00 | 1.50-2.30 | 0.30-0.80 | 1.20-1.80 | 0.20-0.40 |
| SGP50 | 50-55 | 3.00-3.60 | 0.30-1.00 | 1.50-2.30 | 0.30-1.00 | 1.50-2.00 | 0.20-0.40 |
| SGP55 | 55-60 | 3.00-3.60 | 0.50-1.00 | 1.40-2.30 | 0.50-1.00 | 1.50-2.00 | 0.25-0.50 |
| SGP60 | 60-65 | 3.10-3.70 | 0.50-1.00 | 1.30-1.80 | 0.50-1.00 | 1.50-2.50 | 0.30-0.60 |
| SGA60 | 60-70 | 3.10-3.50 | 0.50-0.80 | 1.30-2.00 | 0.50-1.00 | 3.00-3.50 | 0.80-1.10 |
| SGA70 | 70-75 | 3.10-3.50 | 0.50-0.80 | 1.30-2.00 | 0.50-1.00 | 3.50-4.50 | 0.80-1.10 |
Adamite Rolls…
Adamite roll is a type of roll used in hot rolling mills. It is made from a material known as adamite, which is a high-carbon alloy steel. The adamite roll is known for its excellent performance and durability in hot rolling processes. It is able to withstand the high temperatures and intense pressure that occur during the rolling of metals. Adamite rolls are commonly used in the production of steel and other metals, as they provide smooth and efficient rolling operations. These rolls have a long service life and require less maintenance compared to other types of rolls. Overall, adamite rolls play a crucial role in ensuring the smooth and efficient operation of hot rolling mills.
These rolls are special hyper-eutectoid steel rolls alloyed with Nickel, Chromium & Molybdenum. The extra carbon and special alloys give it extra wear resistance and strength These rolls are statically cast and undergo a special high temperature heat treatment process followed by tempering cycle to give a micro structure consisting of fine pearlitic matrix with spherodised / broken carbide. These rolls are suitable for rolling medium and heavy Sections where resistance is very important along with considerable amount of strength and toughness. These rolls are also used for roughing stand of Strip Mill.
| Symbol | Hardness(ShC) | C. | Mn. | Si. | Cr. | Ni. | Mo. |
| ASB-35 | 35-40 | 1.20-1.60 | 0.60-1.40 | 0.30-1.00 | 0.50-1.20 | 0.40-1.00 | 0.20-0.40 |
| ASB-40 | 40-45 | 1.40-1.80 | 0.60-1.40 | 0.30-1.00 | 0.80-1.50 | 0.50-1.20 | 0.20-0.40 |
| ASB-45 | 45-50 | 1.60-2.00 | 0.60-1.40 | 0.30-1.00 | 1.00-1.80 | 0.70-1.50 | 0.20-0.40 |
| ASB-50 | 50-55 | 1.60-2.20 | 0.60-1.40 | 0.30-1.00 | 1.20-2.00 | 1.00-1.50 | 0.25-0.45 |
