A brief introduction to what is the knowledge of rolls
Source：Jiangyin Changfan Machinery Roll Co., Ltd. Author：709
1. Cast iron rolls
The carbon content of cast iron rolls is about 2.5%-3.5%. According to the main materials, they can be divided into four categories: ordinary cast iron rolls, high nickel-chromium infinite chilled composite cast iron rolls, high chromium composite cast iron rolls and alloy nodular cast iron rolls. The common structures in cast iron rolls can be divided into three categories: matrix, cementite, and graphite. The matrix structure is mainly tenite, ferrite, pearlite, bainite and martensite. The shape of graphite in cast iron is generally flakes. shape and spherical
1. Ordinary cast iron roll
Ordinary cast iron rolls can be divided into chilled cast iron rolls, medium and low alloy infinite chilled cast iron rolls, medium and low alloy ductile iron rolls, chilled cast iron is a kind of cast iron obtained by using the supercooling degree of molten iron itself and the cooling of the mold surface. The surface of the roller body is chilled to form a white layer, which has high hardness and good wear resistance. Chilled cast iron rolls can be divided into three categories: non-ductile iron, nodular composite, and spherical core according to the manufacturing process and core material. The infinite chilled cast iron roll is a material between chilled cast iron and gray cast iron. There is graphite in the matrix structure of the working layer of the roll body, and there is no obvious dividing line between the working layer of the roll body and the core. It's this low end roll. Ordinary cast iron rolls are mainly used for rolls for stacked sheet mills, three-roller Lauter-type medium plate mills, wire rod mills, bar mills and section steel mills.
2. High nickel-chromium infinite chilled cast composite iron roll
Infinite chilled cast iron is a material between chilled cast iron and grey cast iron. There is evenly distributed graphite in the matrix structure of the working layer of the infinite chilled cast iron roll body, and the graphite content is from the surface of the roll body to the inside. Increases with depth and decreases hardness
, Therefore, there is no obvious dividing line between the working layer of the roll body and the core, also known as the unbounded chilled cast iron roll. When the material contains high chromium, nickel and molybdenum alloy elements, it is high nickel-chromium infinite chilled cast iron. Rolls are produced by full flushing (overflow method) or centrifugal composite casting process.
There is a large amount of carbides in the matrix structure of the working layer of the high nickel-chromium infinite chilled cast iron roll body, so it has high wear resistance. The existence of graphite in the matrix structure makes it have good heat resistance and is widely used. It is used for finishing rolls in wide, medium and heavy plate mills and strip mills.
3. High chromium composite cast iron roll
High-chromium composite cast iron rolls are made of high-chromium white wear-resistant cast iron with a chromium content of 12-22% as the outer material of the roll body. Generally, ductile iron is used as the roll core and roll neck material, and is produced by centrifugal composite casting process. High-alloy composite cast iron rolls. Due to the existence of lath-shaped Cr7C3-type eutectic carbides, chrysanthemum-shaped Mo2C-type eutectic carbides and granular Cr23C6-type secondary carbides in the matrix, high chromium cast iron rolls have excellent wear resistance and are widely used. Do rough rolling and finishing work rolls of hot strip rolling mills, rough rolling and finishing work rolls of wide and medium plate rolling mills, and finishing rolling of small steel and plate mills
4. Alloy ductile iron roll
Due to the spherical uniform distribution of graphite from the roll body to the core, the alloy ductile iron roll has high tensile strength, can withstand heavy loads, and has good wear resistance. The matrix structure is carbide, pearlite or acicular body. Alloy ductile iron rolls can be roughly divided into two categories according to the matrix structure of the roll body: pearlitic ductile iron rolls and acicular ductile iron rolls. Alloy ductile iron rolls generally use integral casting. However, due to the high alloy content and large casting stress of the needle-shaped cast iron roll, the centrifugal composite casting process can be used to obtain the ideal comprehensive performance. Alloy ductile iron rolls have good thermal shock resistance and wear resistance, and are widely used as rolls for large blooming mills, section steel rolling mills, continuous bar rolling mills and large seamless tube rolling mills.
The carbon content of cast iron rolls is about 2.5%-3.5%. According to the main materials, they can be divided into four categories: ordinary cast iron rolls, high nickel-chromium infinite chilled composite cast iron rolls, high chromium composite cast iron rolls and alloy nodular cast iron rolls. The common structures in cast iron rolls can be divided into three categories: matrix, cementite, and graphite. The matrix structure is mainly tenite, ferrite, pearlite, bainite and martensite. The shape of graphite in cast iron is generally flakes. shape and spherical
1. Ordinary cast iron roll
Ordinary cast iron rolls can be divided into chilled cast iron rolls, medium and low alloy infinite chilled cast iron rolls, medium and low alloy ductile iron rolls, chilled cast iron is a kind of cast iron obtained by using the supercooling degree of molten iron itself and the cooling of the mold surface. The surface of the roller body is chilled to form a white layer, which has high hardness and good wear resistance. Chilled cast iron rolls can be divided into three categories: non-ductile iron, nodular composite, and spherical core according to the manufacturing process and core material. The infinite chilled cast iron roll is a material between chilled cast iron and gray cast iron. There is graphite in the matrix structure of the working layer of the roll body, and there is no obvious dividing line between the working layer of the roll body and the core. It's this low end roll. Ordinary cast iron rolls are mainly used for rolls for stacked sheet mills, three-roller Lauter-type medium plate mills, wire rod mills, bar mills and section steel mills.
2. High nickel-chromium infinite chilled cast composite iron roll
Infinite chilled cast iron is a material between chilled cast iron and grey cast iron. There is evenly distributed graphite in the matrix structure of the working layer of the infinite chilled cast iron roll body, and the graphite content is from the surface of the roll body to the inside. Increases with depth and decreases hardness
, Therefore, there is no obvious dividing line between the working layer of the roll body and the core, also known as the unbounded chilled cast iron roll. When the material contains high chromium, nickel and molybdenum alloy elements, it is high nickel-chromium infinite chilled cast iron. Rolls are produced by full flushing (overflow method) or centrifugal composite casting process.
There is a large amount of carbides in the matrix structure of the working layer of the high nickel-chromium infinite chilled cast iron roll body, so it has high wear resistance. The existence of graphite in the matrix structure makes it have good heat resistance and is widely used. It is used for finishing rolls in wide, medium and heavy plate mills and strip mills.
3. High chromium composite cast iron roll
High-chromium composite cast iron rolls are made of high-chromium white wear-resistant cast iron with a chromium content of 12-22% as the outer material of the roll body. Generally, ductile iron is used as the roll core and roll neck material, and is produced by centrifugal composite casting process. High-alloy composite cast iron rolls. Due to the existence of lath-shaped Cr7C3-type eutectic carbides, chrysanthemum-shaped Mo2C-type eutectic carbides and granular Cr23C6-type secondary carbides in the matrix, high chromium cast iron rolls have excellent wear resistance and are widely used. Do rough rolling and finishing work rolls of hot strip rolling mills, rough rolling and finishing work rolls of wide and medium plate rolling mills, and finishing rolling of small steel and plate mills
4. Alloy ductile iron roll
Due to the spherical uniform distribution of graphite from the roll body to the core, the alloy ductile iron roll has high tensile strength, can withstand heavy loads, and has good wear resistance. The matrix structure is carbide, pearlite or acicular body. Alloy ductile iron rolls can be roughly divided into two categories according to the matrix structure of the roll body: pearlitic ductile iron rolls and acicular ductile iron rolls. Alloy ductile iron rolls generally use integral casting. However, due to the high alloy content and large casting stress of the needle-shaped cast iron roll, the centrifugal composite casting process can be used to obtain the ideal comprehensive performance. Alloy ductile iron rolls have good thermal shock resistance and wear resistance, and are widely used as rolls for large blooming mills, section steel rolling mills, continuous bar rolling mills and large seamless tube rolling mills.