Adamite rolls have a carbon content of 1.5% to 2.3% with various alloy elements such as Cr, Ni, Mo, and V. Generally, the mass fraction of free carbides is about 6% to 10%, with small hardness drop and high wear resistance. The rolls have high performance, good toughness, significantly reduced consumption, improved surface quality of profiles and rail beams, etc. They are widely used to replace cast steel rolls and low-alloy cast iron rolls, such as large-sized steel rough rolls, profile steel rolling mills, intermediate rolling mills, work rolls in the hot rolling strip continuous mill, etc. The carbon content and alloy element content of the semi-steel rolls are adjusted according to the applications of the rolls and the corresponding heat treatment process is used to control the roll structure with different matrix, carbide content and morphology to meet the requirements of different rolling mills.
Adamite Roll
Adamite rolls have good abrasion resistance and the chemical composition contains various alloying elements. The carbon content of the alloy adamite roll is usually between 1.2-2.3%, the rest alloy elements contain Cr, Ni, Mo V, etc. It has the feature of small hardness drop, good wear resistance, good toughness, significantly reduced consumption and the surface are made of the quality of section steel and beams is improved obviously. In addition, the semi-steel adamite roll is cast as a whole and there is no weak interface in compound casting roll, thus it has a better capacity, strength and toughness than cast iron roll. The rolls can be used as work roll, back-up roll and vertical roll for large-class and medium-class rough rolling mill and intermediate rolling mill of section steel, wire rod, rail beams, steel billet, hot rolling steel strip. TINVO adamite rolls have standards including ISO, GB, ASTM, DIN，JIS.
Most of the semi-steel rolls are produced by the static integral casting method. The centrifugal composite semi-steel back-up rolls are made of semi-steel material, the body and neck of the rolls are made of nodular cast iron, and they have been successfully used in hot-rolled strip steel finishing mill. The semi-steel roll ring is produced by composite centrifugal casting. The outer layer of the roll ring is a high-carbon semi-steel. The inner layer of the roll ring is graphite steel or ductile iron. Use a high-speed rotating centrifuge to make two different types of molten steel poured and cast.
Adamite rolls must be subjected to high-temperature diffusion annealing. Generally, semi-steel rolls are required to control the total amount of non-metallic inclusions below 0.05%.
Application
Work roll, back up roll and vertical roll for section steel mill, wire rod and bar rough rolling, medium rolling mill, large and medium section steel rolling mill, rail beams, steel billet mill, universal section steel mill; hot rolling steel and strip rough rolling mill.
Graphitic Steel Roll
Graphitic steel roll is in semi-finished condition. The carbon content and matrix are similar to adamite roll. It also has some features and usage similar to semi-steel roll. The microstructure consists of pearlite, carbide and precipitated graphite, which acts to improve wear-resistance and hardness. The roll is ideal for mills having problems with firecracking. It can be widely used as a work roll of medium plate reversible rolling mill, blooming mill, steel billet rolling mill and high-speed wire rod roughing mill bar. The TINVO graphitic steel roll has quality standards including ISO, GB, ASTM, DIN.
The graphitic steel roll refers to add an appropriate amount of inoculant alloy and nodulizing agent in the molten steel through controlling the content of graphitizing elements and carbide forming elements and the corresponding proportion, to inoculate and nodulate During the solidification process, the rolls form spherical or agglomerated graphite.
The carbon content of graphite steel rolls is equivalent to that of smil-steel roller. The microstructure of the matrix is similar to that of a smil-steel roller. There are still wear-resistant particles with granular and rod-shaped carbides in the matrix structure, and there is a certain amount of spherical graphite in the matrix structure.
According to the purpose of the roll, the carbon content, alloy element content, and hardness requirements of the graphite steel roll can be adjusted, and the content and morphology of carbide and graphite in the structure can be controlled.
Application
work roll of two-high strip mills machine, medium plate reversible rolling mill, rough rolling mill, blooming mill, steel billet rolling mill, high-speed wire rod roughing mill.
For more detailed information, please visit the page of TINVO mill rolls
The research on the material of cold-rolled work rolls has always been highly valued by the roll industry. From the initial bearing steel, it has gradually developed to 2% Cr, 3% Cr, and 5% Cr section steel. Its development is usually based on the continuous improvement of chromium content. In recent years, semi high-speed steel and high-speed steel roll materials have been developed and there have been some reports on their microstructure and carbide research. The technicians have studied the quenching process of a newly developed forged high-speed cold-rolled work roll material and analyzed the quenching temperature on the structure, grain size, residual austenite and hardness of the high-speed steel rolls, which provides the theoretical and experimental basis for the development of high-end cold-rolled work rolls.
The new type forged high-speed steel roll material used in the test was smelted in a 50kg vacuum induction furnace and then forged at a high temperature to produce a 100mm × 100mm × 250mm billet, which was annealed at 700°C for 4h to obtain the test raw material. The metallographic sample is a 15mm × 15mm × 15mm block, which is heated at different temperatures by a box-type resistance furnace and quenched by air cooling. The hardness was measured using a 660RLD / T Rockwell hardness tester and the residual austenite was detected using an X’perPro X-ray diffractometer, the structure and grain size were measured using an Axiovert200MAT optical microscope, and the carbides were observed using a QUANTA400 scanning electron microscope.
The microstructure of the new forged high-speed steel rolls is lower bainite + bainite + a small amount of martensite + bar carbide + granular carbide. Among them, large bar carbide is precipitated during the solidification of molten steel. Primary carbides, granular carbides are secondary carbides precipitated from austenite during cooling, and the carbide content is 3.6%.
The quenching temperature of the forged high-speed steel roll
(1) The quenching temperature affects the dissolution of carbides. As the quenching temperature increases, the carbide content in the quenched structure of high-speed steel rolls gradually decreases. When the temperature increased to 1200 °C, the granular carbides had been basically dissolved, leaving only a small amount of massive carbides.
(2) With the increase of quenching temperature, the grains of high-speed steel continues to grow. When the quenching temperature exceeds 1040 °C, the grain growth tendency is obvious. The quenching temperature exceeds 1160 °C and the grain size reaches 4.5, then the grain coarsening will become very serious.
(3) As the quenching temperature increases, the residual austenite content increases continuously. When the quenching temperature is below 1080 °C, the residual austenite content increases relatively slowly and then its content increases sharply. When the quenching temperature reaches 1160 °C, the residual austenite content increases to 38%. So the quenching temperature should be lower than 1080°C, considering the control of residual austenite content.
(4) When the quenching temperature reaches to 1040 °C, the hardness reaches its peak value of 64.1HRC. At this time, the matching of the structure, grain size and residual austenite content could be the best for the high-speed steel roll.
(5) The quenching temperature of the new-type forged high-speed steel roll materials should be selected between 1020 ～ 1080 °C.
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The purpose of steel rolling production line is to obtain the required shape, such as steel plates, strip steel, wire rods and various sections, another aspect, in order to improve the internal quality of steel like common automotive plates, bridge steel, boiler steel, pipeline steel, etc. Steel rolling is a continuous and uninterrupted operation. The steel strip runs fast on the roller table with automated equipment bringing high efficiency. Depending on the different temperatures in the rolling method, the steel rolling can be classified into hot rolling and cold rolling. According to the different relationships between the relative movement of the rolling stock and the roll during rolling, it can be divided into vertical rolling, horizontal rolling, and diagonal rolling. In the hot rolling production line, the billet is heated to become soft and is sent into the rolling mill by the roller table, finally rolled to the size required by the users. Compared with hot rolling, the processing line in a cold rolling mill is more scattered. The steel coils sent by the hot rolling mill must undergo three consecutive technical treatments and the oxide film must be removed with hydrochloric acid. Through the cold rolling mill, the uncoiler opens the steel coil and then the steel strip is carried to a five-stand continuous rolling mill to be rolled into a thin strip coil.
50K-300K Ton Bar Production Line
The steel bar production line with the annual capacity of 50K to 300K tons for the production of bars Φ8-32mm of common carbon steel, wire rod steel and low-alloy steel. The production Line uses 100×100--150×150 continuous casting billet, which of length 3000mm--6000mm and provided by the internal steelmaking continuous casting workshop. The annual output of 50,000-300,000 tons requires 330,000 tons of continuous casting billet, and the comprehensive finished product rate is 98% (considering negative deviation). It applies regenerative pusher type reheating furnace of gas fuel, the heating capacity is 40-80t/h. There are sixteen rolling mills divided into three group rolling mills of rough rolling, medium rolling and finishing rolling. The layout type is 6+6+4 H-V rolling mills and their main transmission adopts PLC control.
Φ8~32 Rebar Steel Bar Production Line
The steel rebar production line is used for the production of Φ8-Φ32mm round bar, low-alloy steel and carbon structural steel. It is composed of a heating furnace, continuous Rolling mills and cooling bed. The auxiliary equipment includes pinch roller, swinging head scissors, chain type cooling bed, 100 hydraulic metal cutting machine and rolling table. The rebar production line is for sale at TINVO with powerful working team and technology support, best metallurgical design institute and lifelong after-sales & maintenance support.
50K-300K Ton Wire Production Line
The wire production line has an annual production capacity of 50K to 300K tons and can produce welding rod steel, Φ5.5-Φ20mm round bar, bearing steel, etc. The whole line adopts full continuous twistless rolling, and the finishing mill adopts high-precision cantilever rolling mill with high rolling speed, high output, high product precision and high mechanical performance. The main equipment includes rough rolling, pre-finishing rolling mill, finishing mill which is a cantilever type twistless high-speed heavy duty rolling mill, pinch roller, wire laying machine, flying shears, water cooling system, transmission and automation.
The forged steel work roll is solid-forged roll made of alloyed steel, close to eutectoid and hypereutectoid steel. It has a good combination with the hardened surface which creates a strengthened working layer, heat check and tough core resistance to breakage. Heat treatment reduces and equalizes residual internal stress.
Feature
High Hardness
The high hardness and great depth of hardness are needed for cold reduction mills.
Increased Heat Resistance
With the strong heat resistance, the roll can be capable of retaining high hardness with the roll under continuous and constant heating rate.
No Metallurgical Flaws
High Resistance
It is also can ideal hardness and high resistance to spalling, surface flaws, cracks, scaling,etc.
No Microstructure Flaws
The surface microstructure consists of fine grain martensite and finely dispersed chromium carbides.
Application
Tandem mills
Reversing cold rolling mills
Temper mills
Forged Steel Work Rolls Used In Rolling Mills
Hot Rolling Mill
The forged steel work rolls can be used for hot plate mill and these rolls have the features of rich in alignment, high toughness and strong wear ability. They are made of forged steel blanks and can withstand the special heat treatment for excellent hardness.
Cold Rolling Mill
The work roll can be used for cold rolling mill. The forged rolls are produced by steel-making, refining and forging. A homogenous highly dispersed structure provides mechanical properties of the internal layer for complicated heat treatment. It becomes easier for exceptional performance by using the forged rolls which are applied in cold rolling mill.
Forged steel roll is an important mill roll with its outstanding working performance. It can be used as work roll, back up roll and intermediate roll with its high hardness, superior yield strength and high resistance to spalling, fatigue, scaling, etc.
Mill rolls are essential in the metal working industry. They are manufactured to an optimum hardness to resist wear and prevent marking. Forged steel roll is a type of rolling mill rolls. The roll has a microstructure that allows the surface finish to be resistant to thermal shock and a hardness depth prevents rehardening in subsequent applications.
Firstly, we give some basic knowledge about the forged steel roll including the definition, types, feature, chemical composition, etc.
What Are Forged Steel Roll
Forge steel roll provides a mill roller solution for rolling mill. It is one of the most wear parts during the rolling process. It is mainly made of forged steel. It is forged in hydraulic presses for high toughness and pureness, widely used in cold rolling mill, steckel mills and continuous hot strip mills. As different rolling mills have specific requirements and various rolling conditions, different alloy elements can be added into the steel for higher performance of the roll. The roll covers forged steel work roll or intermediate roll, forged steel back up roll.
Forged Steel Roll
Definition
The forged steel rolls are made from steel ingots by forging, which can solve metallurgical defects such as loose and shrinkage holes in the ingot, and crush the coarse cast structure to obtain superior quality roll with high resistance.
The production process includes smelting, ingot casting, forging, post-forging heat treatment, rough processing, final heat treatment and finishing.Feature
High Toughness
Surface Hardness Uniformity
Fatigue Resistance
High Hardness And Durability
Application
It is mainly used as strip rolling mill working roll and backup roll and is a high speed roll (HSS roll) for tandem and reversing cold reduction mills.
Forged Steel Back Up Roll
Definition
The forged back up roll is a mill roll that supports the work roll and intermediate roll for the purpose of avoiding deflection of the work roll and affecting on the yield and quality of the plate and strip rolling mill. This is the key function of back up roll to ensure the operation of the whole rolling mill. The common materials are 9Cr2Mo, 86CrMoV7, 70Cr3Mo with 0.80% to 0.95% carbon content 2% Cr content. The diameter of roll body ranges from 350mm-1600mm.
Feature
High Rigidity
The back up roll requires high rigidity to ensure the smallest deformation for supporting work roll.
Good Fatigue Resistance And High Peeling Resistance
The backup roll always need to support work roll or intermediate roll. Overloadig cause the subcutaneous miccrocrack propagation and roll body peeling off. So the excellent fatigue resistance is necessary.
High Surface Hardness With Good Hardness Uniformity
Outstanding surface hardness ensures the exceptional wear resistance and can reduce the formation of concave roll shape.
Excellent Yield Strength And High ToughnessTo guarantee the long service life, the deep hardened layer of roll body, good strength and toughness of roll neck and roll body and strong anti-accidents are required.
Application
Forged steel back up roll is applicable for 4-Hi mill, 6-Hi mill, and other some small mill.