Composite Cemented Carbide Roll Pros & Cons - part1

(1)Cemented carbide roller install online, cemented carbide roller workers should carefully check the roll cooling water pipes and location, and then received special pipes up from the introduction of the hose. Hose access interface must use lead wire tied tight, to prevent shedding, roll in the cooling water status and cause serious consequences.
(2)Roll rolling process, should pay close attention to the operation state of the bearing, abnormal immediately stop and check.
(3)In order to reduce fatigue cracks, the surface of the cooling cemented carbide roller ring must be washed with water to reduce the surface of the thermal expansion. When rolling contact with the roll torus ring of the roll surface temperature up to 500-600 ° C, cooling water sprayed into the hot cemented carbide roller ring surface, will form a layer of film covering the surface of the roll ring, seriously affect the cooling effect, research that, when cooling the pressure reaches 0.5 MPa or more, the gas film is broken, and thereby improve the cooling effect. Low-speed rolling mill roll ring cooling water pressure should not be too large, to prevent the cooling water splattered not achieve the cooling effect, should ensure that the cooling water pressure 3-4Mpa 40-50 cubic meters of water / hour. The same time, in order to improve the cooling effect, the cooling water cooling water nozzle spray coverage should be a corresponding coincidence, and the outlet should be aligned with the roll ring at the outlet of the cooling water column. Cemented carbide roller rings on the acidity of the water quality there are special requirements: PH ≥ 7.2 weakly alkaline and clean.

Composite Cemented carbide roll lifting maintenance requirements

(1) Metalworking shop lathes and lathe under composite cemented carbide roll, lifting slower placed to light.
(2) Rolling workshop in the process of assembly, disassembly, and non-hard object impact roll.
(3) Roll and from the lifting of the metalworking and hot rolling plant, only one of a crane, shall not be a hanging two, in order to avoid collision damage.
(4) Such as the specification roll temporarily rolling, roll placed not be stacked, should be stored in a dedicated roller shelves. Inspection and maintenance of bearings block.
(5) Roll in the metalworking shop to be processed and rolling shop to be assembled, shall not be placed on the ground but placed in a special wooden mat.

Composite cemented carbide roll care and maintenance

It should establish more stringent, more comprehensive management system about composite cemented carbide roll than the cast iron rolls. On this basis, should note the following:
(1) Composite cemented carbide roll operation should be gently, to prevent the roll ring caused by the collision and impact.
(2)Should be taken annular cooling water pipes, a sufficient amount of cooling water required to provide effective cooling. Non-anhydrous rolling and non-rolling midway without water, without water rolling roll ring temperature higher water supply, will result in a broken roll.
(3) Among the roll, it should be noted that the roll groove anomalies observed in the mill intermittent time, the measured temperature is too high, and observe whether there are other anomalies.
(4)Slot roll tonnage can not be over than under the tonnage, or the surface micro-cracks will cause the roll crack, even if it does not crack will cause the roller ring grinding capacity increase, not economic.
(5) Should be of good quality material roll barrel, in order to ensure the strength of the roll. Often roll neck bearings and other key parts to be checked to avoid roll ring failure caused the accident.
(6) Departments and personnel related to the application of the composite cemented carbide roll respective system should be developed and enforced to help improve the overall management level, generate more economic and social benefits.

Composite cemented carbide roll regrinding

To achieve the rated life (roll tonnage), the correct grinding of cemented carbide roll is very important. In order to reduce, avoid the phenomenon of the cracks caused by the roll grooves of the broken roller, all crack completely worn away before the roll center is very important. Need to pay special attention to the problem of the micro hot cracking on the surface of the rolling groove must be completely worn away. Otherwise, when the rolls to re-start a new round roll with a residual crack, the danger of the broken roller will greatly increase. 

Composite Cemented Carbide Roll Installation

Cemented carbide roller is a high-tech means to create the high temperature thermal cracking of high-performance roller, the correct roll pass processing, maintenance, and can greatly improve the rational use of rolling destroy rolling tonnage, improve rolling stability, the mill production work rate and negative deviation rate. If used improperly, it will produce rolled destroy chunk off the meat, severe depth of the crack of the cemented carbide roller until the roll cracking scrapped, resulting in a serious waste (cemented carbide roller price to high NiCr roll the times). To be reasonable, scientifically cemented carbide roller, reducing the roll consumption, lower production costs, reduce labor intensity of the operator, to offer you the following cemented carbide roller note, for reference.

High Speed Thread Rolls

High speed thread rolls are one of thread rolls, the high speed wire, usually refers to high-speed twist mill rolling wire rod, the common ordinary low-carbon steel twist-free controlled cooling, hot-rolled plate strip (ZBH4403-88) and high-quality carbon steel twist and controlled cooling, hot-rolled wire rod (ZBH44002-88). High rolling speed of the line is in the 80-160 m / sec, per weight (for rent) 1.8-2.5 tons, high dimensional precision (0.02mm), by adjusting the process parameters during the rolling process (especially in the cooling line) to ensure that the different requirements of the product.

Cemented carbide roll ring features

High-speed wire rod mill cemented carbide roll ring has a very high wear resistance, but also has excellent impact toughness and thermal fatigue toughness. Cemented carbide roll ring has the following notable features:
Applicable to the rolling speed of more than 100m / s high-speed wire rod rolling, not easy to crack, broken roller off the meat;
Applicable to ordinary steel, alloy steel, high-speed wire rolling;
Suitable for high-speed cold rolling process;
The single-slot high amount of steel, rolled off the assembly line slot grinding less;

Rack Cemented Carbide Roll Rings Grades

Cemented carbide roll ring is a high hardness, good wear resistance of tools and materials. Hardness and abrasion resistance derived from tungsten carbide, toughness and strength is dependent on the binder metal, and make a hard roll ring to give full play to its high wear resistance, long life, high efficiency advantages in high speed wire rolling, Depending on the rack should be using cemented carbide roll rings select the correct cemented carbide roll rings grades.

How to use Cemented Carbide Roll Rings

Attention should be paid as follows when purchasing and using cemented carbide roll ring:

1. Grades selection
An overall understanding of the properties of cemented carbide grades of is a basis for correctly selecting the grades for cemented carbide roll ring used in the stands of rolling mills and an optimal combination of grades is required for the various stands of rolling mills.

2. Roll rings installation
Steel-case mounting and assembly of cemented carbide roll ring should be strictly performed according to the precision required by design process. Proper fitting is needed for the cemented carbide roll ring, roll mandrel for stands and conical sleeves, which can not be over tight or loose. When it is too tight, the roll rings are in a tensile state and more fluctuation of rolling force will make the roll rings break. When it is too loose, it causes leads the roll rings, roll mandrel and conical sleeve to slide relatively during rolling, which scratches conical sleeves and roll mandrel so resulting in cracks. Before running the mills make a check if thecemented carbide roll ring meets the needs and roll ring. the assembling faces of the conical sleeve and the roll mandrel need to be cleaned. It is forbidden to knock at the roll rings with a hammer or other hard materials when running the mill. It is forbidden for the roll rings to impact each other during the transportation and installation to prevent roll rings from damage.

3. Cooling and cooling water quality
Cooling is intended to reduce the influence on roll rings, thermal corrosion, fatigue and stress during milling. It can prevent the roll rings from cracking and slow down the diffusion of cracks, prolonging the life time of grooves. It plays an important role in optimizing the performance of roll rings. The reference data for cooling are as follows: the temperature of cooling water is below 25 ° C; pressure of cooling water is 5-6 bar with a water volume of 24-30 m3 /hr/stand. The water is jetted in a radial direction and the angle between the water jet and the rotating direction of roll rings is 15-30 degrees. The width of the water column is 2 times that of the groove and the water should be jetted directly into the grooves and the water should not be scattering or misty.

4. Reasonable rolled quantity
During rolling microcracks in grooves can not be avoided, and they need to be reground when they are at a certain depth (normally controlled at 0.2mm). Excess rolling causes the depth of microcracks to extend rapidly and dangers of crushed rolls increases, which should be prevented.

5. Regrinding of grooves
Microcracks will occur after the rolling of the groove for some time and when the microcracks extend to 0.2mm the cemented carbide roll ring has to be reground. Microcracks must be reground thoroughly when regrinding, otherwise the unground microcracks will make the microcracks extend more rapidly during the next rolling and probably make the roll ring crack. 

Cemented Carbide Roll Rings Applications

Cemented carbide roll ring is a kind of tool material which consists of tungsten carbide and cobalt with high hardness and wear resistance. To take advantage of high wear resistance, long life and high efficiency of cemented carbide roll ring during the high speed rolling. 

Three Dimensional Cemented Carbide Roll

3-dimensionall cemented carbide roll rolled ribbed steel appearance quality, dimensionally accurate, clear the ribs, while improving the overall performance of the reinforced. 3-dimensional cemented carbide roll repeatable grinding, grinding rolling capacity can reach 600 to 2000 tons, compared with ordinary tool steel rolls 20-30 times, which can effectively reduce production costs, improve production efficiency.

Metal Cutting Tools Materials

Tool is in mechanical manufacturing of tools for cutting machining, also known as cemented carbide cutting tool. Generalized cutting tool includes both the tool, further comprising abrasive. The vast majority of the tool is to machine, but also with the hand. The tool to be used in the mechanical manufacturing substantially are used for cutting metal material, so the term "tool" is generally understood as a metal cemented carbide cutting tool.

Tool material generally refer to the cemented carbide cutting portion of the cutting tool material. The merits of its performance are an important factor affecting the machining surface quality, and the cutting efficiency, the cemented carbide cutting tool life. Selection of new metal-cemented carbide cutting tool material is not only to improve cutting efficiency, process quality and reduce costs, but also craft key to solve some of the difficult-to-machine materials.

Metal cutting tool material can be divided into four broad categories: tool steel (including carbon tool steel, alloy tool steel, high speed steel), cemented carbide, ceramics, superhard tool materials. Generally, high-speed steel and cemented carbide are often used.

Usually when the high hardness, abrasion resistance is also high; high bending strength, impact toughness is also high. But the hardness of the material is higher, the lower the flexural strength and impact toughness. The high-speed steel has high flexural strength and impact toughness, and good process ability, modern still the most widely used metal cemented carbide cutting tool material, followed by cemented carbide.

Metal Cutting Tools Materials — High speed Steel

The high-speed steel is alloy tool steel containing more alloying elements such as W, Mo, Cr, V, and better overall performance, the widest range of applications of a cutting tool materials. After heat treatment hardness of 62-66HRC, flexural strength of about 3.3GPa, heat resistance to 600 ℃, addition, has the advantages of heat deformation small, can be forged, and easy to grind the sharp edge. The use of high-speed steel is a large proportion, especially for the manufacture of a complex structure of the forming tool. Such as various types of hole machining tools, milling cutters, broaches, thread cutting tools, gear cutting tools, etc.

Metal Cutting Tool Materials Overview

Performances metal cutting tool materials should have

In metal cutting process, the cutting portion of the cutting tools bear great cutting force and intense friction under high temperatures. Intermittent cutting work is along with the shock and vibration and cause cutting temperature fluctuations. Thus, the metal cutting tool materials should have a high hardness and high wear resistance, sufficient strength and toughness, as well as a high heat resistance.

Generally, metal cutting tool materials should have a hardness of more than 60HRC at room temperature. The higher the hardness of the material is the better the abrasion resistance, but relative to the lower impact toughness. So requires metal cutting tool materials to maintain sufficient strength and toughness conditions, as far as possible to have high hardness and abrasion resistance. High heat resistance is able to maintain at high temperatures, a characteristic of the cutting tool, is usually measured with the high temperature value, and to measure the heat resistance temperature value can be allowed when the cutting of the cutting tool. It affects important indicators of metal cutting tool material cutting performance. Cutting speed, the higher the better the heat resistance of the material allows.

Cemented Carbide Tools Cutting Layer & Mode

Cemented carbide cutting tools cutting layer parameters

Cutting layer of the cemented carbide cutting tools is the workpiece material layer to cut through the removal of the workpiece in a single pass of to the cutting portion. Cutting layer shape, size directly affects the deformation of the cutting process, the tool bear the load as well as the cemented carbide cutting tool wear. As shown, when the main and auxiliary cutting edges is straight, and λs = O °, KR> 0 °, the cutting layer to the nominal cross section ABCD is a parallelogram, if Kr = 90 °, or rectangular.

cemented carbide cutting tools cutting layer size refers metric length and width of the cutting layer in a cemented carbide cutting tool base surface, which is related to the cutting parameters ap, ƒ size. However, the direct impact of the cutting process is a cross-sectional view of the cutting layer, and its thickness, the width dimension.

Cemented Carbide Cutting Tools Working Angles

The installation position of the cemented carbide cutting tools, cutting Synthesis of the direction of movement changes, will cause a change in angle of the tungsten carbide cutting tools. Thus research during the cutting process the tool angle, the relative position of the tungsten carbide cutting tools with the workpiece, the relative movement to create a reference system on the basis of this reference system, said reference system. The tool perspective - that of the work reference system defined angle.

Cemented Carbide Tools Cutting Definition

Cemented carbide cutting tools composition

As shown in the figure, turning is made up of head, shank two parts. Head is used for cutting, shank used for clamping.

The cutting portion of tungsten carbide cutting tools is constituted by the rake face, cutting edge. Flank marked with the letter A and the lower corner of a symbol mark, the cutting edge is marked with the letter S. Minor cutting edge and its associated flank plus in the upper right corner of the tag write to show the difference.

Cemented Carbide Cutting Tools Motion

Cemented carbide cutting tools motion in the role played by relative movement of the workpiece and cemented carbide cutting tools machining, divided into the main movement and feed movement.

1. Main motion

The main motion is the most important cutting power consumption up to the movement; it is the relative motion of carbide cutting tool and the workpiece between students. The car, the main motion of the boring machine spindle rotation movement.

2．Feed motion

The feed motion of the additional movement is generated between the cemented carbide cutting tool and the workpiece in order to maintain the cutting performed continuously. Vf is cars cylindrical longitudinal feed speed of movement, it is continuous. Horizontal feed movement is intermittent.

3．Cutting layer

Cutting cemented carbide cutting tools to cut through the removal of the workpiece in a single pass of the workpiece material layer. Workpiece rotation time, the cemented carbide cutting tool just moved from position I to Ⅱ, cut the workpiece material between the layer I and Ⅱ. The quadrilateral ABCD is the nominal cross-sectional area of the cutting layer. Actual cutting layer cross-section is a quadrilateral ABCE , △ AED is the cross-sectional area of the remaining on the surface of the processed.

Cemented Carbide Cutting Tools Angles & Elements

Cemented carbide cutting tools geometry angles and cutting elements is on behalf of a turning tool, cemented carbide cutting tool cutting part of the basic definitions and terminology, tungsten carbide cutting tools geometry analysis and mapping methods.

Cemented carbide cutting tools geometry angles and cutting elements of the movement and cutting the amount of tungsten carbide cutting tools, cutting, cutting basic knowledge of tungsten carbide cutting tools, cutting layers of the working angle of the tungsten carbide cutting tools, tungsten carbide cutting tools and cutting detailed description of the way.

Different types of tungsten carbide cutting tools, the number of its flank, the cutting edge is different. The basic unit is composed of tungsten carbide cutting tools the two flank concurrent cutting edge, referred to both sides of the blade. Any complex tungsten carbide cutting tools can be divided into a basic unit of analysis.

Cemented Carbide Cutting Tools Basic Information

Dimensional accuracy and surface quality of the requirements of parts can be processed by the tungsten carbide cutting tools, the basic machinery manufacturing processing methods. Cutting is the removal of the excess material of the part to be machined tungsten steel cutting tools (cemented carbide cutting tools). Cutting tungsten steel cutting tools play an important role in the national economy.

The late Spring and Autumn Period, one of the earliest extant the engineering technology works Kaogongji, 30 professional and technical knowledge of woodworking, metalworking described above. The book pointed out that, the material art clever "made ​​good device. "Material beauty" refers to the use of fine materials; "Handicraft" refers to the use of a reasonable system of the appropriate process. Speculated by a large number of archaeological finds and literature, the latest in the 8th century (Tang Dynasty) China has the original lathe.

Tungsten Carbide cutting tools wide variety of different classification methods. Way by processing program: divided into turning tools, drills, boring tools, reamers, broaches, milling, thread cutting tools, gear cutting tool, CNC tool. Its catalog is from a single blade to a multi-edge, from simple to complex.

Cemented Carbide Cutting Tools

Parts processed by cemented carbide cutting tools can obtain requirements of dimensional accuracy and surface quality. Cutting is a method of use of cemented carbide cutting tools to remove the excess material of the parts to be processed. Cutting using cemented carbide cutting tools plays an important role in the national economy.

China's cutting technology development facts

Ancient China's cutting has glorious achievements. Years of the Bronze Age in 2000 BC had metal cutting bud. Bronze knives, saws, filing was similar to the modern tools.

AD 1668 (Ming Dynasty) processing a 2m diameter astronomical instruments copper ring of its outside diameter bore, plane and scale accuracy and surface roughness have reached a very high level. As shown, it was using animal power to drive milling cutters for milling and to grind with millstone at that time. The cutters have similar modern veneer mill, the blade blunt shown foot sharpening machine sharpening.