CN116786595A

CN116786595A - Manufacturing and using method of high-alloy steel roller

Info

Publication number: CN116786595A
Application number: CN202310773160.9A
Authority: CN
Inventors: 周守行
Original assignee: SANXIN HEAVY INDUSTRY MACHINERY CO LTD
Current assignee: SANXIN HEAVY INDUSTRY MACHINERY CO LTD
Priority date: 2023-06-27
Filing date: 2023-06-27
Publication date: 2023-09-22

Abstract

The invention relates to a manufacturing and using method of a high alloy steel roller, wherein a roller working layer is made of high chromium, molybdenum, vanadium and tungsten alloy materials, and is integrally manufactured with a roller shaft for supporting the roller working layer through special casting, processing, heat treatment, combined assembly and other technological methods; the special roller cooling method is used together with the roller, so that the application of the high alloy roller in the section steel rolling production is possible. The roller replaces the traditional NiCrMo pearlite, bainite ductile cast iron, semisteel and graphite steel rollers, is used for rolling channel steel, angle steel and H-shaped steel, and the surface quality of the rolled material is effectively improved, the wear resistance of the roller is improved by 3-5 times, and the working efficiency of the rolling mill is improved by more than 2-3 times.

Description

Manufacturing and using method of high-alloy steel roller

Technical Field

The invention relates to the technical field of rollers, in particular to a high-alloy steel roller.

Background

The production materials of the middle and finish rolling type steel rolls at the present stage are mainly static integral and centrifugal casting NiCrMo pearlitic ductile iron (hardness 58-63 HSD) and NiCrMo bainitic ductile iron (63-68 HSD) materials of traditional annealing heat treatment; the 160-220CrNiMo alloy semisteel or graphite steel roller (with the hardness of 55-60 HSD) with open-pore quenching is used for part of oversized steel.

Rolling characteristics of the section steel (mainly comprising angle steel and channel steel): 1) Kong Xingshen (30-200 mm), the thickness of the working layer of the roller is required to be thick (60-300 mm); 2) The rolling material is cooled unevenly at the edge part and the edge angle of a rolling schedule, so that the edge part, the edge angle and other parts of the rolling roll are worn quickly; the whole service life of the roller is lower, and the production efficiency is lower due to frequent roller changing and roller repairing. 3) Because the traditional ductile iron roller has a thicker working layer, the surface of the working layer is naturally cooled and solidified by the roller manufacturing process, and the difference between the structure and hardness of the bottom of the working layer is larger, so that the whole ductile iron roller has lower service life and poorer surface quality in the middle and later stages.

With the continuous progress of the roller materials, the high alloy roller materials such as high-speed steel, high-chromium iron and the like can be applied to rod and wire rolling mills with low requirements (40-70 mm) of the rolling materials on the thickness of the working layer, and good use effects can be obtained.

However, for the section steel with the working layer requiring extra thickness (120-300 mm), the high-speed steel, high-chromium iron and other high alloy material rollers are required, 1) compared with the traditional ductile iron roller, the alloy content is higher (the heat conduction capacity is poorer), the roller cannot exceed the martensitic transformation process in the quenching and tempering processes in the manufacturing process, the transformation stress is enough to cause the roller to burst, so that the section steel high alloy roller cannot be manufactured, and the high alloy roller is one of important influencing factors for restricting the popularization of the high alloy roller. 2) In the use process of the roller, due to the factors of the shape of the rolled material (particularly the male roller hole type), the hole type is wrapped by three sides of the rolled material, the heating surface is 4-5 times larger than that of the traditional rod and wire, under the condition of the traditional cooling mode, the temperature difference between the hole type part and the non-rolling area is too large due to faster temperature rise, so that hole type explosion is a problem that the roller is very easy to occur, and the roller is also an important influence factor for restricting the popularization of the high alloy roller.

In particular to the production of stainless steel sections (grooves and angle steel), the alloy content of the rolled material is high, the rolling resistance is large, and the requirement on the surface quality of the rolled material is higher (the requirement on high wear-resistant roller is very urgent). In the stainless steel rolling environment, the normal rolling temperature is 1260 ℃ (initial rolling) to 1000 ℃ (final rolling), which is higher than the conventional carbon steel rolling material rolling temperature of 1050 ℃ (initial rolling) to 850 ℃ (final rolling) by nearly 200 ℃, and the effect on the hole type local heating is more severe (the use risk of the high alloy roller is increased).

In summary, from the perspective of reducing the structural stress of the roller, the structural stress of the roller is reduced by changing the structural mode of the roller; secondly, the influence and damage to the stress of the whole roller when the local part (hole pattern) of the roller is impacted by heat are reduced through the structure; thirdly, on the premise that the heated environment cannot be changed, the heat of the surface layer of the heated roller is quickly taken away by changing the cooling environment, so that the diathermanous depth of the inside of the hole pattern is reduced, and the damage caused by thermal shock is reduced.

Disclosure of Invention

According to the technical problem to be solved, the high-alloy steel roll is provided.

In order to achieve the aim, the high alloy steel roll comprises a roll outer layer material, wherein the material adopts high alloy wear-resistant alloy of C1.2-2.7%, si0.4-0.8%, mn0.4-1.1%, cr4-18%, ni0.3-1.5%, mo1.0-5.5%, V0.2-5.5% and W0.2-4.0, the material adopts a corresponding casting method and a special structural form according to a hole pattern structure and working layer thickness, the external structural size is finished through corresponding special heat treatment and processing, and the wear resistance index of the roll reaches 2-4 times of that of a traditional pearlite and bainite type roll by matching with a special cooling water cooling use method, and the comprehensive millimeter steel passing index is 3-5 times of that of the traditional roll.

The invention can be further configured in a preferred embodiment to cast the outer layer and the middle layer with centrifugal grooves, and finally complete the whole roll casting by filling core metal liquid, and for smaller hole type sizes, centrifugal composite non-hole type casting can be adopted, and a machining method is adopted to machine the hole type after casting.

The invention can be further configured in a preferred embodiment that the heat treatment method is to soften, anneal and process the effective rolling part of the grooved roller or working layer into a needed rough machining shape, and then heat treat the effective rolling part through grooved quenching and tempering to achieve the needed roller hardness, organization and stress indexes.

The present invention may be further configured in a preferred embodiment such that the working method is to assemble the roll shaft portion manufactured by the forging method, the effective rolling portion and the auxiliary rolling portion of the working layer of the roll which are heat-treated and processed, together by a heat fitting and screw machine joining method.

The invention can be further configured in a preferred embodiment that the cooling water cooling method is used, at least 5 groups of duckbill-shaped cooling water nozzles which are uniformly distributed at intervals of 80-120mm and have the shape similar to the outline of a hole are welded on an annular cooling water tank body which can cover about 1/3 cambered surface along the outer circle of a roller body, a plurality of biconical hole nozzles with taper angles of 90-100 DEG are drilled on the side face of the duckbill which is opposite to the hole, a central through hole phi 3-5mm is formed, and the biconical hole nozzles drilled on the arc angle part of the bottom of the corresponding female roller groove of the duckbill are double rows; the pressure at the outlet of the cooling water is 5-8kg/cm < 2 >, so that the scattered high-pressure water curtain covers the whole hole-shaped section.

The invention can be further configured in a preferred embodiment that the working layer comprises C1.2-1.5%, si0.4-0.8%, mn0.4-1.1%, cr8-13%, ni0.3-1.0%, mo1.0-2.5%, V0.2-0.7% and W0.2-0.5 as high-chromium alloy steel roll components for medium-rolling angle, channel steel rolling, angle steel finish rolling and finished product rolling; the roller surface hardness is 75-80HSD, replaces the traditional pearlite and bainite, and the single-groove steel passing amount is 2-3 times of that of the traditional roller.

The invention can be further configured in a preferred embodiment that the working layer comprises chemical components of C2.3-2.7%, si0.4-0.8%, mn0.4-1.1%, cr13-18%, ni0.8-1.5%, mo0.8-1.5%, V0.2-0.7% and W0.0-1.0, and is used for rolling medium-rolling angle, channel steel, finish rolling angle steel and rolling finished products; the hardness of the roll surface is 68-75HSD, the traditional pearlite and bainite are replaced, and the single-groove steel passing amount of the roll surface is 2-2.5 times of that of the traditional roll.

The invention can be further configured in a preferred embodiment that the working layer comprises chemical components of C1.6-2.3%, si0.4-0.8%, mn0.4-1.1%, cr4-8%, ni0.3-1.0%, mo3-5.5%, V3-5.5% and W0.5-4.0, and is used for middle-rolling angle and channel steel rolling, angle steel finish rolling and finished product rolling; the roller surface hardness is 75-85HSD, replaces the traditional pearlite and bainite, and the single-groove steel passing amount of the roller surface is 3-4 times of that of the traditional roller

The high alloy steel roller has the beneficial effects that the experience and the characteristics of the high alloy (high-speed steel, high-chromium steel and high-chromium iron) roller for the traditional plate strip and the traditional bar line are used as reference; on the basis of a formulation with scientific chemical composition, the special grooved casting or plain roller blank opening type is adopted, and the roller body part is decomposed into an effective rolling part and an auxiliary rolling part; heat treatment is carried out by means of special grooved or effective rolling parts and auxiliary rolling parts respectively and independently; thereby greatly reducing the stress level of the macrostructure in the casting, heat treatment and delivery states of the roller; the problems of cracking and scrapping of the profile steel ultra-thick high alloy roller due to manufacturing stress and heat treatment stress are effectively controlled; the manufacturing of the super-thick high alloy roller is possible. Meanwhile, by means of a special cooling water nozzle and a cooling using method of the high alloy roller, the high alloy roller can be used on a profile steel rolling mill; due to the good structural red hardness and comprehensive wear resistance of the high alloy roller, the roller replaces the roller made of the traditional pearlite and bainite ductile iron, the surface quality of the rolled material is obviously improved, the single-pass steel passing amount of a single groove and the comprehensive millimeter steel passing amount are improved in multiple, the online time of the roller is greatly prolonged, the production efficiency of the rolling mill is improved, and the consumption cost of the comprehensive roller is reduced. Realizes the integration of high quality, long service life and low consumption.

Drawings

The invention will be described in further detail with reference to the drawings and the detailed description.

FIG. 1 is a schematic diagram of the overall structure of the present invention.

FIG. 2 is a schematic view of a cooling nozzle according to the present invention.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Taking a high-speed steel roller phi 746 multiplied by 850 for a finish rolling K7 frame upper roller (parent roller) for rolling 14# stainless steel channel steel as an example, the hole depth is 92.68mm, the single-side effective working layer is required to be 138mm in thickness, the main journal size phi of the roller is 280mm, and the hardness of the finished product is required to be 78-85HSD. A schematic view of the roll structure is shown in fig. 1.

The casting thickness of the outer layer (high-speed steel) of the roller=138 mm of unilateral effective use thickness and 10mm of safe thickness when scrapped, 10mm of corrosion thickness of the outer layer in the casting process and 10-20 mm of thickness of the transition layer are more than or equal to 158mm.

The maximum castable thickness = (required maximum excircle Φ746 mm-roll neck Φ280 mm-minimum roll neck casting allowance 40 mm)/2=213 mm for centrifugal composite casting. Namely, the thickness of the centrifugal layer meets the requirement that the thickness is more than or equal to 158mm required by the centrifugal composite casting method, and the centrifugal layer can be produced by adopting the centrifugal composite casting method.

The ratio of the thickness of the outer layer to the diameter of the roll body = (138+10)/746=19.8% is far greater than the 12% requirement of the ratio of the thickness of the safe use to the diameter of the roll body required by centrifugal composite high-speed steel casting, so that the risk of cracking in the manufacture (casting and heat treatment) is high, and corresponding technical measures must be taken.

Preparing a casting mold:

the roller is divided into: the roll body part and the roll neck part (which are divided into a driving end roll neck and an operating end roll neck).

The roll body part adopts three parts of a metal type plus hole type part annular chill and an upper end cover box and a lower end cover box; the cold type inner cavity is of a cylindrical cavity structure, a part in contact with the hole type annular cold iron is provided with a through hole with diameter of 28-30mm, and the annular cold iron and the cold type are fastened into a whole by bolts; the annular chill is made of ferrite gray cast iron subjected to graphitization annealing at a high temperature of 900-950 ℃, the circumference of the annular chill is equally divided into three 120-degree chill 1/3 rings at 360 degrees, and two adjacent 1/3 chill rings are connected by sliding contact with a male spigot and a female spigot (mortise and tenon joint); the end cover box is manufactured by adopting a metal outer box, traditional clay sand and paint; and hanging the coated sand which takes the chromium ore sand with the thickness of 3-4mm as aggregate on the cold mould surface and the contact surface of the cold iron and the molten metal at 150-180 ℃ on the inner surfaces of the cold mould and the annular cold iron.

The outer layer molten metal adopts high-speed steel molten metal with chemical components of C1.6-2.3%, si0.4-0.8%, mn0.4-1.1%, cr4-8%, ni0.3-1.0%, mo3-5.5%, V3-5.5% and W0.5-4.0, and harmful elements P less than or equal to 0.035%, S less than or equal to 0.03% and [ O ] < 20PPM are controlled by smelting and deoxidizing purification; discharging at 1580deg.C, standing for 10-15 min, removing surface scum, pouring outer layer molten metal into assembled centrifugal casting mold with mold temperature of 80-120deg.C via pouring hopper and launder at 1450-1480deg.C;

before the outer metal approaches the solidification point (semi-solid state) T cavity = tcset +50 ℃; pouring a high silicon graphite steel intermediate layer (the thickness is 15-30 mm) with C of 1.2-1.8%, si of 2.4-2.8%, mn of 0.5-0.8%, P of less than or equal to 0.035% and S of less than or equal to 0.03;

when the core molten metal is completely solidified, the centrifugal rotation is stopped, and the fixing bolt connected between the cold mold and the annular cold iron is loosened (so that the annular cold iron can slide up and down freely when the annular cold iron is cooled and contracted in the later period).

Mold closing and core filling molten metal: the roll body casting mould with the annular chill, the outer layer and the middle layer, the transmission side bottom box and the operation side riser box casting mould are sequentially combined, and the high-temperature (1380-1400 ℃) core high-strength and high-toughness material metal liquid is filled in, wherein the chemical compositions of the core material C2.9-3.3%, si2.4-2.8%, mn0.5-0.8%, P less than or equal to 0.035%, S less than or equal to 0.02%, ni0.5-1.0%, cr less than or equal to 0.2% and Mo less than or equal to 0.1%. The high-silica graphite intermediate layer is eroded by about 10mm, so that good metallurgical bonding is formed between the outer layer high-alloy high-speed steel and the core high-strength ductile cast iron, meanwhile, the inner and outer layer alloy and the structure realize benign transition, and the high alloy is effectively prevented from entering the core in a large amount to embrittle the core structure. The riser covers the heat insulating agent, and when the casting temperature of the roll body is reduced to less than or equal to 500 ℃, the part is wrapped with heat insulating cotton and slowly cooled to room temperature.

Unpacking, rough perforating and processing: removing upper and lower roll neck boxes (bottom box and riser box), metal two end cover boxes, removing the annular chill at the hole part together with the casting and the annular chill from the metal shape, cleaning floating sand on the surface of the casting, sending to a processing workshop, and performing rough machining on the roll body (including hole type) and upper and lower roll necks according to a rough machining drawing before heating (leaving quenching and machining allowance after heating). And (3) completing the grooved casting process, and performing quenching and tempering treatment in a heat treatment process.

The method is suitable for ultra-thick working layer rolls with deeper and wider holes, and for rolls with smaller holes and thinner working layers, flat roll casting (casting without holes) is preferred, and rough hole type heat treatment is carried out after casting blanks before heating.

The method has the advantages of solving the problems of cracking risk, low consumption of outer high alloy and reduction of work load of processing blank high alloy in the casting process of the high-speed steel ultra-thick working layer roller, but has the defects of complicated tool and die and production and manufacturing process, and higher operation requirement on metal mold (including annular chill) precoated sand

It should be noted that in this document relational terms such as first and second, and the like are used solely to distinguish one entity from another entity without necessarily requiring or implying any actual such relationship or order between such entities.

The above examples are merely illustrative of the present invention and are not meant to limit the scope of the present invention, and all designs that are the same or similar to the present invention are within the scope of the present invention.

Claims

1. A high-alloy steel roller is characterized in that the outer layer material of the roller adopts high-alloy wear-resistant alloy of C1.2-2.7%, si0.4-0.8%, mn0.4-1.1%, cr4-18%, ni0.3-1.5%, mo1.0-5.5%, V0.2-5.5% and W0.2-4.0, and according to the hole pattern structure, the thickness of the working layer, a corresponding casting method and a special structural form are adopted, and the corresponding special heat treatment and processing are carried out, so that the overall structural dimension is completed, the wear resistance index of the roller reaches 2-4 times of that of the traditional pearlite and bainitic nodular cast iron roller by matching with a special cooling water using method, and the comprehensive millimeter steel passing index is 3-5 times of that of the traditional roller.

2. The high alloy steel roll according to claim 1, wherein the outer layer and the middle layer are cast by using centrifugal belt grooves, and finally the whole roll casting is completed by filling core metal liquid, and for smaller hole type sizes, centrifugal composite non-hole type casting can be adopted, and after casting, the hole type is machined by adopting a machining method.

3. The high alloy steel roll according to claim 1, wherein the heat treatment method is characterized in that the effective rolling part of the grooved roll or working layer is softened, annealed, processed into a required rough machining shape, and then subjected to grooved quenching and tempering heat treatment to achieve required roll hardness, organization and stress indexes.

4. A high alloy steel roll according to claim 3, wherein the working method is to assemble the roll shaft part manufactured by forging method, the effective rolling part and the auxiliary rolling part of the working layer of the roll which are heat treated and processed, by hot assembling and screw machine assembling method.

5. The high alloy steel roll according to claim 4, wherein the cooling water cooling method is characterized in that at least 5 groups of duckbill-shaped cooling water nozzles which are uniformly distributed at intervals of 80-120mm and have the shape similar to the outline of a hole pattern are welded on a ring-shaped cooling water tank body which can cover about 1/3 cambered surface along the outer circle of the roll body, a plurality of biconical hole nozzles with the cone angle of 90-100 DEG are drilled on the side surface of the duckbill which is opposite to the hole pattern, the center through hole phi is 3-5mm, and the biconical hole nozzles drilled on the circular arc angle part of the bottom of the corresponding female roll groove are double rows; the pressure at the outlet of the cooling water is 5-8kg/cm < 2 >, so that the scattered high-pressure water curtain covers the whole hole-shaped section.

6. The high alloy steel roll according to claim 5, wherein the working layer chemical composition is C1.2-1.5%, si0.4-0.8%, mn0.4-1.1%, cr8-13%, ni0.3-1.0%, mo1.0-2.5%, V0.2-0.7%, W0.2-0.5 for middle-angle, channel steel rolling, and angle steel finish rolling, finished product rolling; the roller surface hardness is 75-80HSD, replaces the traditional pearlite and bainite, and the single-groove steel passing amount is 2-3 times of that of the traditional roller.

7. The high alloy steel roll according to claim 5, wherein the working layer chemical composition is C2.3-2.7%, si0.4-0.8%, mn0.4-1.1%, cr13-18%, ni0.8-1.5%, mo0.8-1.5%, V0.2-0.7%, W0.0-1.0 for mid-roll angle, channel steel rolling, and finish rolling of angle steel, finish rolling; the hardness of the roll surface is 68-75HSD, the traditional pearlite and bainite are replaced, and the single-groove steel passing amount of the roll surface is 2-2.5 times of that of the traditional roll.

8. The high alloy steel roll according to claim 5, wherein the working layer chemical composition is C1.6-2.3%, si0.4-0.8%, mn0.4-1.1%, cr4-8%, ni0.3-1.0%, mo3-5.5%, V3-5.5%, W0.5-4.0 for intermediate angle, channel steel rolling, and finish rolling of angle steel, finished product rolling; the roller surface hardness is 75-85HSD, replaces the traditional pearlite and bainite, and the single-groove steel passing amount is 3-4 times of that of the traditional roller.