CN105483518A - Large-bar finish rolling alloy infinite centrifugal roller - Google Patents

Abstract

The invention discloses a large-bar (phi >=50) finish rolling alloy infinite centrifugal roller, and belongs to the technical field of roller manufacturing. The roller comprises an outer layer and a core part. The outer layer comprises, by weight percent, 3.0-3.5% of C, 0.4-1.2% of Si, 0.5-1.2% of Mn, smaller than or equal to 0.10% of P, smaller than or equal to 0.05% of S, 1.0-3.0% of Cr, 2.6%-4.0% of Ni, 0.2-1.0% of Mo, and the balance Fe and impurities. The core part comprises, by weight percent, 2.9-3.5% of C, 1.5-3.0% of Si, 0.4-1.2% of Mn, smaller than or equal to 0.10% of P, smaller than or equal to 0.03% of S, smaller than or equal to 1.0% of Cr, smaller than or equal to 1.0% of Ni, smaller than or equal to 0.5% of Mo, larger than or equal to 0.04% of Mg, and the balance Fe and impurities. The operation technology is simple, the outer layer only needs to be bred and does not need to be subjected to spheroidizing, pollution generated by spheroidizing can be reduced, and the harm to the health of a worker and the pollution to the environment are reduced. Meanwhile, the effect on the performance of the roller due to recession, slag inclusion, uneven stirring and the like in the spheroidizing process is completely eradicated, the strength, abrasion resistance and hardness of the roller are higher than those of a bainite ductile cast iron centrifugal roller, and the infinite centrifugal roller is applied to the large-bar finish rolling work.

Description

The unlimited Centrifugal rolling of big rod finish rolling alloy

Technical field

The present invention relates to the unlimited Centrifugal rolling of bar finish rolling alloy, be specifically related to a kind of big rod the unlimited Centrifugal rolling of finish rolling alloy, belong to roll manufacturing technology field.

Background technology

For the production of in the typical successive type wall scroll hot rolling rolling mill of bar, steel billet is heated in a process furnace, subsequently rolling mill roughing section and in the section of rolling be subject to pressure rolling, be then drawn towards milling train finish rolling section.As its name suggests, the effect of finish rolling section is exactly error rolled products being finally rolled into various size and having regulation, roughing, in roll, the function of finish rolling is specifically different.Chinese patent discloses one and " rolls unlimited Centrifugal rolling in rod (line) milling train " (patent No. is 201210167306), its application scenario be in the section of rolling (being generally the F6 ~ F10 of frame), for in the section of rolling, stronger hot-cracking resistance and higher charge length accuracy requirement should be had; And for finish rolling section, higher hardness, wear resistance and good finished surface quality should be had, the two requires difference, and therefore, the roll of the section of rolling and finish rolling section cannot use in phase trans-substitution.

Due to big rod as industry steel such as automobile, machinery, military projects, demand rapid development, is widely used in automobile shafts class, pipe series products.Big rod finish rolling section use bainite ductile iron centrifugal roller for a long time always, bainite ductile iron centrifugal roller needs to carry out spheriodizing technique, the uneven defect of hardness is easily formed in nodularization process, in the operation of rolling, bottom land occurs that hardness is uneven, steel are caused to cause useless, the smog produced in the process of nodularization simultaneously has a strong impact on workshop condition, containing a large amount of Mg and various rare metal in smog, serious harm worker at the production line's is healthy, in addition after nodularization, due to the impact of decaying spheroidisation, slag inclusion, the unequal reason of stirring, the impact of breaker roll performance is larger.

Infinitely chilled ductile cast iron is a kind of material between cold hard cast-iron and grey cast iron, compared with cold hard cast-iron, silicone content higher (containing 0.7% ~ 1.6%Si) in its molten iron, therefore alloy unlimited centrifugal roller body of roll working lining matrix is interior except the carbide containing quantity close to white cast iron and ledeburite, also there is a small amount of equally distributed graphite.Body of roll working lining and core do not have obvious line of delimitation, claim unbounded chilled roll yet.The matrix of the unlimited centrifugal roller of alloy is all generally martensite and bainite, and in addition, graphite and carbide breaker roll use and also have a significant impact.Infinitely chilled ductile cast iron is because hardness is high, hardness drop is little, hot-cracking resistance good, and its thermal treatment process is simple, can consider to apply in bar roll.

If but be applied in big rod finish rolling section, because its draught is larger, as the unlimited centrifugal roller surface hardness of alloy for strip continuous-rolling machine is generally 75 ~ 85HS, and it is slightly lower for the hardness of the unlimited centrifugal roller of alloy of plate mill, be generally 70 ~ 80HS, therefore this section requires that roll has larger intensity and higher wear resistance, and conventional infinitely chilled ductile cast iron material cannot meet user demand, therefore needs badly and carry out being applicable to big rod the research and development of the special roller of finish rolling.

Summary of the invention

The technical issues that need to address of the present invention are to provide a kind of for big rod the unlimited centrifugal roller of alloy of finishing stand, can avoid bainite ductile iron centrifugal roller in nodularization process, easily form the uneven defect of hardness, in the operation of rolling, there is hardness problem of non-uniform in bottom land, have and simplify Foundry Production operation, reduce environmental pollution, and the stay-in-grade feature of roll can be made.

For solving the problems of the technologies described above, the technical solution adopted in the present invention is:

The unlimited Centrifugal rolling of a kind of big rod finish rolling alloy, outer field chemical composition and weight percent are: C3.0 ~ 3.5, Si0.4 ~ 1.2, Mn0.5 ~ 1.2, P≤0.10, S≤0.05, Cr1.0 ~ 3.0, Ni2.6 ~ 4.0, Mo0.2 ~ 1.0, and all the other are Fe and inevitable impurity;

The chemical composition of core and weight percent content are: C2.9 ~ 3.5, Si1.5 ~ 3.0, Mn0.4 ~ 1.2, P≤0.10, S≤0.03, Cr≤1.0, Ni≤1.0, Mo≤0.5, Mg >=0.04, and all the other are Fe and inevitable impurity.

The further improvement of technical solution of the present invention is: outer field chemical composition and weight percent are: C3.3 ~ 3.4, Si0.7 ~ 1.2, Mn0.70 ~ 0.8, P≤0.10, S≤0.05, Cr1.4 ~ 2.70, Ni3.0 ~ 3.7, Mo0.3 ~ 0.4, and all the other are Fe and inevitable impurity;

The chemical composition of core and weight percent content are: C2.9 ~ 3.2, Si1.9 ~ 2.6, Mn0.6 ~ 1.0, P≤0.10, S≤0.03, Cr≤0.7, Ni≤0.8, Mo≤0.4, Mg >=0.06, and all the other are Fe and inevitable impurity.

Owing to have employed technique scheme, the technical progress that the present invention obtains is: operating procedure is simple, outer need be carried out breeding not carrying out spheroidizing, just can reduce the pollution produced because of nodularization, thus reduce the harm of the health of workman and the pollution of environment; Stop the performance impact of decline in nodularization process, slag inclusion, the unequal reason breaker roll of stirring, all comparatively bainite ductile iron centrifugal roller is high for the intensity of roll, wear resistance, hardness simultaneously.

In the present invention, the exemplary configurations of big rod milling train is roughing bloomer one frame, intermediate mill four frame, and finishing train four frame, rolled products is big rod.The task that intermediate mill is undertaken is further pressure, and provide excellent steel surface for finishing train, to ensure finishing train energy production any surface finish, accurate in size commercial stock, require that roll has certain intensity, good hot-cracking resistance and higher roll surface hardness, therefore the roll of intermediate mill should have good comprehensive mechanical property.

Intermediate mill roller material, usually select pearlitic ductile iron roll, the body of roll is organized as: globular graphite+perlite+carbide, and hardness of roll body controls at 60 ~ 70HSD; According to blank size, if outer layer thickness can meet, nickel chromium triangle indefinite chill centrifugal roller in also can selecting, the body of roll is organized as: flake graphite+perlite+carbide, hardness of roll body controls at 60 ~ 70HSD.

And the draught of finishing train is very little, main task ensures the excellent surface quality of finished product and reaches strict tolerance of dimension standard.Therefore finishing stand roll requires to have excellent wear resistance and resistance to flaking.

Finishing train roller material, selects bainite ductile iron centrifugal roller usually, and matrix is: globular graphite+bainite+carbide, durometer level is generally at 65 ~ 75HSD.

It is high NiCr infinitely chilled ductile cast iron centrifugal roller that the present invention carries alloy indefinite chill roll, and skin is high NiCr material, and core is then the spheroidal graphite cast iron of high strength.Due to the effect of alloying elements cr, Mo, carbide in outer tissue is (FeCr) 3 alloyed cementite type, carbide amount 25 ~ 35%, working lining is organized as bainite, carbide and fine platy graphite, because alloy content is higher, have a small amount of martensite and residual austenite in matrix, this material roll has higher wear resistance, preferably resistance to flaking.Durometer level is at 65 ~ 75HSD.This material is used for big stick-means of intimidation finishing stand at present, achieves good effect of rolling.

The alloying elements such as Cr, Ni, Mo of the different content added in the unlimited centrifugal roller of alloy, its case depth increases greatly; Ni adds suitable element and can improve its oxidation-resistance, solidity to corrosion, hot strength and improve some physicals, heavy alloyed intensity can be put forward, and keep good plasticity and toughness, and have higher corrosion resistance to soda acid, at high temperature there is antirust and temperature capacity; Cr improves the wear resistance of material and corrosion-resistant, not easily gets rusty.Cr can significantly improve intensity, hardness and wear resistance, can improve again oxidation-resistance and the erosion resistance of steel; Mo postpones proeutectoid ferrite and changes, and improves the obdurability of roll, containing the better heat stability of Mo microalloy element carbonitride, improves the high-temperature behavior of roll, not easily alligatoring under high temperature.

Containing more carbide in alloy unlimited centrifugal roller body of roll matrix, there is good wear resistance; In addition, in matrix, equally distributed a small amount of tiny graphite, serves the effect of lax mechanical stress, is conducive to the scaling defects alleviating body of roll top layer; Meanwhile, graphite itself has good heat conductivility, and in rolling process, during roller surface heat-shock, graphite plays a part to cushion thermal stresses, is conducive to the generation preventing thermal crack.In addition, the graphite of body surface comes off and forms tiny hole, improves the performance of nipping of roll.

The manufacturing cost of the unlimited centrifugal roller of alloy is suitable with the centrifugal magnesium iron of bainite, and uniformity of hardness and stability are much higher than the centrifugal magnesium iron of bainite, and the outer molten iron of the unlimited Centrifugal rolling of alloy is without nodularization, decreases process operations, reduces environmental pollution.

In addition, the unlimited Centrifugal rolling of this bar finish rolling alloy also has higher performance requriements:

1. improve single groove amount of rolling.For rolling big rod during finished frame, the unlimited centrifugal roller of alloy is compared with bainite ductile iron roll, and single groove amount of rolling significantly improves.Adopt bainite ductile iron roll rolling big rod time, each finished product list groove amount of rolling is about 120t.And after applying infinitely chilled ductile cast iron, finished product list groove amount of rolling is 1300 ~ 1440t, improve more than 10 times.

2. improve operating rate of rolling mill.Application carbide roll ring, slotted eye wearing and tearing are little, and roll campaign is high, thus decreases roll change and change groove number of times and time, improves milling train efficiency, rolling mill yield is improved.

3. substitute former bainite ductile iron roll with carbide roll ring, because slotted eye is wear-resisting, rolling tonnage is high, long service life, can reduce and roll year always need reconditioning number of times, and roll year, total reconditioning expense can decrease, thus reduced roll cutting tooling cost.

4. improve lumber recovery.The unlimited Centrifugal rolling of application finish rolling alloy, can significantly improve product size precision, reduces scrap rate.Decrease because of after changing groove, import and export readjusting of guide and guard part and the waste product that may produce the accidents such as heap steel and cause thus.

5. can improve the labour intensity of steel rolling adjustment work and roll rigger.Change because of groove and significantly reduce, alleviate the labour intensity of operator.

6. stocking surface quality significantly improves.The big rod shut out product surface is highly polished, good looking appearance, can improve the market competitiveness.

Accompanying drawing explanation

Fig. 1 is fabrication processing figure of the present invention.

Embodiment

Below in conjunction with embodiment, the present invention is described in further details:

Embodiment 1

Manufacture craft with reference to Fig. 1 is processed.Outer field chemical composition and weight percent are: C3.3, Si0.85, Mn0.7, P≤0.10, S≤0.05, Cr1.30, Ni3.0, Mo0.25, and all the other are Fe and inevitable impurity;

The chemical composition of core and weight percent content are: C3.2, Si2.0, Mn0.45, P≤0.10, S≤0.03, Cr0.2, Ni0.3, Mo0.2, Mg >=0.04, and all the other are Fe and inevitable impurity.

Embodiment 2

Being distinguished as of the present embodiment and embodiment 1: outer field chemical composition and weight percent are: C3.3, Si0.90, Mn0.75, P≤0.10, S≤0.05, Cr1.50, Ni3.3, Mo0.25, and all the other are Fe and inevitable impurity; The chemical composition of core and weight percent content are: C3.25, Si2.05, Mn0.50, P≤0.10, S≤0.03, Cr0.25, Ni0.25, Mo0.2, Mg >=0.04, and all the other are Fe and inevitable impurity.

Embodiment 3

Being distinguished as of the present embodiment and embodiment 1: C3.4, Si0.95, Mn0.75, P≤0.10, S≤0.05, Cr1.80, Ni3.5, Mo0.25, all the other are Fe and inevitable impurity; The chemical composition of core and weight percent content are: C3.25, Si2.05, Mn0.50, P≤0.10, S≤0.03, Cr0.25, Ni0.25, Mo0.2, Mg >=0.04, and all the other are Fe and inevitable impurity.

Embodiment 4

Being distinguished as of the present embodiment and embodiment 1: C3.35, Si1.1, Mn0.75, P≤0.10, S≤0.05, Cr2.70, Ni3.7, Mo0.2, all the other are Fe and inevitable impurity; The chemical composition of core and weight percent content are: C3.3, Si2.10, Mn0.55, P≤0.10, S≤0.03, Cr0.25, Ni0.20, Mo≤0.2, Mg >=0.04, and all the other are Fe and inevitable impurity.

Embodiment 5

Being distinguished as of the present embodiment and embodiment 1: outer field chemical composition and weight percent are: C3.35, Si0.95, Mn0.75, P≤0.10, S≤0.05, Cr2.05, Ni3.35, Mo0.35, and all the other are Fe and inevitable impurity;

The chemical composition of core and weight percent content are: C3.1, Si2.25, Mn0.8, P≤0.10, S≤0.03, Cr0.6, Ni0.7, Mo0.35, Mg0.06, and all the other are Fe and inevitable impurity.

Embodiment 6

Being distinguished as of the present embodiment and embodiment 1: outer field chemical composition and weight percent are: C3.35, Si0.95, Mn0.75, P≤0.10, S≤0.05, Cr2.05, Ni3.35, Mo0.35, and all the other are Fe and inevitable impurity;

The chemical composition of core and weight percent content are: C3.1, Si2.25, Mn0.8, P≤0.10, S≤0.03, Cr0.6, Ni0.5, Mo0.25, Mg0.07, and all the other are Fe and inevitable impurity.

Embodiment 7

Being distinguished as of the present embodiment and embodiment 1: outer field chemical composition and weight percent are: C3.4, Si1.2, Mn0.8, P≤0.10, S≤0.05, Cr2.7, Ni3.7, Mo0.4, and all the other are Fe and inevitable impurity; The chemical composition of core and weight percent content are: C2.9, Si2.5, Mn0.9, P≤0.10, S≤0.03, Cr0.65, Ni0.8, Mo0.4, Mg >=0.06, and all the other are Fe and inevitable impurity.

Embodiment 1 ~ embodiment 7 product carries out Performance Detection, and detected result is in table 1.

Table 1

As shown in Table 1, the unlimited Centrifugal rolling of alloy of the present invention has higher hardness of roll body and roll neck tensile strength, and minimum body of roll working lining hardness drop, and excellent property, is applicable to big rod the use of finish rolling.

Claims (2)

1. the unlimited Centrifugal rolling of big rod finish rolling alloy, it is characterized in that: outer field chemical composition and weight percent are: C3.0 ~ 3.5, Si0.4 ~ 1.2, Mn0.5 ~ 1.2, P≤0.10, S≤0.05, Cr1.0 ~ 3.0, Ni2.6 ~ 4.0, Mo0.2 ~ 1.0, all the other are Fe and inevitable impurity;

The chemical composition of core and weight percent content are: C2.9 ~ 3.5, Si1.5 ~ 3.0, Mn0.4 ~ 1.2, P≤0.10, S≤0.03, Cr≤1.0, Ni≤1.0, Mo≤0.5, Mg >=0.04, and all the other are Fe and inevitable impurity.

2. the unlimited Centrifugal rolling of big rod finish rolling alloy according to claim 1, it is characterized in that: outer field chemical composition and weight percent are: C3.3 ~ 3.4, Si0.7 ~ 1.2, Mn0.70 ~ 0.8, P≤0.10, S≤0.05, Cr1.4 ~ 2.70, Ni3.0 ~ 3.7, Mo0.3 ~ 0.4, all the other are Fe and inevitable impurity;

The chemical composition of core and weight percent content are: C2.9 ~ 3.2, Si1.9 ~ 2.6, Mn0.6 ~ 1.0, P≤0.10, S≤0.03, Cr≤0.7, Ni≤0.8, Mo≤0.4, Mg >=0.06, and all the other are Fe and inevitable impurity.