CN1807671A - Continuous composite high speed steel roll formula - Google Patents

Abstract

The invention discloses a composite high speed steel roll formula, wherein the outer layer roll body comprises (by weight percent) C 1.5-3.5, Cr 2.0-7.0, Mo 2.0-7.0, V 4.0-10.0, W 4.0-10.0, Co 0-10.0, Ni<2.0, and balancing Fe.

Description

Continuous composite high speed steel roll formula

Technical field: the invention belongs to technical field of steel rolling, relate to a kind of metallurgical roller technical recipe, particularly relate to a kind of continuous casting composite high speed steel roll formula.

Technical background: in recent years, the hot rolling technology has obtained very much progress, has roughly experienced following process on material and the manufacturing process in the development of hot-rolling roll: roll material develops into composite roll with high Minvar, the rich chromium cast iron casting high speed steel until recent development gradually from single cast iron, spheroidal graphite cast iron, cast steel; Manufacturing process also develops into composite casting technology from common integral casting process, and wherein composite casting technology develops into centrifugal casting from the static casting method again.

Represent the hot continuous rolling technology of contemporary rolling technique level, the measures that cut down the consumption of energy such as low temperature, heavy reduction, pony roll footpath be rolling have been adopted, be switchboard shape and raising board quality, six rollers, dual crossing, dual roller, pony roll footpath rolling technique have been adopted, make body of roll contact stress increase 1-2.5 doubly, roller footpath thrust increases 3-7 doubly, and stress in bending increases 2-3 doubly, and contact frequency increases several times.Adopt the pony roll footpath rolling, add horizontal curvature, directly the work flexural strength of roll neck of pony roll must be equivalent to the 700MPa tensile strength greater than 250MPa, the variation breaker roll of these rolling techniques is had higher requirement, and domestic existing roll is difficult to reach these requirements at present.Use the roll of original traditional material, except that roller consumption was big, the hot rolling poor quality during as the processing strip, can directly influence the quality of cold rolled sheet, and the result causes light industry with the almost whole dependence on import of thin plate; In addition, the quality of the used roll of China's rolling steel industry compares with industrially developed country that there is a big difference, rolling in roll change frequent, operating rate of rolling mill is low, production cost height, deficiency in economic performance.

At present, the recombining process of producing the high-speed steel roll employing in the world is mainly centrifuging, centrifugal composite high-speed steel roller production technology is will melt good outer molten steel earlier to pour elder generation's formation skin in the mould tube of high speed rotating into, and the melt of then inserting spheroidal graphite cast iron again forms roll neck.Though centrifuging is very sophisticated composite roll manufacturing technology, but there is following shortcoming: contain alloying elements such as more W, Cr, Mo, V in (1) rapid steel, and the carbide density difference of these elements and formation thereof is very big, carbide segregation takes place under centrifugal action, outer V content is low, and W, Mo content height, internal layer is just in time opposite, has had a strong impact on the wear resistance of roll like this.(2) high-carbon high-high-vanadium high-speed steel produces MC proeutectic carbide in crystallisation process, because of its density is littler than molten steel, under centrifugal action, easily is segregated in the inboard of working lining, causes rolling middle frictional coefficient to change, and causes the steel product dimension overproof.Disclose a kind of roll material of reduced in segregation of carbide in the U.S. Pat 6095957, its chemical ingredients (weight %) is 2.4-2.9C, 12.0-18.0Cr, 3.0-9.0Mo, 3.0-7.0V, 0.5-4.0Nb, Si＜1.0, Mn＜1.0, W＜1.0.Japanese patent gazette spy opens the roll material that flat 4-365836 also discloses a kind of reduced in segregation of carbide, and its chemical ingredients (weight %) is 1.5-3.5C, 5.5-12.0Cr, 2.0-8.0Mo, 3.0-10.0V, 0.6-7.0Nb, Si＜1.5, Mn＜1.2, Ni＜5.5.It is to take to add Nb unit usually to improve MC type carbide density, and the high W element of density is added in restriction, though controlled the segregation of carbide effectively, but the Nb element has improved the quenching temperature of steel, the MC type carbide of Nb system is thicker than the MC type carbide of V system in the product in addition, causes easily peeling off in the roll use; It is poor to contain the low rapid steel red hardness of W amount simultaneously, and hot hardness is low, and high temperature abrasion resistance is poor, has reduced the work-ing life of roll.

Summary of the invention: the technical recipe that the object of the present invention is to provide a kind of new continuous composite high-speed steel roller, with exploitation W, V content height, segregation is light, wear resistance is good composite high-speed steel roller, satisfy the hot continuous rolling technology requirement, reduce rolling middle roll change frequency, increase substantially the operating rate of milling train, reduce production costs, increase economic efficiency.

Technical scheme of the present invention is achieved in that and adopts the continuous casting process of the disclosed composite high-speed steel roller of Chinese patent CN1102469C to produce roll, the roller core of at first prefabricated roll; Then roller core vertically is put in the water-cooled crystallizing mould, the outer rapid steel molten steel of fused is poured in the space between roller core and the water-cooled crystallizing mould, make the fusion of outer layer metal and roller core, and make outer layer metal be time and on solidify; To solidify partial continuous at last and pull down and dial, realize that continuous casting is outer.

Roller core adopts the alloy forged steel material of high tenacity.

The outer rapid steel molten steel of fused adopts following technology to carry out melting: at first with iron-based body and Cr, Ni, increase the C agent melting that feeds intake simultaneously, smelt after 1 hour and to drop into Mo and W iron continues melting, melting drops into Co and V iron continuation melting half an hour after 2 hours after, come out of the stove and cast.

The roll of casting quenches and tempering heat treatment after mechanical roughing, carries out machine finshing after the thermal treatment again.

The rapid steel composition that the above-mentioned skin of the roll body of roll adopts is (weight %): 1.5--3.5C, 2.0--7.0Cr, and 2.0--7.0Mo, 4.0--10.0V, 4.0--10.0W, 0-10.0Co, Ni＜2.0, all the other are Fe.

Its mechanical property and common roll relatively see Table 1, its outer chemical ingredients and carbide and common roll relatively see Table 2.

The present invention compared with prior art has following advantage:

1. W, V content height in the working lining have been controlled the segregation of carbide effectively in producing like this, have improved mechanical property, wear resistance and the red hardness of roll, have reduced the quenching temperature of roll simultaneously;

2. the roll that adopts this prescription to produce can reduce rolling middle roll change frequency, increases substantially the operating rate of milling train, reduces production costs, and increases economic efficiency.

The fill a prescription comparison of institute's production roll mechanical property and common roll of table 1 the present invention

The position	Project	Unit	Cladding material
						Rapid steel	Rich chromium cast iron	The high alloy infinitely chilled ductile cast iron
			Outer	Hardness	HsC				75-90	65-75	70-80
Ultimate compression strength	Mpa	2500-3200				1700-2200	1900-2500
				Critical stress intensity factor	Mpa.m -0.5			25-28	21-34	18-25
Tensile strength	MPa	700-1000				700-900	400-600
				Key coat	Tensile strength			Mpa	500-700	300-400	300-500
Core	Tensile strength	MPa	700-1000			400-500	300-500

Table 2 the present invention fill a prescription the roll component of producing and carbide and with the comparison of common roll

Kind	Outer chemical ingredients (Wt%)							Hardness (Hs)	Carbide		Matrix
													C	Cr	Ni	Mo	V	W	Co	Kind	(Hv)	Kind	(Hv)
	Rapid steel	1.5-2.5	2.0-7.0	＜2.0	2.0-7	4	4		0-10	75-90	Mc+M6C	2500-3000												Martensite	650-750
Rich chromium cast iron								2.4-2.8					14-18	1.0-2.0	0.5-1	-	-	65-75	65-75	M7 C3	1200-1600	Martensite	450-500
	High Minvar	3.0-3.5	1.4-1.9	4.3-4.8	0.3-0.6	-	-		70-80	70-80	M3C	800-1200												Martensite	430-600

Claims (2)

1. continuous composite high speed steel roll formula, roller core adopts the alloy forged steel material of high tenacity, it is characterized in that: the rapid steel composition that the outer body of roll adopts is (weight %): 1.5--3.5C, 2.0--7.0Cr, 2.0--7.0Mo, 4.0--10.0V, 4.0--10.0W, 0-10.0Co, Ni＜2.0, all the other are Fe.

2. according to the melting technology of the described prescription of claim 1, it is characterized in that: at first with iron-based body and Cr, Ni, increase the C agent melting that feeds intake simultaneously, smelt after 1 hour and to drop into Mo and W iron continues melting, melting drops into Co and V iron continuation melting half an hour after 2 hours after, come out of the stove and cast.