CN107557680A - Mill coil 65Mn of RE-treated and preparation method thereof - Google Patents

Abstract

The present invention relates to mill coil 65Mn of a kind of RE-treated and preparation method thereof.Preparation method includes：Continuous cast billet is used as hot rolling raw material, successively by heating and rolling, is batched obtained.The mill coil 65Mn of RE-treated provided by the invention preparation method is to use continuous cast billet as hot rolling raw material, heated, roughing, finish rolling, batches, finally gives the hot-strip with excellent mechanical property.Microscopic structure during the steel hot-rolled state is pearlite and ferrite.Compared with prior art, O, N content are relatively low, good mechanical performance by mill coil 65Mn provided by the invention.

Description

Mill coil 65Mn of RE-treated and preparation method thereof

Technical field

The present invention relates to metallurgical material technical field, the mill coil 65Mn and its system of more particularly to a kind of RE-treated Preparation Method.

Background technology

65Mn steel has the advantages that compared with high hardness, quenching degree is good, decarburizing tendency is few, cheap, machinability is good, simultaneously The fatigue resistance of this steel is very good, there is fabulous elasticity.For making flat various small sizes, coil spring, cushion spring, bullet Spring clockwork spring, ring spring, valve spring, clutch reed, brake spring can be also made, there are wide market prospects.Open at present The 65Mn decarburized layer deepness of hair is higher, and comprehensive mechanical property needs further to be improved.

The content of the invention

In view of this, the present invention provides a kind of mill coil 65Mn of RE-treated and preparation method thereof.

The present invention provides a kind of mill coil 65Mn of RE-treated, and its chemical composition is wrapped in percentage by weight Include：

C：0.63~0.69%, Si：0.18~0.37, Mn：0.90~1.20%, P≤0.035%, S≤0.035%, O ≤ 0.003%, N≤0.004%, RE≤0.01%, remaining is iron and other inevitable impurity.

Further, during the thickness of strips≤6.0mm, Rel：430~600MPa, Rm：735~980MPa, A50：>=12%, ψ：>=35%, HARDNESS OF HOT-ROLLED≤250HB.

The present invention also provides a kind of mill coil 65Mn of above-mentioned RE-treated preparation method, and it includes：Using even Casting small billet is hot rolling raw material, successively by heating and rolling, is batched obtained.

Further, the continuous cast billet is prepared as follows：

Smelting and continuous casting：Molten iron carries out desulfurization pretreatment, using top and bottom combined blown converter decarburization, dephosphorization, carries out the outer essence of LF stoves Refining, slab continuous casting, slab cleaning, slab quality inspection.

Further, during the heating and rolling：Slab heating temperature is 1170~1200 DEG C, is carried out after de-scaling Rolling；Rolling is rolled using 3/4 continous way mill coil production line；1090 DEG C~1140 DEG C of roughing start rolling temperature, finish rolling is opened Roll 975 DEG C~1000 DEG C of temperature；

In curly course：740~790 DEG C of coiling temperature, finished product thickness≤6.0mm.

The mill coil 65Mn of RE-treated provided by the invention preparation method is to use continuous cast billet as hot rolling Raw material, it is heated, roughing, finish rolling, batch, finally give the hot-strip with excellent mechanical property.During the steel hot-rolled state Microscopic structure be pearlite+ferrite.

Compared with prior art, O, N content are relatively low by mill coil 65Mn provided by the invention, and continuous casting billet is heated, warm Roll, batch, produce the 65Mn of good mechanical performance.

During steel plate thickness≤6.0mm, Rel：430~600MPa, Rm：735~980MPa, A50：>=12%, ψ：>=35%

HARDNESS OF HOT-ROLLED≤250HB.

Embodiment

The invention discloses mill coil 65Mn of a kind of RE-treated and preparation method thereof, those skilled in the art can To use for reference present disclosure, technological parameter realization is suitably modified.In particular, all similar replacements and change are to this It is it will be apparent that they are considered as being included in the present invention for art personnel.The method of the present invention and application are Be described by preferred embodiment, related personnel substantially can not depart from present invention, in spirit and scope to herein Described methods and applications are modified or suitably changed with combining, to realize and using the technology of the present invention.

The present invention provides a kind of mill coil 65Mn of RE-treated, and its chemical composition is wrapped in percentage by weight Include：

C：0.63~0.69%, Si：0.18~0.37, Mn：0.90~1.20%, P≤0.035%, S≤0.035%, O ≤ 0.003%, N≤0.004%, RE≤0.01%, remaining is iron and other inevitable impurity.

Above-mentioned RE can be the one or more in La, Ce, Pr, Nd.

Further, during the thickness of strips≤6.0mm, Rel：430~600MPa, Rm：735~980MPa, A50：>=12%, ψ：>=35%, HARDNESS OF HOT-ROLLED≤250HB.

The present invention also provides a kind of above-mentioned mill coil 65Mn preparation method, and it includes：Use continuous cast billet for Hot rolling raw material, successively by heating and rolling, batch obtained.

Further, the continuous cast billet is prepared as follows：

Smelting and continuous casting：Molten iron carries out desulfurization pretreatment, using top and bottom combined blown converter decarburization, dephosphorization, carries out the outer essence of LF stoves Refining, slab continuous casting, slab cleaning, slab quality inspection.

Further, during the heating and rolling：Slab heating temperature is 1170~1200 DEG C, is carried out after de-scaling Rolling；Rolling is rolled using 3/4 continous way mill coil production line；1090 DEG C~1140 DEG C of roughing start rolling temperature, finish rolling is opened Roll 975 DEG C~1000 DEG C of temperature；

In curly course：740~790 DEG C of coiling temperature, finished product thickness≤6.0mm.

Further, the heating is heated using recuperative heater, and roughing uses the roughing mills of Ф 550, and finish rolling is stood using 3 7 flat finishing mills.

The mill coil 65Mn of RE-treated provided by the invention preparation method is to use continuous cast billet as hot rolling Raw material, it is heated, roughing, finish rolling, batch, finally give the hot-strip with excellent mechanical property.During the steel hot-rolled state Microscopic structure be pearlite+ferrite.

Compared with prior art, O, N content are relatively low by mill coil 65Mn provided by the invention, and continuous casting billet is heated, warm Roll, batch, produce the 65Mn of good mechanical performance.

During steel plate thickness≤6.0mm, Rel：430~600MPa, Rm：735~980MPa, A50：>=12%, ψ：>=35%

HARDNESS OF HOT-ROLLED≤250HB.

With reference to embodiment, the present invention is expanded on further：

Embodiment 1

The chemical composition of continuous casting billet is as shown in table 1：

Continuous casting billet chemical composition (the unit of table 1：%)

C	Si	Mn	P	S	O	N	RE
								0.065	0.33	0.95	0.012	0.010	0.0018	0.0032	0.0010

Smelting and continuous casting：Molten iron carries out desulfurization pretreatment, using top and bottom combined blown converter decarburization, dephosphorization, carries out the outer essence of LF stoves Refining, slab continuous casting, slab cleaning, slab quality inspection.

Heating and rolling：It is heated to 1180 DEG C to come out of the stove, is rolled after de-scaling, 1110 DEG C of roughing start rolling temperature, finish rolling is opened Roll 980 DEG C of temperature, 750 DEG C of coiling temperature, finished product thickness 2.75mm.Mechanical property and hardness test, test knot are carried out to steel band Fruit is listed in table 2.

The 2.75mm steel bands mechanical property of table 2, hardness

Embodiment 2

The chemical composition of continuous casting billet is as shown in table 3：

Continuous casting billet chemical composition (the unit of table 3：%)

C	Si	Mn	P	S	O	N	RE
								0.065	0.32	1.00	0.010	0.008	0.0017	0.0030	0.0011

Smelting and continuous casting：Molten iron carries out desulfurization pretreatment, using top and bottom combined blown converter decarburization, dephosphorization, carries out the outer essence of LF stoves Refining, slab continuous casting, slab cleaning, slab quality inspection.

Heating and rolling：It is heated to 1190 DEG C to come out of the stove, is rolled after de-scaling, 1110 DEG C of roughing start rolling temperature, finish rolling is opened Roll 990 DEG C of temperature, 760 DEG C of coiling temperature, finished product thickness 2.5mm.Mechanical property and hardness test, test result are carried out to steel band It is listed in table 4.

The 2.5mm steel bands mechanical property of table 4, hardness

Described above is only the preferred embodiment of the present invention, it is noted that for the ordinary skill people of the art For member, under the premise without departing from the principles of the invention, some improvements and modifications can also be made, these improvements and modifications also should It is considered as protection scope of the present invention.

Claims (5)

1. the mill coil 65Mn of a kind of RE-treated, it is characterised in that its chemical composition includes in percentage by weight：

C：0.63~0.69%, Si：0.18~0.37, Mn：0.90~1.20%, P≤0.035%, S≤0.035%, O≤ 0.003%, N≤0.004%, RE≤0.01%, remaining is iron and other inevitable impurity.

2. the mill coil 65Mn of RE-treated according to claim 1, it is characterised in that the thickness of strips During≤6.0mm, Rel：430~600MPa, Rm：735~980MPa, A50：>=12%, ψ：>=35%, HARDNESS OF HOT-ROLLED≤250HB.

3. the mill coil 65Mn of the RE-treated described in claim 1 preparation method, it is characterised in that including：Using Continuous cast billet is hot rolling raw material, successively by heating and rolling, is batched obtained.

4. the mill coil 65Mn of RE-treated according to claim 3 preparation method, it is characterised in that

The continuous cast billet is prepared as follows：

Smelting and continuous casting：Molten iron carries out desulfurization pretreatment, using top and bottom combined blown converter decarburization, dephosphorization, carries out LF external refinings, flat Base continuous casting, slab cleaning, slab quality inspection.

5. the mill coil 65Mn of RE-treated according to claim 3 preparation method, it is characterised in that

During the heating and rolling：Slab heating temperature is 1170~1200 DEG C, is rolled after de-scaling；Rolling uses 3/4 continous way mill coil production line rolls；1090 DEG C~1140 DEG C of roughing start rolling temperature, 975 DEG C of finish rolling start rolling temperature~ 1000℃；

In curly course：740~790 DEG C of coiling temperature, finished product thickness≤6.0mm.