CN101550516B - Method for revolving furnace smelting 45CrMnMo steel - Google Patents

Abstract

The invention relates to a producing method for revolving furnace smelting 45CrMnMo steel, which belongs to metallurgy field. The technical scheme includes the following steps: a) adding desulphurizing hot-metal into the revolving furnace, and smelting with adding lime stock, b) gradually adding the chromium irons, ferro-molybdenum and silicon-manganese alloy confected by proportion into molten steel parcel during the revolving furnace exporting molten steel, and adding coherer aluminum into the molten steel parcel to be deoxidized at the same time, c) blowing argon gas into the molten steel in the ladle after tapping, d) vacuum treating the molten steel and carrying through micro-adjustment with the chemical constituents in the vacuum procedure at the same time, then casting 45CrMnMo steel. The invention provides a method for revolving furnace producing 45CrMnMo steel, in which the recovery rate of chromium iron is higher, saves more time, improves economic benefit, and provides a better choice for producing 45CrMnMo steel.

Description

The method of revolving furnace smelting 45 CrMnMo steel

Technical field

The invention belongs to field of metallurgy, be specifically related to a kind of method of revolving furnace smelting 45 CrMnMo steel.

Background technology

The 45CrMnMo steel is the special steel that is used to produce stone oil drill collar.Drill collar is a key part of forming drill string in the petroleum drilling facility, is the parts that connect drill bit and drilling rod.Main effect is to transmit moment of torsion, drilling pressure is provided, guarantees rigidity, the stability of drill string bottom and prevents the oil drilling tool that well is inclined to one side to drill bit.The chemical ingredients of 45CrMnMo steel (weight %) is: carbon 0.42～0.48%; Silicon 0.15～0.30%; Manganese 0.75～1.20%; Molybdenum 0.15～0.25%; Chromium 0.75～1.20%; Phosphorus≤0.030%; Sulphur≤0.030%.Macrostructure is every≤and 2.0 grades, the every rank of non-metallic inclusion≤2.5 grades, non-metallic inclusion total levels≤16 grade.45CrMnMo steel grain fineness number 〉=5.0 after heat treatment grade, yield strength 〉=820MPa, tensile strength 〉=980MPa, elongation after fracture 〉=13%, ballistic work 〉=54J.Also should have good antifatigue and erosion resistance.

Produce 45CrMnMo both at home and abroad and generally adopt electrosmelting,, do not see the report that uses converter smelting method to obtain uniform tissue and performance.In addition, in the common steel alloy that contains chromium, molybdenum with electric furnace and converter smelting is that chromium, ferro-molybdenum are added in the converter molten steel, chromium has 10% oxide compound that forms chromium to enter in the slag, make the slag retrogradation, yield of alloy is low, has no idea to solve, cause the ferrochrome recovery rate to be lower than 90%, the ferro-molybdenum recovery rate is only about 95%.The while prior art also exists also makes the defective of tap to tap time with corresponding prolongation because will add into chromium, ferro-molybdenum.

Summary of the invention

Technical problem to be solved by this invention provides the method that a kind of converter smelting is efficiently produced the 45CrMnMo steel.The technical scheme of the method for this revolving furnace smelting 45 CrMnMo steel comprises and may further comprise the steps:

A, in converter, add desulphurised hot metal, and add the lime material and smelt;

B, in converter tapping liquid process, ferrochrome, ferro-molybdenum and the silicomanganese of preparation are in proportion progressively added in the molten steel bag, also metallic aluminium is added simultaneously and carries out deoxidation in the molten steel bag;

C, the back blowing argon gas in molten steel ladle of having tapped;

D, molten steel is carried out vacuum treated method, in vacuum process, chemical ingredients is carried out trace adjustment, the 45CrMnMo steel of casting then simultaneously.

Wherein, sulphur content≤0.020 of the desulphurised hot metal described in the aforesaid method step a, lime material add-on be desulphurised hot metal quality 0.03%～0.04%.

Wherein, the end point carbon of the tapping described in the aforesaid method step b is controlled in 0.35～0.45% scope, 〉=1660 ℃ of tapping temperature controls,

Wherein, the pressure of blowing argon gas is 0.4～0.6Mpa described in the aforesaid method step c, and liquid steel temperature is controlled at 1600～1650 ℃.

Wherein, below 400Pa, in 16～20 minutes treatment times, temperature is controlled at 1580～1650 ℃ to the vacuum-treat described in the aforesaid method steps d with vacuum degree control, also adjusts [Als] in the molten steel simultaneously in 0.015～0.035% scope.

Further the inventive method may further comprise the steps:

A, in converter, add the desulphurised hot metal of sulphur content≤0.020%, and add 0.035% lime material and carry out oxygen top blown and smelt;

The end point carbon of b, tapping is controlled in 0.35～0.45% scope, 〉=1660～1700 ℃ of tapping temperature controls, go out in the molten steel process 0.018% the ferrochrome that contains chromium 60% by the desulphurised hot metal quality, 0.044% the ferro-molybdenum that contains molybdenum 60% by the desulphurised hot metal quality, by the desulphurised hot metal quality 0.13% contain manganese 66%, siliceous 16% silicomanganese progressively adds in the molten steel bag, and add 3.5～3.6Kg metallic aluminium by molten steel per ton and carry out deoxidation;

C, the back of having tapped be with the blowing argon gas in molten steel ladle of 0.4～0.6Mpa pressure, and blowing argon gas time 〉=3 minute general 3～6 minutes, are controlled at the molten steel ladle temperature 〉=1600～1650 ℃.

D, below vacuum tightness 400Pa molten steel was carried out vacuum-treat 17～20 minutes, temperature is controlled at 1580～1650 ℃, simultaneously chemical ingredients is carried out trace adjustment, the 45CrMnMo steel of casting then.

The inventive method by top-blown oxygen converter smelting, microalloying, stove after processing steps such as Argon, electrical heater molten steel, vacuum-treat be implemented in and produce the 45CrMnMo steel in the converter, the product obdurability of the 45CrMnMo steel of producing is good, macrostructure is every≤and 2.0 grades, the every rank of non-metallic inclusion≤2.5 grades, non-metallic inclusion total levels≤16 grade, grain fineness number after heat treatment 〉=5.0 grade, yield strength 〉=820MPa, tensile strength 〉=980MPa, elongation after fracture 〉=13%, ballistic work 〉=54J. also has good antifatigue and erosion resistance.Ferrochrome, ferro-molybdenum add can make in the molten steel bag ferrochrome rate of recovery can reach 〉=95%.Simultaneously, to produce the 45CrMnMo steel be progressively adding in the molten steel bag in the tapping process such as chromium, molybdenum alloy and silicomanganese, can shorten the heat so about 10 minutes, increasing economic efficiency in the present invention.For the production of 45CrMnMo steel alloy provides a kind of better new selection.

Embodiment:

Embodiment one uses the inventive method to produce the 45CrMnMo steel

140 tons of molten iron that add sulphur content≤0.020% in converter add 5 tons lime material and carry out conventional oxygen top blown and smelt the back tapping.The end point carbon of tapping is controlled in 0.35～0.45% scope, 1660～1700 ℃ of tapping temperature controls, go out in the molten steel process the ferrochrome 2500kg that contains chromium 60% by 140 tons of molten steel preparations, contain the molybdenum-iron 620kg of molybdenum 60% and contain manganese 66%, siliceous 16% silicomanganese 1950kg progressively adds in the molten steel bag.With carrying out deoxidation in the metallic aluminium adding molten steel bag, add the 50Kg metallic aluminium by per 140 tons of molten steel and add in the molten steel with iron alloys such as ferrochrome, molybdenum-irons.The intact back of tapping steel was with the blowing argon gas in molten steel ladle of 0.4～0.6Mpa pressure 3 minutes.Adopt electrically heated method that molten steel ladle is heated, heating and temperature control is at 1600～1650 ℃.Employing is carried out vacuum treated method to molten steel, vacuum degree control below 400Pa, 18 minutes treatment times.In vacuum process, chemical ingredients is carried out trace adjustment.The chemical ingredients carbon of 45CrMnMo steel is 0.43%; Silicon 0.29%; Manganese 10.9%; Molybdenum 0.25%; Chromium 1.14%; Phosphorus 0.026%; Sulphur 0.014%.[Als] in the molten steel is 0.03%.Liquid steel temperature after the vacuum-treat is 1580～1650 ℃.Adopt die casting or continuous cast method casting 45CrMnMo steel then immediately.

The 45CrMnMo product made from steel performance that the inventive method and prior art are produced is compared as follows:

1, chemical ingredients: (%)

C

Si

Mn

P

S

Mo

Cr

Prior art

0.42～ 0.48

0.15～ 0.30

0.75～ 1.20

≤ 0.030

≤ 0.030

0.15～ 0.25

0.75～ 1.20

This example

0.43

0.29

10.9

0.026

0.014

0.25

1.14

2, mechanical property:

	Rp0.2(Mpa)	Rm(Mpa)	A(％)	Akv(J)
					Prior art	≥820	≥980	≥13％	≥54
This example	990	1090	18	124

Annotate: Rp0.2 (Mpa)-yield strength;

Rm (Mpa)-tensile strength;

A (%)-elongation after fracture:

Akv (J)-ballistic work.

3, non-metallic inclusion (level):

4, macrostructure check grading (level):

From last table 1, table 2, table 3, table 4 as can be seen, the 45CrMnMo steel that adopts the inventive method to produce, ferrochrome recovery rate 96.03%, ferro-molybdenum recovery rate 95.93%; Yield strength (Rp0.2)＞820Mpa, tensile strength (Rm)＞980Mpa, elongation after fracture (A)＞13%, ballistic work (Akv)＞54J.Non-metallic inclusion rank＜2.5 grades simultaneously, non-metallic inclusion total levels＜16 grade, the every index of macrostructure＜2.0 grades has surpassed the requirement of existing 45CrMnMo steel.

Claims (2)

1. the method for revolving furnace smelting 45 CrMnMo steel is characterized in that may further comprise the steps:

A, in converter, add desulphurised hot metal, and add the lime material and smelt; The sulphur content of described desulphurised hot metal≤0.020%, lime material add-on be desulphurised hot metal quality 0.03%～0.04%;

B, in converter tapping liquid process, ferrochrome, ferro-molybdenum and the silicomanganese of preparation are in proportion progressively added in the molten steel bag, also metallic aluminium is added simultaneously and carries out deoxidation in the molten steel bag; The end point carbon of described tapping is controlled in 0.35～0.45% scope, 〉=1660 ℃ of tapping temperature controls;

C, the back blowing argon gas in molten steel ladle of having tapped; The pressure of described blowing argon gas is 0.4～0.6MPa, and liquid steel temperature is controlled at 1600～1650 ℃;

D, molten steel is carried out vacuum treated method, in vacuum process, chemical ingredients is carried out trace adjustment, the 45CrMnMo steel of casting then simultaneously; Below 400Pa, in 16～20 minutes treatment times, temperature is controlled at 1580～1650 ℃ with vacuum degree control in described vacuum-treat, also adjusts [Als] in the molten steel simultaneously in 0.015～0.035% scope.

2. the method with revolving furnace smelting 45 CrMnMo steel as claimed in claim 1 is characterized in that may further comprise the steps:

A, in converter, add the desulphurised hot metal of sulphur content≤0.020%, and add 0.035% lime material and smelt;

The end point carbon of b, tapping is controlled in 0.35～0.45% scope, 〉=1660～1700 ℃ of tapping temperature controls, go out in the molten steel process 0.018% the ferrochrome that contains chromium 60% by the desulphurised hot metal quality, 0.044% the ferro-molybdenum that contains molybdenum 60% by the desulphurised hot metal quality, by the desulphurised hot metal quality 0.13% contain manganese 66%, siliceous 16% silicomanganese progressively adds in the molten steel bag, and add 3.5～3.6kg metallic aluminium by molten steel per ton and carry out deoxidation;

C, the back of having tapped be with the blowing argon gas in molten steel ladle of 0.4～0.6MPa pressure, and blowing argon gas time 〉=3 minute are controlled at 1600～1650 ℃ with the molten steel ladle temperature;

D, below vacuum tightness 400Pa molten steel was carried out vacuum-treat 17～20 minutes, temperature is controlled at 1580～1650 ℃, simultaneously chemical ingredients is carried out trace adjustment, the 45CrMnMo steel of casting then.