CN102242322A - Improved 40CrNiMo steel and preparation method thereof - Google Patents
Improved 40CrNiMo steel and preparation method thereof Download PDFInfo
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Abstract
The invention relates to improved 40CrNiMo steel and a preparation method thereof, and belongs to the technical field of alloy steel. The improved 40CrNiMo steel comprises the following chemical elements in percentage by weight: 0.37 to 0.45 percent of C, 1.65 to 1.85 percent of Cr, 0.45 to 0.65 percent of Ni, 0.15 to 0.25 percent of Mo, 0.90 to 1.20 percent of Mn, 0.40 to 0.55 percent of Si, 0.0025 to 0.0045 percent of B, 0.22 to 0.28 percent of N, 0.007 to 0.012 percent of Ca, 0.002 to 0.005 percent of Mg, 0.03 to 0.06 percent of Nb, 0.04 to 0.08 percent of Ti, 0.02 to 0.06 percent of RE, less than or equal to 0.015 percent of S, less than or equal to 0.025 percent of P, less than or equal to 0.0008 percent of Al and the balance of Fe. The invention has the advantages that: the improved 40CrNiMo steel has low nickel content, so that cost can be reduced; the steel has a fine structure, the number of impurities is obviously reduced, and the impurities have a small size and are uniformly distributed, so that the performance of the steel is obviously improved; and a few process steps are performed in the preparation method, so that energy is saved, and the requirement of industrial scale-up production is met.
Description
Technical field
The present invention is carbon ultrahigh-strength steel and preparation method thereof in the low-alloy, and particularly a kind of modified version 40CrNiMo steel and preparation method thereof belongs to the steel alloy technical field
Background technology
The 40CrNiMo steel belongs to carbon ultrahigh-strength steel in the low-alloy.This material after heat treatment has good comprehensive mechanical performance, and the adding of alloying elements such as chromium, nickel makes its hardening capacity better and ferritic intensity and toughness are improved; The adding of carbide forming element such as molybdenum, chromium can stop austenite crystal to be grown up, and improves the temper resistance of steel, and certain impact resistance and fracture toughness property and high fatigue strength in use can be arranged.
The main component of 40CrNiMo steel commonly used is: 0.60～0.90%Cr, 1.25～1.65%Ni, 0.15～0.25%Mo, 0.50～0.80%Mn, 0.37～0.45%C, 0.17～0.37%Si ,≤0.025%S ,≤0.025%P.Salient features after its modifier treatment is: tensile strength sigma
b
〉=980MPa, elongation δ
5
〉=12%, relative reduction in area ψ 〉=55%, ballistic work A
Kv
〉=78J, notched bar impact strength α
Kv
〉=98J/cm
2
For intensity and other mechanical properties of improving steel, Chinese invention patent application CN101514389A discloses a kind of 600MPa grade high-plasticity submicron crystal grain ferrite low carbon steel plate and manufacture method.The yield strength of described sheet material is 600～660MPa, and tensile strength is 720～780MPa, and breaking elongation is 17～21%, and uniform elongation is 12～17%, and yield tensile ratio is 0.82～0.84.Described method is: 14MnNb (Q345) soft steel with the 350MPa level is cast into strand; Strand is heated to 1180～1220 ℃ of insulations 8～10 hours, carries out the controlled rolling air cooling, 980～1020 ℃ of roughing finishing temperatures, 900～920 ℃ of finish rolling finishing temperatures, air cooling to 680 after the finish rolling～740 ℃, water spray cool to room temperature; It is cold rolling to carry out multi-pass then, and total reduction is 60～70%; Roll post-heating to 550～570 ℃ 1～2 hour air cooling of insulation to room temperature, obtain the 600MPa grade high-plasticity submicron crystal grain ferrite low carbon steel plate of 1～3 mm thick.
Chinese invention patent application CN101333629A also discloses a kind of production method of the medium high carbon high-strength steel based on sheet bar process.Its technical scheme is: through steel-making, refinery practice, sheet billet continuous casting, heating, soaking, hot continuous rolling, cool off and batch.Wherein: thin slab thickness is 50～90mm, the continuously cast bloom pulling rate is 2.5～6.0m/min, furnace temp is 900～1100 ℃, Soaking Pit Temperature is 1000～1250 ℃, start rolling temperature is 1000～1200 ℃, finishing temperature is 650～950 ℃, and coiling temperature is 450～850 ℃, and steel plate thickness is 1～12mm.The chemical ingredients of medium high carbon high-strength steel is: carbon content is that 0.25～1.25wt%, Al are that 0.001～0.1wt%, Ca are 0.0010～0.0050wt%, and all the other are in Fe, unavoidable impurities and all alloying elements one or more.
Chinese invention patent application CN101307411A also discloses and has a kind ofly contained Nb medium high carbon high-strength steel and manufacture method thereof based on sheet bar process.The chemical ingredients of the steel grade described in its technical scheme is: C is 0.25～1.25wt%, and Nb is 0.01～0.15wt%, and Al is 0.001～0.1wt%, and Ca is 0.0010～0.0050wt%, and all the other are Fe, unavoidable impurities and alloying element; Prepared steel plate yield strength is 350～1500MPa.Sheet bar process and processing parameter are: thin slab thickness is 50～90mm; The slab pulling rate is 2.5～6.0m/min; It is 900～1100 ℃ that strand enters furnace temp; It is 1000～1250 ℃ that strand enters Soaking Pit Temperature; Start rolling temperature is 1000～1200 ℃; Finishing temperature is 650～950 ℃; It is 1～12mm with steel plate thickness that coiling temperature is 450～850 ℃.This invention can be improved the quality of products, and improve to make efficient, reduces manufacturing cost, economizes on resources and the energy etc.
Chinese invention patent application CN1654695A also discloses low carbon high-strength degree complex intensifying superfine crystal particle hot rolling wire, its chemical ingredients (wt%) is: C 0.17%～0.25%, Si 0.20%～0.80%, Mn 0.60%～1.60%, P＜0.02%, S＜0.025%, surplus is iron Fe and unavoidable impurities, its metallographic structure is that grain-size is the ferrite of 4.5～7.5 μ m, 5%～20% bainite and a small amount of pearlitic heterogeneous structure.Corresponding production technique is: 1. rolling technology: strand is carried out 950～1000 ℃ burn steel; In the austenite recrystallization district, the controlled rolling of non-recrystallization district, 950 ℃ ± 20 ℃ of roughing start rolling temperatures, 800 ℃ ± 30 ℃ of roughing finishing temperatures; Roll 800 ℃～820 ℃ of temperature in going into; Go into 760 ℃～800 ℃ of finish rolling start rolling temperatures, water-cooled between finishing stand, 840 ℃～900 ℃ of finish rolling finishing temperatures; 2. roll postcooling technology: by 80 ℃～150 ℃ of water tank coolings, 690 ℃～800 ℃ of laying temperatures loose and roll up 15 ℃/s of speed of cooling～25 ℃/s after the finish rolling.This invention has good comprehensive mechanical properties, replaces the Hi-Stren steel muscle with intensity rank, can reduce production costs significantly, has also increased the returnability of steel simultaneously.
Chinese invention patent application CN1064506A also discloses a kind of high-carbon silicomanganese Ao-Bei and has organized low-alloy super-strength steel and thermal treatment process thereof, the chemical ingredients of this ultrahigh-strength steel: 0.6～0.8%C, 1.5～2.5%Si, 0.8～1.4%Mn, 0～1.2%Cr ,≤0.04%S, ≤ 0.04%P, the part that described ultrahigh-strength steel is made is heated to 870～900 ℃, and isothermal processes 40 to 60 minutes in 280～340 ℃ of scopes is cooled to normal temperature subsequently in air then.This low-alloy super-strength steel not only uses no or little rare your element, and is cheap, and mechanical property, can match in excellence or beauty with external famous low-alloy super-strength steel such as 4340 grades.
Chinese invention patent application CN1537967A also discloses a kind of preparation method of low-carbon (LC) 520MPa grade composite strengthening ultrafine grain belt steel, with the chemical component weight ratio is C:0.12～0.15%, Si:0.15～0.40%, Mn:1.10～1.30%, Nb:0.007～0.015%, P＜0.01%, S＜0.01%, all the other are raw material for the Fe of equal amount, through smelting, and continuous casting becomes blank, is 1190～1210 ℃ with blank heating to temperature; In the austenite recrystallization district, non-recrystallization district and the controlled rolling of deformation induced phase change zone, the roughing start rolling temperature is 1140～1160 ℃, the roughing finishing temperature is 1040～1050 ℃, intermediate blank thickness is 32～45mm, the finish rolling start rolling temperature is 1000～980 ℃, the finish rolling finishing temperature is 790～820 ℃, between finishing stand, carry out water-cooled, roll 20～30 ℃/s of postcooling speed, coiling temperature is 430～470 ℃, the ferrite matrix that the product metallographic structure is grain-size 2～4 μ m that obtains, other is the pearlitic heterogeneous structure of 10～20% bainite and＜5%: the yield strength of band steel is 520～570MPa, and tensile strength is 630～690MPa; This product can substitute the Hi-Stren steel with intensity rank fully, saves alloying element effectively and reduces steel product cost.
But there is following shortcoming in the disclosed technology contents of above-mentioned patent documentation: the hardening capacity of first steel is lower, and does not provide the technology enlightenment of reasonable adding such as nitrogen and boron; It two is because of the higher economy of losing of nickel content; It three is that physicals such as tensile strength, yield strength, elongation, relative reduction in area, ballistic work and the notched bar impact strength of steel still is not enough to reach gratifying degree; It four is complicated process of preparation
Summary of the invention
The present invention is directed to the deficiency that the carbon ultrahigh-strength steel exists in producing in the existing low-alloy, a kind of modified version 40CrNiMo steel is provided, in 40CrNiMo, adds the nitrogen, the boron that improve hardening capacity, reduce the content of nickel element significantly, thereby reach the purpose of obvious reduction 40CrNiMo cost.Suitably improve chromium content to 1.25～1.55% in addition, improve the temper resistance energy of steel.Strict control residual aluminum amount prevents to generate the AlN that distributes along the casting crystal boundary less than 0.0008%.Adopt the silicocalcium pre-deoxidation, the magnesium final deoxygenation, thus guarantee the quality of steel; The present invention also provides preparation technology the preparation method of terse a kind of modified version 40CrNiMo steel at the shortcoming of the complicated process of preparation in the prior art.
Purpose of the present invention can realize by following measure:
A kind of modified version 40CrNiMo steel, its chemical element weight % is: 0.37～0.45% C, 1.65～1.85% Cr, 0.45～0.65% Ni, 0.15～0.25% Mo, 0.90～1.20% Mn, 0.40～0.55% Si, 0.0025～0.0045% B, 0.22～0.28% N, 0.007～0.012% Ca, 0.002～0.005% Mg, 0.03～0.06% Nb, 0.04～0.08% Ti, 0.02～0.06% RE, the Al of≤0.015% S and≤0.025% P and≤0.0008%, Fe is a surplus.
In a specific embodiment of the present invention, described chemical element weight % is: 0.38% C, 1.66% Cr, 0.64% Ni, 0.20% Mo, 1.03% Mn, 0.44% Si, 0.0035% B, 0.28% N, 0.012% Ca, 0.003% Mg, 0.05% Nb, 0.05% Ti, 0.04% RE, 0.013% S, 0.022% P and 0.0005% Al, Fe are surplus.
In another specific embodiment of the present invention, described chemical element weight % is: 0.45% C, 1.70% Cr, 0.51% Ni, 0.25% Mo, 0.91% Mn, 0.53% Si, 0.0027% B, 0.23% N, 0.008% Ca, 0.004% Mg, 0.06% Nb, 0.05% Ti, 0.03% RE, 0.014% S, 0.019% P and 0.0007% Al, Fe are surplus.
In another specific embodiment of the present invention, described chemical element weight % is: 0.42% C, 1.85% Cr, 0.47% Ni, 0.16% Mo, 1.15% Mn, 0.42% Si, 0.0042% B, 0.26% N, 0.010% Ca, 0.005% Mg, 0.03% Nb, 0.07% Ti, 0.05% RE, 0.008% S, 0.020% P and 0.0003% Al, Fe are surplus.
Of the present invention also have a purpose to reach like this, and a kind of preparation method of modified version 40CrNiMo steel adopts electrosmelting, may further comprise the steps:
1. with ordinary scrap steel, carburelant, nickel plate and the fusing of molybdenum-iron Hybrid Heating, the molten clear back of molten steel adds ferromanganese and ferrosilicon;
2. the stokehold is adjusted to branch and temperature is risen to 1630～1650 ℃ after qualified, adds the silicocalcium pre-deoxidation, then add successively particle size 12～18mm and 550～650 ℃ of preheating 2～3h contain nitrogenous ferrochrome, ferro-niobium and ferrotianium after come out of the stove;
3. ferro-boron and magnesium-rare earth are crushed to the fritter of particle size 5～10mm, behind 220～250 ℃ of oven dry 2～3h, place the casting ladle bottom, molten steel is carried out the microalloy processing with pouring method in the bag;
4. molten steel is poured into ingot casting in metal pattern, 1460～1480 ℃ of pouring molten steel temperature;
5. be cooled to temperature when being lower than 820 ℃ when ingot solidification, in ingot mold, take out steel ingot, steel ingot is reheated to 1120～1150 ℃, insulation 4～6h, forge processing then, 1120～1150 ℃ of steel ingot initial forging temperatures, 820～850 ℃ of final forging temperatures, the steel ingot forging is placed on holding furnace or burial pit slowly cools off;
6. after forging the modified version 40CrNiMo steel ingot roughing after the slow cooling, be heated to 860～880 ℃ earlier, insulation 1～2h, oil cooling, and then be heated to 580～600 ℃, insulation 3～5h, water-cooled then is heated to 180～200 ℃, insulation 8～10h, stove is chilled to the air cooling of coming out of the stove after temperature is lower than 120 ℃, is refined to specified dimension and precision at last, the type that is improved 40CrNiMo steel finished product.
Technical scheme provided by the invention compared with prior art has following technique effect:
1) modified version 40CrNiMo steel nickel content of the present invention is low, compares with common 40CrNiMo steel, and product per ton can reduce cost 1000～1200 yuan;
2) modified version 40CrNiMo steel of the present invention is after element multiple microalloyings such as niobium, titanium, calcium, rare earth and magnesium are handled, and organizes tinyly, and The amount of inclusions obviously reduces, and the inclusion size is little, is evenly distributed, and causes the performance of steel obviously to improve, wherein tensile strength sigma
b
〉=1180MPa, yield strength σ
s
〉=930MPa elongation δ
5
〉=14%, relative reduction in area ψ 〉=58%, ballistic work A
Kv
〉=85J, notched bar impact strength α
Kv
〉=106J/cm
2
3) preparation method's processing step is few, helps save energy, and can satisfy the industrial amplification production requirement.
Embodiment
The performance of alloy material is by the metallographic structure decision, and certain tissue depends on chemical ingredients and thermal treatment process, and chemical ingredients of the present invention is to determine like this:
Carbon: carbon is the principal element in the modified version 40CrNiMo steel, and the carbon solid solution can obviously improve the intensity of steel, but add-on is too much in matrix, and the plasticity of steel and toughness are descended, and takes all factors into consideration carbon content is controlled at 0.37～0.45%.
Nickel: nickel is to improve the hardening capacity element, adds the hardening capacity that can obviously improve steel in the steel, improves the intensity and the toughness of steel, and still, nickel content is too high, can obviously increase the production cost of steel, therefore its content is controlled at 0.45～0.65%.
Nitrogen: nitrogen can improve the intensity and the plasticity of steel, enlarges the austenitic area, and crystal grain thinning improves processing characteristics.Add-on is too much, is prone to pore, reduces the compactness of steel, therefore is controlled at 0.22～0.28%.
Chromium: improve the anti-temper softening ability of steel, make steel have good obdurability, add-on is too much, easily at grain boundary segregation, damages the intensity and the toughness of steel, takes all factors into consideration chromium content is controlled at 1.65～1.85%.
Molybdenum, silicon and manganese: add molybdenum and mainly work to alleviate temper brittleness.Molybdenum also has the temper resistance of raising and improves the effects such as intensity of steel, but costs an arm and a leg, and add-on is too much unsuitable, should be controlled at 0.15～0.25%.Silicon and manganese have desoxydatoin preferably, and manganese also has the effect that improves hardening capacity, and silicon has the reinforcement matrix, improve the effects such as intensity of steel, the manganese too high levels, and ingot casting is prone to crackle, and silicone content is too high, and is easy to crack in the quenching process.Therefore silicone content is controlled at 0.40～0.55%, and manganese content is controlled at 0.90～1.20%.
Boron: add an amount of boron and mainly be in order to improve the hardening capacity of modified version 40CrNiMo steel, add-on is too much, is prone to brittle boride at crystal boundary, reduces the intensity and the toughness of modified version 40CrNiMo steel, and suitable add-on is 0.0025～0.0045%.
Calcium: calcium and oxygen have very big avidity, and the deoxidizing capacity of calcium is very strong.Calcium has remarkable effect to steel inclusion rotten, add an amount of calcium in the steel and can change the strip sulfide inclusion in the steel into globular CaS or (Ca, Mn) S is mingled with, add an amount of calcium in the steel and also significantly reduce sulphur poly-partially at crystal boundary, hot-cracking resistance was very useful when calcium solidified the fragility that reduces steel and raising modified version 40CrNiMo steel.But add too much calcium steel inclusion will be increased, it is unfavorable that the steel flexible is improved, and suitable calcium contents is 0.007～0.012%
Magnesium: magnesium and sulphur, oxygen have great avidity, and violent metallurgical reaction can take place, and remove oxygen and sulphur in the steel, reduce oxide compound and sulfide inclusion in the steel.When the part MgO in deoxidation, the desulfurization product and MgS have little time to float when getting rid of to the molten steel face, just become being mingled with of steel after solidifying.During solidification of molten steel, at first form MgO, it can be used as MgS, MnS and other core that is mingled with after coagulation.Because MgO disperses in molten steel especially, so magnesium can change type, quantity, size, form and the distribution of steel inclusion.An amount of magnesium can make steel inclusion become tiny, disperse.Life size is big, the Al of band corner angle
2
O
3
Be mingled with by size MgO little, spherical in shape and the duplex impurity that contains MgO and replace; Life size is big, the MnS of strip is mingled with by little, subglobose MgO of size and MgS.MgO duplex impurity and replaces, thereby has improved inclusion and formation of matrix opposing crackle and the ability of expanding, and has improved the toughness of steel.Magnesium add-on deficiency can not make sufficient deoxidation, desulphurization reaction will take place in the steel, be unfavorable for the removal of inclusion.Add-on too much not only causes the waste of magnesium, and owing to reaction is too violent, MgO, the MgS etc. that float to the molten steel surface on making is mingled be involved in again in the molten steel, can produce adverse influence to modified version 40CrNiMo rigidity.Therefore Mg content is controlled at 0.002～0.005%.
Niobium and titanium: niobium and titanium are strong carbon, nitride forming element, with carbon, nitrogen very big avidity is arranged all, in modified version 40CrNiMo steel, niobium and titanium are mainly with Nb (C, N), Ti (C, N) form exists, and is distributed on the matrix, and Nb (C, N), Ti (C, N) separate out temperature greater than 1350 ℃, more than the liquidus line of steel just forming core separate out, Nb (C, N), Ti (C, a large amount of enrichments of iron, chromium, manganese element in the melt impelled primary austenite at Nb (C around separating out N) caused, N), Ti (C, N) separate out on every side by forming core.Niobium and titanium content are high more, the Nb that separates out (C, N), Ti (C, N) quantity is many more, the austenite nucleus of preferentially separating out on its surface is also many more, austenitic refining effect just better.Niobium and titanium add-on are too much, organize Nb (C, N), Ti (C, N) quantity increases, size increases, and increases the fragility of steel on the contrary, therefore content of niobium is controlled at 0.03～0.06%, titanium content is controlled at 0.04～0.08%.
Rare earth: add an amount of rare earth element in the modified version 40CrNiMo steel, have deoxidation, desulfurization, crystal grain thinning, improve the intensity and the toughness effect of steel, rare earth also blocks the forging process performance that can be apt to steel, prevent that cracking from appearring in steel ingot in forging process, suitable add-on is 0.02～0.06%.
Aluminium, sulphur and phosphorus: aluminium, sulphur, phosphorus are harmful elements, and wherein aluminium easily combines with nitrogen, generate the AlN that distributes along crystal boundary, reduce the toughness of steel.In order to guarantee the performance of modified version 40CrNiMo steel, it is limited, wherein aluminium content is lower than 0.0008%, and sulphur content is lower than 0.015%, and phosphorus content is lower than 0.025%.
The performance of alloy material is also relevant with thermal treatment process, and thermal treatment process of the present invention is to determine like this: after the modified version 40CrNiMo steel ingot roughing after the forging slow cooling, be heated to 860～880 ℃ earlier, insulation 1～2h, realize austenitizing, oil cooling obtains tiny martensitic stucture then.And then be heated to 580～600 ℃, and insulation 3～5h, water-cooled obtains the tempering troostite tissue.The main purpose of water-cooled is to prevent temper brittleness behind the high tempering, is heated to 180～200 ℃ at last, insulation 8～10h, stove is chilled to the air cooling of coming out of the stove after temperature is lower than 120 ℃, can fully eliminate stress, stabilizing tissue guarantees that modified version 40CrNiMo steel has excellent obdurability.
Below in conjunction with embodiment the present invention is further described:
Embodiment 1
Smelt modified version 40CrNiMo steel of the present invention in 5000 kilograms of medium-frequency induction furnaces, concrete processing step is as follows:
Modified version 40CrNiMo steel electrosmelting of the present invention, its manufacturing technology steps is:
1. with ordinary scrap steel, carburelant, nickel plate and the fusing of molybdenum-iron Hybrid Heating, the molten clear back of molten steel adds ferromanganese and ferrosilicon;
2. the stokehold is adjusted to branch and temperature is risen to 1632 ℃ after qualified, adds the silicocalcium pre-deoxidation, then add successively particle size 12～18mm and 550 ℃ of preheating 3h contain nitrogenous ferrochrome, ferro-niobium and ferrotianium after come out of the stove;
3. ferro-boron and magnesium-rare earth are crushed to the fritter of particle size 5～10mm, behind 250 ℃ of oven dry 2h, place the casting ladle bottom, molten steel is carried out the microalloy processing with pouring method in the bag;
4. molten steel is poured into ingot casting in metal pattern, 1463 ℃ of pouring molten steel temperature;
5. be cooled to temperature when being lower than 820 ℃ when ingot solidification, in ingot mold, take out steel ingot, steel ingot is reheated to 1120 ℃, insulation 6h forges processing, 1120 ℃ of steel ingot initial forging temperatures then, 822 ℃ of final forging temperatures, the steel ingot forging is placed on holding furnace and slowly cools off;
6. after forging the modified version 40CrNiMo steel ingot roughing after the slow cooling, be heated to 880 ℃ earlier, insulation 1h, oil cooling, and then be heated to 580 ℃, and insulation 5h, water-cooled is heated to 200 ℃ at last, insulation 8h, stove is chilled to the air cooling of coming out of the stove after temperature is lower than 120 ℃, is refined to specified dimension and precision at last.The composition of steel sees Table 1, and the mechanical property of steel sees Table 2.
Embodiment 2
Smelt modified version 40CrNiMo steel of the present invention in 5000 kilograms of medium-frequency induction furnaces, concrete processing step is as follows:
Modified version 40CrNiMo steel electrosmelting of the present invention, its manufacturing technology steps is:
1. with ordinary scrap steel, carburelant, nickel plate and the fusing of molybdenum-iron Hybrid Heating, the molten clear back of molten steel adds ferromanganese and ferrosilicon;
2. the stokehold is adjusted to branch and temperature is risen to 1649 ℃ after qualified, adds the silicocalcium pre-deoxidation, then add successively particle size 12～18mm and 650 ℃ of preheating 2h contain nitrogenous ferrochrome, ferro-niobium and ferrotianium after come out of the stove;
3. ferro-boron and magnesium-rare earth are crushed to the fritter of particle size 5～10mm, behind 220 ℃ of oven dry 3h, place the casting ladle bottom, molten steel is carried out the microalloy processing with pouring method in the bag;
4. molten steel is poured into ingot casting in metal pattern, 1475 ℃ of pouring molten steel temperature;
5. be cooled to temperature when being lower than 820 ℃ when ingot solidification, in ingot mold, take out steel ingot, steel ingot is reheated to 1150 ℃, insulation 4h forges processing, 1150 ℃ of steel ingot initial forging temperatures then, 846 ℃ of final forging temperatures, the steel ingot forging is placed on burial pit and slowly cools off;
6. after forging the modified version 40CrNiMo steel ingot roughing after the slow cooling, be heated to 860 ℃ earlier, insulation 2h, oil cooling, and then be heated to 600 ℃, insulation 3h, water-cooled is heated to 180 ℃ at last, insulation 10h, stove is chilled to the air cooling of coming out of the stove after temperature is lower than 120 ℃, is refined to specified dimension and precision at last.The composition of steel sees Table 1, and the mechanical property of steel sees Table 2.
Embodiment 3
Smelt modified version 40CrNiMo steel of the present invention in 1500 kilograms of medium-frequency induction furnaces, concrete processing step is as follows:
Modified version 40CrNiMo steel electrosmelting of the present invention, its manufacturing technology steps is:
1. with ordinary scrap steel, carburelant, nickel plate and the fusing of molybdenum-iron Hybrid Heating, the molten clear back of molten steel adds ferromanganese and ferrosilicon;
2. the stokehold is adjusted to branch and temperature is risen to 1641 ℃ after qualified, adds the silicocalcium pre-deoxidation, then add successively particle size 12～18mm and 600 ℃ of preheating 2.5h contain nitrogenous ferrochrome, ferro-niobium and ferrotianium after come out of the stove;
3. ferro-boron and magnesium-rare earth are crushed to the fritter of particle size 5～10mm, behind 230 ℃ of oven dry 2.5h, place the casting ladle bottom, molten steel is carried out the microalloy processing with pouring method in the bag;
4. molten steel is poured into ingot casting in metal pattern, 1470 ℃ of pouring molten steel temperature;
5. be cooled to temperature when being lower than 820 ℃ when ingot solidification, in ingot mold, take out steel ingot, steel ingot is reheated to 1140 ℃, insulation 5h forges processing, 1140 ℃ of steel ingot initial forging temperatures then, 839 ℃ of final forging temperatures, the steel ingot forging is placed on holding furnace and slowly cools off;
6. after forging the modified version 40CrNiMo steel ingot roughing after the slow cooling, be heated to 870 ℃ earlier, insulation 2h, oil cooling, and then be heated to 590 ℃, and insulation 4h, water-cooled is heated to 190 ℃ at last, insulation 9h, stove is chilled to the air cooling of coming out of the stove after temperature is lower than 120 ℃, is refined to specified dimension and precision at last.The composition of steel sees Table 1, and the mechanical property of steel sees Table 2.
Table 1 be the modified version 40CrNiMo steel of the embodiment of the invention 1 to 3 chemical element (massfraction, %)
| Element | C | Cr | Ni | Mo | Mn | Si | N | B | Ca |
| Embodiment 1 | 0.38 | 1.66 | 0.64 | 0.20 | 1.03 | 0.44 | 0.28 | 0.0035 | 0.012 |
| Embodiment 2 | 0.45 | 1.70 | 0.51 | 0.25 | 0.91 | 0.53 | 0.23 | 0.0027 | 0.008 |
| Embodiment 3 | 0.42 | 1.85 | 0.47 | 0.16 | 1.15 | 0.42 | 0.26 | 0.0042 | 0.010 |
| Element | Mg | Nb | Ti | RE | Al | S | P | Fe | ? |
| Embodiment 1 | 0.003 | 0.05 | 0.05 | 0.04 | 0.0005 | 0.013 | 0.022 | Surplus | ? |
| Embodiment 2 | 0.004 | 0.06 | 0.05 | 0.03 | 0.0007 | 0.014 | 0.019 | Surplus | ? |
| Embodiment 3 | 0.005 | 0.03 | 0.07 | 0.05 | 0.0003 | 0.008 | 0.020 | Surplus | ? |
Table 2 is the mechanical property of the embodiment of the invention 1 to 3 modified version 40CrNiMo steel
| Mechanical property | Tensile strength sigma b (MPa) | Yield strength σ s (MPa) | Elongation δ 5 (％) | Relative reduction in area ψ (%) | Ballistic work A kv (J) | Impelling strength α kv (J/cm 2 ) |
| Embodiment 1 | 1195 | 935 | 16.7 | 63.7 | 90.5 | 113.1 |
| Embodiment 2 | 1220 | 950 | 15.1 | 60.8 | 85.4 | 106.8 |
| Embodiment 3 | 1210 | 955 | 15.6 | 61.0 | 87.1 | 108.9 |
Modified version 40CrNiMo steel of the present invention has the good mechanical performance, successfully be used to make rear axle shaft, axle, excentric shaft and the connecting rod etc. of the bigger gear shaft of heavy duty, cross section, gear, truck, safe and reliable, non-cracking, metamorphism occur in the use, and result of use has met or exceeded the level of 40CrNiMo steel commonly used.Modified version 40CrNiMo steel nickel content of the present invention is low, compares with common 40CrNiMo steel, and product per ton can reduce cost 1000～1200 yuan.Use product of the present invention, have good economic benefits
Claims (5)
1. modified version 40CrNiMo steel, it is characterized in that its chemical element weight % is: 0.37～0.45% C, 1.65～1.85% Cr, 0.45～0.65% Ni, 0.15～0.25% Mo, 0.90～1.20% Mn, 0.40～0.55% Si, 0.0025～0.0045% B, 0.22～0.28% N, 0.007～0.012% Ca, 0.002～0.005% Mg, 0.03～0.06% Nb, 0.04～0.08% Ti, 0.02～0.06% RE, the Al of≤0.015% S and≤0.025% P and≤0.0008%, Fe is a surplus.
2. modified version 40CrNiMo steel according to claim 1 is characterized in that described chemical element weight % is: 0.38% C, 1.66% Cr, 0.64% Ni, 0.20% Mo, 1.03% Mn, 0.44% Si, 0.0035% B, 0.28% N, 0.012% Ca, 0.003% Mg, 0.05% Nb, 0.05% Ti, 0.04% RE, 0.013% S, 0.022% P and 0.0005% Al, Fe are surplus.
3. modified version 40CrNiMo steel according to claim 1 is characterized in that described chemical element weight % is: 0.45% C, 1.70% Cr, 0.51% Ni, 0.25% Mo, 0.91% Mn, 0.53% Si, 0.0027% B, 0.23% N, 0.008% Ca, 0.004% Mg, 0.06% Nb, 0.05% Ti, 0.03% RE, 0.014% S, 0.019% P and 0.0007% Al, Fe are surplus.
4. modified version 40CrNiMo steel according to claim 1 is characterized in that described chemical element weight % is: 0.42% C, 1.85% Cr, 0.47% Ni, 0.16% Mo, 1.15% Mn, 0.42% Si, 0.0042% B, 0.26% N, 0.010% Ca, 0.005% Mg, 0.03% Nb, 0.07% Ti, 0.05% RE, 0.008% S, 0.020% P and 0.0003% Al, Fe are surplus.
5. the preparation method of a modified version 40CrNiMo steel is characterized in that adopting electrosmelting, may further comprise the steps:
1. with ordinary scrap steel, carburelant, nickel plate and the fusing of molybdenum-iron Hybrid Heating, the molten clear back of molten steel adds ferromanganese and ferrosilicon;
2. the stokehold is adjusted to branch and temperature is risen to 1630～1650 ℃ after qualified, adds the silicocalcium pre-deoxidation, then add successively particle size 12～18mm and 550～650 ℃ of preheating 2～3h contain nitrogenous ferrochrome, ferro-niobium and ferrotianium after come out of the stove;
3. ferro-boron and magnesium-rare earth are crushed to the fritter of particle size 5～10mm, behind 220～250 ℃ of oven dry 2～3h, place the casting ladle bottom, molten steel is carried out the microalloy processing with pouring method in the bag;
4. molten steel is poured into ingot casting in metal pattern, 1460～1480 ℃ of pouring molten steel temperature;
5. be cooled to temperature when being lower than 820 ℃ when ingot solidification, in ingot mold, take out steel ingot, steel ingot is reheated to 1120～1150 ℃, insulation 4～6h, forge processing then, 1120～1150 ℃ of steel ingot initial forging temperatures, 820～850 ℃ of final forging temperatures, the steel ingot forging is placed on holding furnace or burial pit slowly cools off;
6. after forging the modified version 40CrNiMo steel ingot roughing after the slow cooling, be heated to 860～880 ℃ earlier, insulation 1～2h, oil cooling, and then be heated to 580～600 ℃, insulation 3～5h, water-cooled then is heated to 180～200 ℃, insulation 8～10h, stove is chilled to the air cooling of coming out of the stove after temperature is lower than 120 ℃, is refined to specified dimension and precision at last, the type that is improved 40CrNiMo steel finished product.
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| CN103056339A (en) * | 2012-12-25 | 2013-04-24 | 江苏联兴成套设备制造有限公司 | Casting technique of cross-beam temperature measuring device of blast furnace |
| CN103173686A (en) * | 2013-03-07 | 2013-06-26 | 上海大学 | Troostite pre-hardened plastic die steel and its preparation method |
| CN104747584A (en) * | 2015-03-26 | 2015-07-01 | 宁波祥瑞机械有限公司 | Eccentric shaft |
| CN105214796A (en) * | 2015-11-12 | 2016-01-06 | 张磊 | A kind of crush maize agricultural machinery |
| CN105525197A (en) * | 2015-12-21 | 2016-04-27 | 武钢集团昆明钢铁股份有限公司 | Molten forging steel used for manufacturing eccentric shaft of crusher and smelting method for molten forging steel |
| CN105779707A (en) * | 2016-05-26 | 2016-07-20 | 镇江市经纬工程机械有限公司 | Thermal treatment method of cast eccentric shaft |
| CN105886738A (en) * | 2016-05-03 | 2016-08-24 | 成都亨通兆业精密机械有限公司 | Heat treatment technology for hinge pin |
| CN107779566A (en) * | 2017-10-30 | 2018-03-09 | 山东伊莱特重工股份有限公司 | A kind of heat treatment method of high-intensity high-tenacity 40CrNiMo forging |
| CN113151664A (en) * | 2021-03-31 | 2021-07-23 | 甘肃酒钢集团宏兴钢铁股份有限公司 | Mixed heating method for industrial high-purity nickel plate blank and stainless steel |
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| CN103056339A (en) * | 2012-12-25 | 2013-04-24 | 江苏联兴成套设备制造有限公司 | Casting technique of cross-beam temperature measuring device of blast furnace |
| CN103173686A (en) * | 2013-03-07 | 2013-06-26 | 上海大学 | Troostite pre-hardened plastic die steel and its preparation method |
| CN104747584A (en) * | 2015-03-26 | 2015-07-01 | 宁波祥瑞机械有限公司 | Eccentric shaft |
| CN104747584B (en) * | 2015-03-26 | 2016-04-27 | 宁波祥瑞机械有限公司 | A kind of eccentric shaft |
| CN105214796A (en) * | 2015-11-12 | 2016-01-06 | 张磊 | A kind of crush maize agricultural machinery |
| CN105525197B (en) * | 2015-12-21 | 2017-09-15 | 武钢集团昆明钢铁股份有限公司 | A kind of forging steel molten steel and its smelting process for being used to manufacture broken eccentric drive shaft |
| CN105525197A (en) * | 2015-12-21 | 2016-04-27 | 武钢集团昆明钢铁股份有限公司 | Molten forging steel used for manufacturing eccentric shaft of crusher and smelting method for molten forging steel |
| CN105886738A (en) * | 2016-05-03 | 2016-08-24 | 成都亨通兆业精密机械有限公司 | Heat treatment technology for hinge pin |
| CN105779707A (en) * | 2016-05-26 | 2016-07-20 | 镇江市经纬工程机械有限公司 | Thermal treatment method of cast eccentric shaft |
| CN107779566A (en) * | 2017-10-30 | 2018-03-09 | 山东伊莱特重工股份有限公司 | A kind of heat treatment method of high-intensity high-tenacity 40CrNiMo forging |
| CN113151664A (en) * | 2021-03-31 | 2021-07-23 | 甘肃酒钢集团宏兴钢铁股份有限公司 | Mixed heating method for industrial high-purity nickel plate blank and stainless steel |
| CN113151664B (en) * | 2021-03-31 | 2023-02-28 | 甘肃酒钢集团宏兴钢铁股份有限公司 | Mixed heating method for industrial high-purity nickel plate blank and stainless steel |
| CN114427024A (en) * | 2021-12-17 | 2022-05-03 | 山西平阳重工机械有限责任公司 | Process for eliminating temper brittleness of outer cylinder of hydraulic support |
| CN114427024B (en) * | 2021-12-17 | 2024-01-23 | 山西平阳重工机械有限责任公司 | Process for eliminating tempering brittleness of outer cylinder of hydraulic support |
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