CN107974637A

CN107974637A - A kind of hot die steel and preparation method thereof

Info

Publication number: CN107974637A
Application number: CN201711373455.8A
Authority: CN
Inventors: 唐佳丽; 谢珍勇; 蔡武; 胡峰荣; 任金桥; 屈小科; 刘迎骥; 吴欣容; 张璨; 王建
Original assignee: Pangang Group Jiangyou Changcheng Special Steel Co Ltd
Current assignee: Pangang Group Jiangyou Changcheng Special Steel Co Ltd
Priority date: 2017-12-19
Filing date: 2017-12-19
Publication date: 2018-05-01
Anticipated expiration: 2037-12-19
Also published as: CN107974637B

Abstract

The present invention provides a kind of hot die steel, by mass percentage, including：C：0.45%~0.55%, Si：0.10%~0.35%, Mn：0.15%~0.35%, P：≤ 0.010%, S：≤ 0.003%, Cr：4.30%~5.10%, Mo：2.80%~3.20%, V：0.50%~0.80%, Ni：≤ 0.20%, Cu：≤ 0.10%, the Fe of impurity element and surplus less than or equal to 0.04%.Material composition of the present invention from hot die steel, the composition and ratio of raw material are selected and adjusted, obtains being used for warm forging, particularly high rigidity, high tenacity and the high life mould steel of hot-forging die, it can be suitable for harsher hot-forging die working environment, meet the multi-aspect demand in market.

Description

A kind of hot die steel and preparation method thereof

Technical field

The invention belongs to mould steel preparing technical field, is related to a kind of hot die steel and preparation method thereof, more particularly to A kind of high performance hot-work die steel for being used for warm forging or hot forging and preparation method thereof.

Background technology

Mould steel is the steel grade for manufacturing the moulds such as cold-punching mould, hot-forging die, compression mod, and mould is machine-building, nothing The main machining tool of part is manufactured in the industrial departments such as line electricity instrument, motor, electric appliance, its quality directly affects pressure processing The quality of technique, the precision yield of product and production cost, the quality and service life of usual mould, rely primarily on rational knot Structure design, machining accuracy, mold materials and and heat treatment etc. several respects., can be by mould steel point by the service condition of mould For four major classes, including cold work die steel, hot die steel, plastic die steel and plastic mould steel.Hot-work die is among these Refer to, for the metal of heating or liquid metals to be made to the frock of required product, such as hot forged mould, thermal upsetting die, hot extruding die Tool, die casting and high-speed molding mould etc., and used various die steels are referred to as hot die steel.

With Industry Quick Developments such as the automobile industry in China, track traffic, aerospace, engineering machinery, all kinds of machineries Equipment forging demand is significantly increased, and is increased using metal forming machinery processing forging, forge die steel using amount demand is very big, only southwestern Chengdu, the forge die steel market annual requirement of Chongqing region are at 10,000 tons or so, the especially high-end mould steel of hot-forging die class. Due to hot-work die, surface and the center portion temperature difference are larger under running conditions, to the performance requirements of hot forming dies materials also compared with It is high, it is necessary to hardness and strength performance, toughness, thermal fatigue resistance, chemical stability, wearability and thermal conductivity etc. etc. into Row requires.Particularly hot-forging die is heated repeatedly at work and water cooling and bears very big impact force, so as to hot forging mold materials It is more demanding, such as high intensity, high tenacity, high thermal stability.

In addition, hot forming dies materials are different by heat resistance, low heat resistant steel (350~370 DEG C), middle heat resistance can be divided into With steel (550~600 DEG C), high-fire resistance steel (580~650 DEG C)；It can be divided into tungsten system hot-work die by alloying element classification Steel, chromium series hot die steel, chrome molybdenum system and chromium tungsten series hot die steel etc.；The hot-work die of particular/special requirement uses high temperature sometimes Alloy and refractory alloy manufacture.Standard GB/T 1299-85《Alloy tool steel technical conditions》It has been included in 12 hot die steels Grade of steel, being broadly divided into three classes, " one kind is former old steel grade, such as 5CrMnMo, 5CrNiMo, 3Cr2W8V；One kind be it is domestic voluntarily The new steel grade of development, such as 5Cr4Mo3SiMoVA1,3Cr3Mo3W2V, 5Cr4W5Mo2V, 4Cr5MoSiV；Another kind of is to introduce External general steel grade, such as 4Cr5MoSiV (H11), 4Cr5MoSiV1 (H13), 4Cr5W2VSi (W2).

In in the industry, H13 and 3Cr2W8V are most popular two kinds of hot work tool steels, but due to heat-resisting in the conduct of H13 steel Type hot die steel, no more than 600 DEG C, its application is restricted its operating temperature；And 3Cr2W8V steel, temperature in use are reachable 650 DEG C, but because toughness plasticity level is low, cold-heat fatigue property and poor thermal conductivity, easily produce cracking because of cool-hot fatigue, or even because Cause to be broken for toughness deficiency.

Therefore, a kind of hot die steel with more preferable performance how is designed, especially can be used for the heat work of hot-forging die Mould steel, it has also become many R＆D enterprises and a line researcher widely one of focus of attention.

The content of the invention

In view of this, the technical problem to be solved in the present invention is to provide a kind of hot die steel and preparation method thereof, special It is not to prepare a kind of high performance hot-work die steel for warm forging or hot forging, hot die steel prepared by the present invention has higher Hardness, toughness and service life, can be used in the working environment of hot-forging die harshness, meet the multi-aspect demand in market.

The present invention provides a kind of hot die steel, by mass percentage, including：

C：0.45%~0.55%；

Si：0.10%~0.35%；

Mn：0.15%~0.35%；

P：≤ 0.010%；

S：≤ 0.003%；

Cr：4.30%~5.10%；

Mo：2.80%~3.20%；

V：0.50%~0.80%；

Ni：≤ 0.20%；

Cu：≤ 0.10%；

The Fe of impurity element and surplus less than or equal to 0.04%.

2nd, hot die steel according to claim 1, it is characterised in that the hot die steel, by quality percentage It is described than meter

C：0.47%~0.51%；

Si：0.20%~0.30%；

Mn：0.20%~0.30%；

P：≤ 0.008%；

S：≤ 0.002%；

Cr：4.5%~5.0%；

Mo：3.0%~3.15%；

V：0.65%~0.75%.

Preferably, the hot die steel is the hot die steel for hot forging or warm forging；

The impurity element includes the one or more in As, Sn, Pb, Sb and Bi；

Non-metallic inclusion is further included in the hot die steel.

Preferably, the mass content of the As is less than or equal to 0.01%；

The mass content of the Sn is less than or equal to 0.01%；

The mass content of the Pb is less than or equal to 0.01%；

The mass content of the Sb is less than or equal to 0.01%；

The mass content of the Bi is less than or equal to 0.01%.

Preferably, the non-metallic inclusion in the hot die steel, A classes are slightly that requirement is less than or equal to 0.5；

Non-metallic inclusion in the hot die steel, A classes are carefully that requirement is less than or equal to 0.5；

Non-metallic inclusion in the hot die steel, B classes are slightly that requirement is less than or equal to 1.0；

Non-metallic inclusion in the hot die steel, B classes are carefully that requirement is less than or equal to 1.5；

Non-metallic inclusion in the hot die steel, C classes are slightly that requirement is less than or equal to 0.5；

Non-metallic inclusion in the hot die steel, C classes are carefully that requirement is less than or equal to 0.5；

Non-metallic inclusion in the hot die steel, D classes are slightly that requirement is less than or equal to 1.0；

Non-metallic inclusion in the hot die steel, D classes are carefully that requirement is less than or equal to 1.5.

Present invention also offers a kind of preparation method of the hot die steel as described in above-mentioned technical proposal any one, bag Include following steps：

1) by after electroslag remelting under raw material progress vacuum metling and protective atmosphere, steel ingot is obtained；

2) steel ingot that above-mentioned steps obtain is obtained into hot die steel after too fast forging and finish forge.

Preferably, the temperature of the vacuum metling is 1550~1560 DEG C；

When the time of the vacuum metling is 8~10 small；

The protective atmosphere includes nitrogen and/or argon gas；

The most preferably molten speed of the electroslag remelting is 9~11kg/min；

The slag temperature of the electroslag remelting is 1600~1900 DEG C；

When the time of the electroslag remelting is 13~15 small.

Preferably, the forging ratio forged soon is more than or equal to 8；

The pressure forged soon is less than or equal to 35MPa；

The forging ratio of the finish forge is 35%~60%；

The pressure of the finish forge is less than or equal to 35MN.

Preferably, the step 2) is specially：

21) by the steel ingot that above-mentioned steps obtain after too fast forging, middle blank is obtained；

The fast forging includes upset pulling forging and the forging of FM methods；

Include homogenize process step during the upset pulling forging；

22) the middle blank for obtaining above-mentioned steps obtains hot die steel after finish forge.

Preferably, the number of the upset pulling forging is 2~5 times；

The upset ratio of the upset pulling forging is 0.3~0.7；

The ratio of height to diameter of the pulling of the upset pulling forging is 2.2~2.5；

The temperature of the homogenize process is 1230~1275 DEG C；

When the time of the homogenize process is 22~26 small；

The anvil width ratio of the FM methods forging is 0.4~0.8；

The forging ratio of the FM methods forging is more than or equal to 8..

The present invention provides a kind of hot die steel, by mass percentage, including：C：0.45%~0.55%, Si： 0.10%~0.35%, Mn：0.15%~0.35%, P：≤ 0.010%, S：≤ 0.003%, Cr：4.30%~5.10%, Mo：2.80%~3.20%, V：0.50%~0.80%, Ni：≤ 0.20%, Cu：≤ 0.10%, it is miscellaneous less than or equal to 0.04% The Fe of prime element and surplus.Compared with prior art, the present invention is heated and water cooling and holds repeatedly at work for hot-forging die By very big impact force, so that the characteristics of to hot-forging die material requirements high intensity, high tenacity and high thermal stability, and it is existing The most popular two kinds of hot work tool steels of H13 and two kinds of 3Cr2W8V exist, heat resistant type hot die steel during H13 steel is used as, its Operating temperature is no more than 600 DEG C so that the problem of application is restricted；And 3Cr2W8V steel, although temperature in use is up to 650 DEG C, but because toughness plasticity level is low, cold-heat fatigue property and poor thermal conductivity, easily produce cracking because of cool-hot fatigue, or even because Toughness deficiency causes the defects of fracture.

For the present invention from the material composition of hot die steel, composition and ratio to raw material have carried out the selection of creativeness And adjustment, obtain can adapt to warm forging, particularly high rigidity, high tenacity and the high life mould steel of hot-forging die, can be suitable for Harsher hot-forging die working environment, meets the multi-aspect demand in market.

Test result indicates that the hot die steel for preparing of the present invention is under the high rigidity of 52~53.5HRC, horizontal center portion U Type notch shock work(average value can reach 23J, and red hardness, thermal conductivity are good, and quenching degree is high, and thermal coefficient of expansion is small.

Brief description of the drawings

Fig. 1 is the metallograph of the annealing microinhomogeneity under 50 times of hot die steel prepared by the embodiment of the present invention 1；

Fig. 2 is the metallograph of the annealing microscopic structure under 500 times of hot die steel prepared by the embodiment of the present invention 1.

Embodiment

The above is only the preferred embodiment of the present invention, it is noted that for the ordinary skill people of the art For member, various improvements and modifications may be made without departing from the principle of the present invention, these improvements and modifications also should It is considered as protection scope of the present invention.

All raw materials of the present invention, are not particularly limited its source, commercially buying or according to people in the art Known to member prepared by conventional method.

All raw materials of the present invention, are not particularly limited its purity, and present invention preferably employs technical pure or mould steel to prepare The conventional purity that field uses.

All raw materials of the present invention, its trade mark and abbreviation belong to this area routine trade mark and abbreviation, each trade mark and abbreviation In the field of its associated uses be it is explicit, those skilled in the art according to the trade mark, abbreviation and corresponding purposes, It can be commercially available from city's mid-sales or conventional method is prepared.

All techniques of the present invention, its abbreviation belongs to the conventional abbreviation of this area, each referred to as in the neck of its associated uses It is explicit in domain, those skilled in the art are according to referred to as, it is to be understood that its conventional processing step.

C：0.45%~0.55%；

Si：0.10%~0.35%；

Mn：0.15%~0.35%；

P：≤ 0.010%；

S：≤ 0.003%；

Cr：4.30%~5.10%；

Mo：2.80%~3.20%；

V：0.50%~0.80%；

Ni：≤ 0.20%；

Cu：≤ 0.10%；

The Fe of impurity element and surplus less than or equal to 0.04%.

Hot die steel provided by the invention, is a kind of hot die steel suitable for hot forging or warm forging, is more preferably used for heat Forging, forms by mass percentage, and the mass percentage content of the Elements C is preferably 0.45%~0.55%, more preferably 0.47%~0.53%, more preferably 0.49%~0.51%, are specifically as follows 0.47%~0.51%, are most preferably 0.49%.The source of Elements C is not particularly limited in the present invention, with the source or city of Elements C well known to those skilled in the art The Elements C sold；The purity of Elements C is not particularly limited in the present invention, is used to prepare with well known to those skilled in the art The purity of the Elements C of mould steel.

The present invention forms by mass percentage, and the mass percentage content of the elements Si is preferably 0.10%~ 0.35%, more preferably 0.15%~0.30%, more preferably 0.20%~0.25%, it is specifically as follows 0.20%~ 0.30%, it is most preferably 0.24%.The source of elements Si is not particularly limited in the present invention, with well known to those skilled in the art The source of elements Si or commercially available elements Si；The purity of elements Si is not particularly limited in the present invention, with art technology The purity of the elements Si of mould steel is used to prepare known to personnel.

The present invention forms by mass percentage, and the mass percentage content of the element M n is preferably 0.15%~ 0.35%, more preferably 0.17%~0.33%, more preferably 0.20%~0.30%, more preferably 0.22%~0.28%, Most preferably 0.23%.The source of element M n is not particularly limited in the present invention, with element M n well known to those skilled in the art Source or commercially available element M n；The purity of element M n is not particularly limited in the present invention, ripe with those skilled in the art That knows is used to prepare the purity of the element M n of mould steel.

The present invention forms by mass percentage, and the mass percentage content of the element P, which is preferably less than, to be equal to 0.010%, more preferably less than equal to 0.008%, more preferably less than equal to 0.007%, more preferably less than it is equal to 0.0065%.The source of element P is not particularly limited in the present invention, with the source of element P well known to those skilled in the art or Commercially available element P；The purity of element P is not particularly limited in the present invention, is used to make with well known to those skilled in the art The purity of the element P of standby mould steel.

The present invention forms by mass percentage, and the mass percentage content of the element S, which is preferably less than, to be equal to 0.003%, more preferably less than equal to 0.0028%, more preferably less than equal to 0.0025%, more preferably less than it is equal to 0.002%.The source of element S is not particularly limited in the present invention, with the source or city of element S well known to those skilled in the art The element S sold；The purity of element S is not particularly limited in the present invention, is used to prepare with well known to those skilled in the art The purity of the element S of mould steel.

The present invention forms by mass percentage, and the mass percentage content of the element Cr is preferably 4.30%~ 5.10%, more preferably 4.40%~5.00%, more preferably 4.50%~4.90%, more preferably 4.60%~4.80%, It is specifically as follows 4.5%~5.0%, is most preferably 4.63%.The source of element Cr is not particularly limited in the present invention, with ability The source of element Cr known to field technique personnel or commercially available element Cr；The present invention does not limit the purity of element Cr especially System, with the purity of the element Cr well known to those skilled in the art for being used to prepare mould steel.

The present invention forms by mass percentage, and the mass percentage content of the elements Mo is preferably 2.80%~ 3.20%, more preferably 2.85%~3.15%, more preferably 2.90%~3.10%, more preferably 2.95%~3.05%, It is specifically as follows 3.0%~3.15%, is most preferably 3.13%.The source of elements Mo is not particularly limited in the present invention, with this The source of elements Mo known to field technology personnel or commercially available elements Mo；The present invention is not special to the purity of elements Mo Limitation, with the purity of the elements Mo well known to those skilled in the art for being used to prepare mould steel.

The present invention forms by mass percentage, and the mass percentage content of the element V is preferably 0.50%~0.80%, More preferably 0.55%~0.75%, more preferably 0.60%~0.70%, are specifically as follows 0.65%~0.75%, most preferably For 0.7%.The source of element V is not particularly limited in the present invention, with the source or city of element V well known to those skilled in the art The element V sold；The purity of element V is not particularly limited in the present invention, is used to prepare with well known to those skilled in the art The purity of the element V of mould steel.

The present invention forms by mass percentage, and the mass percentage content of the element Ni, which is preferably less than, to be equal to 0.20%, more preferably 0.01%~0.2%, more preferably 0.05%~0.15%, more preferably 0.06%~0.10%, most Preferably 0.06%.The source of element Ni is not particularly limited in the present invention, with element Ni's well known to those skilled in the art Source or commercially available element Ni；The purity of element Ni is not particularly limited in the present invention, with known to those skilled in the art The element Ni for being used to prepare mould steel purity.

The present invention forms by mass percentage, and the mass percentage content of the element Cu, which is preferably less than, to be equal to 0.10%, more preferably 0.01%~0.10%, more preferably 0.03%~0.08%, more preferably 0.05%~0.06%, Most preferably 0.06%.The source of element Cu is not particularly limited in the present invention, with element Cu well known to those skilled in the art Source or commercially available element Cu；The purity of element Cu is not particularly limited in the present invention, ripe with those skilled in the art That knows is used to prepare the purity of the element Cu of mould steel.

Classification of the present invention to the impurity element is not particularly limited, with customary impurities well known to those skilled in the art Element, those skilled in the art can make choice and adjust according to practical condition, product requirement and quality requirement Whole, impurity element of the present invention preferably includes the one or more in As, Sn, Pb, Sb and Bi, more preferably As, Sn, Pb, Sb and Bi.

The content of the impurity element is not particularly limited in the present invention, with customary impurities well known to those skilled in the art The content control range of element, those skilled in the art can want according to practical condition, product requirement and quality Ask and make choice and adjust, the content of impurity element of the present invention is preferably smaller than equal to 0.04%, is more preferably less than equal to 0.03%, more preferably less than equal to 0.02%.

The content of the As is not particularly limited in the present invention, with customary impurities element well known to those skilled in the art Content control range, those skilled in the art can carry out according to practical condition, product requirement and quality requirement Selection and adjustment, the mass content of As of the present invention is preferably smaller than equal to 0.01%, more preferably less than equal to 0.008%, More preferably less than it is equal to 0.006%, more preferably less than equal to 0.004%.

The content of the Sn is not particularly limited in the present invention, with customary impurities element well known to those skilled in the art Content control range, those skilled in the art can carry out according to practical condition, product requirement and quality requirement Selection and adjustment, the mass content of Sn of the present invention is preferably smaller than equal to 0.01%, more preferably less than equal to 0.008%, More preferably less than it is equal to 0.006%, more preferably less than equal to 0.004%.

The content of the Pb is not particularly limited in the present invention, with customary impurities element well known to those skilled in the art Content control range, those skilled in the art can carry out according to practical condition, product requirement and quality requirement Selection and adjustment, the mass content of Pb of the present invention is preferably smaller than equal to 0.01%, more preferably less than equal to 0.008%, More preferably less than it is equal to 0.006%, more preferably less than equal to 0.004%.

The content of the Sb is not particularly limited in the present invention, with customary impurities element well known to those skilled in the art Content control range, those skilled in the art can carry out according to practical condition, product requirement and quality requirement Selection and adjustment, the mass content of Sb of the present invention is preferably smaller than equal to 0.01%, more preferably less than equal to 0.008%, More preferably less than it is equal to 0.006%, more preferably less than equal to 0.004%.

The content of the Bi is not particularly limited in the present invention, with customary impurities element well known to those skilled in the art Content control range, those skilled in the art can carry out according to practical condition, product requirement and quality requirement Selection and adjustment, the mass content of Bi of the present invention is preferably smaller than equal to 0.01%, more preferably less than equal to 0.008%, More preferably less than it is equal to 0.006%, more preferably less than equal to 0.004%.

Non-metallic inclusion is inevitably further included in hot die steel of the present invention, the present invention is raising Forming Die Has the performance of steel, the non-metallic inclusion is preferably controlled in specific scope.Wherein, the non-gold in the hot die steel Belong to field trash, A classes are slightly that requirement is preferably smaller than equal to 0.5；Non-metallic inclusion in the hot die steel, carefully system will for A classes Ask and be preferably smaller than equal to 0.5；Non-metallic inclusion in the hot die steel, B classes are slightly that requirement is preferably smaller than equal to 1.0, More preferably less than or equal to 0.5；Non-metallic inclusion in the hot die steel, B classes are carefully that requirement is preferably smaller than equal to 1.5, More preferably less than or equal to 1.0, more preferably less than or equal to 0.5；Non-metallic inclusion in the hot die steel, slightly system will for C classes Ask and be preferably smaller than equal to 0.5；Non-metallic inclusion in the hot die steel, C classes are carefully that requirement is preferably smaller than equal to 0.5； Non-metallic inclusion in the hot die steel, D classes are slightly that requirement is preferably smaller than equal to 1.0, more preferably less than or equal to 0.5； Non-metallic inclusion in the hot die steel, D classes are carefully that requirement is preferably smaller than equal to 1.5, more preferably less than or equal to 1.0, More preferably less than or equal to 0.5.

The present invention, using the low Si of the high Mo and special ratios of special ratios, substantially increases mould in elemental constituent The quenching degree of steel, and in the Si contents of this ratio, moreover it is possible to significantly mitigate banded segregation；C content is brought up to specific at the same time Ratio, improves the intensity and wearability of steel；And the special ratios content control of V, being capable of preferably thinning microstructure and crystal grain.This hair The control of the bright ratio for element, can be on the premise of other performances not be influenced, to the quenching degree, hardness, intensity of mould Lifted with wearability, increased thermal conductivity and can reduce thermal coefficient of expansion, compounds, rises by the collaboration of each content special ratios The synergistic effect that 1+1 is more than or equal to 2 is arrived.

The present invention to the ratio of required raw material and product and selection in above-mentioned preparation method, and corresponding optimum principle, It can be corresponded to the ratio of corresponding raw material and selection in foregoing hot die steel, and corresponding optimum principle, This is no longer repeated one by one.

The present invention by after electroslag remelting under raw material progress vacuum metling and protective atmosphere, obtains steel ingot first.

The feed postition of the raw material is not particularly limited in the present invention, is routinely added to well known to those skilled in the art Mode, those skilled in the art can make choice and adjust according to practical condition, product requirement and quality requirement It is whole, raw material of the present invention preferably with pure iron (S preferably≤0.003%, P preferably≤0.007%), metal Cr, metal Mn, metal The form of Mo, Fe-V, Fe-Si and C block adds.

The parameter and step of the vacuum metling is not particularly limited in the present invention, with well known to those skilled in the art true The parameter and step that sky is smelted, those skilled in the art can want according to practical condition, product requirement and quality Ask and make choice and adjust, the present invention is to further improve the degree of purity of product, reduces gas content in steel ingot, and then strengthen production The performance of product, the refining temperature of the vacuum metling is preferably 1550~1560 DEG C, more preferably 1552~1558 DEG C, more preferably For 1554~1556 DEG C.When the time of the vacuum metling is preferably 8~10 small, more preferably 8.2~9.8 it is small when, more preferably For 8.5~9.5 it is small when.

The present invention is refinement and complete process step, further improves the degree of purity of product, reduces gas content in steel ingot, And then strengthening the performance of product, the specific steps of the vacuum metling can be that raw material is carried out vacuum metling, pour into electrode Rod.It is more specific to be preferably：

1st, raw material requirement：Pure iron (S≤0.003%, P≤0.007%), J-Cr, J-Mn, Fe-V, J-Mo, Fe-Si block, C blocks.

2nd, furnace body requirement：New crucible smelts this steel after washing 2 stoves with smart steel iron；

3rd, vacuum：Hot final vacuum≤1Pa (equipment requirement), gas leakage degree≤10Pa/min；

4th, feed：2/3 carbon is incorporated, J-Cr, J-Mo load with pure iron and (cannot want scaling loss with stove).Wherein J-Mn, Fe-V, Fe-Si blocks are used for adjusting component, also do not load with stove.

5th, iron and steel stock starts to require vacuum≤5Pa during fusing, if vacuum ＞ 5Pa, drop power continues to evacuate.

6th, 1550~1560 DEG C of refining period refining temperature, vacuum≤2Pa, is kept for 20 minutes under high-power stirring.Refining Power, which is subject to, ensures refining temperature, and refining period adds remaining 1/3C blocks, Al deoxidations.Refining period will ensure that reaction between carbon and oxygen is tied substantially Beam.

7th, refining terminates 25 Torrs of argon filling, adds J-Mn, Fe-V.Stirring samples for 15 minutes, and sample is tuned into point after returning.After component qualification Stirring 5 minutes, temperature is tapped in the range of 1595~1610 DEG C.

8th, sky is broken after casting complete after furnace cooling 15min, mould is cold >=12h after demould, obtain electrode bar.

The parameter and step of the electroslag remelting is not particularly limited in the present invention, with electricity well known to those skilled in the art The parameter and step of slag remelting, those skilled in the art can want according to practical condition, product requirement and quality Ask and make choice and adjust, the present invention is to further improve the degree of purity of product, reduces gas content in steel ingot, and then strengthen production The performance of product, the optimal molten speed of the electroslag remelting is preferably 9~11kg/min, and more preferably 9.3~10.8kg/min is more excellent Elect 9.5~10.5kg/min as, be specifically as follows and gradually successively decreased by 11~9kg/min.The temperature of the electroslag remelting, i.e. slag temperature Preferably 1600~1900 DEG C, more preferably 1650~1850 DEG C, more preferably 1700~1800 DEG C.The electroslag remelting when Between be preferably 13~15 it is small when, more preferably 13.5~14.5 it is small when.The protective atmosphere is preferably nitrogen and/or argon gas, more Preferably nitrogen or argon gas, are most preferably argon gas.

The present invention is refinement and complete process step, further improves the degree of purity of product, reduces gas content in steel ingot, And then strengthening the performance of product, the specific steps of the electroslag remelting can be the electroslag weight under protective atmosphere again by electrode bar It is molten, finally obtain steel ingot.It is more specific to be preferably：

1st, electrode bar carries out surface barreling after having moved back fire, removes scale on surface, dummy electrode is welded after sawing riser.

2nd, using CaF₂:Al₂O₃=70:30 (%) binary slag systems, 190 ± 10kg of the quantity of slag, it is desirable to slag charge process >=700 DEG C, >=6 it is small when baking after use.

3rd, setting value (mohm) is waved in slag resistance：0.40 ± 0.05, melt speed setting value (kg/min):11~9 successively decrease, during filling Between >=55min, 60~70min of furnace cooling time, smelting process whole process argon filling gas shielded.

4th, it is red after ESR ingot is come out of the stove to send annealing.

The present invention obtains hot die steel finally by the steel ingot that above-mentioned steps obtain after too fast forging and finish forge.

The present invention is not particularly limited the parameter forged soon and step, is forged soon with well known to those skilled in the art Parameter and step, those skilled in the art can be selected according to practical condition, product requirement and quality requirement Select and adjust, the present invention strengthens production to further improve the uniformity of the tropisms such as steel, component and tissue, crystal grain thinning The performance of product, the forging ratio forged soon is preferably greater than or equal to 8, more preferably greater than equal to 8.5, more preferably greater than equal to 9.It is described The pressure forged soon is preferably smaller than equal to 35MPa, more preferably less than or equal to 30MPa, more preferably less than or equal to 25MPa.

The present invention is refinement and complete process step, further improves the uniformity of the tropisms such as steel, component and tissue, carefully Change crystal grain, and then strengthen the performance of product, the specific steps forged soon preferably include upset pulling forging and the forging of FM methods, more Upset pulling forging is preferably carried out successively and the forging of FM methods, i.e., described step 2) are more specifically preferably：

21) by the steel ingot that above-mentioned steps obtain after too fast forging, middle blank is obtained；The fast forging includes upset pulling forging Make and forged with FM methods；Include homogenize process step during the upset pulling forging.

The parameter and step of the upset pulling forging is not particularly limited in the present invention, with known to those skilled in the art Upset pulling forging parameter and step, those skilled in the art can according to practical condition, product requirement with And quality requirement makes choice and adjusts, the number of upset pulling forging of the present invention is preferably 2~5 times, more preferably 3~ 4 times.The upset ratio of the upset pulling forging is preferably 0.3~0.7, more preferably 0.35~0.65, more preferably 0.4~ 0.6, it is specifically as follows 0.5.The ratio of height to diameter of the pulling of the upset pulling forging is preferably 2.2~2.5, more preferably 2.25~ 2.45, more preferably 2.3~2.4.

The parameter and step of the homogenize process is not particularly limited in the present invention, with well known to those skilled in the art The parameter and step of homogenize process, those skilled in the art can be according to practical condition, product requirement and matter Amount requirement makes choice and adjusts, and homogenize process of the present invention preferably carries out after upset for the first time.It is of the present invention equal The temperature of matterization processing is preferably 1230~1275 DEG C, more preferably 1240~1265 DEG C, more preferably 1250~1255 DEG C.Institute When the time for stating homogenize process is preferably 22~26 small, more preferably 23~25 it is small when, more preferably 23.5~24.5 it is small when.

The parameter and step of FM methods forging is not particularly limited in the present invention, with FM well known to those skilled in the art The parameter and step of method forging, those skilled in the art can want according to practical condition, product requirement and quality To ask and make choice and adjust, the anvil width ratio of FM methods forging of the present invention is preferably 0.4~0.8, and more preferably 0.45~0.75, More preferably 0.5~0.7, more preferably 0.55~0.65.The forging ratio of the FM methods forging is preferably greater than or equal to 8, more preferably More than or equal to 8.5, more preferably greater than equal to 9.

The present invention is refinement and complete process step, further improves the uniformity of the tropisms such as steel, component and tissue, carefully Change crystal grain, and then strengthen the performance of product, the step of fast forging more specifically can be：

1st, it is slowly heated below 850 DEG C of ESR ingot, pays attention to ensureing that material temperature is uniform, prevents male and female face；Starting forging temperature >=1100 DEG C, final forging temperature >=870 DEG C；First fire reheating in furnace time >=2.5h, reburn the time >=2h per fire later；Total forging ratio >=8, Forged using multiple upsetting pull+FM methods.

2nd, pincers handle is beaten after steel ingot is come out of the stove, then carries out multiple jumping-up, upset forging process：(steel ingot length is not to 1/2 height for jumping-up First can suitably be pulled out when sufficient makes steel ingot ratio of height to diameter properly >=2.0), ratio of height to diameter about 2.2~2.5 is arrived in then pulling.

The step of fast forging more specifically can be：

3rd, after the wherein first upset pulling, homogeneous when obtained matched 1230~1275 DEG C of insulations 22~26 of progress afterwards of material are small Change is handled.

4th, the famine side after homogenizing come out of the stove again jumping-up to 1/2 height, then forge forging stock；Last fiery deflection >= 40% is split into use for finish forge machine base.

5th, last fiery heating-up temperature drops to 1180 ± 10 DEG C during press cogging, last fiery deflection >=40%.

Stringent control final forging temperature, prevents cryogenic forging crackle.

22) the middle blank that the present invention finally obtains above-mentioned steps obtains steel after finish forge.

The parameter and step of the finish forge is not particularly limited in the present invention, with finish forge well known to those skilled in the art Parameter and step, those skilled in the art can be selected according to practical condition, product requirement and quality requirement To select and adjust, the forging ratio of finish forge of the present invention is preferably 35%~60%, and more preferably 40%~55%, more preferably 45%~50%.The pressure of the finish forge is preferably smaller than equal to 35MN, more preferably less than or equal to 30MN, more preferably less than or equal to 25MN。

The present invention is refinement and complete process step, further improves the uniformity of the tropisms such as steel, component and tissue, carefully Change crystal grain, and then strengthen the performance of product, the step of finish forge more specifically can be：

The middle base forged using forging press, precise forging machine deflection 35%~60%, press is red to be turned blank and enters stove to exist Forging is opened after 1150 ± 10 DEG C of insulation 2.5h.Precise forging machine spreads air-cooled to≤200 DEG C out after stopping forging, and then shove charge is annealed.

Above-mentioned steps of the present invention provide a kind of high performance hot-work die steel for hot forging and preparation method thereof.The present invention From the material composition of hot die steel, composition and ratio to raw material have carried out the selection and adjustment of creativeness, using spy The low Si of the high Mo and special ratios of certainty ratio, substantially increase the quenching degree of mould steel, and in the Si contents of this ratio, Banded segregation can also significantly be mitigated；C content brings up to special ratios at the same time, improves the intensity and wearability of steel；And V's is specific Proportional amount controls, being capable of preferably thinning microstructure and crystal grain.The present invention can not influenced for the control of the ratio of element On the premise of other performances, the quenching degree of mould, hardness, intensity and wearability are lifted, increased thermal conductivity can and be reduced Thermal coefficient of expansion, compounds by the collaboration of each content special ratios, plays the synergistic effect that 1+1 is more than or equal to 2.The present invention is again With reference to special parameter and the preparation process of step, the degree of purity of product is improved, reduces gas content in steel ingot, and then strengthen product Performance, further improve the tropisms such as steel, the uniformity of component and tissue, crystal grain thinning, and then strengthen the performance of product, most Obtain can adapt to warm forging eventually, particularly high rigidity, high tenacity and the high life mould steel of hot-forging die, can be suitable for more Harsh hot-forging die working environment, meets the multi-aspect demand in market.

In order to further illustrate the present invention, with reference to embodiments to a kind of hot die steel provided by the invention and its system Preparation Method is described in detail, but it is to be understood that these embodiments are carried out in fact lower premised on technical solution of the present invention Apply, give detailed embodiment and specific operating process, simply to further illustrate the features and advantages of the present invention, and It is not limiting to the claimed invention, protection scope of the present invention is also not necessarily limited to following embodiments.

Embodiment 1

Technological process：

Vacuum metling → electroslag remelting → 45MN press cogging → 18MN finish forges are become a useful person → is examined.

Vacuum drying oven smelting process

Electroslag smelting technique

4th, it is red after ESR ingot is come out of the stove to send annealing.

Processing：

Forging processing is forged soon with 45MN press, is forged using multiple upsetting pull and FM methods, total forging ratio >=8, are processed into middle base The forging of 18MN precise forging machines is become a useful person after material, finish forge deflection 35~60%.Steel pass through homogenize process.

The fast forging process of 45MN press：

3rd, homogenize technique：Expect homogenize process when matched 1230~1275 DEG C of insulations 22~26 of rear progress are small,

4th, jumping-up is come out of the stove to 1/2 height by the famine side after homogenizing, and then forges forging stock；Last fiery deflection >=40% is opened Into use for finish forge machine base.

18MN precise forging machine techniques

The middle base forged using press.Precise forging machine deflection 35%~60%.Press is red turn blank enter stove 1150 ± Forging is opened after 10 DEG C of insulation 2.5h.Precise forging machine spreads air-cooled to≤200 DEG C out after stopping forging, and then shove charge is annealed, and finally obtaining specification is Φ 255mm high performance hot-work die steels.

The hot die steel prepared to the embodiment of the present invention 1 is tested.

Inspection project includes ultrasonic examination, surface quality testing, low power, high power, mechanical properties test.

The chemical composition result of laboratory test of the hot die steel prepared referring to table 1, table 1 for the embodiment of the present invention 1.

Table 1

The non-metallic inclusion result of laboratory test of the hot die steel prepared referring to table 2, table 2 for the embodiment of the present invention 1.

Table 2

Regulation according to GB10561-2005 to the micro- evaluation of nonmetallic inclusionsin steel, field trash is according to its form and divides Cloth is divided into tetra- class of A, B, C, D, is divided into thick system and thin system by the difference of thickness or diameter per type impurity, is divided into 1~5 by quantity Level, rank is higher, and inclusion content is also more.Wherein, A classes are sulfide-based strip field trash, and B classes are alumina type fragment String-like field trash, C classes are Silicate inclusion thing, and D classes are the oxide-based field trash of spherical Dispersed precipitate.Its numeral 0.5, 1.0th, 1.5 etc. be each type impurity grading.

Hot die steel is examined to annealing microscopic structure under 500 times, banded segregation is examined under 50 times, and press NADCA# 207-2003 standards judge picture grading microscopic structure and microinhomogeneity.

Referring to Fig. 1, Fig. 1 is the annealing microinhomogeneity under 50 times of hot die steel prepared by the embodiment of the present invention 1 Metallograph.

Referring to Fig. 2, Fig. 2 is the metallographic of the annealing microscopic structure under 500 times of hot die steel prepared by the embodiment of the present invention 1 Photo.

The metallographic structure rating result of the hot die steel prepared referring to table 3, table 3 for the embodiment of the present invention 1.

Table 3

	Annealing inhomogeneities	Annealing microscopic structure
			(NADCA#207)	AS1-AS9 (picture of green background)	BS1-BS4 (picture of green background)
Embodiment 1	AS2, AS2	BS2, BS2

Impact ductility test：

Impact specimen blank preheats 45 minutes through 780 DEG C, oil quenching after 1050 DEG C of austenitizings are handled 30 minutes, >=560 DEG C Tempering >=3 times, when tempering >=2 is small every time, is air-cooled to room temperature between tempering every time, after being heat-treated to 50-55HRC hardness, processing Into 2mmU type notched impact specimens, Charpy toughness test is carried out.Cast out peak in 5 result of the tests and minimum Value, takes the average value and minimum value of remaining 3 result of the tests.

Referring to table 4, the U-shaped notch impact toughness of horizontal center portion for the hot die steel that table 4 is prepared for the embodiment of the present invention 1.

Table 4

Grain size is tested：

Grain size sample through 1050 DEG C ± 10 DEG C keep the temperature 30 minutes, grade quench to 730 DEG C ± 10 DEG C keep the temperature 30 minutes, so After be air-cooled to room temperature.Grade by GB/T 6394.

The grain size test result of the hot die steel prepared referring to table 5, table 5 for the embodiment of the present invention 1.

Table 5

	Grain size (level)
		(NADCA#207)	≥7
Embodiment 1	8.5

Embodiment 2

Technological process：

Vacuum metling → electroslag remelting → forging of 45MN press is become a useful person → is examined.

Vacuum drying oven smelting process

Electroslag smelting technique

4th, it is red after ESR ingot is come out of the stove to send annealing.

Processing：

Forging processing is forged soon with 45MN press, is forged using multiple upsetting pull and FM methods, total forging ratio >=8.Steel pass through homogeneous Change is handled.

The fast forging process of 45MN press：

4th, jumping-up is come out of the stove to 1/2 height by the famine side after homogenizing, and is then forged into finished product, finished product Module specifications：165mm* 600mm。

The hot die steel prepared to the embodiment of the present invention 2 is tested.

The chemical composition result of laboratory test of the hot die steel prepared referring to table 6, table 6 for the embodiment of the present invention 2.

Table 6

The non-metallic inclusion result of laboratory test of the hot die steel prepared referring to table 7, table 7 for the embodiment of the present invention 2.

Table 7

The metallographic structure rating result of the hot die steel prepared referring to table 8, table 8 for the embodiment of the present invention 2.

Table 8

	Annealing inhomogeneities	Annealing microscopic structure
			(NADCA#207)	AS1-AS9 (picture of green background)	BS1-BS4 (picture of green background)
Embodiment 2	AS1, AS1	BS1, BS1

Impact ductility test：

Referring to table 9, the U-shaped notch impact toughness of horizontal center portion for the hot die steel that table 9 is prepared for the embodiment of the present invention 2.

Table 9

Grain size is tested：

The grain size test result of the hot die steel prepared referring to table 10, table 10 for the embodiment of the present invention 2.

Table 10

	Grain size (level)
		(NADCA#207)	≥7
Embodiment 2	8.5

Embodiment 3

Technological process：

Vacuum drying oven smelting process

Electroslag smelting technique

4th, it is red after ESR ingot is come out of the stove to send annealing.

Processing：

The fast forging process of 45MN press：

18MN precise forging machine techniques

The middle base forged using press.Precise forging machine deflection 35%~60%.Press is red turn blank enter stove 1150 ± Forging is opened after 10 DEG C of insulation 2.5h.Precise forging machine spreads air-cooled to≤200 DEG C out after stopping forging, and then shove charge is annealed, and finally obtaining specification is Φ 185mm high performance hot-work die steels.

The hot die steel prepared to the embodiment of the present invention 3 is tested.

The chemical composition result of laboratory test of the hot die steel prepared referring to table 11, table 11 for the embodiment of the present invention 3.

Table 11

The non-metallic inclusion result of laboratory test of the hot die steel prepared referring to table 12, table 12 for the embodiment of the present invention 3.

Table 12

The metallographic structure rating result of the hot die steel prepared referring to table 13, table 13 for the embodiment of the present invention 3.

Table 13

	Annealing inhomogeneities	Annealing microscopic structure
			(NADCA#207)	AS1-AS9 (picture of green background)	BS1-BS4 (picture of green background)
Embodiment 3	AS1, AS1	BS1, BS1

Impact ductility test：

Referring to table 14, the U-shaped notch shock of horizontal center portion for the hot die steel that table 14 is prepared for the embodiment of the present invention 3 is tough Property.

Table 14

Grain size is tested：

The grain size test result of the hot die steel prepared referring to table 15, table 15 for the embodiment of the present invention 3.

Table 15

	Grain size (level)
		(NADCA#207)	≥7
Embodiment 3	8.0

Above to a kind of high performance hot-work die steel for warm forging or hot forging provided by the invention and preparation method thereof into Detailed introduction is gone, specific case used herein is set forth the principle of the present invention and embodiment, and the above is real The explanation for applying example is only intended to help the method and its core concept for understanding the present invention, including best mode, and also so that originally Any technical staff in field can put into practice the present invention, including manufacture and using any device or system, and implement any knot The method of conjunction.It should be pointed out that for those skilled in the art, the premise of the principle of the invention is not being departed from Under, some improvement and modification can also be carried out to the present invention, these are improved and modification also falls into the protection of the claims in the present invention In the range of.The scope of patent protection of the present invention is defined by the claims, and may include those skilled in the art it is conceivable that Other embodiment.If these other embodiments have the structural element for being not different from claim character express, or If they include equivalent structural elements of the character express without essence difference with claim, then these other embodiments It should include within the scope of the claims.

Claims

A kind of 1. hot die steel, it is characterised in that by mass percentage, including：

C：0.45%~0.55%；

Si：0.10%~0.35%；

Mn：0.15%~0.35%；

P：≤ 0.010%；

S：≤ 0.003%；

Cr：4.30%~5.10%；

Mo：2.80%~3.20%；

V：0.50%~0.80%；

Ni：≤ 0.20%；

Cu：≤ 0.10%；

The Fe of impurity element and surplus less than or equal to 0.04%.
2. hot die steel according to claim 1, it is characterised in that the hot die steel, by mass percentage, It is described

C：0.47%~0.51%；

Si：0.20%~0.30%；

Mn：0.20%~0.30%；

P：≤ 0.008%；

S：≤ 0.002%；

Cr：4.5%~5.0%；

Mo：3.0%~3.15%；

V：0.65%~0.75%.
3. hot die steel according to claim 1, it is characterised in that the hot die steel is for hot forging or warm forging Hot die steel；

The impurity element includes the one or more in As, Sn, Pb, Sb and Bi；

Non-metallic inclusion is further included in the hot die steel.
4. hot die steel according to claim 3, it is characterised in that the mass content of the As is less than or equal to 0.01%；

The mass content of the Sn is less than or equal to 0.01%；

The mass content of the Pb is less than or equal to 0.01%；

The mass content of the Sb is less than or equal to 0.01%；

The mass content of the Bi is less than or equal to 0.01%.
5. hot die steel according to claim 3, it is characterised in that the nonmetal inclusion in the hot die steel Thing, A classes are slightly that requirement is less than or equal to 0.5；

Non-metallic inclusion in the hot die steel, A classes are carefully that requirement is less than or equal to 0.5；

Non-metallic inclusion in the hot die steel, B classes are slightly that requirement is less than or equal to 1.0；

Non-metallic inclusion in the hot die steel, B classes are carefully that requirement is less than or equal to 1.5；

Non-metallic inclusion in the hot die steel, C classes are slightly that requirement is less than or equal to 0.5；

Non-metallic inclusion in the hot die steel, C classes are carefully that requirement is less than or equal to 0.5；

Non-metallic inclusion in the hot die steel, D classes are slightly that requirement is less than or equal to 1.0；

Non-metallic inclusion in the hot die steel, D classes are carefully that requirement is less than or equal to 1.5.
6. it is a kind of as claimed in any one of claims 1 to 5, wherein hot die steel preparation method, it is characterised in that including with Lower step：

1) by after electroslag remelting under raw material progress vacuum metling and protective atmosphere, steel ingot is obtained；

2) steel ingot that above-mentioned steps obtain is obtained into hot die steel after too fast forging and finish forge.
7. preparation method according to claim 6, it is characterised in that the refining temperature of the vacuum metling for 1550~ 1560℃；

When the time of the vacuum metling is 8~10 small；

The protective atmosphere includes nitrogen and/or argon gas；

The most preferably molten speed of the electroslag remelting is 9~11kg/min；

The slag temperature of the electroslag remelting is 1600~1900 DEG C；

When the time of the electroslag remelting is 13~15 small.
8. preparation method according to claim 6, it is characterised in that the forging ratio forged soon is more than or equal to 8；

The pressure forged soon is less than or equal to 35MPa；

The forging ratio of the finish forge is 35%~60%；

The pressure of the finish forge is less than or equal to 35MN.
9. preparation method according to claim 6, it is characterised in that the step 2) is specially：

21) by the steel ingot that above-mentioned steps obtain after too fast forging, middle blank is obtained；

The fast forging includes upset pulling forging and the forging of FM methods；

Include homogenize process step during the upset pulling forging；

22) the middle blank for obtaining above-mentioned steps obtains hot die steel after finish forge.
10. preparation method according to claim 9, it is characterised in that the number of the upset pulling forging is 2~5 times；

The upset ratio of the upset pulling forging is 0.3~0.7；

The ratio of height to diameter of the pulling of the upset pulling forging is 2.2~2.5；

The temperature of the homogenize process is 1230~1275 DEG C；

When the time of the homogenize process is 22~26 small；

The anvil width ratio of the FM methods forging is 0.4~0.8；

The forging ratio of the FM methods forging is more than or equal to 8.