CN103966530B

CN103966530B - A kind of pre-hard plastic sealing rubber die steel

Info

Publication number: CN103966530B
Application number: CN201410218357.7A
Authority: CN
Inventors: 胡财基
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-05-22
Filing date: 2014-05-22
Publication date: 2016-02-03
Anticipated expiration: 2034-05-22
Also published as: CN103966530A

Abstract

A kind of pre-hard plastic sealing rubber die steel, Mn is adjusted to 1.30 ~ 1.60% by 0.60 ~ 1.00% by described 3Cr2MnMo die steel, Ni is defined in 0.10 ~ 0.30%, and add micro-nucleator element nb? 0.05 ~ 0.10%, die steel is control P≤0.015%, S≤0.003% strictly, and adds Pre-hardening treatment through becoming more meticulous again after polytropism deformation.Die steel 3Cr2MnMo of the present invention, due to the adjustment of alloying in the as-cast structure of steel, improves the hardening capacity of steel, and the over-all properties that the bending strength had, ultimate compression strength and impelling strength etc. are good.Strict control P, S harmful element, promotes clarity and the polishing performance of steel.Adopt polytropism deformation, refinement microstructure, that improves steel waits phasic property, and adopting becomes more meticulous adds pre-hardening thermal treatment process, makes the further refinement of the microstructure of steel, defines evenly tiny sorbite tissue.

Description

A kind of pre-hard plastic sealing rubber die steel

Technical field

The present invention relates to a kind of pre-hard plastic sealing rubber die steel, belong to metal material field.

Background technology

C:0.28 ~ 0.40% in 3Cr2MnMo plastic mould steel (P20) standard GB/T1299-2000; Si:0.20 ~ 0.80%; Mn:0.60 ~ 1.00%:Cr:1.40 ~ 2.00%; Mo:0.30 ~ 0.55%; P :≤0.030%; S≤0.030%.The as-cast structure of existing 3Cr2MnMo plastic mould steel mostly is thick sheet F, P and a little M tissue, accounts for that 86.5%, Fe3C accounts for 10.5%, Cr7C3, Cr23C6 accounts for 2.8% through X-ray diffractometer test F, and remaining M2C accounts for 0.20%.In hot-work and heat treatment process, Fe3C, Cr23C6, Cr7C3 carbide is solidly soluted in matrix successively, do not have pinning effect, though M2C → M6C+MC has certain pinning effect, but trace cannot stop pre-hardening type die steel to occur thick sheet columnar ferrite, sorbite and grain coarsening phenomenon, causes the quality problems such as large section material hardening capacity is poor, hardness is uneven.In addition, the clarity of 3Cr2MnMo (P20) large section material is deteriorated, usual A, B, C, D be slightly, be carefully the many fluctuations of inclusion at 1.0 ~ 2.5 grades, cause polishing performance unstable, mold surface finish is fluctuated.Factor hinders the application & development of this steel in sum.

Summary of the invention

The object of the invention is the shortcoming existed to overcome prior art, providing a kind of and adding micro-nucleator (carbide) Nb to improve the hardening capacity of steel by adjustment Mn, Ni, improving the one pre-hard plastic sealing rubber die steel of hardness ununiformity.

The technical scheme of a kind of pre-hard plastic sealing rubber die steel of the present invention is: it is characterized in that Mn is adjusted to 1.30 ~ 1.60% by 0.60 ~ 1.00% by described 3Cr2MnMo die steel (P20 national standard), Ni is defined in 0.10 ~ 0.30%, and add micro-nucleator element nb 0.05 ~ 0.10%, described die steel is control P≤0.015%, S≤0.003% strictly, and adds Pre-hardening treatment through becoming more meticulous again after polytropism deformation.

A kind of pre-hard plastic sealing rubber die steel of the present invention, described die steel mass percent:

C：0.20%~0.40%；

Si：0.20~0.80%；

Mn：1.30~1.60%；

P：≤0.015%；

S：≤0.003%；

Cr：1.80~2.10%；

Mo：0.30~0.55%；

Ni：0.10~0.30%；

Nb：0.05~0.10%；

Cu：≤0.25%；

N：≤0.006%（≤60PPM）；

Fe: surplus;

Described die steel adopts polytropism deformation heat processing technique (operation) and becomes more meticulous and adds pre-hardening thermal treatment process (operation).

The present invention is by adjustment Mn, Ni, add micro-nucleator (carbide) Nb to improve the hardening capacity of steel, improve hardness ununiformity, concrete scheme is as follows: Mn is adjusted to 1.30 ~ 1.60% by 0.60 ~ 1.00%, Ni is defined in 0.10 ~ 0.30%, and add micro-nucleator (carbide) 0.05 ~ 0.10%Nb, the as-cast structure of steel is except forming Fe3C, Cr23C6, Cr7C3 carbide, outside trace M2C carbide, turn increase NbC, NbN alloy phase, measure F through X-ray diffractometer and be down to 85.50% by 86.50%, Fe3C is down to 9.80% by 10.50%, Cr23C6, Cr7C3 is down to 2.5% by 2.8%, M2C keeps 0.2%, Ni3Al intermetallic compound is 0.11%, in addition, turn increase 1.89%NbC, NbN strong carbide, nitride alloy phase.Due to the existence of NbC, NbN alloy phase, not only refinement as-cast structure, and in heat-processed, due to the pinning effect of strong carbide, nitride, not only refinement forging rolling state microstructure, and improve the hardening capacity of steel and the homogeneity of hardness.In addition, due to the ageing strengthening effect in drawing process of Ni3Al intermetallic compound, the hardening capacity of steel and the homogeneity of hardness is further increased.

The present invention is except adjustment Mn, Ni content, add outside carbide Nb, again at reduction steel inclusion, technological improvement has been carried out in the clarity aspect improving steel, concrete scheme is as follows: P≤0.030% in the former technological standard of 3Cr2MnMo (P20 GB), S≤0.030%, the clarity of metallographic examination finished product material steel is poor, usual: A, B, C, D is slightly, be carefully that inclusion fluctuates at 1.0 ~ 2.5 grades often, especially sulfide (A), oxide compound (B) is slightly, be carefully that inclusion fluctuates at 1.5 ~ 2.5 grades often, have a strong impact on the polishing performance of steel, reduce mold surface finish.3Cr2MnMo technical standard of enterprise P≤0.015% after improvement, S≤0.003%, the clarity of alloy inspection finished product material steel significantly improves.Usually, A, B, C, D be slightly, be carefully inclusion all at 0.5 ~ 1.0 grade, especially sulfide (A), oxide compound (B) slightly system, when being carefully inclusion all at 0 ~ 0.5 grade.Not only increase polishing performance and the mould smooth finish of steel, and also improve mould corrosion resisting property.

The present invention, except the lifting of the improvement of the alloying of steel, clarity, is out of shape by radial-axial again and changes polytropism deformation in hot-work, and described polytropism deformation comprises die steel radial direction, axially forge distortion combines with transverse direction, longitudinal multidirectional deformation.Have employed in thermal treatment becomes more meticulous adds Pre-hardening treatment technique, described process of refinement: with the temperature of the die steel of finished product thickness after forging for starting point, heat to 880 ± 10 DEG C, after 3min/mm insulation, be 70 DEG C by temperature after oil quenching, and then heat to 780 ± 10 DEG C, after 3min/mm insulation, in stove, be cooled to 550 DEG C with the temperature of≤30 DEG C/h again, finally come out of the stove and be cooled to normal temperature in atmosphere.Described Pre-hardening treatment: heat to 550 ± 10 DEG C from 70 DEG C with the die steel of finished product thickness, with 3min/mm insulation, is then warming up to 880 ± 10 DEG C, then with 3min/mm insulation, then temper is carried out after oil quenching to 70 DEG C.Which further improves hardening capacity and the die surface polishing performance of steel.Steel surface after tone pitch and core rigidities difference≤2HRC; Innovated by above-mentioned three technology, 3Cr2MnMo heavy section, heavy die block hardening capacity obtain obvious lifting, and the polishing performance of steel obtains basic improvement, and mold surface finish improves an order of magnitude.

Beneficial effect of the present invention is:

Plastic mould steel 3Cr2MnMo of the present invention, due to the adjustment of alloying in the as-cast structure of steel, especially Nb element adds, and defines NbC, NbN strengthening phase, not only increase hardening capacity, and the over-all properties that the bending strength had, ultimate compression strength, impelling strength etc. are good.In plastic mould steel of the present invention, P, S control of deleterious element adds sternly, improves the clarity of steel, improves the polishing performance of steel, impels mold surface finish to improve an order of magnitude.

Adopt multidirectional deformation, not only refinement microstructure, what also improve steel waits phasic property, adopting becomes more meticulous add pre-hardening thermal treatment process after, make the further refinement of the microstructure of steel, define evenly tiny sorbite tissue.

The reform of these techniques is all to the hardening capacity of steel, and the raising of mold polish performance has promoter action.

To sum up three technology innovation replaces steel ingot usually to adopt High temperature diffusion (steel ingot 1210 ~ 1230 DEG C of * 20 ~ 25h) heating process, not only save energy consumption, reduce the scaling loss of steel, there is the remarkable performance of enterprises, mainly improve environment, there is obvious social benefit.

Accompanying drawing explanation

Fig. 1 is this die steel 3Cr2MnMo process of refinement schematic diagram;

Fig. 2 is this die steel 3Cr2MnMo Pre-hardening treatment schematic diagram.

Embodiment

Following non-limiting example can make the present invention of those of ordinary skill in the art's comprehend, but does not limit the present invention in any way.

Embodiment 1

The mass percent of the plastic mould steel 3Cr2MnMo after alloy phase improves comprises following composition:

C：0.35%；

Si：0.55%；

Mn：1.52%；

P：≤0.008%；

S：≤0.0004%；

Cr：1.98%；

Mo：0.45%；

Ni：0.23%；

Nb：0.08%；

Cu：≤0.11%；

N：0.004%（40PPM）

Fe:: surplus.

Smelting technology is as follows:

Converter provides low-phosphorous, low-sulfur molten steel → EAF deoxidation, degas, go to be mingled with → LF stove refining → VD vacuum refinement---→ bet ingot/ESR ingot

Polytropism deforming technique (operation): comprise die steel radial direction, axis forges distortion and combines with horizontal, longitudinal multidirectional deformation.

Process of refinement technique (operation): with the temperature of the die steel of finished product thickness after forging for starting point, heat to 880 ± 10 DEG C, after 3min/mm insulation, it is 70 DEG C by temperature after oil quenching, and then heat to 780 ± 10 DEG C, after 3min/mm insulation, then be cooled to 550 DEG C with the temperature of≤30 DEG C/h in stove, finally come out of the stove and be cooled to normal temperature in atmosphere.

Add Pre-hardening treatment technique: heat to 550 ± 10 DEG C with the die steel of finished product thickness from 70 DEG C, with 3min/mm insulation, be then warming up to 880 ± 10 DEG C, then with 3min/mm insulation, then temper is carried out after oil quenching to 70 DEG C.

It is as shown in table 1 that example 1 die steel 3Cr2MnMo improves forward and backward mechanical shock toughness test result:

Table 1

The tropisms such as the tropisms such as the 3Cr2MnMo after reform are 0.92,3Cr2MnMo are before the reform 0.53, wait tropism to improve 0.32 by contrast.

Example 2 die steel 3Cr2MnMo reforms forward and backward polishing performance test result (with roughness of polished) and represents,

Table 2

The roughness of 3Cr2MnMo polishing material is far above the roughness of 3Cr2MnMo after reform before the reform, and namely roughness becomes 0.3 μm from 0.5 μm.

Claims

1. a pre-hard plastic sealing rubber die steel, it is characterized in that the pre-hard plastic sealing rubber die steel improved 3Cr2MnMo die steel, the mass percent of pre-hard plastic sealing rubber die steel comprises following composition:

C：0.35%；

Si：0.55%；

Mn：1.52%；

P：≤0.008%；

S：≤0.0004%；

Cr：1.98%；

Mo：0.45%；

Ni：0.23%；

Nb：0.08%；

Cu：≤0.11%；

N：0.004%；

Fe:: surplus;

Described die steel adopts polytropism deformation heat processing technique and becomes more meticulous and adds pre-hardening thermal treatment process.

2. a kind of pre-hard plastic sealing rubber die steel as claimed in claim 1, it is characterized in that described polytropism deformation comprises die steel and comprises die steel radial direction, axially forge distortion with horizontal, longitudinal multidirectional deformation combines, described process of refinement: with the temperature of the die steel of finished product thickness after forging for starting point, heat to 880 ± 10 DEG C, after 3min/mm insulation, it is 70 DEG C by temperature after oil quenching, and then heat to 780 ± 10 DEG C, after 3min/mm insulation, 550 DEG C are cooled to the temperature of≤30 DEG C/h again in stove, finally come out of the stove and be cooled to normal temperature in atmosphere, described Pre-hardening treatment: heat to 550 ± 10 DEG C from 70 DEG C with the die steel of finished product thickness, be incubated with 3min/mm, then be warming up to 880 ± 10 DEG C, be incubated with 3min/mm again, temper is carried out again after oil quenching to 70 DEG C.