CN104745780A - Production method for forging and thermally treating Cr12MoV steel - Google Patents

Abstract

The invention relates to a production method for forging and thermally treating Cr12MoV steel. According to the production method, sectional heating is adopted and a heating speed is controlled, when a blank is charged, a temperature in a furnace is 300-400 DEG C, heat is insulated for 3-4h after the charging, then the temperature rises to 850-880 DEG C at a speed of 40-50 DEG C/h, heat is insulated for 3-4h, then the temperature rises to 1100-1130 DEG C at a speed of 60-80 DEG C/h, and heat is insulated for 4-5h; the blank is subjected to 5-6 times of axial repeated upsetting and drawing-out during a forging process; a rolling reduction is controlled according to the temperature of the blank, and normalizing and spheroidizing annealing treatments are carried out after the forging. The yield of the Cr12MoV steel forged pieces produced by the production method disclosed by the invention is increased to 90-100% from the original 40-50%; network carbides and band carbides are eliminated; the unevenness of eutectic carbides is improved to 1-2 levels from the original 5-6 levels, and the production costs of forged piece production enterprises and the procurement costs of using units for the forged pieces are reduced, therefore, waste for social resources and pollution for environment are also reduced.

Description

A kind of Cr12MoV steel forging and heat treated production method

Technical field

The present invention relates to the forging of a kind of Cr12MoV steel and heat treated production technology and technology field.In particular to the heating of Cr12MoV steel forgings, forging and heat treatment after forging processing method.

Background technology

Cr12MoV steel belongs to ledeburite cold work die steel in high alloy through, is usually used in cold roll collars.Because this steel contains higher carbon and chromium, the product adopting traditional process for forging to produce, is easy to produce burning in heat-processed, cracks and cause waste product in forging process.The internal soundness of forging product is also poor, easily residual carbide network or Cold Roll, and the irregularity of eutectic carbides is more serious.

Patent CN1727502A discloses the forging method of Cr12MoV steel.Its shortcoming is:

1., when Heating temperature reaches 1150 ~ 1300 DEG C, easily produce overheated or burning, easily crack in blank surface during forging and cause waste product.

2. after forging, directly slow cooling, to 100 DEG C, does not carry out heat treatment after forging, not thorough to the elimination of carbide network.

3. pair forging deformation amount does not control, and easily produces forge crack and causes waste product.

Patent CN101748251A discloses a kind of forging method of Cr12MoV cold work die steel module.Its shortcoming is:

1., when Heating temperature reaches 1190 ~ 1220 DEG C, it is overheated easily to produce.

2. after forging, directly slow cooling, to 100 DEG C, does not carry out heat treatment after forging, not thorough to the elimination of carbide network.

3. pair forging deformation amount does not control, and easily produces forge crack and causes waste product.

Forging yield rate is low, forging process is wayward, forging quality is unstable, adds the production cost of forging manufacturing enterprise and forging use enterprise, also result in the waste of a large amount of social resources and the pollution to environment.

Summary of the invention

Technical problem to be solved by this invention overcomes the deficiencies in the prior art, the object of this invention is to provide the forging of a kind of Cr12MoV steel and heat treated production method, improve forging yield rate, eliminate netted or Cold Roll, improve the irregularity of eutectic carbides.

For achieving the above object, the present invention realizes by the following technical solutions:

A kind of Cr12MoV steel forging and heat treated production method, adopt zone heating and control to carry out normalizing and Spheroidizing Annealing process by after blank temperature control draught, forging in heat-up rate, forging process.Concrete operation step is:

(1) heating phase: during blank shove charge, in-furnace temperature 300 ~ 400 DEG C, is incubated 3 ~ 4h after shove charge, then is raised to 850 ~ 880 DEG C with the speed of 40 ~ 50 DEG C/h, insulation 3 ~ 4h, then is raised to 1100 ~ 1130 DEG C with the speed of 60 ~ 80 DEG C/h, insulation 4 ~ 5h;

(2) stage is forged: 5 ~ 6 axis jumping-up, pullings are repeatedly carried out to blank;

Blank periphery is first touched one time, draught 10 ~ 20mm before jumping-up;

Jumping-up time-division 2 ~ 5 slow pressures, each draught 50 ~ 100mm, upset ratio is 2 ~ 3;

Determine draught according to the temperature of blank during pulling, pull out than being 5 ~ 8;

1050 DEG C≤blank temperature < 1100 DEG C, draught 10 ~ 20mm;

950 DEG C≤blank temperature < 1050 DEG C, draught 30 ~ 50mm;

900 DEG C≤blank temperature < 950 DEG C, draught 10 ~ 20mm;

Last deformation amount controlling of fiery time is between 20 ~ 30%, and final forging temperature is 900 DEG C ~ 950 DEG C;

(3) heat treatment stages: carry out normalizing and Spheroidizing Annealing process after forging;

After forging, blank charging temperature is 300 ~ 350 DEG C, 890 ~ 910 DEG C are raised to the speed of 40 ~ 60 DEG C/h, after insulation 3 ~ 4h, air cooling is to 380 ~ 400 DEG C, insulation 3 ~ 4h, 850 ~ 870 DEG C are raised to again with the speed of 50 ~ 60 DEG C/h, after insulation 3 ~ 4h, air cooling is to 720 ~ 740 DEG C, and be as cold as 400 DEG C with the speed stove of 10 ~ 20 DEG C/h again after insulation 5 ~ 6h, then air cooling is to room temperature.

Compared with prior art, the invention has the beneficial effects as follows:

1. type of heating of the present invention can ensure the Heating temperature uniformity of blank and the thermal stress making blank in heat-processed is tending towards minimum, prevents blank from producing overheated or burning;

2. touch blank periphery before jumping-up the carbide network of blank surface to be smashed, prevent surface crack; Determine that draught can make the deformation comparison of blank even according to the temperature of blank when jumping-up time-division 2 ~ 5 slow pressures and pulling, be conducive to the distribution of eutectic carbides in blank more even; Carbide in blank can constantly be crashed to pieces to the deflection that jumping-up, pulling number of times and last fire are secondary by Control Shaft, crystal grain is more tiny;

3. heat treatment after forging can eliminate the remaining carbide network in forging, make carbide be particulate state, tiny, be uniformly distributed.

The Cr12MoV steel forgings that the present invention produces, yield rate brings up to 90 ~ 100% by original 40 ~ 50%; Eliminate carbide network and Cold Roll; The irregularity of eutectic carbides is improved as 1 ~ 2 grade by original 5 ~ 6 grades, reduces the production cost of forging manufacturing enterprise and the purchase cost of forging applying unit, therefore decreases the waste to social resources and the pollution to environment.

Accompanying drawing explanation

Fig. 1 is embodiment one Cr12MoV steel ingot blank heating process curve figure.

Fig. 2 is normalizing and carbide annealing process graphic representation after the forging of embodiment one Cr12MoV steel forgings.

Fig. 3 is embodiment two Cr12MoV steel ingot blank heating process curve figure.

Fig. 4 is normalizing and carbide annealing process graphic representation after the forging of embodiment two Cr12MoV steel forgings.

Embodiment

Below in conjunction with embodiment, the present invention is further described:

The chemical composition (massfraction %) of Cr12MoV is in table one.

Table one:

Cr12MoV steel gas content (ppm) is in table two.

Table two:

[O]	[H]
		≤15	≤1.5

A kind of Cr12MoV steel forging and heat treated production method, adopt zone heating technique, and axial jumping-up, pulling technique repeatedly, carry out forging rear normalizing and Spheroidizing Annealing process.

Embodiment one

To forge external diameter for Φ 560mm, internal orifice dimension is Φ 240mm, and thickness is the cold roll collars of 280mm is example, and concrete operation step is:

(1) steel ingot is adopted to be starting material, during shove charge, in-furnace temperature 300 ~ 400 DEG C, be incubated 4h after shove charge, then be raised to 850 ~ 870 DEG C with the speed of 40 ~ 50 DEG C/h, insulation 4h, 1110 ~ 1130 DEG C are raised to again, insulation 5h, forging of then coming out of the stove with the speed of 60 ~ 70 DEG C/h.

(2) axis jumping-up, pulling is repeatedly carried out to blank; Blank periphery is first touched one time, draught 10 ~ 20mm before jumping-up.

During a jumping-up, point 5 slow pressures, each draught 50 ~ 80mm, upset ratio is 2.3.When once pulling out, blank temperature is 1080 DEG C, draught 10 ~ 20mm, pulls out than being 1.5; During secondary jumping-up, point 4 slow pressures, each draught 70 ~ 100mm.During secondary pulling, blank temperature is 1040 DEG C, draught 30 ~ 50mm, pulls out than being 1.5; During three jumping-ups, point 3 slow pressures, each draught 70 ~ 100mm.During three pullings, blank temperature is 1000 DEG C, draught 30 ~ 50mm, pulls out than being 2; After three pullings, blank is divided into 2 sections, carries out axis jumping-up, pulling repeatedly to every section respectively;

Blank after segmentation carry out four piers thick time, points of 3 times slow pressures, each draught 50 ~ 80mm, during four pullings, blank temperature is 1050 DEG C, draught 10 ~ 20mm.Pull out than being 2.When five times pier is thick, points of 3 times slow pressures, each draught 50 ~ 70mm, during five pullings, blank temperature is 1000 DEG C, draught 30 ~ 50mm, pulls out than being 1.5; When six times pier is thick, point 2 slow pressures, each draught 50 ~ 80mm.Last fire time deformation amount controlling between 20 ~ 30%, final forging temperature 900 DEG C ~ 950 DEG C.

(3) normalizing and Spheroidizing Annealing process is carried out after forging.After forging, blank charging temperature is 300 ~ 350 DEG C, 890 ~ 910 DEG C are raised to the speed of 40 ~ 60 DEG C/h, after insulation 4h, air cooling is to 380 ~ 400 DEG C, insulation 4h, 850 ~ 870 DEG C are raised to again with the speed of 50 ~ 60 DEG C/h, after insulation 4h, air cooling is to 720 ~ 740 DEG C, and be as cold as 400 DEG C with the speed stove of 10 ~ 20 DEG C/h again after insulation 6h, then air cooling is to room temperature.

Embodiment two

To forge external diameter for Φ 400mm, internal orifice dimension is Φ 140mm, and thickness is the cold roll collars of 265mm is example, and concrete operation step is:

(1) steel ingot is adopted to be starting material, during shove charge, in-furnace temperature 300 ~ 400 DEG C, be incubated 3h after shove charge, then be raised to 860 ~ 880 DEG C with the speed of 40 ~ 50 DEG C/h, insulation 4h, 1100 ~ 1130 DEG C are raised to again, insulation 4h, forging of then coming out of the stove with the speed of 70 ~ 80 DEG C/h.

(2) axis jumping-up, pulling is repeatedly carried out to blank; Blank periphery is first touched one time, draught 10 ~ 20mm before jumping-up.

During a jumping-up, point 4 slow pressures, each draught 60 ~ 90mm, upset ratio is 2.When once pulling out, blank temperature is 1050 DEG C, draught 10 ~ 20mm, pulls out than being 1.4; During secondary jumping-up, point 3 slow pressures, each draught 80 ~ 100mm.During secondary pulling, blank temperature is 1000 DEG C, draught 40 ~ 50mm, pulls out than being 1.5; During three jumping-ups, point 3 slow pressures, each draught 80 ~ 100mm.During three pullings, blank temperature is 980 DEG C, draught 30 ~ 40mm, pulls out than being 1.6; By blank segmentation after three pullings, carry out axis jumping-up, pulling repeatedly to every section respectively;

Blank after segmentation carry out four piers thick time, points of 4 times slow pressures, each draught 60 ~ 80mm, during four pullings, blank temperature is 1100 DEG C, draught 10 ~ 20mm.Pull out than being 1.5.When five times pier is thick, points of 3 times slow pressures, each draught 50 ~ 70mm, deformation amount controlling of last fire time between 25 ~ 30%, final forging temperature 900 DEG C ~ 950 DEG C.

(3) normalizing and Spheroidizing Annealing process is carried out after forging.After forging, blank charging temperature is 300 ~ 350 DEG C, 890 ~ 910 DEG C are raised to the speed of 40 ~ 60 DEG C/h, after insulation 3h, air cooling is to 380 ~ 400 DEG C, insulation 3h, 850 ~ 870 DEG C are raised to again with the speed of 50 ~ 60 DEG C/h, after insulation 3h, air cooling is to 720 ~ 740 DEG C, and be as cold as 400 DEG C with the speed stove of 10 ~ 20 DEG C/h again after insulation 5h, then air cooling is to room temperature.

Be only ultimate principle of the present invention above, not impose any restrictions the present invention, the present invention of every foundation carries out equivalent variations and modification to it, all within the category of the art of this patent protection scheme.

Claims (1)

1. the forging of Cr12MoV steel and a heat treated production method, is characterized in that, adopts zone heating and control to carry out normalizing and Spheroidizing Annealing process by after blank temperature control draught, forging in heat-up rate, forging process.Concrete operation step is:

(1) heating phase: during blank shove charge, in-furnace temperature 300 ~ 400 DEG C, is incubated 3 ~ 4h after shove charge, then is raised to 850 ~ 880 DEG C with the speed of 40 ~ 50 DEG C/h, insulation 3 ~ 4h, then is raised to 1100 ~ 1130 DEG C with the speed of 60 ~ 80 DEG C/h, insulation 4 ~ 5h;

(2) stage is forged: 5 ~ 6 axis jumping-up, pullings are repeatedly carried out to blank;

Blank periphery is first touched one time, draught 10 ~ 20mm before jumping-up;

Jumping-up time-division 2 ~ 5 slow pressures, each draught 50 ~ 100mm, upset ratio is 2 ~ 3;

Determine draught according to the temperature of blank during pulling, pull out than being 5 ~ 8;

1050 DEG C≤blank temperature < 1100 DEG C, draught 10 ~ 20mm;

950 DEG C≤blank temperature < 1050 DEG C, draught 30 ~ 50mm;

900 DEG C≤blank temperature < 950 DEG C, draught 10 ~ 20mm;

Last deformation amount controlling of fiery time is between 20 ~ 30%, and final forging temperature is 900 DEG C ~ 950 DEG C;

(3) heat treatment stages: carry out normalizing and Spheroidizing Annealing process after forging;

After forging, blank charging temperature is 300 ~ 350 DEG C, 890 ~ 910 DEG C are raised to the speed of 40 ~ 60 DEG C/h, after insulation 3 ~ 4h, air cooling is to 380 ~ 400 DEG C, insulation 3 ~ 4h, 850 ~ 870 DEG C are raised to again with the speed of 50 ~ 60 DEG C/h, after insulation 3 ~ 4h, air cooling is to 720 ~ 740 DEG C, and be as cold as 400 DEG C with the speed stove of 10 ~ 20 DEG C/h again after insulation 5 ~ 6h, then air cooling is to room temperature.