CN1727502A - Method for forging Crl2MoV steel - Google Patents

Abstract

A technology for forging Cr12MoV steel includes such steps as heating for homogenizing, forging and cooling. It features that the temp, temp variation speed and temp-holding time for each step are controlled.

Description

The forging method of Cr12MoV steel

Technical field

The present invention relates to forging production method, the especially forging method of cold-work die steel Cr12MoV steel of metallurgy industry and die industry Cr12 type worker mould steel.

Background technology

The Cr12MoV cold-work die steel can not only bear heavier load, also has high wear resistance, the while low price, therefore be widely used in making moulding stock such as cold-punching mould, cold heading die, cold extruding die, wortle, thread rolling die, but also be used to make the molding roller of stainless steel and non-ferrous metal.The basic cast structure of Cr12MoV is the ledeburite+martensite along casting crystal boundary net distribution.In forging process, if Heating temperature is too high, ledeburite melts, and becomes liquid, causes the material burning, can not forging molding.Present Forge Heating temperature is generally about 1000 ℃, it is ledeburite+austenite two-phase region casting, but because netted ledeburite contains a large amount of brittle carbides, cause forging deformation cracking easily, thereby extremely difficult forging molding, the key reason that is to say extremely difficult forging molding is the carbide in the ledeburite of net distribution, under this forging temperature, matrix is the higher austenite of plasticity, is the very big carbide of fragility around these austenite particulate, is difficult to forging deformation so naturally.Its yield rate of the forging of moulding is very low in this way, though moulding do not pass through sufficient forging deformation yet, that is to say that the net distribution form of ledeburite does not have wide variation, so it is very low naturally work-ing life to be used in the tool and mould that this forging produces.According to investigations, the forging of domestic Cr12MoV steel and processing mold manufacturing factory, all exist and forge modification difficulty and tool and mould short these two difficult problems in work-ing life, tool and mould work-ing life is short then forges the modification difficulty and causes that distribution of carbides is inhomogeneous to be caused, so the forging deformation difficulty becomes the bottle footpath that this material uses.Country such as Japan, Germany, France uses special-purpose forging equipment, Russia is except that using special forging equipment, also use the super method for forging and molding of moulding to solve this problem of forging deformation difficulty, the instrument moulding is not regular for Cr12MoV forging that therefore external ox produces or tool and mould, and be several times to tens times of home products work-ing life, but these special forging equipment investment costs are big, and the super forging method of moulding is difficult to grasp.

Summary of the invention

The object of the present invention is to provide a kind of forging method of Cr12MoV steel, this method not only can thoroughly be eliminated the harm of carbide network to forgeability, make forging can carry out abundant forging deformation, the carbide unevenness of material is brought up to below 2 grades by the 5-8 level before forging, thereby make improve several times to tens times the work-ing life of tool and mould, and this method facility investment is little, need not a large amount of technological transformation funds, can reduce production costs.

For reaching above purpose, the technical solution adopted in the present invention is: the forging method of this Cr12MoV steel, comprise it is characterized in that the treatment process of " adding thermally homogenising+forging deformation+forging postcooling ", and the steps include:

(1) add thermally homogenising: forging stock is warmed up to 700-800 ℃ with stove, is incubated 1-2 hour; With the heat-up rate of 50-100 ℃/h, be warming up to 1000-1300 ℃ again, be incubated 2-3 hour, between soak forging stock is stood up, to reduce the male and female face temperature head.

(2) forging deformation: open and forge 1000-1300 ℃ of temperature, final forging temperature 900-950 ℃, upsetting pull is 4-5 time repeatedly, makes forging ratio＞8; When the forging temperature is lower than 900-950 ℃ of scope, be heated 1000-1300 ℃, be incubated and forge again after 2-3 hour.

(3) forge postcooling: the cooling rate with 30 ℃/h is cooled to 100 ℃ with forging.

Beneficial effect of the present invention is: need not investment in technological transformation; To forging deformation amount and forging ' s block dimension without limits; The yield rate of forging can reach more than 95%, the forging Key Quality Indicator, and promptly the carbide unevenness can reach the 1-2 level of GB14979-1994 standard code; Compare with the tool and mould of traditional forging manufacturing work-ing life with the tool and mould of this forging manufacturing and to improve 1 times at least.

Specific embodiment

Embodiment 1

Use the present invention, adopt the Cr12MoV steel casting that adds thermally homogenising, forging deformation, forging postcooling three step forgings, 60 * 60 * 150mm and 200 * 200 * 200mm, the steps include: 1, add thermally homogenising: forging stock is warming up to 750 ℃ with stove, is incubated 1.5 hours; With the heat-up rate of 95 ℃/h, be warming up to 1150 ℃ again, be incubated 2-3 hour, between soak forging stock is stood up 2 times.2, forging deformation: open and forge 1150 ℃ of temperature, 900 ℃ of final forging temperatures; Upsetting pull is 4 times repeatedly, makes forging ratio＞8, and when 900 ℃ of forging temperature, reheat to 1150 ℃ was incubated after 2-3 hour, forged again.3, forge postcooling: the cooling rate with 30 ℃/h is cooled to 100 ℃, is finished product.Through check, this finished product forging deformation ability is as good as with general structural carbon steel, through the low power inspection, and forging macrostructure uniform and delicate, all flawless; Press the GB14979-1994 standard rating, the carbide unevenness reaches the 1-2 level.

Embodiment 2

Adopt step with embodiment 1.For each 50 of the cake spares of the ring body of certain mould factory success forging external diameter 310mm, internal diameter 210mm, high 90mm and external diameter 180mm, high 80mm, be used for the manufacturing of trombone slide mould.Its yield rate is 98%; Forging is pressed the GB14979-1994 standard rating, and the carbide unevenness is by 7 grades before forging 1.5 grades of bringing up to after the forging; Be 3 times of other producers the work-ing life of mould.

Embodiment 3

Adopt step with embodiment 1.Be 5 of the templates of success forging 1500 * 800 * 100mm of certain machine works.Its yield rate is 100%; Forging is pressed the GB14979-1994 standard rating, and the carbide unevenness is by 8 grades before forging 2 grades of bringing up to after the forging; Other producers can only accomplish the 6-7 level, and yield rate is less than 50%.

Description of drawings

Fig. 1 is distribution of carbides figure before embodiment 3 forges, and is 8 grades by the GB14979-1994 standard rating.

Fig. 2 is that embodiment 3 forges back distribution of carbides figure, is 2 grades by the GB14979-1994 standard rating.

Claims (1)

1, a kind of forging method of Cr12MoV steel comprises it is characterized in that the treatment process of " adding thermally homogenising+forging deformation+forging postcooling ", the steps include:

(1) add thermally homogenising: forging stock is warmed up to 700-800 ℃ with stove, is incubated 1-2 hour; With the heat-up rate of 50-100 ℃/h, be warming up to 1000-1300 ℃ again, be incubated 2-3 hour, between soak forging stock is stood up.

(2) forging deformation: open and forge 1000-1300 ℃ of temperature, final forging temperature 900-950 ℃, upsetting pull is 4-5 time repeatedly, makes forging ratio＞8; When the forging temperature is lower than 900-950 ℃ of scope, be heated 1000-1300 ℃, be incubated and forge again after 2-3 hour.

(3) forge postcooling: the cooling rate with 30 ℃/h is cooled to 100 ℃ with forging.

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