CN106702295B - A method of improving GH4698 disk forging tissues and the smooth fatigue behaviour of high temperature - Google Patents

Abstract

The present invention relates to a kind of methods of improvement GH4698 disk forging tissues and the smooth fatigue behaviour of high temperature.Under normal conditions, the production of GH4698 disks forging need to pass through upsetting cake base, die forging, secondary solution treatment and aging strengthening model several process, and wherein base includes Forge Heating again with die forging process and deforms process.The formulation of all heating processes should follow the tissue change feature of GH4698 materials when heated, and the formulation of all deformation processes should also fully understand the internal association between nominal deflection and each region true strain amount.The present invention starts with from the setting of GH4698 heating parameters, deformation work step distribution etc. emphatically, can effectively refine, homogenize GH4698 disk forging tissues, finally improve the smooth fatigue behaviour of its high temperature.

Description

A method of improving GH4698 disk forging tissues and the smooth fatigue behaviour of high temperature

Technical field：

The invention belongs to the technical field of hot working of high temperature alloy, it is related to a kind of improvement GH4698 disk forging tissues and high temperature The method of smooth fatigue behaviour.

Background technology：

GH4698 is the nickel base superalloy strengthened with elements such as aluminium, titanium, molybdenum, niobiums, is mended on the basis of GH4033 alloys It fills made of alloying development, there is high enduring quality and good comprehensive performance within the scope of 500~800 DEG C.The alloy It is widely used in the important load parts such as the turbine disk, compressor disc, flow deflector, the force bearing ring of manufacture aero-engine.Operating temperature Up to 750~800 DEG C.

The formulation of aero-engine all heating processes of GH4698 products should follow the group of GH4698 materials when heated Knit Variation Features；The formulation of all deformation processes should also be fully understood between nominal deflection and each region true strain amount simultaneously Internal association.Otherwise GH4698 disk forging can be caused such as tissue odds, coarse grains, dynamic recrystallization crystal grain occur to subtract Less, phenomena such as shear twin crystal grain increases.

The setting for heating step temperature should be according to the tissue change feature of GH4698 materials when heated：Original bar tissue For single-phase γ matrixes+a small amount of primary carbide and boride；It is bar heating and thermal insulation certain time between 980~1010 DEG C, main Large-sized γ ＇ hardening constituents (main disperse is in austenitic matrix inside and crystal boundary) are precipitated, 1000 DEG C are precipitation cutting edge of a knife or a sword；With heating Time increases, and quantity is precipitated and increases, and crystal grain and intercrystalline strengthening effect are reinforced, and the limitation that crystal grain is grown up while reinforcing, grain growth Rate slows down；Bar is dissolved in 1020 DEG C of temperatures above long-time heatings, various hardening constituents, is organized for single-phase γ；It is brilliant at this time Grain growth limitation weakens, and growth rate is accelerated.Therefore, the heating step of setting should be " 800 DEG C of preheating insulations, rise to 990 again~ 1000 DEG C of preheating insulations finally rise to the heat preservation of 1100~1120 DEG C of high-temperature region ".A large amount of forging technologies are primary concern is that high-temperature region The setting of heating temperature and the range of final forging temperature, and emphasis consider high-temperature region heating before it is not adjacent preheating step it is reasonable Temperature range.Preheating temperature is directly for example set as 1050~1070 DEG C or so, because in technology establishment person, preheating temperature The lower crystal grain of degree will not grow up, and the temperature spread between shortening high-temperature region and adjacent preheating step is conducive to metal and is preheating first At a temperature of heat penetration to reduce high-temperature region soaking time, to reduce the amplitude that crystal grain is grown up in high-temperature region.But it is true really not so, Because GH4698 materials are under 1020 DEG C or more heating conditions, almost single phase austenite tissue, the dispersion-strengtherning item dissolved γ ＇ do not have the effect of limitation, and austenite grain will start rapidly recovery and recrystallization, gradual coalescence.By this temperature platform Rank sets, and is preheated 3~4 hours at a temperature of 1050~1070 DEG C first per fire time blank, then in high-temperature region 1110~1120 DEG C heat preservation 2~3 hours, is equivalent to the recovery and recrystallization that 5~7 hours time have occurred per fire for austenite structure.If or else can protect Card has suitable deflection, forging tissue and fatigue behaviour to would become hard to reach requirement.

Per fire time deflection, ensureing per 25%~35% deformation of fire time can (should not mistake for reasonable distribution upsetting cake, die forging work step Greatly), fire time is made by oneself, and when heating is come out of the stove after reaching predetermined high temperature area soaking time using alumina silicate heat-preservation cotton Soft Roll set.Especially , it is emphasized that the setting per fire time deflection cannot only consider whole large deformation, it should also consider small deformation area, be unlikely to deform area Deformation state.If the setting of upsetting cake overall deformation is excessive (being set as 50% deflection, one fire to complete), even if having taken packet Cover Insulation, it is also difficult to avoid in prolonged deformation process part temperature by serious situation, maximum distortion region from Can be more than so 50% deflection, but small deformation area or deformation dead zone are also bound to exist.Tissue is exacerbated first not in this way Uniformity followed by results in and largely the original big crystal grain of dynamic recrystallization does not occur and because dynamic recrystallization is short of power, directly Connected the chaotic distribution of the feather organization of shear formation.

Reasonable set solution heat temperature for the first time：It preheats step to set with reference to temperature in Forge Heating, high-temperature region temperature is answered Selection lower limit temperature (usual 1100~1120 DEG C of ranges) as possible.It is dissolved soaking time for the first time to fix 8 hours, under this condition, Recovery and recrystallization can further occur for crystal grain, and stock size can increase by 1~1.5 times, if do not carried out very to blank when forging Good improvement, basis is poor, then (although having certain homogenization), tissue will continue to be deteriorated after solid solution, it is special Be not super large crystal grain (more than 2.0mm) presence can cause have children outside the state plan the performances severe exacerbation such as wave inspection and the smooth fatigue of high temperature.

Emphasis of the present invention is started with from the setting of GH4698 heating parameters, deformation work step distribution etc., can effectively be refined, uniformly Change GH4698 disk forging tissues, finally improves the smooth fatigue behaviour of its high temperature.

Invention content：

The technical problem to be solved by the present invention is to：In order to solve, GH4698 disk forging structural homogenities are poor, coarse grains And the problem that the smooth fatigue behaviour of high temperature is unstable.

The technical scheme is that：

A kind of forging method of GH4698 alloy discs forging is provided, is included the following steps：

Step 1 heats bar, is heated to 800 DEG C, heat insulating coefficient 0.8mm/min, later with 50~70 DEG C/ The heating speed of min is warming up to 990~1000 DEG C, heat insulating coefficient 0.8mm/min, is warming up to 1100~1120 DEG C later, protects Warm coefficient is 0.8mm/min；The bar after heating is used into alumina silicate heat-preservation cotton Soft Roll set later, is protected at 1100~1120 DEG C Warm 30min；

Step 2 carries out more fire time upsetting cakes to jacket bar, obtains waste base, ensures that per fire time deflection be 25%~35%；

Step 3 carries out more fire time die forgings to waste base, obtains forging and air-cooled, ensure to be 25% per fire time deflection~ 35%；

Step 4 carries out solution treatment for the first time to forging, and forging is first heated to 800 DEG C, heat insulating coefficient 0.8mm/min, 990~1000 DEG C, heat insulating coefficient 0.8mm/min are warming up to the heating speed of 50~70 DEG C/min later, are warming up to later 1100 DEG C, heat preservation 8 hours after it is air-cooled；

Step 5 carries out Secondary Solid Solution Treatment to forging, and forging is first heated to 800 DEG C, heat insulating coefficient 0.8mm/min, It is air-cooled after being warming up to 990~1000 DEG C with the heating speed of 50~70 DEG C/min later, keep the temperature 4 hours；

Step 6 carries out ageing treatment to forging, forging is sent directly into air-cooled after keeping the temperature 16 hours in 700 DEG C of electric furnace.

The beneficial effects of the invention are as follows：Follow the tissue change feature of GH4698 materials when heated, rational heating Technological parameter；The stringent relationship distinguished between overall deformation and local true strain amount, reasonable, optimal design-aside forging deformation fire Secondary and every fire time deflection can effectively solve GH4698 disk forging tissue odds, coarse grains, the smooth fatigue behaviour shakiness of high temperature The problems such as determining (forging state ontology crystallite dimension 0.5mm~0.6mm for being, after heat treatment crystallite dimension in 1.2mm hereinafter, and organizing Uniformly).

Specific implementation mode：

The manufacture for choosing aviation type machine turbine disk forging below, carries out specifically the process step of the invention It is bright.

A kind of forging method of GH4698 alloy discs forging is provided, is included the following steps：

Step 1 heats bar, is heated to 800 DEG C, heat insulating coefficient 0.8mm/min, later with 50~70 DEG C/ The heating speed of min is warming up to 990~1000 DEG C, heat insulating coefficient 0.8mm/min, is warming up to 1100~1120 DEG C later, protects Warm coefficient is 0.8mm/min；The bar after heating is used into alumina silicate heat-preservation cotton Soft Roll set later, is protected at 1100~1120 DEG C Warm 30min；

Step 2 carries out more fire time upsetting cakes to jacket bar, obtains waste base, ensures that per fire time deflection be 25%~35%； Step 3 carries out more fire time die forgings to waste base, obtains forging and air-cooled, ensures that per fire time deflection be 25%~35%；

Step 4 carries out solution treatment for the first time to forging, and forging is first heated to 800 DEG C, heat insulating coefficient 0.8mm/min, 990~1000 DEG C, heat insulating coefficient 0.8mm/min are warming up to the heating speed of 50~70 DEG C/min later, are warming up to later 1100 DEG C, heat preservation 8 hours after it is air-cooled；

Step 5 carries out Secondary Solid Solution Treatment to forging, and forging is first heated to 800 DEG C, heat insulating coefficient 0.8mm/min, It is air-cooled after being warming up to 990~1000 DEG C with the heating speed of 50~70 DEG C/min later, keep the temperature 4 hours；

Step 6 carries out ageing treatment to forging, forging is sent directly into air-cooled after keeping the temperature 16 hours in 700 DEG C of electric furnace.

In conclusion GH4698 disks forging even tissue produced by the invention, tiny, every mechanical property is (especially The smooth fatigue behaviour of high temperature) meet technology requirement, Project R＆D task needs can be met.

Claims (1)

1. a kind of forging method of GH4698 alloy discs forging, includes the following steps：

Step 1 heats bar, 800 DEG C, heat insulating coefficient 0.8mm/min is heated to, later with 50~70 DEG C/min's Heating speed is warming up to 990~1000 DEG C, heat insulating coefficient 0.8mm/min, is warming up to 1100~1120 DEG C, heat insulating coefficient later For 0.8mm/min；The bar after heating is used into alumina silicate heat-preservation cotton Soft Roll set later, is kept the temperature at 1100~1120 DEG C 30min；

Step 2 carries out more fire time upsetting cakes to jacket bar, obtains waste base, ensures that per fire time deflection be 25%~35%；

Step 3 carries out more fire time die forgings to waste base, obtains forging and air-cooled, ensures that per fire time deflection be 25%~35%；

Step 4 carries out solution treatment for the first time to forging, forging is first heated to 800 DEG C, heat insulating coefficient 0.8mm/min, later It is warming up to 990~1000 DEG C, heat insulating coefficient 0.8mm/min with the heating speed of 50~70 DEG C/min, is warming up to 1100 later DEG C, heat preservation 8 hours after it is air-cooled；

Step 5 carries out Secondary Solid Solution Treatment to forging, forging is first heated to 800 DEG C, heat insulating coefficient 0.8mm/min, later It is air-cooled after being warming up to 990~1000 DEG C with the heating speed of 50~70 DEG C/min, keep the temperature 4 hours；

Step 6 carries out ageing treatment to forging, forging is sent directly into air-cooled after keeping the temperature 16 hours in 700 DEG C of electric furnace.