How hard is GH4720LI alloy

GH4720LI alloy is developed on the basis of UDIMET720 alloy (domestic grade GH4720), which has a very high degree of alloying and is mainly strengthened phase'The phase is as high as 40% to 50% in the service state, ranking first among deformed superalloys, and is a typical hard-to-deform superalloy. Therefore, the study of the thermal deformation behavior of GH4720Li alloy has always been a hot topic in academia and engineering.

Superplastic forming has the advantages of high plasticity, small deformation resistance, one-time precision forming, and forming parts, and has been applied in a variety of superalloys. More and more attention has been paid to the easy formability of hard-to-deform superalloys with the help of superplastic forming process. GH4720LI alloy has fine-grained superplasticity conditions when the initial grain structure is uniform and the grain size is not coarse than ASTM grade 10.

Therefore, the researchers used the experimental method of isothermal compression to study the superplastic deformation behavior of the initial uniform fine-grained microstructure, determined the superplastic deformation range according to the strain rate sensitivity factor m, and analyzed the microstructure evolution law in the process of isothermal deformation, so as to provide a basis for improving the hot workability of GH4720LI hard-to-deform nickel-based superalloy and solving the key technologies of microstructure control of the alloy. The experimental GH4720Li nickel-based superalloy was smelted by vacuum induction + vacuum self-consumption (VIM+VAR) duplex process, and its chemical composition (mass percentage, %) Ni margin. The alloy ingots are first annealed by homogenization diffusion, and then forged into bars by multiple fires.

Using field emission scanning electron microscopy (FESEM), the initial grain size of the bar structure was determined to be ASTM class 10. An 8mm 12mm thermally simulated compression specimen is then cut from the bar. In the thermal compression experiment, in order to ensure uniform deformation, high-temperature glass lubricant is added at both ends of the sample to reduce the influence of friction on the stress state, and thermocouples are welded on the surface of the sample to compensate for the change of sample surface temperature, and the deformation structure is retained by water cooling immediately after the thermal compression experiment.

Thermal compression simulation experiments were carried out on GH4720Li alloy samples under different deformation temperatures, strain rates and deformation amounts. The deformation conditions of deformation temperature and 1130, strain rate of 3 and 5 10 3s 1 and 50% of the engineering deformation amount are adopted. After the GH4720Li alloy specimen was hotly compressed, the grains were analyzed by optical microscopy (OM) and Fesem, respectively'phase to conduct tissue studies.

The test results show that: (1) The uniform fine-grained GH4720Li alloy is effective inIn the 0001 deformation interval, the value of the strain rate sensitivity factor m decreases with the increase of deformation temperature and the increase of deformation amount Under the condition of 4 5 10 3s 1, the fine-grained alloy has the ability of superplastic deformation, and at 1130, regardless of the strain rate, the alloy no longer has the ability of superplastic deformation. (3) The strain rate corresponding to the optimal superplastic deformation of uniform fine-grained alloys is higher at higher deformation temperatures, and lower strain rates are required for the optimal superplastic deformation to occur at low temperature deformation.

The factory hardness is about 220HB, which can improve the hardness of solution aging.

1. GH4720LI Introduction:

GH4720LI is a Ni-Cr-Co-based precipitation-hardening deformed superalloy with a service temperature of up to 750 degrees Celsius. The alloy has high strength, high sulfur corrosion resistance, oxidation resistance and good microstructure stability.

2. GH4720LI Applications and Characteristics:

GH4720LI alloy is suitable for engine integral turbines, discs, ground gas turbine turbines, discs and other parts working below 750 degrees Celsius.

3. GH4720LI similar grades:

High Temperature New NameHigh Temperature Old Name Corrosion Resistant New Name Corrosion Resistant Old Name National Standard Grade: GH4720LIGH720Li, Japan JIS, American Standard, ASTM, American Standard, UNS, SAE, German Standard, DIN European EN

4. GH4720LI chemical composition:

Carbon C, Silicon, Si, Manganese, Mn, Phosphorus, P, Sulfur, Chromium, Nickel, Nimolybdenum, Mo, Cobalt, Copper, Cu, Fe, Niobium, NB, Ti, Ti, Aluminum, Alzr, Tungsten, W, Cerium.

5. GH4720LI material specifications:

Hot Rolling Bar 10 100mm, Forging Rod: 100mm 350mm, Cold Rolling Sheet, Hot Rolling Plate: 4mm 14mm, with 2mm-10mm, Forging Rings of Various Sizes and Specifications, Inventory Individual Grades Variable Length.

6. Physical properties of GH4720LI:

Density g cm magnetic thermal conductivity w (

65-900 resistivity.

（ω.mm2/m)

100 specific heat capacity.

kg (25-800 linear expansion factor.

10-6/k)

20-700 no temperature, 0 25600700 modulus of elasticity, e GPA227196189

7. Mechanical properties of GH4720LI:

Variety: heat treatment temperature: 0 °C, tensile strength b mpa

Elongation a %.

Section shrinkage z % hot rolled rod standard heat treatment 201530910

7. GH4720LI processing and welding performance:

GH4720LI alloy is developed on the basis of UDIMET720 alloy. Therefore, it is also called (domestic brand) GH4720

Chemical composition of GH4720 nickel-base superalloy (%)

Grade: GH4720

Carbon C: Silicon Si:

Manganese mn:

Phospho: sulfur s:

Chromium Cr: Copper Cu:

Titanium Ti: Aluminum Al:

Tungsten W: Zirconium Zr:

Cobalt Co: Molybdenum Mo:

Boron B: Iron Fe:

Nickel ni: margin.

Shanghai Bohu Group GH4720Li alloy is a Ni-Cr-Co-based precipitation hardening deformed superalloy with a service temperature of 750, and the alloy has high high temperature strength, fatigue resistance and creep resistance. With good corrosion resistance and oxidation resistance, as well as long-term structural stability, it is suitable for making aero engine turbine discs and turbine blades. GH4720LI alloy has been used to make aero engine turbine discs and passed the test test. It is also used to make a new generation of strategic missiles and high-thrust engine integral turbine rotors, as well as ground gas turbine turbine turbine discs and other parts that work for a long time below 750.

GH4720LI alloy is a high-strength nickel-based superalloy that uses the dispersion precipitation Y' phase to achieve precipitation strengthening, which is mainly used for compressor discs with a working temperature of 650 750 and 900 turbine discs for a short time. The alloy is characterized by a high Al+Ti content, reaching % which greatly increases the content of the main strengthening phase Y phase to 40%-50% 12-4]. The addition of Zr element to the alloy can reduce the influence of harmful element S on the grain boundary to a certain extent, but the presence of Z element promotes the formation of y+y' phase eutectic in the as-cast structure of the alloy and forms a low melting point phase in the alloy5.

The presence of a large number of y+y' phase eutectic in the as-cast structure will have a certain impact on the forging and opening of the alloy. At the same time, if the heating temperature exceeds the initial melting temperature of the low melting point phase during the homogenization process, the liquid zone will be generated in the alloy, which will promote the enrichment of more alloying elements to the liquid region and aggravate the element segregation. At home and abroad, there have been studies on the degree of a crack zone of the alloy [11], in which Du Jinhui et al. have studied the as-cast structure and homogenization process of the alloy.

However, none of the previous studies have addressed the distribution of low-melting point phases in the as-cast microstructure of alloys and their influence on the homogenization process.

In this study, the as-cast dendritic phase of the alloy was studied. The solidification process and homogenization process were analyzed, and the two-stage homogenization process was proposed and verified, which provided a reference for further research on the alloy.

1. Experimental materials and experimental methods.

Experimental materials. The alloy ingot with an external size of 100mm x200mm is melted and poured by vacuum induction furnace, and the alloy ingredient composition (mass fraction) is: co, mo, w, ti, al, c, b, ni bal.

1 .2. Experimental methods.

Samples were cut at the core, quarter diameter and edge of the ingot, and electrolytically corroded with 5% E phosphoric acid aqueous solution under a metallographic microscope. The specimen was observed under a scanning electron microscope (SEM), and the composition of each phase was analyzed by electron probe (EPMA). The ingot core specimen was subjected to different temperatures.

Homogenization experiments were carried out at different leakage times to observe the tissue transformation.

Analysis of alloy microstructure and solidification behavior.

Cast structure. The as-cast structure of the alloy is shown in Figure 1Figure 2. The dendrite stem is bright white and darker between the dendrites (see Figure 1), and a large number of second phases are precipitated between the dendrites (see Figure 2).

Metallographic and scanning electron microscopy (SEM) observations showed that the precipitation on the dendrite stem was relatively simple, and only some carbide phases were sporadically distributed. These carbides are also precipitated between the dendrites and in much more quantities than the dendrite stems.

Grade GH4720Li

Corresponding to the standard of special alloy steel.

Tags: Zheng grinding and burning, precipitation, hardening, deformation, superalloy.

GH4099 (GH99) is a highly alloyed nickel-based aging plate alloy, which is comprehensively strengthened with cobalt, tungsten, and aluminum, titanium and other elements, so that the alloy has a high thermal force, and can be used for a long time with a maximum working temperature of 1000.

The alloy has stable structure, and has satisfactory cold and hot processing forming and welding process performance, suitable for the manufacture of aero-engine combustion chamber and afterburner combustion chamber and other high-temperature plate bearing welded structural parts, the alloy made of large plate structural parts, can be directly used after solution treatment without time combustion treatment. The main products are plates and wires, and plates and forgings can also be produced.

GH4099 (GH99) heat treatment system.

The plate is 1140 1160 and air-cooled; The welding wire is 1100 1140 and air-cooled.

Material brand leather year concession number.

gh4099(gh99)

Similar grades 693, 68 Russia).

Technical standards for materials.

GJB 1952-1994 "Specification for Cold-rolled Sheet of Superalloy for Aviation".

GB 5333-1985 "Technical Conditions for HGH99 Alloy Welding Wire for Aviation".

BZ 44-903B-06 "Technical Conditions for GH99 Alloy Cold Rolled Sheet" (Fushun Steel Mill Enterprise Standard) Chemical Composition:

gh3128

China Grade: GH3128 GH128 nickel-based superalloy.

Russian grade: 435 XH78T

1. Overview of GH3128 nickel-based superalloy:

GH3128 is a nickel-based alloy with tungsten and molybdenum solution strengthened and reinforced with boron, cerium and zirconium at grain boundaries, which has high plasticity, high durability creep strength, good oxidation resistance and stamping, welding and other properties. Its comprehensive performance is better than that of similar nickel-based solid solution alloys such as GH3044 and GH3536. It is suitable for manufacturing the combustion chamber flame cylinder, afterburner shell, adjusting plate and other high-temperature parts and components of the aviation hall empty engine that has been working for a long time under 950, and the main products are cold-rolled sheets, and can also be dressed as cavity hot-rolled plates, bars, forgings, wires and pipes.

1. GH3128 material grade: GH3128 (GH128, Hongxing No. 11) 2. GH3128 similar grade:

3. Technical standard for GH3128 material:

4. GH3128 chemical composition: see Table 1-1.

GH4169 is a Fe-Ni-Cr based precipitation hardening deformed superalloy, with a long-term service temperature range of -253 650, a short-term service temperature of 800, high strength, good toughness and oxidation and corrosion resistance in high and low temperature environments. As well as good processability and welding performance and long-term structural stability.

GH4169 is suitable for the production of rings, blades, fasteners and structural parts in aviation, aerospace and petrochemical industry, mainly rods, plates, tubes, belts, wires, etc.

GH4169 implements the standard DIN, UNS, ASTM, GBT14992, and GH4169 corresponds to the grade.

GH4169 chemical composition.

GH4169 chemical composition.

Applications of GH4169.

Applications of GH4169.

GH4169 mechanical properties.

Typical room temperature performance with annealing temperature of 1800°

Tensile strength psi: 135,000

Yield strength psi: 70,000

Elongation: 45

GH4169 Rockwell hardness: 100

GH4169 machining: machining is carried out after solution treatment, taking into account the work hardenability of the material, and unlike austenitic stainless steel, it is suitable for low surface cutting speeds.

GH4169 welding performance: precipitation hardening type GH4169 alloy is very suitable for welding, and there is no tendency to crack after welding. Weldability, ease of processing, and high strength are the advantages of this material.

GH4169 is suitable for arc welding, plasma welding, etc. Before welding, the surface of the material should be clean, free of oil stains, powder, etc., and the polishing should be exposed within 25mm around the weld.

GH4169 application and characteristics: The alloy has been used in the production of rings, blades, fasteners and structural parts in aviation, aerospace and petrochemical industry, and a variety of parts used in petrochemical industry, which can be mass-produced and has good usability. The alloy can be cooled by the cooling process when it is remelted at vacuum self-consumption, which can effectively reduce the segregation of niobium elements, the ring parts can be produced by the injection molding process, which can reduce the cost and cycle, and the production range can be expanded by superplastic molding.

GH4169 round bar.