GH3128
Chinese Grade: GH3128/GH128 Nickel-based Superalloy
Russian Grade: ЭИ435/XH78T
1. Overview of GH3128 nickel-based superalloy:
GH3128 is a nickel-based alloy with tungsten and molybdenum solution strengthened and boron, cerium and zirconium strengthened at grain boundaries, which has high plasticity, high durable 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 combustion chamber flame cylinders, afterburner shells, adjusting sheets and other high-temperature parts and components of aero engines working for a long time at 950°C, the main products are cold-rolled sheets, and hot-rolled plates, bars, forgings, wires and pipes can also be supplied.
1. GH3128 Material grade: GH3128 (GH128, Hongxing No. 11)
2. GH3128 Similar grade:
3. GH3128 Technical standards for materials:
4. GH3128 Chemical composition: see Table 1-1.
Table 1-1%.

Note: B, Ce, and Zr are added according to the amount of calculation.
5. GH3128 heat treatment system: the solution temperature in the delivery state is 1140~1180°C, and the air cooling is air-cooled. The high-temperature performance was tested after 1200°C supplemental solution treatment.
6. GH3128 variety specifications and supply status: cold-rolled sheet δ0.8~4.0mm, hot-rolled plate δ4~14mm, cold-drawn welding wire d0.3~10mm. Cold-rolled and hot-rolled plates are supplied after solution and pickling; Welding wires are supplied in cold-drawn, semi-hard or solution and pickled states.
7. GH3128 smelting and casting process: non-vacuum or vacuum induction furnace plus electroslag remelting.
8. GH3128 Application Overview and Special Requirements: The alloy is suitable for manufacturing aero engine combustion chamber and afterburner parts working below 950 °C, and the use effect is good.
2. GH3128 Physical and chemical properties:
1. GH3128 Thermal properties:
(1) GH3128 (GH128) melting temperature range: 1340~1390 °C^[1]。
(2) GH3128 (GH128) thermal conductivity: see Table 2-1.
Table 2-1^[2]

(3) GH3128 linear expansion coefficient: see Table 2-2.
(4) GH3128 Thermal diffusivity: see Table 2-3.
Table 2-2^[2]

2. GH3128 density: ρ=8.81g/cm^3[2]。
3. GH3128 electrical properties: electrical resistivity table 2-4.
4. GH3128 magnetic properties: the alloy is non-magnetic.
Table 2-3^[2] 

Table 2-4^[2] 

5. Chemical properties of GH3128:
(1) Oxidation resistance of GH3128: The oxidation rate of the alloy after 100h of test in air medium is shown in Table 2-5.
Table 2-5^[1]

(2) Corrosion resistance: The corrosion performance of marine gas is shown in Table 2-6.
Table 2-6^[3] 

Note: The test conditions were that the ratio of air to fuel was 39:1 and the salt concentration was 106×10^-6, fuel is No. 0 diesel.
3. Mechanical properties of GH3128: The properties specified in the GH3128 standard are shown in Table 3-1.
Table 3-1

Note: The initial test of long-lasting performance is performed according to Specification I. If the inspection according to Specification I fails, it is allowed to re-inspect according to Specification II.
4. GH3128 (GH128) Organizational structure:
1. GH3128 phase change temperature:
2, GH3128 time-temperature-tissue transition curve: the precipitation curve of the μ phase is shown in Figure 4-1.
3. Microstructure of GH3128 alloy: The alloy is a single-phase austenite structure in the solid solution state, containing a small amount of fine and uniformly distributed TiN and M₆C。 M is precipitated during the long-term aging process₆C、μ、α_wand M₂₃C₆Appearance. The precipitation temperature of the μ phase is in the range of 700~1050°C, and the maximum precipitation is 3.49%. M₂₃C₆The phase was precipitated after aging at 700~800 °C, and the precipitation amount was only 0.14%. a_wThe phase was found after long-term aging at 900°C, and the precipitation peak reached at 200h, and its amount was 0.86%. The aging time is intermittently extended, and the plate output decreases. The effect of aging time on the precipitation amount is shown in Figure 4-2.
 
5. GH3128 (GH128) process performance and requirements:
1. The temperature of the furnace for ingot forging is not higher than 700 °C, and the final forging temperature is greater than 900 °C.
2. The average grain size of the alloy is closely related to the deformation degree of the forging and the final forging temperature.
3. The alloy can be welded by argon arc welding, spot welding, seam welding and other methods.
6. Variety, specification and supply status of GH3128:
1. Variety classification: the production of various specifications of GH3128 seamless pipe, GH3128 welded pipe, GH3128 plate, GH3128 bar, GH3128 forging, GH3128 ring, GH3128 wire and GH3128 supporting welding consumables.
2. Delivery status: seamless tube: solid solution + acid white, length can be fixed; Plates: solid solution, pickling, trimming; Welded pipe: solid solution acid white + RT% flaw detection, forgings: annealing + polishing; The bar is in a forged state, the surface is polished or polished; The strip is delivered by cold rolling, solution soft state, and descaling; The filaments are delivered in solution pickled discs or straight strips, solution straight strips in finely polished condition.