GH1131
Chinese grade: GH1131/GH131 iron-based high-temperature alloy
Similar grades: Х21Н28В5М3БАР
ЭЛ126，ВЖ100 (Russia)
1.Overview of GH1131 iron-based high-temperature alloy:
GH1131 is a high-performance iron-based high-temperature alloy strengthened by solid solution with elements such as tungsten, molybdenum, niobium, and nitrogen, with a nickel content of about 28%. However, its thermal strength level is comparable to that of the GH3044 alloy. The alloy has good hot working plasticity and welding, cold forming process performance. The main varieties include cold-rolled thin plates, hot-rolled medium plates, bars, flat steel, and wires. It can be used to make high-temperature components for rocket engines that operate for a short time at 700-1000℃ and for aircraft engines that operate for a long time at 700-750℃.
1. GH1131 (GH131) heat treatment system: Hot-rolled plates and cold-rolled thin plates: 1130-1170℃, air cooling; bars: 1160℃±10℃, air cooling treatment.
2. Varieties, specifications, and conditions: Cold-rolled thin plates, hot-rolled plates, bars, welding wires, etc. Hot-rolled plates and cold-rolled thin plates are supplied after solution treatment, pickling, straightening, and edge trimming; bars are supplied without heat treatment; welding wires are supplied in cold-drawn state, heat-treated and pickled state, or semi-hard state.
3. GH1131 (GH131) smelting and casting process: GH1131 alloy is produced using non-vacuum induction furnace with electroslag remelting or arc melting with electroslag remelting process.
4. GH1131 (GH131) application overview and special requirements: This alloy is mainly used for high-temperature components of rocket engines. In aircraft engines, adjustable nozzle housings and regulating plates have been produced and put into production. Compared with nickel-based alloys for similar applications, the alloy has poorer microstructural stability for high-temperature oxidation resistance, and its room temperature plasticity decreases and forming performance deteriorates after long-term use at 700-900℃.
2.Technical standards for GH1131 (GH131) materials:
1. GB/T14992-1994 "High-temperature alloy grades"
2. GB/T14995-1994 "High-temperature alloy hot-rolled steel plates"
3. GJB 1952-1994 "Specifications for cold-rolled thin plates of high-temperature alloys for aviation"
4. GJB 2612-1996 "Specifications for cold-drawn wires of high-temperature alloys for welding"
5. YB/T5245-1993 "Hot-rolled and forged bars of high-temperature alloys for general load-bearing components"
3.Chemical composition of GH1131 (GH131) high-temperature alloy:See Table 1-1:
Table 1-1                                                     

4.Physical and chemical properties of GH1131 (GH131):
1. GH1131 (GH131) thermal properties
(1) Melting temperature range of GH1131 (GH131)
(2) Thermal conductivity of GH1131 (GH131):
Table 2-1

(3) Linear expansion coefficient of GH1131 (GH131):
Table 2-2

2. Density of GH1131 (GH131): ρ=8.33g/cm3
3. Electrical resistivity of GH1131 (GH131):
Table 2-3

4. GH1131 (GH131) magnetic energy type: alloy non-magnetic
5. GH1131 (GH131) chemical properties: GH1131 (GH131) oxidation resistance performance. The oxidation rate and grain boundary oxidation depth of the alloy tested in air medium for 100 hours are shown in Table 2-4.
Table 2-4

Five,GH1131 (GH131) microstructure:
1. Phase transformation temperature
2. Time-temperature-structure transformation curve
3. Alloy microstructure: The microstructure of the alloy in the solid solution state, in addition to the austenite matrix, also includes primary Z phase [(W, Nb)CrN] and trace NbC, which together account for about 1.43% of the alloy, distributed uniformly in an impurity form. After aging at 700~950℃ for 20 hours, L phase and a small amount of M6C phase precipitate, and Z phase also has supplementary precipitation, but the precipitation changes little with the extension of aging time. L phase belongs to the FeMo type, with a peak precipitation at 800℃, and begins to redissolve at 900℃. M6C precipitates more at 950℃ aging, while the precipitation amount at other aging temperatures remains unchanged.
Six,GH1131 (GH131) process performance and requirements:
1. Forming performance:
The forging heating temperature for steel ingots is 1120℃±20℃, the opening forging temperature is above 980℃, and the final forging temperature is not lower than 900℃, with a deformation degree of 40% for one heating. The heating temperature for slab rolling is 1150℃±20℃, the opening rolling temperature is above 1050℃, and the final rolling temperature is not lower than 900℃, with the last reduction rate not less than 10%. The rough rolling heating temperature for hot-rolled thin plates is 1160℃±10℃, the precision rolling heating temperature is 1060℃±10℃, the opening rolling temperature is above 1000℃, and the final rolling temperature is not lower than 800℃, with no limit on the number of heating and rolling passes for hot rolling. The intermediate quenching temperature is 1150℃±10℃. The cold rolling reduction rate is 20%~30%, and the flatness is 1%~3%.
2. Welding performance:
The alloy has good welding performance and can be connected using methods such as spot welding, seam welding, and argon arc welding, achieving satisfactory joint temperatures. This alloy can be welded with alloys such as GH3030, GH3039, GH3044, and GH1140, with good joint performance.
3. Heat treatment process for parts:
The final heat treatment temperature for plate parts is 1150℃±10℃ or 1080℃~1120℃, with an intermediate heat treatment temperature of 1000℃±10℃. Air cooling.
4. Surface treatment process:
The alloy thin plates require alkaline and acid cleaning after softening heat treatment and finished product heat treatment if the oxidation scale on the plates is not removed. In addition to alkaline and acid cleaning for the thin plates after finished product heat treatment, whitening treatment is also required.
Seven,GH1131 (GH131) variety specifications and supply status:
1. Variety classification: seamless pipes, steel plates, round steel, forgings, flanges, rings, welded pipes, steel strips, wires, and matching welding materials.
2. Delivery status: Seamless pipes: solid solution + acid white, length can be customized; plates: solid solution, acid cleaning, edge cutting; welded pipes: solid solution acid white + RT% flaw detection, forgings: annealed + turned; bars in forged and rolled state, surface polished or turned; strips delivered after cold rolling, solid solution soft state, and descaling; wires delivered in solid solution acid washed coil or straight bar form, solid solution straight bar fine polished state.