GH684

GH684 is a nickel-based superalloy. Huanickel GH684 alloy is strengthened by adding cobalt, chromium and molybdenum, adding aluminum and titanium to form a γ’ precipitation strengthening phase, and adding boron and zirconium to purify and strengthen the grain boundaries. It has good oxidation and corrosion resistance; The processing plasticity is good and the microstructure is stable. It is suitable for making parts such as turbine discs, working blades, high-temperature fasteners, flame cylinders, shafts and turbine casings.

GH684 Chemical composition：

	Ni	C	Cr	Co	Mo	AI	Ti	B	Zr	Fe	Mn	Si	P	S	Cu
Min	Bal	0.03	18	12	3.5	1.6	2.75	0.003	0.02	≤
Max		0.1	21	15	5	1.2	3.25	0.01	0.08	2	0.1	0.15	0.015	0.015	0.1

GH684 Physical properties：

Density	8.22g/cm³
Melting point	1330~1360℃
Magnetic properties	not

Coefficient of linear expansion

θ/℃	20～100	20～200	20～300	20～400	20～500	20～600	20～700	20～800	20～900
α/(10-6℃-()	12.47	12.73	13.04	13.53	13.97	14.47	15.05	15.68	15.95

Resilient performance

θ/℃	20	100	200	300	400	500	600	700	800	850	900
Ed/GPa	224	219	213	206	200	193	185	178	169	一	156
E/GPa	215	—	—	一	一	178	166	137	126	113	一
G/GPa	85	一	一	一	一	一	71	67	62	一

GH684 Mechanical properties：

Standard numberVariety	Specimen status	Plate thicknessδ/mm	Tensile properties				730℃Long-lasting performance			Room temperature hardness
			θ/℃	σb/MPa	σp0.2/MPa	δ₅/%	σ/MPa	τ/h	δ₅/%
QJ/DT01.6 3026Cold-rolled strip	Supply status	≤0.40	20	≤1035	≤585	≥25				≤100HRB or Equivalent
		>0.40		≤1000	≤550	≥35				≤100HRB or Equivalent
QJ/DT01.63 026Cold-rolled strip	Supply status +995℃±15℃× 2.0h±0.25h/AC Or faster cold ten stabilization ten aging>	≤0.50	20	≥1170	≥760	≥15	—	一	一	(34～44)HRC or Equivalent
			540	≥1000	≥690	>13	一	一	一	—
		>0.50	20	≥1205	≥795	≥20				(34～44)HRC or Equivalent
			540	≥1035	≥725	≥15	一	—	—	—
		0.40～0.50	—	一	一	一	430	≥23	≥4	—
		>0.50	—	一	一	一	430	≥23	≥4	一

GH684 Alloy properties：

High-temperature strength: GH684 and Huanickel GH738 nickel-based superalloys have excellent high-temperature strength and can maintain good mechanical properties in high-temperature environments. This allows the alloy to withstand stress and deformation at high temperatures, ensuring the normal operation of the equipment.

Corrosion resistance: The alloy has good corrosion resistance and can resist the erosion of a variety of corrosive media. This allows the alloy to maintain stable performance in harsh working environments, extending the life of the equipment.

Oxidation resistance: GH684 and GH738 nickel-base superalloys have good oxidation resistance and can maintain stable performance in high-temperature oxidation environments. This enables the alloy to maintain good mechanical properties and corrosion resistance under high-temperature oxidation conditions, improving the reliability of the equipment.

Processability: GH684 alloy has good machinability and can adapt to a variety of complex processing processes. This enables the alloy to meet the requirements of different fields for the shape and size of parts, improving production efficiency and product quality.

GH684 Uses of alloys：

It is widely used in the field of rotating parts of aviation, aerospace, petroleum, chemical industry and power generation equipment, such as compressor blades, turbine discs, valve bodies, ring parts and shafts and other rotating parts.

GH684 Process performance：

Welding process: The alloy is difficult to weld and can be welded by argon arc welding. Generally, it is welded in a solution state and the same alloy is used as the welding wire.

The high-temperature strength of the weld after heat treatment is slightly lower than that of the base metal after heat treatment, so the weld should not be in a high-stress position. In addition, because the alloy has thermal brittleness and strain crack susceptibility, welding should be carried out in a solid solution state, and the welded parts should be solution treated again.

Relevant standards：

GB/T14992、 HB/Z140、 Q/5B4017、QJ/DT 01.63026 、QJ/DT 01.63056、 QJ/DT 01.63080、 QJ/DT 01.63099