Alloy VT8

Designation

Name	The value
Designation GOST Cyrillic	ВТ8
Designation GOST Latin	BT8
Transliteration	VT8
By chemical elements	ВTe8

Description

Alloy VT8 is used: for the manufacture of semi-finished products (sheets, strips, foils, strips, plates, bars, rods, profiles, tubes, forgings and forged blanks) by the strain, and bars; parts for various purposes, operating at temperatures up to +480 °C; parts of gas turbine aircraft engines (discs, vanes, low pressure compressor, mounting parts fan).

Note

Titanium alloy with high corrosion resistance. Alloy VT8 provides higher strength and heat resistant properties in comparison with rafting VT6 due to the high content of aluminum and silicon alloying. Alloy VT8 (and VT8−1 and VT8−1M) exceeds the alloys VT3−1 and VT9 heat stability, plasticity, workability and characteristics of fracture toughness. Double and isothermal annealing provide the best combination of properties; the content of b — phase in the annealed alloy to about 10%. Alloy thermally hardened.
A satisfactory alloy is deformed in the hot state. Technological properties during pressure treatment worse than that of alloy VT6.
Welding of alloy VT8 is not recommended.

Standards

Name	Code	Standards
Non-ferrous metals, including rare, and their alloys	В51	GOST 19807-91, OST 1 90000-70, OST 1 90013-81, OST 1 90197-89, OST 1 90002-86
Bars	В55	GOST 26492-85, OST 1 92020-82, OST 1 90266-86, OST 1 90173-75, OST 1 90107-73, OST 1 90006-86, TU 1-9-672-78
Bars and shapes	В52	OST 1 92039-75, OST 1 92051-76, OST 1 90101-73

Chemical composition

Standard	C	Si	Fe	N	Al	Ti	Mo	O	Zr	H
OST 1 90013-81	≤0.1	0.2-0.4	≤0.3	≤0.05	5.8-7	Rest	2.8-3.8	≤0.15	≤0.5	≤0.015

Ti is the basis.
According to GOST 19807-91 and OST 1 90013-81 the total content of other impurities is ≤ 0.30%. The mass fraction of hydrogen is indicated for ingots. In the alloy, a partial replacement of molybdenum by tungsten in an amount not exceeding 0.3% is allowed. The total mass fraction of molybdenum and tungsten should not exceed the norms specified in the table for molybdenum. The mass fraction of chromium and manganese should not exceed 0.15% (in total). The mass fraction of copper and nickel should not be more than 0.10% (in total), including nickel not more than 0.08%.
According to OST 1 90013-81 in the semi-finished products of VT8 alloy, in addition to punching blades, disks and blanks thereof, the aluminum content is allowed up to 7.30%.

Mechanical properties

Section, mm	σ_U, MPa	d₅, %	d	y, %	KCU, kJ/m²	HB, MPa	HRC
The blades of aircraft engines is made by forging after double annealing (microgravity (Mg) is the projected area up to 20 cm2, small (M) - 20-250 cm2, midsize (C) - 250-550 cm2, bulk (K) - 550-1500 cm 2)
Мг, М	980-1180	≥10	-	≥30	≥294	269-363	30-40.5
The pressed bars for OST 1 92020-82. Annealing. The longitudinal samples
≤60	1030-1226	-	≥9	≥30	≥294	-	-
Forged discs and shafts after heat treatment OST 1 90197-89 all weight categories
-	≥685	-	-	-	-	-	-
The blades of aircraft engines is made by forging after double annealing (microgravity (Mg) is the projected area up to 20 cm2, small (M) - 20-250 cm2, midsize (C) - 250-550 cm2, bulk (K) - 550-1500 cm 2)
С, К	980-1180	≥8	-	≥25	≥294	269-363	30-40.5
The pressed bars for OST 1 92020-82. Annealing. The longitudinal samples
60-100	1030-1226	-	≥9	≥25	≥294	-	-
Forged discs and shafts after heat treatment OST 1 90197-89 all weight categories
-	≥620	-	-	-	-	-	-
The blades of aircraft engines is made by forging with the use of high-temperature thermomechanical treatment after aging (compact (M) - the projected area cm2 20-250, medium (C) - 250-550 cm2, bulk (K) - 550-1500 cm 2)
М, С, К	1180-1380	≥6	-	≥22	≥245	321-415	36.5-45.5
The pressed bars for OST 1 92020-82. Annealing. The longitudinal samples
100	≥735	-	-	-	-	-	-
Forgings weighing up to 200 kg after annealing
-	≥667	-	-	-	-	-	-
The blades of aircraft engines is made by forging with application of thermomechanical treatment after aging (microgravity (Mg) is the projected area up to 20 cm2, small (M) - 20-250 cm2, midsize (C) - 250-550 cm2, bulk (K) - 550-1500 cm 2)
Мг, М	1080-1280	≥7	-	≥22	≥265	269-363	30-40.5
Forgings weighing up to 200 kg after annealing
-	≥540	-	-	-	-	-	-
The blades of aircraft engines is made by forging with application of thermomechanical treatment after aging (microgravity (Mg) is the projected area up to 20 cm2, small (M) - 20-250 cm2, midsize (C) - 250-550 cm2, bulk (K) - 550-1500 cm 2)
С, К	1030-1230	≥8	-	≥25	≥294	269-363	30-40.5
Bars and rods, hot-rolled. Annealing
-	≥736	-	-	-	-	-	-
Forged discs and shafts after heat treatment OST 1 90197-89 (samples cut in Cordova direction; specified blank weight categories)
≤50	960-1160	≥10	-	≥25	≥343	-	-
Bars and rods, hot-rolled. Annealing
-	≥589	-	-	-	-	-	-
Forged discs and shafts after heat treatment OST 1 90197-89 (samples cut in Cordova direction; specified blank weight categories)
50-100	960-1160	≥9	-	≥22	≥343	-	-
100-200	950-1150	≥8	-	≥22	≥343	-	-
200-500	940-1140	≥8	-	≥20	≥343	-	-
Forgings weighing up to 200 kg after annealing
101-150	932-1177	≥7	-	≥16	≥294	269-363	-
151-250	932-1177	≥6	-	≥16	≥294	269-363	-
100	981-1226	≥9	-	≥25	≥294	269-363	-
Bars hot rolled autogenie ordinary quality GOST 26492-85 (longitudinal samples)
10-12	≥980	≥8	-	≥20	-	-	-
100-150	≥930	≥6	-	≥15	198	-	-
12-100	≥980	≥8	-	≥20	≥294	-	-
Bars hot rolled autogenie high-quality according to GOST 26492-85 (longitudinal samples)
10-12	980-1230	≥9	-	≥30	-	-	-
100-150	930-1180	≥7	-	≥19	≥294	-	-
12-60	980-1230	≥9	-	≥30	≥294	-	-
60-100	980-1180	≥9	-	≥25	≥294	-	-
Forged square bars and round after annealing
≤150	932-1177	≥7	-	≥16	≥294	269-363	-
151-250	932-1177	≥6	-	≥16	≥294	269-363	-
	961-1177	≥8	-	≥20	≥294	269-363	-

Description mechanical marks

Name	Description
σ_U	Limit short-term strength
d₅	Elongation after rupture
d	Elongation after rupture
y	The relative narrowing
KCU	Toughness
HB	Brinell hardness number
HRC	Rockwell hardness (indenter diamond spheroconical)