Alpha-alpha-and pseudo alloys
alloys belonging to the first group: alpha-alloys (BT1-00 VT1-0, VT5; BT5-1, 4200) and the pseudo-alpha-alloys (OT4-0, OT4-1, OT4, VT4, OT4-2, AT2, ATZ, AT4, VT20, TC5) are low-alloy (J-stabilizing-forming alloys with elements of $ K <= 0.25. These alloys are well welded by all types of welding and weld strength and Plasticity is approaching the base metal. alloys do not require stabilizing annealing after welding. Since the weld may be present then, the strength of the welded joint is taken into account by a factor of welding weakening equal to 0.9-0.95 of the strength of the base material. With the increase strength of welded joints of these alloys are more susceptible to weld defects (pores, stress concentrators, etc.) and a slight increase in the difference between strength and ductility of the weld and base metal. Technical titanium VT1-00 is made of the purest grades of titanium sponge. It contains fewer impurities such as carbon, iron, silicon, oxygen, than allowed for other titanium alloys. Titanium VT1-00 has low strength characteristics and high plasticity. Well deformed in the hot and cold conditions. Of titanium VT1-00 made virtually all types of semi-finished: aluminum foil, tape, sheet, plate, forgings, stampings, profiles, tubes, wire, etc. Typical mechanical properties of titanium VT1-G0 at room and elevated temperatures are given in Technical Titanium grades 1-00 Tues due to its low strength as a structural material used is limited. When welding with an addition of a filler material used welding wire in titanium VT1-00 and VT1-0. The welded joints of titanium VT1-00, received Td H doped with VT1-00, after partial annealing have the following mechanical properties at room temperature: a * = 0.9, aB base metal; en> = 9.0 kgf * m/sm2 and = 180 ° to the sheet thickness of 1.5 mm and a = 140 ° for a sheet thickness of 3.0 mm.
Technical titanium VT1-0 prepared from unalloyed sponge, somewhat inferior in purity titanium sponge, used for the manufacture of titanium VT1-00. Nevertheless, the content of impurities in titanium VT1-0 is less than in the doped titanium alloys.
The alloy VT1-0 with a smaller ductility compared to the technical titanium VT1-00 has a higher strength and under-wide changes as a structural material. Typical mechanical properties at room and elevated temperatures of titanium VT1-0 are shown in Table. 28. Titan brand BT1-0 is well welded by all types of welding. From Tues 1-0 produce sheets, strips, foils, rods, profiles, tubes, wire, etc. The alloy VT1-0 used in the construction of continuously operating at temperatures ranging from -253 to +150 ° C. The welds are plastic and allow considerable cold deformation [52]. The ductility of the welded joint (bending angle a) is practically not affected by cold work up to 20% (Fig. 64). Heat treatment after welding is not required. Mechanical properties of welded joints of titanium VT1-0, obtained with an addition of H DT, after partial annealing have the following mechanical properties at room temperature: GMT = 0.9, aB base metal; en> = 7 kgf m/sm2, and = 135 ° C for sheet thickness of 1.5 mm and a = 110 ° to the sheet thickness of 3.0 mm. When welding with an addition of a filler material is used for welding wire of VT1-00 and VT1-0. Alloy VT5 is a typical single-phase a-titanium alloy system T1-Al. VT5 alloy forgings are manufactured, stamping, forged and rolled bars and rods, welded rings. The alloy VT5 has moderate strength low ductility. These explained that this alloy does not produce leafy semis. alloy VT5 are well welded by all types of welding applied to titanium. Tensile strength at short-term and long-term tensile strength of the welded joint are equal to 0.9 and 0.9 and aB ^ base material, respectively, at all operating temperatures. As the filler wire is used in titanium VT1-00 alloy, or BT2.
Alloys with alpha + β-structure of the martensitic type This group includes srednelegirovannye p-stabilizing elements yuschimi alloys with Ka = 0.3-0.9, thermally hardened by quenching and aging. The alloys of this group immediately after the welding has reduced weld ductility due to the formation of the joint structure is quite strong martensitic a'-phase. To restore the ductility of welded joints in alloys of this type use a stabilizing heat treatment, which resulted in a 'phase becomes stable in a + p-components. Most welded structures of a + b-martensitic alloys are made with the strength of welded joints of 85-100 kg / mm2. Less commonly, welded construction is subjected to hardening heat treatment on the strength of 105-130 kgf/mm2, and then the joints thicken, and annealed, and the strength balance achieved by the design and provide sufficient the reliability of the welded joint. alloy VT6 - analogue of the widely used overseas alloy Ti-6Al- 4V [2, 121], as well as domestic VT6S alloy. Made in the form of a sheet of alloy plates, bars, forgings, stampings, welded rings. The alloy can be used both in the annealed and thermally hardened in the I (quenching + aging) conditions. Hardening heat treatment the strength of the alloy can be increased by 15-20%. Alloy satisfactorily welded by all kinds of welding used for titanium. Welded joints of VT6 alloy immediately after welding has a number of reduced ductility. To restore the ductility of welded joints requires a stabilizing heat treatment. The strength of welded joints of alloy VT6 made AArDES non-consumable electrode without the additive is, after annealing at 760 - 800 ° C and after quenching from 900 ° C and aging at 500 ° C for 2 h and 105 kgf/mm2 95-100, respectively. Alloy I welded sheet with all titanium alloys. As the filler wire is used in alloys VT1-00, BT1-0, BT2, SPT2, VT6S. VT6 alloy is used for welded parts, for a long time working in the Institute was annealed at temperatures up to 450 ° C, and in the thermally hardened state - with temperatures up to 400 ° C. Alloy VT6S recommended for the manufacture of stamped and welded structures; working for a long time at temperatures up to 400-450 ° C and briefly at temperatures up to 700-750 ° C. The tensile strength of welded joint, fusion welding is not less than 90% of the tensile strength of the base metal. When welding heavy sections of metal use progressive methods of welding, submerged arc welding for example, joints VT6S alloy obtained in this way, of equal strength annealed base metal, and their toughness higher by 1,2-4,0 kgf m/sm2.
See also:
Heat Treatment of Welded Joints of Titanium Alloys
Annealing of Titanium Welded Joints
Hardening Heat Treatment of Titanium Welded Joints
Special Modes of Hardening Heat Treatment of Welded Structures
Effect of Welding on the Structure and Properties of Different Zones of the Welded Joint
Structure and Properties of Heat Affected Zone
Structure and Properties of Welded Joints
Properties and Structure of Welded Joints of Industrial Titanium Alloys
Welding of Titanium
No comments:
Post a Comment