SU1731851A1 - Charge for melting billets of low-alloy titanium - Google Patents

Abstract

This invention relates to the metallurgy of titanium based alloys. The aim of the invention is to increase the strength of the alloy while reducing costs and maintaining ductility and corrosion resistance. The mixture containing titanium sponge and waste of the alloyed alloy is additionally injected with waste from a + / 3-titanium alloys in the following ratio, wt%: waste of the alloyed alloy 10-25%; waste about. + / 3 titanium alloys 5–7%; sponge titanium of a certain hardness the rest. The tensile strength of sheets obtained using the mixture of this composition is 8–20% higher, and the cost of the charge is 15–19% lower. 2 tab.

Description

SP

WITH

The invention relates to metallurgy, in particular to the production of titanium alloys, intended as structural and corrosion-resistant materials, for example, for the manufacture of structures in chemical engineering.

The known composition of the mixture for the production of a-titanium alloy VT1-0 of the specified purpose, comprising up to 25% of the waste of the alloy VT1-0 and VT1-00, the rest is spongy titanium.

The disadvantage of this mixture is the reduced strength of the resulting alloy.

The composition of the mixture of low-alloyed α-titanium alloys of the same purpose is known, including 0.4% AI, 0.05% 02, own waste up to 25%, the rest is spongy titanium.

The disadvantage of the known composition of the mixture is that the alloys obtained from it

have an insufficient level of strength and high cost.

The purpose of the invention is to develop the composition of the charge for melting ingots of low-alloyed pseudo-a-titanium alloys with an increased level of strength while maintaining ductility, corrosion resistance and cost reduction.

The goal is achieved by the fact that the proposed composition of the mixture contains, wt%:

Waste composition of melted titanium alloy 10-25 Waste a + / 3-titanium alloys5-7

Sponge titaniumEther

and used sponge titanium with strength determined from the ratio of K1

, Mr. An (in Too + with Too) ...

о1 / л 1 v U

3

with

(L

one

K + 1 100

where ob is the calculated tensile strength of titanium sponge, kgf / mm,

An is the average tensile strength of the base of the titanium alloy melted, kgf / mm,

B is the average tensile strength of wastes produced by titanium alloy, kgf / mm,

C - the average ultimate strength of waste a + p - titanium alloys, kgf / mm2,

K is the mass fraction of the waste of titanium alloy melted into the mixture,

%

1 - the mass fraction introduced into the mixture

waste and L-fi-titanium alloys,%.

The difference of the proposed composition of the charge from the known one is that the a + (3-titanium alloys are additionally introduced, and sponge titanium takes a certain hardness.

Example. Cooked are given in table. 1 the following composition of the composition of the mixture for smelting ingots of low-alloyed pseudo-e-titanium alloys (1-5) and the known composition (6).

Here, the titanium sponge brand is determined as follows.

According to the relation (1), the required strength of titanium sponge ob is calculated. based on statistical data, the average tensile strength of the base alloy for forged and rolled semi-finished products kg / mm, the average tensile strength of the waste alloy produced kg / mm2, and the average tensile strength of the waste (chips) a +/- titanium alloys kg / mm2 are obtained.

From the known ratio, the required hardness of titanium sponge, 2 ° b, is determined by which the grade of titanium sponge is established.

360 mm ingots were smelted from the charge; For each composition of the charge on the sheets after annealing, mechanical and corrosion properties are determined. In addition, according to the standard method and the current price list, the cost of 1 ton of charge is calculated.

Corrosion tests are carried out on specimens of size 20x30x2 mm. Before testing, the samples are cleaned with C 240 sandpaper, washed with tap water, then with distilled water, degreased with acetone and kept for 6 days with a 6 desiccator with fresh calcium calcine.

Corrosion tests at elevated temperatures are carried out in glass beakers equipped with refluxing refrigerators under natural aeration conditions.

Aggressive media are hydrochloric acid and acidified concentrated chloride solution.

In the first case, the samples were tested in 3% HCI at 60 ° C for 5 h, in the second case - in 30% MgCla + HCI at 100 ° C with a holding time of 100 h.

0 The obtained data of mechanical, corrosion properties and cost of the charge are given in table. 2

Claims (1)

As can be seen from the table. 2, obtained using the mixture, the proposed compositions (1-3) have an increased by 8–20% level of tensile strength while maintaining plasticity, corrosion resistance, and the cost of the mixture is reduced by 15–19%. With extreme composition of the mixture, the cost is also lower, but in comparison with the known composition of the mixture with them there is either a decrease in tensile strength (4) or plasticity (5). Invention Formula 5 The mixture for smelting ingots of low-alloyed α-titanium alloys, containing sponge titanium and waste of titanium alloy, characterized in that, in order to increase the strength of the alloy at 0 cost reduction and preservation of plasticity and corrosion resistance, the mixture additionally contains waste a + D-titanium alloys in the following ratio of ingredients, wt.%: 5 Titanium alloy waste 10-25 Waste a + / - titanium alloys5-7 Sponge titaniumEther moreover, sponge titanium is used with a strength determined from the ratio An (In Tm + S Tlp) 100 one K + 1 100 where Oh - the calculated tensile strength of titanium sponge, kgf / mm; An is the average tensile strength of the base of the titanium alloy melted, kgf / mm2; B is the average tensile strength of waste of titanium alloy, kgf / mm2; C is the average ultimate strength of the waste a H- / 3-titanium alloys, kgf / mm2; K - mass fraction of titanium alloy wastes introduced into the mixture,%; 1 - the mass fraction introduced into the mixture waste a + {3-titanium alloys,%, Table 1 Table 2