KR20020032594A - Iron-nickel alloy with low thermal expansion coefficient and exceptional mechanical properties - Google Patents

Abstract

The invention relates to creep-resistant iron-nickel alloys with a low expansion coefficient that contain (in weight %), in addition to 0.02 to 0.3 % C, a maximum of 1 % Mn, and a maximum of 1 % Si, an Mo content of 0.1 to 2.5 % and/or a Cr content of 0.1 to 2.5 % </=1.0 % Nb, as well as an Ni content of 31.0 to 45.0 %, remainder iron and production-related impurities. The inventive alloy has a thermal expansion coefficient of <6.0 x 10<-6>/K in the temperature range of 20 to 100 DEG C.

Description

TECHNICAL FIELD [0001] The present invention relates to an iron-nickel alloy having a low thermal expansion coefficient and excellent mechanical properties,

The present invention relates to an iron-nickel alloy having a low thermal expansion coefficient and excellent mechanical properties.

It is a well-known fact that iron-base alloys containing about 36% nickel have a low coefficient of thermal expansion in the temperature range of 20-100 [deg.] C. Thus, these alloys have been used for many years when a constant length is required, even with temperature changes, such as precision machines, watches or bimetals. The use of iron-nickel materials as a shadow mask application is increasing, especially considering the development of color TV receivers and computer monitors that are oriented towards high resolution, real color and high contrast, especially when they tend to be flatter and larger.

Technical iron-nickel alloys containing about 36% nickel are described in "Stahl-Eisen Werkstoffblatt" (SEW-385, 1991) at a universal 20-100 ° C temperature range for conventional screen tubes The thermal expansion coefficient in the soft-annealed state is 1.2 - 1.8 x 10 ^-6 / K. More advanced materials containing about 36% nickel are also used for shadow masks, and have a low thermal expansion coefficient of 0.6-1.2 x 10 ^-6 / K at 20-100 ° C temperature range.

There is a demand for a low expansion material having a higher creep resistance than alloys used so far for a shadow mask pre-stretched in a frame. The blank parts for shadow mask and shadow mask are subjected to a so-called black-annealing process at a temperature of about 580 DEG C or lower. This produces a dark iron oxide layer, which gives a better visual image with better quality.

Iron-base alloys containing about 36% nickel used so far have creep resistance A ₈₀ of about 2.6% under test conditions of 138 MPa loading at 580 ° C for 1 hour.

The shadow mask is pre-stressed in the vertical direction by the vertical frame parts. Up to now, iron-nickel alloys containing about 41% nickel have been used and these alloys are known as materials for melting metals in glass, for example lead frame materials. The technical characteristics are as follows: creep resistance A ₈₀ is measured at about 0.5% at 138 MPa loading, 1 hour at 580 ° C under the same test conditions as described above for alloys containing 36% nickel. Depending on the thermal expansion coefficient of about 4.8 x ^10-6 / K at temperatures in the range of 20-100 degrees Celsius, vertical frame parts made of such alloys are longer than shadow masks made of iron-nickel alloys containing about 36 percent nickel.

The newly developed horizontal frame component material should have the same low thermal expansion characteristics as the iron-nickel alloy used for the shadow mask to date, including irons and about 36% nickel, as well as minor residues generated during manufacturing.

As for the shadow mask, a material having better creep resistance at a temperature of 580 DEG C or less is also required for frame parts. The magnetic and temperature-dependent curves of the expansion coefficient should be approximately the same as the materials used so far.

It is also known that suitable additives for iron-nickel alloys can increase hardness. For this reason, molybdenum and chromium can be considered in addition to carbon. At the same time, the permanent drawing limit and strength are also increased.

However, if the total amount of molybdenum, chromium, and carbon elements exceeds, the coefficient of thermal expansion may excessively increase.

As the wire material of the overland line, iron-nickel alloys containing about 38% Ni, 2% Mo, 0.8% Cr and 0.25% C and iron residues and impurities produced at the time of production are known. The thermal expansion coefficients of these alloys in the solution-annealed state are about 4 x 10 ^-6 / K at 20-100 ° C. The tensile strength can reach 1000 N / mm &lt; ² &gt; in the cured state.

It is an object of the present invention to develop a creep-resistant iron-nickel alloy that does not have the drawbacks of the state of the art, is economical to manufacture and has a low thermal expansion so that it can be used in a number of different technical applications.

This object is achieved by adding not only Ni of 35.0-38.0% (by mass%) but also 0.02-0.3% of C, 1% of Mn and 1% of Si, 0.01-2.5% of Mo and / or 0.1-2.5% of Cr , A creep-resistant, low-expansion iron-nickel alloy having a thermal expansion coefficient of less than 6.0 x 10 &lt; ^-6 &gt; / K at 20-100 &lt; ⁰ &gt; C, which contains 1.0% Nb and the remainder is irons and impurities during manufacture.

Further advantageous embodiments of the invention are indicated in the dependent claims.

In particular, the technical characteristics required for use as a material for vertical frame parts of a shadow mask can be selected using the iron-nickel alloy of the present invention, and Ni, Mo, Cr and C Can be selected.

The object of the present invention can be advantageously used for the following purposes in addition to the shadow monitor and frame parts for screens and monitors:

- Thermal - passive parts of bimetal

- parts of laser technology

- Lead frame

- Electron gun, especially parts of TV tube

- Parts for the manufacture, storage and transport of liquefied gases.

Hereinafter, preferred alloys of the present invention are compared with respect to the alloy of the present invention in terms of mechanical properties.

A preferred composition E1 of the present invention alloy used as a material for a vertical frame, for example a screen, comprises, in addition to 37-39% Ni (by mass%), at most 1% Mn, at most 1% Si, at most 1% As well as 1.6-2.0% Mo, 0.6-1.0% Cr, 0.22-0.28% C, and very small amounts of conventional impurities generated during the manufacturing process. The thermal expansion coefficient is about 4.2 x 10 &lt; ^-6 &gt; / K at 20-100 DEG C and the total temperature-dependent transition of the expansion coefficient at a temperature of from room temperature to 600 DEG C includes only irons and about 42% Ni, It is comparable to the transition or value of the two-material alloy T1 used so far in the current technology. The improvement in the mechanical properties required in the application is particularly important for the inventive alloy &lt; RTI ID = 0.0 &gt; A80 &lt; / RTI &gt; as long as the creep-resistance value, measured by loadings above 200 MPa for 1 hour, . The present invention alloy E1 is excellent in performance and requires no additional processing steps in the manufacture. This means that there is no need for additional curing / heating treatments, as was necessary, for example, in (&apos; - precipitation hardenable alloys to obtain good mechanical properties. The frame can be bent and formed directly in the cold- The long-term stability of the thermal properties also meets all the requirements.

Another preferred inventive alloy composition E2 used as a material for a vertical frame, for example a monitor, contains 35% to 38% Ni (by mass%), at most 1% Mn, at most 1% Si, at most 1% Mo of 1.0-1.6%, Cr of 0.2-0.6%, and ordinary impurities which are issued in a very small amount during the manufacturing process. The coefficient of thermal expansion is about 2.8 x 10 &lt; ^-6 &gt; / K at 20-100 DEG C, which is lower than that of the present invention alloy E1. The improvement in the mechanical properties required in the application can also be achieved with the inventive alloy E2, in particular as long as the creep-resistance value measured at elongation A80 on a cold-rolled sample of 1.4 mm thickness at 580 DEG C is about 0.003%. . The present invention alloy E2 is also excellent in performance and requires no additional processing steps in the manufacture. This means that no additional curing / heat treatment is required to obtain particularly good mechanical properties. The frame can be bent and formed directly in the cold-rolled state. In this state, the above-mentioned mechanical properties exist. In addition, the long-term stability of the thermal properties meets all requirements.

In particular, the mechanical properties required for use as a material for a horizontal frame part of a shadow mask can be obtained with the iron-nickel alloy of the present invention. In this case, the Ni, Mo, Cr, and C contents are adjusted to obtain the intended thermal expansion coefficient and mechanical properties. The composition can be selected.

For example, another preferred inventive alloy composition E3 for use as a material for a horizontal frame of a screen comprises, in addition to 35-38% Ni (by mass%), at most 1% Mn, at most 1% Si, at most 1% As well as 0.7-1.1% Mo, less than 0.2% Cr, 0.08-0.12% additional C, and a very small amount of conventional impurities produced during the manufacturing process. The coefficient of thermal expansion is as low as about 2.0 x 10 &lt; ^-6 &gt; / K at 20-100 [deg.] C, which is the same as the iron- nickel alloy T2 used in the current technology, which contains only irons and about 36% It is very similar to the thermal expansion coefficient. The improvement in the mechanical properties required in the application is particularly important for the inventive alloy &lt; RTI ID = 0.0 &gt; (I) &lt; / RTI &gt; as long as the creep-resistance value, measured by loading above 200 MPa for 1 hour, E3. The present invention alloy E3 is excellent in performance and requires no additional processing steps in the manufacture. This means that there is no need for additional curing / heating treatments as required, for example, in (&apos; - precipitation hardenable alloys to obtain good mechanical properties). The frame can be bent and formed directly in the cold- The long-term stability of the thermal properties also meets all the requirements.

For example, another preferred inventive alloy composition E4 for use as a material for a horizontal frame of a monitor comprises at most 1% Mn, at most 1% Si, at most 1% (in mass%), in addition to 35-38% 0.4-0.8% Mo, 0.1-0.3% Cr, 0.08-0.12% additional C, and a very small amount of conventional impurities produced during the manufacturing process. The coefficient of thermal expansion is as low as about 1.8 x 10 ^-6 / K at 20-100 ° C, which is very comparable to the coefficient of thermal expansion of the iron-nickel alloy T2 used so far in the current technology. The improvement in the mechanical properties required for the application is particularly important in the invention as long as the creep-resistance value measured at a temperature-rolled sample of 1.4 mm thick as elongation A ₈₀ at 580 ° C, even with a loading of over 200 MPa for 1 hour, is about 0.03% Alloy E4. The present invention alloy E4 is excellent in performance and requires no additional processing steps in the manufacture. This means that no additional curing / heat treatment is required to obtain particularly good mechanical properties. The frame can be bent and formed directly in the cold-rolled state. The long-term stability of the thermal properties also meets all the requirements.

E2, E3 and E4 as compared to the properties of alloys T1 and T2 of the current technology, as measured in a high temperature-drawing test without loading at a test temperature of 580 占 폚, as well as thermal expansion coefficient and coercivity field strength Are shown in Table 1.

Table 1: Coefficient of thermal expansion of inventive alloys E1, E2, E3 and E4 as compared to current alloys T1 and T2 and creep resistance measured at 580 DEG C for 1 hour with loading of 138 MPa or 200 MPa as measured in high temperature drawing tests Mechanical properties such as maximum elongation at 580 ° C, tensile strength, and permanent elongation limits. The test sample was made from a 1.4 mm low temperature-rolled band.

Examples of the chemical compositions of the alloys E1, E2, E3 and E4 of the present invention compared with the compositions of the alloys T1 and T2 of the present invention are shown in Table 2. [

Table 2: Examples of the chemical compositions of the inventive alloys E1, E2, E3 and E4 as compared to the composition examples of alloys T1 and T2 of the current technology.

In some applications, it may be advisable to add the amount (mass%) of cobalt indicated in the present invention alloy. The preferred addition (mass%) of cobalt is 0.5-7%, so the nickel content should be adjusted subsequently.

Claims (15)

(Up to 1% Mn and up to 1% Si, 0.1-2.5% Mo and / or 0.1-2.5% Cr, 1.0% Nb and 31.0- Resistant iron-nickel alloy having a thermal expansion coefficient of 45.0% Ni and the balance of irons and impurities at the time of manufacture and having a thermal expansion coefficient of less than 6.0 x 10 ^-6 / K at 20-100 ° C. 4. The steel according to claim 1, wherein the content (by mass%) is at most 1% Mn, at most 1% Si, at most 1% Nb, as well as 38-39% Ni, 1.6-2.0% Mo, % Cr and 0.122-0.28% C, based on the total weight of the iron-nickel alloy. 2. The steel according to claim 1, wherein the content is at most 1% (by mass%) of Mn, at most 1% of Si, at most 1% of Nb, 35-38% of Ni, 1.0-1.6% of Mo, iron, characterized in that selected such that the% C of Cr, 0.1-0.18% of the nickel-alloy. 5. The composition of claim 4, wherein the content is at most 1% Mn, at most 1% Si, at most 1% Nb, 35-38% Ni, 1.7-1.1% Mo, Of Cr and 0.08-0.12% of C, based on the total weight of the iron-nickel alloy. 5. The steel according to claim 3 or 4, wherein the content (by mass%) is at most 1.0% Mn, at most 1% Si, at most 1% Nb, 35-38% Ni, 0.4-0.8% Mo , 0.1-0.3% Cr, and 0.08-0.12% C, based on the total weight of the iron-nickel alloy. Any one of claims 1 to A method according to any one of claim 5, wherein the iron, characterized in that the addition of 0.5-7% of the cobalt (by mass%) - nickel alloys. The method of claim 6, wherein the nickel content of the iron, characterized in that is selected such that 31-45% (in mass%) - nickel alloys. Use of the iron-nickel alloy of any one of claims 1 to 7 as a frame part of a shadow mask as well as a shadow mask of a screen and a monitor. Use of the iron-nickel alloy of any one of claims 1 to 7 as a passive component of a thermal micrometal. Use of the iron-nickel alloy of any one of claims 1 to 7 in the production, storage and transport of liquefied gases. Use of the iron-nickel alloy of any one of claims 1 to 7 as a component of a laser technology. Use of the iron-nickel alloy of any one of claims 1 to 7 as a lead frame. Use of the iron-nickel alloy according to any one of claims 1 to 7 for melting metal and glass. Use of the iron-nickel alloy of any one of claims 1 to 7 as a frame part of a screen or monitor shadow mask. Use of the iron-nickel alloy of any one of claims 1 to 7 as an electron gun part, especially as a television tube.