JPS60251227A - Production of low-expansion fe-ni steel sheet - Google Patents

Abstract

PURPOSE:To produce a mild thin steel sheet having a small coefft. of thermal expansion and excellent resistance to rust by executing annealing before and after final cold rolling in a specific temp. range in the stage of producing said sheet by hot rolling and cold rolling of an Fe-Ni steel ingot. CONSTITUTION:The Fe-Ni steel contg. 30-45% Ni, 0.05-1.0% Co and 0.10- 5.0% Cr is worked to the thin steel sheet by hot rolling and cold rolling. The annealing before and after the final cold rolling in the cold rolling stage is executed in the temp. range delineated by ABCDA in figure at 800-1,200 deg.C. The mild thin steel sheet which has a small coefft. of thermal expansion and excellent resistance to rust and is suitable for a shadow mask for a television picture tube and the lead frame of an IC is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing a low thermal expansion steel plate used as various functional materials such as shadow masks for television picture tubes and IC lead frames.

[Conventional technology]

Fs-Nl steel sheets containing 30 to 45 tB of Ni have an extremely small coefficient of thermal expansion over a wide temperature range from liquid nitrogen temperature to 350°C, so they have been used for liquefied gas containers, etc., but recently they have been used for TV picture tubes. Shadow mask and I
Its use is also expanding as a variety of functional materials such as C lead frames. However, such materials are extremely susceptible to rusting, and for example, parts of copper strips and steel plates often rust during the production process of cold-rolled steel strips or during the production of the various types of equipment listed above. There were strong expectations for improved resistance to induction.

Furthermore, when this material is used as various functional materials, it is subjected to bending, press forming, drawing, and stretching, but because it has higher strength than ordinary steel sheets, it is difficult to prevent springback after processing. Shape defects are likely to occur. Therefore, it has been strongly desired to make the material softer.

Here, as a material with improved induction resistance, Ni is
45%, CO, 051 or less, cr Q, 2-0.4
Chi and (Cr-0,1)%≦Co≦Cr%,
PO,005 or less, SO,001 or less, OO
,003% or less, NO,002% or less and the balance is substantially F.
This is known from Japanese Patent No. 661.

(2) [Problems to be solved by the invention] The purpose of the present invention is to produce a soft F/-N1 steel sheet that has a small coefficient of thermal expansion in the temperature range from room temperature to 350°C, has excellent induction resistance, and is soft. shall be.

[Means and effects for solving the problems] The present inventors have attempted to improve the above problems (F-- consisting of 30 to 45% Ni).
As a result of conducting various experiments focusing on the effect of alloy addition and the influence of cold rolling manufacturing conditions using Ni steel sheets as a base, we found that the base component contained trace amounts of CO and CF, and furthermore, We have discovered that by controlling the annealing temperature within an appropriate range, it is possible to obtain a Fe-N1 thin steel sheet that has low thermal expansion, excellent induction resistance, softness, and excellent workability, and has arrived at the present invention.

In the present invention, Nt: 30 to 45%* Co: 0.0
5-1.0 To, Cr: 0.10-5. Of
When producing a thin steel plate (including a coil and a cut plate) by cold rolling a hot rolled plate (including a coil and a cut plate) of Fe-Ni steel containing b, the annealing temperature before and after the final cold rolling. is defined in the range ABCDA (including on the line) in Figure 1.

Note that when a hot rolled sheet is rolled in one stage of cold rolling to the product thickness without annealing during cold rolling, this one stage of cold rolling is referred to as final cold rolling in the present invention. That is, a partial list of the steps of the present invention is as follows.

(1)〈1st cold rolling〉 Hot rolled sheet → annealing (conditions shown in Figure 1) → cold rolling → annealing (1st stage cold rolling)
(Conditions in Figure 1) (2) <Two-stage cold rolling, hot rolled plate annealing> Hot rolled plate → annealing → cold rolling → annealing (conditions in Figure 1) → cold rolling → annealing (
(Conditions in Figure 1) (2-stage cold rolling in 3, no hot rolled plate annealing> Hot rolled plate → cold rolling → annealing (conditions in Figure 1) → cold rolling → annealing (conditions in Figure 1) (4) <3-stage cold rolling, hot rolled plate with annealing> Hot rolled plate → annealing → cold rolling → annealing → cold rolling → annealing (conditions shown in Figure 1) →
Cold rolling → annealing (conditions shown in Figure 1) (5) <3-stage cold rolling, no hot rolled sheet annealing> Hot rolled sheet → cold rolling → annealing → cold rolling → annealing (conditions shown in Figure 1) → Cold rolling → Annealing (conditions shown in Figure 1) Therefore, for the n-stage cold rolling method, it is cold rolling n times, annealing n or (n+1) times,
Annealing before final cold rolling and after final cold rolling is performed under the conditions shown in FIG. However, in the case of the one-stage cold rolling method, cold rolling is performed once and annealing is performed twice under the conditions shown in FIG. 1.

The main element N constituting the matrix has a small coefficient of thermal expansion in the temperature range from room temperature to 350°C and has excellent resistance to induction.
The reason for limiting i + Co * Cr is as follows.

Nl: A basic element that controls the coefficient of thermal expansion, and exhibits minimum thermal expansion at around 36% on the room temperature side and around 42 inches on the high temperature side. However, if it is less than 30 inches or more than 45 inches, the thermal expansion coefficient becomes significantly large, so the range of Ni is 3.
The range was 0 to 45 inches.

C6: Like Ni, this is an element that reduces the coefficient of thermal expansion, and the higher the content, the higher the lower limit of the Ni content. Furthermore, although it is an effective element for improving induction resistance, it is necessary to add at least 0.05% of (5) in order for the effect to appear. However, if the gold content exceeds 1.0%, the mechanical properties will deteriorate and the cost will increase, so the content is limited to 0.05 to i,o%.

Cr: Cr has the effect of improving induction resistance, and its effect becomes apparent at 0.101 or higher. However, 5.
If it is contained in an amount exceeding 0.0%, the coefficient of thermal expansion will increase.
It was limited to 10 to 5.0 inches.

In addition, C is usually about 0.005 to 0.05%, N
Generally, the content is about 0.0005 to 0.01%, but a lower content is preferable in order to lower the strength.

Sl and Mn are used as deoxidizers and are usually 0.01 to
The content is about 0.5 -, but as mentioned above, a lower content is desirable in order to lower the strength.

Furthermore, Ni: 30-45% lCO: 0-05-i,
.

% + Cr: F consisting of O-i 0-5.0%
The strength of a cold rolled annealed e-Ni steel sheet is strongly influenced by the annealing temperatures before and after cold rolling. As an example, a hot-rolled sheet containing the above components is annealed and pickled, the surface is treated with a coil eaves removal machine, and then cold rolled at a rolling reduction of 77 inches.
It is annealed three times at 950.1100°C (6) and then cold rolled at a rolling reduction of 71 inches, and the yield strength must be 27i2 or less as a softening condition that will not cause any problems during the final annealing process. However, this condition can be satisfied when the annealing temperature before and after the final cold rolling is higher than the straight line ABC in FIG.

Note that high-temperature annealing at temperatures exceeding 1200°C requires special heating and a heat-resistant treatment furnace, so the upper limit is set to 1200°C.
℃.

〔Example〕

Cold-rolled thin steel sheets were produced by hot-rolling steels having the components shown in Table 1 and then applying various rolling methods of 1 to 3 stages. At this time, the annealing temperature was set to 800℃.
The temperature was varied between 1150°C and 1150°C.

Table 1: JISZ23 test for induction resistance of plates after final annealing
A salt spray test and an indoor exposure test were conducted according to No. 71.

The salt spray test was judged by the degree of rust after 3 hours of spraying, and the indoor exposure test was judged by the degree of rust after 10 days of exposure.

In addition, a tensile test was performed on the plate after final annealing to examine its strength. The test results are shown in Table 2. In both materials, Ni is 3
Since the coefficient of thermal expansion is in the range of 0 to 45 degrees Celsius, the coefficient of thermal expansion is small in the temperature range from room temperature to 350 degrees Celsius, but F, G, and H, which do not contain Co or Cr, are extremely susceptible to rusting, and all of them cover almost the entire surface. Red rust occurred.

However, Co O, 05-1.0%, Cr 0.1
A-E containing 0 to 5.0% has significantly improved induction resistance and can prevent rusting if stored indoors.

Regarding strength, after hot-rolled steel strip is annealed as necessary, the annealing temperature at least before the final cold rolling and after the final cold rolling is set at the first temperature in the manufacturing process of the cold rolled thin steel sheet. It can be made softer by keeping it within the range shown in the figure.

(9) [Effects of the invention] The method of the present invention significantly improves the induction resistance while maintaining the basic properties of a di-impaired steel sheet, such as low thermal expansion and other properties, and at the same time reduces the strength of mechanical properties. be able to. Therefore, the steel sheet manufactured by the method of the present invention can be widely applied to various functional materials such as shadow masks for television picture tubes and IC lead frames when drawing, stretching, bending, etc. are performed.

[Brief explanation of drawings]

Figure 1 shows the annealing temperatures before and after the final cold rolling in the method of the present invention, and Figure 2 shows the annealing temperatures before and after the final cold rolling on the yield strength of the product plate. FIG. (11)

Claims (1)

[Claims] N1: 30-45%, Co: o, o 5-1.0
4 aCr: F・- containing 0.10 to 5.0
When producing a thin steel plate by cold rolling a hot rolled sheet of Ni-based steel, the annealing temperature before and after the final cold rolling should be 800°C or more and 1200°C or less and within the range of ABCDA in Figure 1. Low thermal expansion F・-N characterized by a temperature of
Method for manufacturing 1 series steel plate.