JPH03277540A - Titanium clad steel sheet good in workability and production thereof - Google Patents

Abstract

PURPOSE:To obtain a titanium clad steel sheet good in workability by limiting both the content of hydrogen and nitrogen contained in titanium and the range of the componental composition in steel of the base material and limiting the temp. range in a time for hot rolling and heating. CONSTITUTION:Amount of oxygen and hydrogen contained in titanium is regulated to 0.15% and 0.01% respectively as the upper limit and deterioration of flexural properties is prevented. Amount of nitrogen contained in titanium is regulated to <=0.04%. When steel of the base material is regulated to <=0.1% C, <=0.1% Si and <=0.5% Mn, drawing is enabled as working of a thin steel sheet. Furthermore, when one or more kinds of <=0.1% Al, <=0.5% Ti, and <=0.5% Nb are incorporated in this conditions, deep drawing is enabled. Heating temp. in a time for hot rolling and heating is regulated to 700-950 deg.C. When copper is especially utilized as the intermediate medium bonding material and a molten intermetallic compd. of titanium and copper is utilized and junction is performed in the atmosphere, the lower limit temp. is regulated to 850 deg.C. Furthermore the amount of hydrogen and oxygen contained in nitrogen being the annealing atmosphere is regulated to <=0.2% and <=0.5% respectively and dew point is regulated to -25 deg.C or below. It is prevented that hydrogen and oxygent infiltrate into the titanium layer and that workability is deteriorated. Annealing temp. is regulated to 600-750 deg.C and annealing time is regulated to 0.2-10min. Growth of the intermetallic compd. in the interface is inhibited and workability of titanium and steel of the base material can be exhibited.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a titanium clad steel plate with good workability and a method for manufacturing the same. However, among the applications that require excellent corrosion resistance, there are many so-called thin plate applications that are thin and have complex shapes, and the present invention is suitable for such thin plate applications. The present invention relates to a titanium clad mesh plate with good workability and a method for manufacturing the same.

[Conventional technology] In the production of titanium clad steel, the cast-in method, which is performed at the level of molten steel, is not applicable because if a layer of brittle Fe-Ti intermetallic compounds or TiC forms at the interface between titanium and steel, it will peel off at the interface. Since this is not possible, bonding at the solid phase level is used.

Among these, the explosive bonding method is currently widely used because it does not use an intermediate bonding material and has high reliability in terms of bonding strength.

In addition, the pressure welding method is more advantageous than the explosion bonding method because it has high productivity, allows a relatively flexible plate thickness, and can be applied to conventional manufacturing processes. However, in the pressure welding method, there is a very high possibility that a brittle layer such as an intermetallic compound will be formed at the bonding interface, and if oxides or the like are present at the interface, bonding becomes impossible. Especially in the case of hot welding,
These risks are high because the diffusion and oxidation rates are fast.

As a method for bonding while suppressing the formation of a brittle intermediate layer at the interface, Japanese Patent Application Laid-Open No. 62-6783 describes limitations on hot rolling heating conditions, and, for example, Japanese Patent Application Laid-Open No. 55-48468.

JP-A-57-109588, JP-A-57-11298
No. 5 and Japanese Unexamined Patent Publication No. 57-192256 propose a method in which a plate or foil of pure iron, nickel, copper, or the like is sandwiched as an intermediate bonding material at the cladding interface.

Since titanium clad steel sheets require a large manufacturing cost, they have mostly been used for special purposes such as chemical equipment. For this reason, titanium clad steel sheets have rarely been required to have the workability necessary for thin sheet applications.

In response to this, the present inventors have previously invented a method that makes it possible to manufacture clad steel in the atmosphere by actively utilizing an intermetallic compound of titanium and copper (Japanese Patent Application Laid-Open No. 1-1-226
Publication No. 77). Since this method has dramatically reduced costs compared to conventional methods, there has been an increasing demand for its application to daily necessities such as building materials, automobile parts, and even household appliance parts. As a result, titanium clad steel sheets are now required to have the same workability as thin steel sheets.

[Problem to be solved by the invention]

As mentioned above, titanium clad copper plates have not required the workability required for thin plates, so the reality is that they are materials that prioritize bondability at interfaces. Therefore, even if conventional titanium clad steel sheets are thinned by cold rolling or the like, and the thickness falls within the range of thin sheets, it has not been possible to manufacture titanium clad thin steel sheets that can withstand processing such as pressing.

In other words, there has been no titanium clad E1m plate with excellent workability that can withstand processing such as pressing.

The present invention provides a titanium crand steel plate with good workability that can withstand processing such as pressing by carefully selecting materials and defining manufacturing conditions, and a method for manufacturing the same.

[Means for solving problems]

A titanium clad steel sheet manufactured for thick plates is cold-rolled in the same way as steel to form a thin plate with a thickness of 1.0 mm, and then recrystallization annealing, which is also carried out with deep drawing m plates, is performed to produce a titanium clad thin steel sheet. I made a prototype.

However, titanium clad steel sheets made from this conventional material and heat-treated under the conventionally known suitable temperature and time conditions for the base material were subjected to square cylinder drawing with a tip angle of 40R, and the corner portions were joined to the laminate. Both the base metal broke and the titanium layer of the cladding material was broken at the tip of the punch. After investigating the cause of this problem, we found that steel for thick plates has a high C content and has poor deep drawability even with proper recrystallization annealing. Poor drawing properties, mainly limiting the amount of oxygen in titanium,
It has been found that it is necessary to reduce precipitated hydrides.

Based on this knowledge, we investigated the effects of the amount of oxygen and hydrogen in titanium on the bendability of titanium-clad steel sheets.

Figure 1 shows a titanium layer thickness of 100 to 120 μm and a total thickness of 1
．． The effect of the amount of oxygen contained in titanium on the 1806 titanium external bending test results of a 0 mm titanium clad steel plate was shown. In the figure, the mark O indicates that the titanium was bent well without cracking, and the mark X indicates that a crack occurred on the titanium surface. When the oxygen content is 0.15% or less, the bending radius becomes 0.5-
m (t/2), the titanium surface was bent well without cracking, and furthermore, it was found that when the amount of oxygen contained was 0.01% or less, no cracking occurred even in close bending. Conversely, when the content of oxygen exceeds 0.15%, the bendability deteriorates rapidly, and cracks occur even when bent at a bending radius of 0.5 mm (t/2) or even when bent at 180° with a bending radius of 1-m (t).

Figure 2 shows a titanium layer with a total oxygen content of 100 to 120 μm and a total thickness of 1, On+.
The effect of the amount of hydrogen contained in titanium on the 180° titanium external bending test results of a titanium clad steel plate of 300 m was shown. The marks in the figure are the same as in Figure 1. When the hydrogen content is 0.01% or less, the bending radius is 180° with 0.5ms + (t/2).
It was found that the titanium surface could be bent well without cracking. However, when it exceeds 0.01%, the bendability deteriorates rapidly, and cracks occur not only at a bending radius of 0.5 11 (t/2) but also at 180° bending of 1 ms+(t).

The present inventors accomplished the present invention based on these findings.

That is, the present invention first includes (1) O: 0.15% or less, H: 0.01% or less, N: 0.04% or less, Fe: 0.2% or less, and other unavoidable impurities and Ti. We have invented a titanium clad steel plate with good workability using pure titanium as the laminating material and steel as the base material.

Furthermore, depending on the application such as pressing, deep drawability is required for the base material that makes up the majority of the plate thickness, so we took this into account. (2) The base material has C: 0.1% or less, Si: 0 .1% or less.

(3) A titanium clad steel plate with good workability as described in item (1) above, which is a steel containing Mn: 0.5% or less, other unavoidable impurities, and Fe.(3) The base material is C: 0.1% or less, Si : 0.1% or less.

Mn: 0.5% or less, Af of 0.1% or less, 0.
We have invented a titanium clad steel sheet with good workability as described in item (I) above, which is a mesh containing at least 5% Ti, 0.5% or less Nb, and other unavoidable impurities and Pe.

In addition, the same effect is observed for titanium clad steel sheets manufactured using intermediate medium welding materials.For titanium clad steel sheets manufactured using intermediate medium welding materials, (4) The difference between the base metal mesh and the titanium interlayer between copper steel alloy,
(1) above, sandwiching an intermediate welding material such as nickel or pure iron;
We have invented a titanium clad steel sheet with good workability as described in (2) or (3).

The oxygen and hydrogen mainly limited in the titanium clad steel sheet according to the present invention are not sufficient if they are limited only by the material before cladding. That is, there is a possibility that it will invade titanium during the manufacturing process. Also titanium clad #! If manufacturing conditions are not properly controlled, intermetallic compounds at the interface of the plate will grow coarsely. Since intermetallic compounds generally have high hardness and poor workability, no matter how much workability of the titanium layer or base material is ensured, the workability of the titanium crand plate will deteriorate.

The present inventors focused on this point, reviewed the manufacturing process, and further accomplished the present invention. That is, (5) O: 0
．． 15% or less, H: 0.01% or less, N: 0.04% or less, Fe: 0.2% or less, and other unavoidable impurities and Ti. An intermediate bonding material such as copper, copper alloy, nickel, or pure iron is sandwiched in between, and the product is heated to a temperature of 700°C or more and 950°C or less, hot rolled, and then cold rolled to have a hydrogen content of 0.2% by volume or less. , oxygen content is 0.5% by volume or less, dew point is -25
A method for producing a titanium clad steel sheet with good workability, characterized by annealing at a temperature of 600°C or more and 750°C or less for a time of 0.2 min or more and 10 min or less in a nitrogen atmosphere at or below of the titanium clad steel sheet with good workability as described in item (5) above, which contains C: O, 1% or less, Si: 0.1% or less, Mn: 0.5% or less, and other unavoidable impurities and Pe. Manufacturing method, (7) Overlapping steel contains C: 0.1% or less, Si: 0.1% or less, Mn: 0.5% or less, and further A of 0.1% or less.
f.

The method for producing a titanium clad mesh plate with good workability as described in item (5) above, which contains one or more of 0.5% or less Ti, 0.5% or less Nb, and other unavoidable impurities and Fe, 8) The intermediate joint material is copper or a copper alloy containing 30% or more of copper, the heating temperature during hot rolling is 850°C or more and 950°C or less, and the metal is made of molten titanium and copper during hot rolling. (5) above, hot rolling while extruding the intermediate compound; (
6) or the method for producing a titanium clad steel sheet with good workability as described in item (7).

[For production]

Next, the limiting conditions and effects of the present invention will be explained.

As shown in Figure 1, the oxygen content in titanium is 0.
．． If it exceeds 15%, the bendability will begin to deteriorate rapidly.
The upper limit was set at 0.15%. The lower the oxygen content, the better the processability, but the cost for oxygen reduction also increases. Therefore, in industrial production, the lower limit is naturally set depending on the intended use and production volume, so there is no limitation in the present invention.

As shown in Figure 2, the hydrogen content in titanium is 0.
．． If it exceeds 0.01%, the bendability will deteriorate drastically, so
．． The upper limit was set at 0.01%. The lower the hydrogen content, the better the processability, but the cost for hydrogen reduction also increases. Therefore, in industrial production, the lower limit is naturally set depending on the intended use and production volume, so there is no limitation in the present invention.

When the amount of nitrogen in titanium is 0.04% or less, there is no significant influence on workability, but if it exceeds that amount, TiN precipitates and workability is reduced, so the upper limit was set.

Processing of thin steel plates ranges from light processing such as bending to heavy processing such as deep drawing. The C content of the base steel is 0.1% or less, and the Si
When Mn is limited to 0.1% or less and Mn to 0.5% or less,
Drawing processing becomes possible. Furthermore, the C content of the base metal steel is reduced to 0.
．． 1% or less, 53 0.1% or less, Mn 0.5%
Limited to the following, 0.1% or less 47! , 0.5% or less of Ti, and 0.5% or less of Nb improves deep drawability, such as making deep drawing possible.

In this case, Af, Ti, and Nb are each 0.1%.

0.5%. Even if it is added in excess of 0.5%, no further improvement in drawing property is observed, so the upper limit was set.

The heating temperature during hot rolling heating was set at an upper limit because if it exceeds 950° C., intermetallic compounds at the interface will grow, reducing the bonding strength and deteriorating the workability of the interface. In addition, heating below 700"C requires a large rolling mill blade for rolling, which not only requires huge equipment costs, but also increases rolling surface flaws, resulting in incomplete joints. In particular, when copper is used as an intermediate welding material and bonding is performed in the atmosphere using molten intermetallic compounds of titanium and copper, it is essential to generate and melt the intermetallic compounds. The lower limit temperature was set at 850° C., which is the temperature at which intermediate compounds are formed.

If the amount of hydrogen in the annealing atmosphere of nitrogen exceeds 0.2%, hydrogen will enter the titanium layer and deteriorate workability.
The upper limit was set at 0.2%. The lower the amount of hydrogen, the less it will penetrate into titanium, which will prevent deterioration in the workability of titanium clad steel, but will increase the cost. Therefore, in industrial production, the lower limit is naturally set depending on the intended use and production volume, so there is no limitation in the present invention.

If the amount of oxygen in the annealing atmosphere of nitrogen exceeds 0.5%, oxygen will enter the titanium layer and deteriorate workability.
The upper limit was set at 0.5%. The lower the amount of oxygen, the less it will penetrate into the titanium (this will prevent deterioration in the workability of titanium crush steel, but it will also increase the cost. Therefore, in industrial production, the usage and production volume Since the lower limit is naturally set by the above, the present invention does not limit the lower limit.

If the dew point temperature of nitrogen, which is an annealing atmosphere, exceeds 125°C, hydrogen and oxygen will enter the titanium layer and deteriorate workability, so -25°C was set as the upper limit. The lower the dew point, the less hydrogen and oxygen will penetrate into the titanium, which will prevent deterioration in the workability of titanium clad steel, but will increase the cost. Therefore, in industrial production, the lower limit is naturally set depending on the intended use and production volume, so there is no limitation in the present invention.

The annealing temperature should be set at 600°C as the lower limit because the softening and recrystallization of the steel will not proceed if it is less than 600°C, and if it exceeds 750°C, the growth of intermetallic compounds at the interface will progress and deteriorate the workability of the interface, so the lower limit should be 750°C. The upper limit was set.

In addition, if the annealing time is less than 0.2 min, it is difficult to control industrially and some unrecrystallized parts may remain locally.
．． The lower limit was set at 2 min, and if it exceeded 10 min, the growth of intermetallic compounds at the interface progressed and the workability of the interface deteriorated, so the upper limit was set at 1 min.

In the present invention, the amount of oxygen and hydrogen in the titanium layer is limited.

By limiting oxygen, the hardness of titanium itself decreased and its ductility increased, and the difference in deformability between titanium and steel that occurs at the interface became smaller, improving workability. Additionally, the limitation of hydrogen, which had not been considered in titanium clad steels, reduced the amount of hydrides in titanium and improved the ductility and toughness of titanium.

By limiting the hot rolling heating temperature, it is possible to suppress the growth of intermetallic compounds at the interface without impeding bonding properties, prevent fractures that occur from the interface, and exhibit the workability of titanium and base material steel. It became a thing.

By limiting the hydrogen, oxygen, and dew point of the annealing atmosphere, it was possible to prevent hydrogen and oxygen from entering the titanium, and it was possible to prevent deterioration of the workability of titanium.

By limiting the annealing temperature and time, it is possible to suppress the growth of intermetallic compounds at the interface while ensuring softening recrystallization, preventing fractures that occur from the interface, and demonstrating the workability of titanium and base material steel. It became a thing.

As explained above, the present invention improves the workability of titanium clad steel sheets, making it possible to process them into objects by bending and drawing.

[Example] Titanium whose chemical composition is shown in Table 1 and steel whose chemical composition is shown in Table 2 are combined and stacked as appropriate as shown in Table 3, and under the conditions also shown in Table 3. Titanium layer thickness 100~
A 130ulI titanium clad steel plate with a total thickness of 1.0 mm was manufactured. It was found that all of the examples of the present invention could be bent well by t/2 degrees, and had excellent workability.

In addition, when the steel composition of the base material is limited to the low C side, the punch tip angle can be drawn to RIO, and furthermore, IN! ,
When Ti and Nb were added singly or in combination, the punch tip angle was successfully reduced to R1.

Table 3 Tik and tlh numbers The chemical composition of the titanium part of the titanium clad steel plate manufactured by the manufacturing method shown in Table 3 corresponding to the numbers in Tables 1 and 2 is within the analytical precision except for Nα15 to 17. This coincided with the chemical composition analysis value of titanium as a raw material, and was consistent with the titanium clad steel of the present invention. However, Nα1
In 5, hydrogen is up to 0.0138%, in Nα16, oxygen is up to 0.17%, and in Nα17, hydrogen and oxygen are each 0.
．． It increased to 0.0110% and 0.16%, which was different from the titanium clad steel of the present invention. For this reason, N.

In steels Nos. 15 to 17, cracks occurred on the titanium surface during the bending test.

In addition, in the titanium clad steel sheets manufactured by methods No. 14 and 18 to 19 in Table 3, there was no particular change in the titanium components, but as a result of the bending test, there was a tendency for peeling at the interface between titanium and steel. The situation caused a crack.

Although the cause of this has not been clearly analyzed, it is presumed that the intermetallic compound at the interface has grown thick.

The titanium clad steel plate manufactured using the same method as described in <20.
Although the manufacturing conditions were within the appropriate range of the present invention, t/2 bending cracks occurred due to the high oxygen content in the titanium material.

[Effects of the Invention] As explained above, according to the present invention, a titanium clad steel plate with excellent corrosion resistance can be used even in the field of thin plates that require complicated shapes and processing. As a result, corrosion resistance is significantly improved, which extends the lifespan of utensils and provides significant industrial benefits such as material savings.

Furthermore, since maintenance can be significantly reduced, there are great economic benefits, and not only does surface staining disappear, but health and hygiene concerns associated with rusting are also eliminated.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the influence of the amount of oxygen contained in titanium on the bendability of titanium clad steel sheets, and Figure 2 is a diagram showing the influence of the amount of hydrogen contained in titanium on the bendability of titanium clad steel sheets. It is.

Claims (1)

[Claims] (1) O: 0.15% or less, H: 0.01% or less, N:
A titanium clad steel sheet with good workability, using pure titanium as a laminated material and containing 0.04% or less Fe, 0.2% or less Fe, and other unavoidable impurities and Ti, and using steel as a base material. (2) The base material is C: 0.1% or less, Si: 0.1% or less,
The titanium clad steel sheet with good workability according to claim (1), which is a steel containing Mn: 0.5% or less, other unavoidable impurities, and Fe. (3) The base material is C: 0.1% or less, Si: 0.1% or less,
Mn: 0.5% or less, further 0.1% or less Al, 0.
The titanium clad steel sheet with good workability according to claim 1, which is a steel containing one or more of 5% or less Ti, 0.5% or less Nb, and other unavoidable impurities and Fe. (4) Claim (1) in which an intermediate bonding material such as copper, copper alloy, nickel, or pure iron is sandwiched between the base material steel and the mating material titanium.
), (2) or (3), the titanium clad steel plate having good workability. (5) O: 0.15% or less, H: 0.01%
Hereinafter, pure titanium containing N: 0.04% or less, Fe: 0.2% or less, other unavoidable impurities and Ti is stacked on steel, or copper, copper alloy, nickel, etc. are placed between titanium and steel. Temperatures above 700°C9 with an intermediate welding material such as pure iron in between
After heating to 50°C or less and hot rolling, and then cold rolling, the hydrogen content is 0.2% by volume or less and the oxygen content is 0.5% by volume.
Hereinafter, a method for manufacturing a titanium clad steel sheet with good workability, characterized in that annealing is performed at a temperature of 600°C or more and 750°C or less for a time of 0.2 min or more and 10 min or less in a nitrogen atmosphere with a dew point of -25°C or less. . (6) Good workability according to claim (5), wherein the overlapping steel contains C: 0.1% or less, Si: 0.1% or less, Mn: 0.5% or less, and other unavoidable impurities and Fe. A manufacturing method for titanium clad steel sheets. (7) The overlapping steel contains C: 0.1% or less, Si: 0.1% or less, Mn: 0.5% or less, and Al containing 0.1% or less,
Claims containing one or more of 0.5% or less Ti, 0.5% or less Nb, and other unavoidable impurities and Fe (
5) The method for producing a titanium clad steel sheet with good workability as described above. (8) The intermediate joint material is copper or a copper alloy containing 30% or more of copper, the heating temperature during hot rolling is 850°C or more and 950°C or less, and titanium and copper are melted during hot rolling. Claim (5), (5) Hot rolling is carried out while extruding the intermetallic compound.
6) or the method for producing a titanium clad steel plate with good workability as described in (7).