JPH1161369A - Member for hot dip metal bath and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve corrosion resistance and wear resistance of a member used under an adversed condition like a roll journal part, which is immersed in a hot dip galvanizing bath, a hop dip Al bath, etc., and slides under a loading condition, and to extend a durable life in a continuous hot dip equipment, etc. SOLUTION: The hot dip metal bath member is formed with a dense cermet layer, which is made of a ceramic and heat resistant/corrosion resistant metal thermodynamically stable for a molten Al, on a base metal 10 surface, The ceramic preferably consists of one kind of two kinds or more among TiN, TiC, TiB2 , ZrN, ZrC, ZrB2 , NbC, VC, further, the heat resistant/corrosion metal preferably consists of Ti or Cr. The dense cermet layer is formed by a cladding by welding method, a thermal spray method and a HIP method, a member made of cermet only is formed by a HIP method. Equipment maintenance is made efficient and productivity of a hot dip steel sheet, etc., is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a member used in a molten metal bath and a method for producing the same in a continuous hot-dip plating facility for manufacturing a hot-dip Al-plated steel sheet, a hot-dip Zn-plated steel sheet, and the like. is there.

[0002]

2. Description of the Related Art Hot-dip Al-plated steel sheets and hot-dip Zn-plated steel sheets are produced by continuously immersing steel strips in these molten metal baths in a continuous hot-dip plating line. As an example of the hot-dip plating equipment, as shown in FIG.
Is continuously introduced into the pot 2, immersed in a molten metal bath 3 of Al, Zn, or the like, turned around by a pot roll 4 and led out. At this time, the lead-out line is kept constant by the support roll 5, and the amount of plating applied is controlled by the wiping nozzle 6.

In such continuous hot-dip plating equipment,
The pot 2, the pot roll 4, and the support roll 5 are required to have corrosion resistance to the molten metal bath 3. The pot roll 4 and the support roll 5 are connected to the molten metal bath 3.
Since it is rotatably supported inside, the roll bearing portion is also required to have wear resistance. The types of hot-dip plating include Zn-Al, Al
There is also an alloy plating such as -Si.

As a member having improved corrosion resistance and abrasion resistance in molten Zn or molten Zn-Al, Japanese Patent Application Laid-Open No.
No. 94048 discloses that a matrix containing 5 to 15% of Co and, if necessary, 10% or less of Cr contains
A member having a surface formed with a cermet layer in which one or more of C, WB, and MoB and, if necessary, one or more of TiC, NbC, MoC, and TiB ceramics are dispersed. Have been. As a means for forming the cermet layer, a plasma spraying method and a high-speed gas spraying method are disclosed.

Japanese Patent Laid-Open Publication No. Sho 52-146729 discloses a member having improved corrosion resistance in molten Al or molten Zn and improved adhesion to a substrate.
One or more of WC, CrC, TiC
1 contains 30% or more, and molten Zn contains 10% or more, with the balance being a heat-resistant metal such as Co, Ni, Si or A
A member having a surface coating layer made of an oxide such as l ₂ O ₃ , TiO ₂ and SiO ₂ has been proposed. As a means for forming the coating, a thermal spraying method is disclosed.

[0006]

In a continuous hot-dip plating apparatus, a pot roll 4 and a support roll 5 which are used by being immersed in a molten metal bath 3 of molten Al, molten Zn or the like have excellent wear resistance as well as corrosion resistance. Is required.
In particular, in the case where the amount of plating applied is controlled by the wiping nozzle 6 as shown in FIG. 1, the lead-out line of the steel strip 1 from the molten metal bath 3 is kept constant in order to enhance the control accuracy. Will slide under load. Further, in the hot-dip Al plating equipment used under severe conditions, the continuous operation period of the equipment is restricted by the uneven wear of the bearing part of the pot roll 4 in particular, and especially, the wear resistance of the roll bearing part is improved. Was desired.

The technique disclosed in Japanese Patent Application Laid-Open No. 3-94048 is directed to a member used by being immersed in a hot-dip Zn plating bath or a hot-dip Zn-Al plating bath containing about 2% of Al. Therefore, it is difficult to apply to a hot-dip Al plating bath at a higher temperature and a high reactivity with oxygen. In particular, for a member that slides under a load, such as a roll bearing of a pot roll or a support roll, there is a problem that a life extension effect cannot be expected due to abrasion resistance. Further, the technique disclosed in Japanese Patent Application Laid-Open No. 52-146729 discloses molten Al.
However, there is also a problem of wear resistance with respect to a member that slides under a load.

The present invention relates to a hot-dip Al-plated steel sheet or hot-dip Zn
For molten metal baths used under severe conditions, such as roll bearings immersed in a molten Zn bath or molten Al bath and slid under load in continuous hot-dip plating equipment for manufacturing plated steel sheets, etc. An object of the present invention is to improve the corrosion resistance and wear resistance of a member and extend the service life.

[0009]

According to a first aspect of the present invention, there is provided a member for forming a molten metal on a surface of a base metal.
A member for a molten metal bath, wherein a dense cermet layer made of ceramics and a heat-resistant and corrosion-resistant metal that is thermodynamically stable to 1 is formed. And the ceramic is TiN, TiC, TiB ₂ , ZrN, Zr
It is preferable that one or more of C, ZrB ₂ , NbC, TaC, and VC and unavoidable impurities are included, and the heat-resistant and corrosion-resistant metal is preferably formed of Ti or Cr and unavoidable impurities. Further, it is preferable that the dense cermet layer is formed by a build-up method or a thermal spraying method, and it is preferable that the dense cermet layer is formed by a hot isostatic pressing method.

A second invention member of the present invention is a member for a molten metal bath characterized by being formed of a dense cermet made of ceramics which are thermodynamically stable to molten Al and a heat-resistant and corrosion-resistant metal. And the ceramic is TiN, TiC, TiB ₂ , ZrN, ZrC, Zr
Preferably, one or more of B ₂ , NbC, TaC, and VC and inevitable impurities are included, and the heat-resistant and corrosion-resistant metal preferably includes Ti or Cr and inevitable impurities. Further, it is preferable that the dense cermet is formed by a hot isostatic pressing method.

Next, a first invention method of the present invention for achieving the above object is to provide a dense cermet made of a ceramic which is thermodynamically stable to molten Al and a heat-resistant and corrosion-resistant metal on a surface of a base metal. A method for manufacturing a member for a molten metal bath, comprising forming a layer to form a member having a predetermined shape. And the ceramic is TiN, TiC, Ti
B ₂ , ZrN, ZrC, ZrB ₂ , NbC, TaC, V
It is preferable that one or more kinds of C and inevitable impurities are included, and the heat-resistant and corrosion-resistant metal is preferably formed of Ti or Cr and inevitable impurities.
Further, it is preferable that the dense cermet layer is formed by a build-up method or a thermal spraying method, and that the dense cermet layer is formed by a hot isostatic pressing method.

The second invention method of the present invention is characterized in that a dense cermet made of ceramics and a heat-resistant and corrosion-resistant metal which is thermodynamically stable with respect to molten Al is formed into a member having a predetermined shape. This is a method for producing a metal bath member.
And the ceramic is TiN, TiC, Ti
B ₂ , ZrN, ZrC, ZrB ₂ , NbC, TaC, V
It is preferable that one or more kinds of C and inevitable impurities are included, and the heat-resistant and corrosion-resistant metal is preferably formed of Ti or Cr and inevitable impurities.
Further, the dense cermet is preferably formed by a hot isostatic pressing method.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A molten metal bath member according to the present invention is used by being immersed in a molten metal bath 3 in a molten metal plating facility or the like as shown in FIG. 5 mag is the target. In particular, it is effective to use the roll bearings of the pot roll 4 and the support roll 5. The molten metal includes molten Al for plating, molten Zn, molten Zn-Al, molten Al-Si, and the like. In addition, members that are immersed in or contact with various molten metal baths can also be targeted.

As an example of the roll bearing, a pot roll 4
As shown in FIG. 2, the shaft of the pot roll 4 is supported by a hanger 9 via a sleeve 7 and a bush 8, and the sleeve 7 and the bush 8 slide as shown in FIG. Therefore, it is particularly effective to apply the molten metal bath member of the present invention to the sleeve 7 and the bush 8 of such a roll bearing.

The first member of the invention is, as exemplified in FIG.
A cermet layer 11 is formed on the surface of a base metal 10, and the cermet layer 11 is a dense cermet made of ceramics and a heat-resistant and corrosion-resistant metal that are thermodynamically stable to molten Al. The dense cermet is a cermet having few pores formed by a cladding method or a thermal spraying method, or a cermet having almost no pores as produced by a hot isostatic pressing method.

A ceramic which is thermodynamically stable with respect to molten Al is defined as a free energy of formation ΔG at an operating temperature.
However, in the case of carbide, it is smaller than ΔC of AlC, for example, TiC, ZrC, NbC, TaC, VC, etc.
In the case of nitride, it is smaller than ΔG of AlN, for example, TiN, ZrN or the like. In the case of boride, the material is smaller than ΔG of AlB, for example, TiB ₂ or ZrB ₂ .

Since ΔG of AlC is smaller than ΔG of ZnC, ΔG of AlN is smaller than ΔG of ZnN, and ΔG of AlB is smaller than ΔG of ZnB, the above carbides, nitrides and borides are converted into molten Zn. Also thermodynamically stable. Further, these carbides, nitrides, and borides are thermodynamically stable to molten Zn—Al and molten Al—Si.

The heat and corrosion resistant metal is a metal having heat and corrosion resistance in molten Al, and may be a pure metal such as Ti or Cr, or an alloy such as NiCr, NiCrBSiFe or MCrAlX. preferable. Here, M of MCrAlX indicates a main constituent metal or alloy of a Fe group element and a high melting point metal element or a combination thereof, and Ni, Co, Fe, Ti, V, Z
r, Ta, Ni-Fe, Ni-Co, etc., X is Al, Cr
And Y, Hf, Sc, Ta, Zr, Ti, and the like. The base metal is SCH2 specified in JIS G 5122.
For example, heat-resistant cast steel such as No. 2 can be employed.

Further, the first invention member includes the cermet layer 1 described above.
Preferably, 1 is formed by a cladding method or a thermal spraying method. Examples of the thermal spraying method include a plasma spraying method, a reduced pressure plasma spraying method, an explosive spraying method, and a high-speed gas spraying method (HV).
OF method) or the like can be employed. Preferably, the cermet layer 11 is formed by a hot isostatic pressing method. The thickness of the cermet layer 11 is 0.1 mm or more.
Preferably it is 5 mm.

The second invention member is formed only of the cermet. The cermet is a dense cermet made of ceramics that are thermodynamically stable to molten Al and a heat-resistant and corrosion-resistant metal, as in the first invention member. Dense cermets are porosity-free cermets, such as those produced by hot isostatic pressing. The same ceramics and metals as those used in the first invention member can be used for forming the cermet.

Next, in the first invention method, as illustrated in FIG. 3, a cermet layer 11 is formed on the surface of a base metal 10 to form a member having a predetermined shape. As the cermet layer 11, as described in the first invention member, a dense cermet made of ceramics and a heat-resistant and corrosion-resistant metal that is thermodynamically stable to molten Al is formed. It is preferable that the thickness of the cermet layer 11 be 0.1 mm to 5 mm.

It is preferable that such a dense cermet layer is formed by a cladding method or a thermal spraying method. As the thermal spraying method, a plasma thermal spraying method, a low pressure plasma thermal spraying method, an explosive thermal spraying method, a high-speed gas thermal spraying method (HVOF method) or the like can be adopted. The cermet layer 11 having very few pores can be obtained by the overlaying method or the thermal spraying method. Further, it is preferable to form by hot isostatic pressing. In the hot isostatic pressing, the cermet layer 11 having almost no pores is obtained.

In the second invention method, a member having a predetermined shape is formed only by the cermet. As a cermet,
As described in the first invention member, a dense cermet made of ceramics and a heat-resistant and corrosion-resistant metal that is thermodynamically stable to molten Al is formed. Such a dense cermet is preferably formed by hot isostatic pressing. According to the hot isostatic pressing method, a cermet having almost no pores can be obtained.

[0024]

EXAMPLES Table 1 shows the cermet forming means, metal components and ceramic components of the cermet, their ratios, and the thickness of the cermet for the first invention example, the second invention example and the comparative example of the present invention. Table 1 summarizes the corrosion resistance and wear resistance test results and their evaluation. Both have a diameter of 50
A cylindrical sample having a length of 100 mm and a length of 100 mm was prepared.

No. 1 to No. 8 of the first invention are heat-resistant cast steel SC
A cermet layer 11 is formed on the outer peripheral surface of a base metal 10 made of H22 by a cladding method, a thermal spraying method and a hot isostatic pressing method (HIP method). The metal components and ceramic components of the cermet and their ratios are as shown in Table 1.

In the cladding method, a granulated powder having an average particle size of 150 μm, which is composed of a ceramic powder and a metal powder mixed in the ratio shown in Table 1, is applied to the outer peripheral surface of the base metal 10 by plasma welding. Two layers of beads were formed by the powder welding overlay method. In the thermal spraying method, granulated powder having an average particle diameter of 20 μm to 40 μm, which is composed of a ceramic powder and a metal powder mixed in a ratio shown in Table 1, is coated on the outer peripheral surface of the base metal 10 by hydrocarbon (C ₃ H ₈ ). -Formed by a high-speed gas spraying method (HVOF method) using the combustion energy of oxygen.

In the hot isostatic pressing method, first, a particle size of 0.1
Ceramic powder of about 10 to 10 μm and particle size of 0.1 to 5
A metal powder of about 0 μm was prepared, mixed at a ratio shown in Table 1, mixed and adjusted for raw materials, and mixed by a mixing stirrer so as to obtain a homogeneous mixed state. This was granulated by a rotary press granulator, and further sintered, pulverized and classified to adjust to a granulated powder having a particle size of 3 to 8 mm. This was mechanically pulverized by a stamp mill under an Ar atmosphere and classified to obtain a powder material having a size of 250 μm or less.

Next, the composite powder thus produced was filled in a HIP can together with the base metal at a temperature of 1200 ° C. However, when the composite powder contained Ti, the temperature was 1400 ° C., the pressure was 1200 kgf / cm ² , and the holding period was 180 minutes. The cermet layer 11 was formed on the outer peripheral surface of the base metal 10 by hot isostatic pressing. No. 9 and No. 10 of the second invention are examples in which a base material is not used and only the above composite powder is filled in a HIP can to form a member consisting only of cermet.

The No. 11 and No. 12 comparative examples use ceramics that are not thermodynamically stable to molten Al on the outer periphery of the base metal 10 as in the first invention example. No. 11 was formed by a plasma spraying method using Cr ₃ C ₂ as a ceramic component, and No. 12 was formed by an explosive spraying method using WC as a ceramic component. No. 13 of the comparative example shows that the heat-resistant and corrosion-resistant metal M
An o-6.4B layer was formed by explosive spraying.

In Table 1, the cermet metal component NiCrBSiFe is 17% Cr, 3%
Alloy containing B, 4% Si, 5% Fe, CoNiCrAl
Y is 32% Ni, 21% Cr, 8% A on Co base
1, alloy containing 0.5% Y, NiCr is 2% on Ni base
An alloy containing 0% Cr.

For each of the examples shown in Table 1, immersion tests and abrasion tests in a molten metal bath were performed, and the results of evaluating corrosion resistance and abrasion resistance are shown in Table 2. In the immersion test, after immersion in a molten metal bath at a predetermined temperature for a predetermined time, the state of damage on the member surface was observed and evaluated. Condition 1 was for 1000 hours in a molten metal bath containing Zn as a main component at a temperature of 470 ° C., and Condition 2 was for 100 hours in a molten metal bath containing Al as a main component at a temperature of 680 ° C. is there. In the evaluation of the corrosion resistance by this immersion test, those with no damage such as erosion were marked with a circle, and those with damage were marked with a cross.

In the wear test, a stainless steel sample having a width of 10 mm, a thickness of 10 mm and a length of 100 mm was pressed against a surface of a cylindrical sample having a diameter of 50 mm and a length of 100 mm in a molten metal bath at a predetermined temperature under a load of 50 kg. While the sample is 100rpm
The specific wear after rotation for a predetermined time was measured. Here, the specific wear amount = sample wear volume / (sliding distance × load applied), and each unit is such that the sample wear volume is mm ³ ,
The sliding distance is mm, the applied load is kg, and the specific wear is mm ² / k
g.

The condition 1 of the wear test was performed in a molten metal bath containing Zn as a main component at a temperature of 470 ° C. The condition 2 was
The test was performed in a molten metal bath containing Al as a main component at a temperature of 680 ° C. Evaluation of abrasion resistance was 1 × 10 under condition 1.
^-6 or less, 、 １: 1 × 10 ^-5 or less, ○: 1 × 10 ^{-5 or} more, ×: Under condition 2, 1 × 10 ^-5 or less: ◎, 1 × 10 ^-4 or less: 1 × 10 ^{− More} than ^{4 was} marked as x. In addition, the comprehensive evaluation combining the corrosion resistance and the abrasion resistance was as follows: ◎ when the corrosion resistance was か つ and the abrasion resistance was ◎, ○ when the corrosion resistance was か つ and the abrasion resistance was ○, In the case where the abrasion resistance was "x" in "x", "x" was given.

As is clear from Tables 1 and 2, both the first and second invention examples of the present invention show excellent corrosion resistance and abrasion resistance. Above all, No. 9 and No. 10 of the second invention example comprising only the cermet by the hot isostatic pressing method, and No. 8 of the first invention example in which the cermet layer was formed by the hot isostatic pressure method, exhibited wear resistance. The properties are particularly excellent. Further, No. 1 and No. 3 of the first invention example in which the metal component of the cermet layer is Ti or Cr also have particularly excellent wear resistance.

No. 11 and No. 12 of the comparative examples were made of molten Zn
Under condition 1 for the bath, no damage was observed in the immersion test, but in the wear test, the specific wear amount was high and the wear resistance was poor. Under Condition 2 for the molten Al bath, the coating was melted in both the immersion test and the abrasion test. In addition, N of the comparative example where metal was sprayed instead of cermet
In o.13, under both conditions 1 and 2, the coating was eroded in both the immersion test and the abrasion test.

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

According to the first invention member of the present invention, a dense cermet layer made of ceramics and a heat-resistant and corrosion-resistant metal which is thermodynamically stable to molten Al is formed on the surface of a base metal; Since the second invention member is formed only of the dense cermet, such as a roll bearing portion immersed in a molten Zn bath or a molten Al bath and slid under load in a continuous hot-dip plating facility or the like, Corrosion resistance and wear resistance of members used under severe conditions are improved, and the service life can be extended. The production is carried out by the established existing cladding method, thermal spraying method or hot isostatic pressing method (H
IP method). Therefore, the continuous operation period is extended, equipment maintenance is made more efficient, and productivity of plated steel sheets and the like is improved.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an example of a continuous hot-dip metal plating facility to which the present invention is applied.

FIG. 2 is an explanatory diagram illustrating an example of a roll bearing unit to which the present invention is applied.

FIG. 3 is a sectional view showing an example of the member of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Steel strip 2 ... Pot 3 ... Molten metal bath 4 ... Pot roll 5 ... Support roll 6 ... Wiping nozzle 7 ... Sleeve 8 ... Bush 9 ... Hanger 10 ... Base metal 11 ... Cermet layer

Claims (18)

[Claims] 1. A member for a molten metal bath, wherein a dense cermet layer made of ceramics and a heat and corrosion resistant metal which is thermodynamically stable to molten Al is formed on a surface of a base metal. 2. The method according to claim 1, wherein the ceramic is TiN, TiC,
TiB ₂ , ZrN, ZrC, ZrB ₂ , NbC, Ta
2. The member for a molten metal bath according to claim 1, comprising one or more of C and VC and unavoidable impurities. 3. The heat-resistant and corrosion-resistant metal is Ti or Cr.
3. The member for a molten metal bath according to claim 1, wherein the member is made of unavoidable impurities. 4. The member for a molten metal bath according to claim 1, wherein the dense cermet layer is formed by a cladding method or a thermal spraying method. 5. The molten metal bath member according to claim 1, wherein the dense cermet layer is formed by hot isostatic pressing. 6. A molten metal bath member characterized by being formed of a dense cermet made of ceramics which are thermodynamically stable to molten Al and a heat-resistant and corrosion-resistant metal. 7. The method according to claim 7, wherein the ceramic is TiN, TiC,
TiB ₂ , ZrN, ZrC, ZrB ₂ , NbC, Ta
The member for a molten metal bath according to claim 6, comprising one or more of C and VC and unavoidable impurities. 8. The heat and corrosion resistant metal is Ti or Cr.
8. The member for a molten metal bath according to claim 6, wherein the member is made of unavoidable impurities. 9. The method according to claim 6, wherein the dense cermet is formed by hot isostatic pressing.
9. The member for a molten metal bath according to 7 or 8. 10. A member having a predetermined shape is formed on a surface of a base metal by forming a dense cermet layer made of ceramics and a heat and corrosion resistant metal which is thermodynamically stable to molten Al. A method for producing a member for a molten metal bath. 11. The method according to claim 11, wherein the ceramic is TiN, TiN.
C, TiB ₂ , ZrN, ZrC, ZrB ₂ , NbC, T
The method for producing a member for a molten metal bath according to claim 10, comprising one or more of aC and VC and unavoidable impurities. 12. The heat and corrosion resistant metal is Ti or C.
The method for producing a member for a molten metal bath according to claim 10, comprising r and unavoidable impurities. 13. The method according to claim 10, wherein the dense cermet layer is formed by a cladding method or a thermal spraying method.
13. The method for producing a member for a molten metal bath according to 11 or 12. 14. The method according to claim 10, wherein the dense cermet layer is formed by hot isostatic pressing.
13. The method for producing a member for a molten metal bath according to 11 or 12. 15. A method for manufacturing a member for a molten metal bath, comprising forming a dense cermet made of ceramics and a heat-resistant and corrosion-resistant metal which is thermodynamically stable with respect to molten Al to obtain a member having a predetermined shape. 16. The method according to claim 1, wherein the ceramic is TiN, TiN.
C, TiB ₂ , ZrN, ZrC, ZrB ₂ , NbC, T
The method for producing a molten metal bath member according to claim 15, comprising one or more of aC and VC and unavoidable impurities. 17. The heat and corrosion resistant metal is Ti or C.
The method for producing a member for a molten metal bath according to claim 15 or 16, comprising r and unavoidable impurities. 18. The method according to claim 15, wherein the dense cermet is formed by hot isostatic pressing.
18. The method for producing a member for a molten metal bath according to 6 or 17.