JPH0475791A - Production of clad steel plate - Google Patents

Abstract

PURPOSE:To save stages and energy by welding a baser metal having a specific component compsn. to a cladding metal consisting of a stainless steel, etc., to assemble a slab and rolling the slab at a specific heating temp., draft and rolling end temp. then cooling the slag at a specific cooling rate from a specific temp. after air cooling. CONSTITUTION:The cladding metal 2 is constituted of the stainless steel or nickel alloy. The base metal 1 is constituted of the compsn. which contains, by weight %, 0.01 to 0.12% C, 0.6 to 1.9% Mn, 0.01 to 0.05% Nb, 0.01 to 0.025% Ti, etc., satisfies <= 0.40% in formula I and contains the balance Fe. The slab is assembled by welding 5 of the cladding metal 2 and the base metal 1. After this slab is heated to 1100 to 1250 deg.C, the slab is rolled at >= 5 draft and 850 to 1050 deg.C rolling end temp. The slab is then cooled down to an arbitrary temp. at 5 to 40 deg.C/sec cooling rate from the high temp. of <= 750 deg.C after air cooling for 60 to 300 seconds. The product of a low cost is provided in this way.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention uses a high alloy material with excellent corrosion resistance such as stainless steel or nickel alloy for the laminates 1 and 1, and a low alloy steel as the base material. , relates to a method of manufacturing clad steel by rolling.

(Prior art) In general, pipes and structural materials used in chemical 7TX, oil and gas wells are required to have excellent corrosion resistance. 46 is shorter in low-alloy steels, and stainless steel or nickel alloys are used, and this tends to increase. However, these high alloy materials are very expensive;
Due to its low strength, when designing structures, thicker walls (7
This results in high layer costs. For this reason, high 8-karat gold thalassod steel has been attracting more and more attention recently.
There are 7. High-alloy clad steel is extremely useful for the above purpose because it has both corrosion resistance, high strength, and high toughness.

This type of steel plate is made of stainless steel or nickel alloy to provide corrosion resistance, and the base material is low alloy steel to ensure strength and toughness.
Manufactured by means such as rolling, welding, and explosive welding. The most common manufacturing method is compression by hot rolling, but if the cladding is hot rolled, it will elongate 1. This results in an austenitic structure, which deteriorates corrosion resistance. In order to improve this, the high alloy clad steel plate after rolling is subjected to solution treatment 17.

For example, in Japanese Patent Publication No. 2-5217, Ceq≦0.4
5% low alloy steel as base material] 7. After hot rolling clad steel made of stainless steel or nickel alloy as base material, 850 ~
- It is disclosed that solution treatment is performed at a temperature of 113% or less and N: 0.006%.

Since solution treatment for rad steel is a treatment of dissimilar materials, it is difficult to treat both materials under conditions that are effective.Usually, the main body of this treatment is stainless steel or high-grade materials such as nickel alloys. In other words, even if the corrosion resistance of alloy crat materials is improved, the strength of the base material may be insufficient or the toughness may not be improved.

(Problem to be solved by the invention) The solution treatment described above consumes a large amount of engineer and thermal energy, and the benefit of omitting it is extremely large. The present invention provides high strength and high toughness steel L/S steel or nickel-based high alloy clad steel sheet that has excellent corrosion resistance as hot-rolled without the need for solution treatment such as No. 52. The purpose is to provide

(Means for Solving the Three Problems) In order to achieve the above object, the present invention has the following configuration. That is, <1) Stainless steel 1, a laminated shrine made of copper or nickel alloy, and C: 0.01-0.12%, Si + 0.5% or less, Mn: O, [li ~ 1.99o] , P:
0.02% or less, S: 0.0015% or less,
Nb: 0.01-〇, 05%, Ti: 0.010
~0.025%, A, l/: 0.05% or less, N:
Contains 0.008% or less, and cE (carbon equivalent) -
C+Mn/6+ (Cr 10Mo +V) /15~1
- Satisfies (Ni + Cu)/15 or 0.40% or less1
2. Assemble a slab by welding the base metal, the remainder of which is Fe and unavoidable impurities, and heat this to 1100-125% or less, N: 0.006%, rolling reduction ratio of 5 or more, rolling end temperature 850-105% % or less, rolling with N: 0.006%
- 75% or less after air cooling for 160 to 300 seconds, N: 0
．． A method for manufacturing a clad steel sheet, characterized in that it is cooled from a high temperature of 0.006% or higher to an arbitrary temperature at a cooling rate of 5 to bsee, and (2) a cladding material made of stainless steel or a nickel alloy, and a So C: 0. Old ~ 0.12%, Si: 0.5% or less, M
n + 0.6 to 1.9%, P, 2% or less,
S: 0.0015% or less, Nb:O, old ~ 0
, 05%, Ti: 0.010-0.025%, A
, [7: 0.05% or less, N: O, 0OG9fi or less, further, v: 0.01-0.1%, Ni: 0.05-1.
0%, Cu: 0.05-0.6%, Cr
: 0.05~1. Mouth%, Mo + 0.05
~0.5? o, Ca: 0.001”0.0
05% of one or more types, and CE (carbon equivalent)"C+Mn/6→ (Cr +
Mo +V)/15+ (Ni →-CI)/15 is 0
．． 40% or less j2, the balance consists of Fe and unavoidable impurities, and the base material is welded l~ to assemble a slab, and after heating it to 1100 = 125% or less, N: 0.006%, the reduction ratio is 5 or more, Rolled at a rolling finish temperature of 850-105% or less, N: 0.006%, and air-cooled for 60-300 seconds.
A clad steel plate characterized by cooling from a high temperature to an arbitrary temperature at a cooling rate of 5 to 4% or less, N: 0.006%/sec. This is the shiso making method.

The stainless steel of the present invention refers to austenitic, ferritic, martenzite, two-phase, etc., and the nickel alloy is a nickel alloy such as Incoloy 825 and Incoloy 625, which is a material with excellent corrosion resistance. It is. In addition, the base material has the above-mentioned components, especially CE (carbon equivalent) of 0.4.
Specify the range of 09ゎ or less 2, target strength at 1~XBD-X65 (API standard), toughness 2vE
-: 3% or less, N: 0.006%>716Hf-m, and is a low alloy copper with high strength and high toughness.

The present invention will be explained in detail below.

The present invention involves assembling rat materials as shown in Figure 1, that is, placing a laminate material (hereinafter the laminate material after being rolled into a clad steel plate will be referred to as cladding material) 2 on the surface of a base material 1. A vacuum device 4 connected to a perforation 3 that communicates from the side of the base material 1 to the bonding surface joins the four circumferences of the joining material 2 to the base material 1 while eliminating air present at the joint surface of the art materials. A cladding material slab is constructed by welding 5 using a welding material suitable for the phase component.
It is preferable to clean the surface of the adhesive surface by rough degreasing or polishing.

It may be possible to hot-roll the slab assembled in this way, but warping may occur due to the difference in linear expansion coefficient between the base material and the composite H, resulting in incompatibility with the clad steel plate product in 17. Therefore, as shown in the partial cross section of Fig. 2, two sets of cladding materials (A) and (B) were prepared, and the surfaces of the cladding materials (A) and (B) were brought into close contact with each other, and they were welded all around. , to form a sandwich-like slab 1-1, and apply pressure g-d. At this time, if a coating material 6 is applied between the slab mating materials, the clad steel plates can be easily separated after rolling. In addition, the four-circumference welding is performed by direct TIG or MI
G multi-layer welding may be performed, but cracks may occur due to boundary separation due to different types of multi-layer welding. Therefore, as shown in FIG.
By welding 1 and 1 with a metal-based welding rod, there is no interference with the welding material 5 and the welding material 5, and the occurrence of cracking can be prevented.

The present invention is based on the above 1. The assembled slab formed as described above is heated 17, the heating temperature is 1100-125% or less, N: 0
．． This is necessary in order to simultaneously maintain the corrosion resistance of the laminate and the strength and toughness of the base material. Specific 1. ': Lower limit temperature 110% or less, N: 0.006%
To ensure that the rolling end temperature is 85% or less, N: 0.006% or more, and to improve the corrosion resistance of the laminated material, especially when the laminated material is stainless steel, the minimum heating to dissolve Cr carbide is necessary. It's temperature. When the L'lJ-L heating temperature is 125% or lower and N: 0.006% or higher, soustenite grains become coarse and deteriorate. However, the heating temperature is preferably within the above-mentioned range, and the sandwich-like stacked clad slab is rolled at a rolling reduction ratio of 5 degrees or more. Figure 3 shows heating temperature ('C)
The relationship between and rolling reduction ratio (clad slab thickness 5/finished clad steel plate thickness) showed the adhesion between the base material and the laminate. For the laminating material: ＼STEROY C276 (60%N i 1
5% Cr 15% Mo system), and the cladding ratio (cladding material thickness/clad steel sheet metal thickness) 10.6~) and 1~
Eight side bending test pieces were taken from each clad steel plate that had been rolled at each heating temperature and reduction J and t, and the side bending test was performed on the clad steel plate after rolling to evaluate the adhesion 1-t-8. As shown in FIG.
% or less, N: 0.006%, and the reduction ratio is 5 or more, it can be seen that good adhesion can be obtained in all cases.

1. (1-1) Adhesion deteriorates as the heating temperature decreases, and peeling of the adhesive surface increases in side bending tests. Therefore, if the heating temperature is low, it may be necessary to increase the reduction ratio.

At the lower limit of the heating temperature of 1100° C. in the present invention, good adhesion can be obtained by setting the pressure F ratio to 8 or more.

Next, in the present invention, the rolling of the clad steel plate is 850-105%.
Hereinafter, the N: 0.006% range is used.

That is, it is assumed that rolling is not performed at a temperature of 85% or less and N: 0.006% or less.

It is intended to ensure the corrosion resistance necessary for the damper material by finishing rolling at a temperature of 85% or less and N: 0.006% or more. However, if the rolling end temperature is too high, the orstenite grains will become coarser, which is not necessarily desirable, especially in terms of the strength and toughness balance of the base metal, and the J-limit temperature should be set to 105% or less, N: 0.006%
and 1. Ta.

Figure 4 shows Incoloy 825 (40%N i
-200oCr -3%M0 series), the rolling end temperature (water cooling performed after rolling), the microstructure of the laminate, and the corrosion resistance evaluation results are shown in Figure 5.
Hereinafter, the microstructure of the N: 0.006% material (A) is not a complete recrystallized structure, and the rolling end temperature is 940''C.
: The sample (B) has a recrystallized structure. The corrosion resistance evaluation results also correspond to the microstructure, that is, the rolling finish temperature is 82% or less, and the pitting corrosion test temperature is 35°C for N: 0.006%.
Pitting corrosion occurred in 2 out of 3 samples. On the other hand, a material with a rolling finish temperature of 94% or lower and an N content of 0.006% shows good corrosion resistance with no pitting occurring even at 35°C. From the viewpoint of corrosion resistance, the rolling finish temperature is preferably within the above range (- .

Next, after finishing rolling, air cooling I7 for 60 to 300 seconds, then 75
% or less, N: 5-b from a high temperature of 0.006% or more. Setting the air cooling time after rolling is the main point of the present invention in order to make the recrystallization of the laminate more effective. In other words, according to the study results of the present inventors, several publications have shown that the corrosion resistance can be further improved by setting the air cooling time within the above range after the completion of rolling and after the recrystallization has finished rolling. . The higher the rolling end temperature, the shorter the air cooling time may be, and the lower the temperature, the longer the air cooling time. (7) However, if it is too long, C carbides will precipitate during air cooling, so it is preferable that the air cooling time be within the above range.

In addition, by rapidly cooling from a high temperature of 75% or less and N: 0.006% or more to a desired temperature, it is possible to not only suppress the precipitation of carbides in the laminated material, but also suppress the precipitation of carbides in the laminate. When the cooling rate, which is most important for maintaining toughness, is less than 5τ:/sec, the effect of refining the matrix structure is particularly small. On the other hand, if the cooling rate is too fast, the cooling rate is too high and the host H structure tends to become a bainite structure, which deteriorates the toughness.

Therefore, the cooling rate is preferably within the above range. Note that the cooling stop temperature is not particularly limited in the present invention, but it is preferable to set it to GOO"C: or less. Also, for cooling, the method using water pressure is recommended because it is simple in terms of equipment and allows controlled cooling. .2 or (7) It is not limited to this.

The components of the base material of the present invention are specified below (2 houses - the reason will be explained).

C is required in an amount of o, oi% or more to ensure the desired strength in the base metal, but if the amount increases, weldability and HAZ toughness deteriorate. Also, since it affects the low-temperature toughness of the base metal, O
, 129o was set as 7th period.

Sl is an element included in the steel for deoxidation purposes, but when added in large quantities, it deteriorates the HAZ toughness. 0.5% for that
The following was made.

Mn is added in an amount of 026° or more to maintain strength and toughness. In addition, Mn has the effect of suppressing the formation of coarse pro-eutectoid phallite at the γ grain boundaries and improving the toughness of the base metal, and has the effect of improving the HAZ toughness, but when the amount is large, the hardenability improves. This results in deterioration of weldability and HAZ toughness. Therefore, the upper limit was set at 1.9%.

P is included as an impurity, and in order to prevent the occurrence of weld metal cracking due to micro-segregation, the content should be kept as low as possible.

S is also an impurity element, but its inclusion in large amounts forms coarse sulfide-based inclusions12 and reduces the toughness of the base material. Especially Mn
It forms S and absorbs hydrogen, which can cause cracking, so it is useful for steels that require sour resistance. For this reason, it is preferable to reduce L as much as possible to less than 0.0015%.

Nb is an element that forms nitrides and carbides, and is finely precipitated to improve the toughness of steel. Also, excellent HAZ
It is an essential element for obtaining toughness, and has the effect of suppressing the formation of tuborite at the γ grain boundaries and promoting the formation of fine intragranular acicular ferrite with Ti2O3 as the nucleus.

Therefore, 0.01% or more is required. 1. Kashi 0
If the amount exceeds 0.05%, the above effects tend to be hindered.

Tj is the formation of fine TiN in the steel L7, when heating the slab,
Is it effective in controlling the coarsening of austenite grains during welding and improving base metal toughness and HAZ toughness? If it is less than 0.01%, no effect can be expected. However, if there is too much, TIC and the like will be formed, resulting in negative effects. That t second 1
The second limit was set at 0.025%.

AΩ is usually added together with a deoxidizing agent. Nitride formation also helps refine the knee steel. That t5~Meni0,05
It is permissible to add up to %.

N is an impurity element, and the less it is, the better.
006% indicates the allowable -L limit.

V, Ni, Cu, Cr, Mo, and Ca are elements added as necessary. Like Nb, V is added to improve HAZ toughness, and Ni also improves base material strength and toughness. Cu has no effect on corrosion resistance, hydrogen-induced cracking resistance, etc. In addition, C is added as an element that can increase the strength of the base metal and welded joint, and Mo is also added as an element that can improve the base metal strength and toughness.These are effective in their respective ranges.Ca is Suppresses the form of sulfide (MnS),
In addition to improving low-temperature toughness, it also has the effect of improving hydrogen-induced cracking when used in line pipe materials, etc. For that purpose, 0.001 to 0.005 Qo is added.

In the present invention, CE is set as carbon equivalent. This is to adjust the addition of elements that affect hardenability, and if it exceeds 049o, the hardenability becomes excessive, and as a result, it only affects the increase in strength, resulting in significant deterioration of toughness, which is preferable. do not have. In the present invention, the rolling end temperature is set to 11, which is higher than that of ordinary steel sheets, and it is necessary to cool from a relatively high temperature, so it is preferable to set the CE value as low as possible within a range that can ensure the target strength ( ,stomach.

(Example) The present invention base material component (8) shown in Table 1 and the conventional component (B
) slab (slab thickness 144.5 mm) L, the surface of the laminated material shown in Table 2 (laminated material thickness 25.5 mm) was polished and degreased, and a clad slab was assembled using the method shown in Figure 1. Using the method shown in Figure 2, a clad slab of Xandwich quibs was assembled by stacking them in a Zandwich shape and applying a separated phase in the middle. Its slab size (unit brewing) is 340 tons
x 100OW x 1%0 N-, and a clad steel plate was manufactured under the rolling conditions shown in Table 3. The rolling reduction ratio at this time was 85 and j~t, 2.

The obtained clad steel plate size is 40t x 18GO
Vll' (execution of tentering) The strength and toughness of the base metal and the corrosion resistance of the laminate were investigated.

The evaluation of adhesion was carried out on a material of N-shape classification A with a rolling finish temperature of 9%°C. The test is shown in Figure 6.

The shear strength test method of JIS GO601 was used to test clad steel, and the results are shown in the figure.

The heating temperature and rolling pressure f ratio are within the range of the conditions of the present invention. : i,
Since it is y, its shear strength is 40 kg in both Ch directions.
f/lIi or less (7, extremely good).

Table 3 also shows the rolling winter crop of the clad slab and the grain yield of the steel plate base material. The base material category A may be the material of the present invention, or may have good results in both strength and toughness within the manufacturing conditions of the clad steel plate presented earlier1, whereas the base material of the conventional component has a high Although the strength was achieved (7), the toughness showed a very poor result.As shown in Table 1, this is because the CE (carbon equivalent) is high, so W4 is not suitable for the rolling conditions of the present invention. In addition, Table 3 also shows the evaluation results of the corrosion resistance of the cladding material, which is outside the condition range of the present invention, that is, only the 821) °C material with the end of rolling temperature has a bad result, and the results are poor in the other condition ranges. All of them had good corrosion resistance.

1-However, in order to omit the solution treatment of the clad steel plate after rolling and to simultaneously improve the strength, toughness, and corrosion resistance of the cladding material, it is necessary to Is it necessary to limit the conditions?

(Effects of the invention) According to the present invention, by specifying the rolling conditions, it is possible to produce high-grade iris metal with excellent toughness, corrosion resistance, strength, and toughness, which previously required solution treatment. In the present invention, since it can be omitted, energy saving can be achieved, and the industrial effect is extremely large. At the same time, it is also a great advantage to be able to provide low-cost products.

[Brief explanation of drawings]

Figures 1 and 2 are schematic explanatory diagrams showing (partially) the assembled state of the clad steel of the present invention, Figure 3 is a diagram showing the relationship between heating temperature and pressure F ratio regarding the adhesion state, and Figure 4 Figure (A),
(B) shows the L7 structure at different rolling end temperatures of the cladding material, and FIG. 5 is a diagram showing the relationship between the rolling end temperature and corrosion resistance (pitting corrosion resistance) of the cladding material. 61st m
is a diagram showing the shear strength of cladding material-1 in different test directions. Multi-agent patent attorney Hiroaki Tamura tr370I! l0qO/θoNθ) 2011
(Meshi M/I L1-Nefu) () size! On the other hand, N C direction trial completion method for the 9th red maple boat Procedural amendment - Ringen 111 yo each month of 1990

Claims (2)

[Claims] (1) A composite material made of stainless steel or nickel alloy, and in weight percent, C: 0.01 to 0.12%, Si: 0.5% or less, Mn
: 0.6 to 1.9%, P: 0.02% or less, S: 0.0
015% or less, Nb: 0.01-0.05%, Ti: 0
．． 010-0.025%, Al: 0.05% or less, N:
0.006% or less, and CE (carbon equivalent)=C+Mn/6+(Cr+Mo+
V)/15+(Ni+Cu)/15 satisfies 0.40% or less, and the remainder consists of Fe and unavoidable impurities.The slab is assembled by welding with a base material of 1100 to 1250%.
After heating to ℃, reduction ratio 5 or more, rolling end temperature 850-10
Rolled at 50℃, air cooled for 60-300 seconds, then 750℃
A method for manufacturing a clad steel sheet, characterized by cooling from a high temperature above to an arbitrary temperature at a cooling rate of 5 to 40° C./sec. (2) A composite material made of stainless steel or nickel alloy, C: 0.01 to 0.12%, Si: 0.5% or less, Mn in weight%
: 0.6 to 1.9%, P: 0.02% or less, S: 0.0
015% or less, Nb: 0.01-0.05%, Ti: 0
．． 010-0.025%, Al: 0.05% or less, N:
0.006% or less, further V: 0.01 to 0.1%, Ni: 0.05 to 1.0%,
Cu: 0.05-0.6%, Cr: 0.05-1.0%
, Mo: 0.05-0.5%, Ca: 0.001-0.
005%, and CE (carbon equivalent)=C+Mn/6+(Cr+Mo+
V)/15+(Ni+Cu)/15 satisfies 0.40% or less, and the remainder consists of Fe and unavoidable impurities.The slab is assembled by welding with a base material of 1100 to 1250%.
After heating to ℃, reduction ratio 5 or more, rolling end temperature 850-10
Rolled at 50℃, air cooled for 60-300 seconds, then 750℃
A method for manufacturing a clad steel sheet, characterized by cooling from a high temperature above to an arbitrary temperature at a cooling rate of 5 to 40° C./sec.