JPH0660369B2 - Cr-Ni type stainless steel that is less likely to crack during the casting process or the subsequent hot rolling process - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a process for producing a Cr-Ni-based stainless steel by using a so-called synchronous continuous casting method in which there is no relative speed difference between a slab and a mold. The present invention relates to a Cr-Ni-based stainless steel that does not cause cracks in the material during the casting process and the hot rolling process when performing continuous casting in a form in which the thickness of the slab is close to the product gauge.

(Prior Art) Conventionally, in order to obtain a stainless steel strip, for example, as disclosed in JP-A-56-139278, continuous casting of molten steel is performed while vibrating the mold in the casting direction at a frequency of 2-3 Hz. After casting, a slab having a thickness of 100 mm or more is obtained, then the slab is surface-cleaned, heated to 1000 ° C. or more in a heating furnace, and then hot-rolled by a rolling mill train composed of a plurality of rolling mills. To get a hot strip, which is the material.

However, this conventional process is problematic in that it requires a long hot rolling facility and requires a large amount of energy for heating the slab and rolling power.

When cold rolling this hot strip,
In order to obtain the shape (flatness), material and surface properties required for the final product, the hot strip that has undergone strong hot working is softened by annealing to facilitate cold rolling, and
It has to be performed in advance to remove scale flaws and the like generated on the hot strip during the hot rolling process by grinding after the pickling step. Such a conventional technique has the same problem not only in the thin plate but also in the wire rod and the thick plate.

On the other hand, in order to roll a slab having a thickness of 100 mm or more, which is a basic problem in the above-mentioned conventional technique, into a hot strip, a long hot rolling facility, a large amount of heating energy, and a rolling power are required. In order to solve the problem, research on a process for obtaining a slab having a thickness equal to or close to that of hot strip in the process of continuous casting is under way.

For example, in "Iron and Steel"'85, A197 to '85, A256,
In a special paper, the above-mentioned process for directly obtaining hot strip by continuous casting is disclosed.

In such a continuous casting process, when the gauge of the slab (strip) to be obtained is in the level of 1 to 10 mm, the twin drum system is used, and when the gauge is in the level of 20 to 50 mm. , Twin Belt method is applied exclusively. These casting methods are called synchronous continuous casting methods in contrast to the conventional mold vibration method, and many studies are being conducted with the aim of casting in a shape as close to the product shape as possible.

In the above research, the biggest problem at present is to cast in a shape close to the product, the surface area becomes large during solidification, uneven solidification tends to occur, and cracks occur during the solidification process from casting. This is an easy point.

For example, in the twin-drum type continuous casting method, the solidification tends to become uneven in the width direction particularly with the expansion of the width of the slab, which causes cracks in the slab during the casting process. Also, cracking is likely to occur when hot rolling directly from a thick gauge.

This type of slab cracking becomes a significant bottleneck in the process of manufacturing stainless steel strips which incorporates the process of directly obtaining the strip by continuous casting.

As a technical means for preventing cracks in the slab during the casting process and the subsequent hot rolling process, the solidification in the width direction is made uniform by devising the casting method, the casting machine or the operation method. Although it is possible to approach it,
Approaching methods to solve problems by steel composition are also extremely important.

This is an extremely important issue especially for high alloy steels and stainless steels, which will be important in the future, but such technical means has not been disclosed so far.

(Problem to be Solved by the Invention) The present invention is a production process for a Cr-Ni-based stainless steel strip, which includes a process of directly obtaining a strip by continuous casting of molten steel, and has a sufficiently wide width. The object was to provide a Cr-Ni-based stainless steel that does not cause cracks in the slab during the casting process and the subsequent hot rolling process even when the strip is targeted.

(Means for Solving the Problem) The gist of the present invention is as follows.

(1) By weight, Cr: 11-40%, Ni: 5-70%, S
i: 0.05 to 2.0%, Mn ≤ 7.0%, C ≤ 0.2
%, N ≦ 0.4%, the equilibrium distribution coefficient during solidification is small and S, B, P, and O are particularly susceptible to S ≦ 0.00.
6%, B ≦ 0.0015%, P ≦ 0.035%, O ≦ 0.015%, and the relationship between Ni + 30 × N amount and ΔS in the alloy (where ΔS = S−0.8 × Ca−0.5 × Y). -0.3 x Mg-
Casting characterized in that 0.3 × Ce) satisfies ΔS ≦ 0.0141−0.009 log (Ni + 30N) and the relationship between Ni + 30 × N amount and P amount satisfies P ≦ 0.060−0.025 log (Ni + 30N). Cr-Ni stainless steel that is less likely to crack during the process or the subsequent hot rolling process.

(2) Cr: 11-40%, Ni: 5-70%, S by weight
i: 0.05 to 2.0%, Mn ≤ 7.0%, C ≤ 0.2
%, N ≦ 0.4%, Y ≦ 0.06%, Ce ≦
It contains 0.02%, Mg ≦ 0.02%, Ca ≦ 0.01%, or 2 or more kinds, and has a small equilibrium distribution coefficient during solidification and is easily segregated. S, B, P, and O are S. ≤ 0.006%,
B ≦ 0.0015%, P ≦ 0.035%, O ≦ 0.015%, and the relationship between ΔS and the amount of Ni + 30 × N in the alloy (however, ΔS
= S-0.8xCa-0.5xY-0.3xMg-0.3x
Ce) satisfies ΔS ≦ 0.0141−0.009 log (Ni + 30N), and the relationship between the amount of Ni + 30 × N and the amount of P satisfies P ≦ 0.060−0.025 log (Ni + 30N). Cr-Ni series stainless steel that does not easily crack during the hot rolling process.

(3) Cr: 11-40%, Ni: 5-70%, S by weight
i: 0.05 to 2.0%, Mn ≤ 7.0%, C ≤ 0.2
%, N ≦ 0.4%, Mo ≦ 7%, Cu ≦ 4%,
Containing one or more of Al ≤ 7%, Nb ≤ 1%, Ti ≤ 1%, Zr ≤ 0.2%, and having a small equilibrium distribution coefficient during solidification, which is particularly prone to segregation, S, B, P, O S ≦ 0.006%, B
≤0.0015%, P≤0.035%, O≤0.015%, and the relationship between the amount of Ni + 30 × N in the alloy and ΔS (where ΔS = S
-0.8 x Ca-0.5 x Y-0.3 x Mg-0.3 x Ce)
Satisfying ΔS ≦ 0.0141-0.009 log (Ni + 30N) and the relationship between Ni + 30 × N content and P content satisfying P ≦ 0.060-0.025 log (Ni + 30N). Cr-Ni-based stainless steel that does not easily crack during the rolling process.

(4) By weight, Cr: 11-40%, Ni: 5-70%, S
i: 0.05 to 2.0%, Mn ≤ 7.0%, C ≤ 0.2
%, N ≦ 0.4%, Y ≦ 0.06%, Ce ≦
One or more of 0.02%, Mg ≦ 0.02%, Ca ≦ 0.01% and Mo ≦ 7%, Cu ≦ 4%, Al ≦ 7%, Nb ≦
1%, Ti ≦ 1%, Zr ≦ 0.2%, or one or more kinds, and has a small equilibrium distribution coefficient during solidification, which is particularly prone to segregation. For S, B, P and O, S ≦ 0.006%, B ≦ 0.0015
%, P ≦ 0.035%, O ≦ 0.015%, and the relationship between the amount of Ni + 30 × N in the alloy and ΔS (where ΔS = S−0.
8 × Ca−0.5 × Y−0.3 × Mg−0.3 × Ce) satisfies ΔS ≦ 0.0141−0.009 log (Ni + 30N), and the relation between the amount of Ni + 30 × N and the amount of P is P ≦ Cr-Ni-based stainless steel that is resistant to cracking during the casting process or the subsequent hot rolling process, which is characterized by satisfying 0.060-0.025 log (Ni + 30N).

The present invention will be described in detail below.

As described above, in the process of obtaining a slab (strip) having a thickness as close as possible to the product gauge by the so-called synchronous continuous casting method, for example, in the twin drum (twin roll method) process, the slab (strip) is used. Along with the widening of, stress due to local shrinkage due to uneven solidification in the width direction, if the ductility limit of the material is exceeded,
Cracks are likely to occur on the surface of the slab immediately after solidification. Also, when a slightly thick slab is cast and the slab is directly hot-rolled, cracks may occur from the non-uniform solidification portion.

In order to prevent slab cracking as described above, (1) advances in casting machines and casting methods that homogenize solidification and prevent local shrinkage, and (2) slabs immediately after solidification It is necessary to take measures on both sides of designing the alloy so that it is as ductile as possible.

Conventionally, various studies have been made on the elucidation of cracking phenomenon in a hot rolling process after reheating a normal cast slab having a thickness of 100 mm or more and a means for preventing the cracking phenomenon.

However, as in the twin drum type or twin belt type continuous casting process, the gauge (thickness) of the slab
The slab that is cast in a state close to the product and rapidly solidified, and the crack phenomenon in the subsequent hot rolling process and the research on crack prevention means have not been sufficiently researched.

The inventors of the present invention conducted research on means for preventing cracking of a thin gauge slab that is rapidly cooled and strengthened, in the direction of imparting ductility to a material (slab) immediately after solidification.

For various alloys, a round bar tensile test piece is electrically heated,
The temperature is raised until the center of the parallel part begins to melt, the melting start temperature is measured, and then it is rapidly cooled to 2 from the melting start temperature.
The test piece was held at low temperatures of 0 ° C., 40 ° C., 60 ° C., 80 ° C. and 100 ° C., and a tensile test was carried out to measure the drawing (%) and tensile strength of the test piece until breaking. The ductility of the alloy was evaluated by measuring the temperature at which the drawing reaches 60% or more. An alloy showing a drawing rate of 60% or more at a higher temperature is a material having large ductility just below the melting point. The alloy composition investigated is a Cr-Ni alloy mainly composed of austenitic stainless steel and has the following composition.

Compositions are given in weight percent.

C: 0.005-0.10% O: 0.002-0.015% Si: 0.05-4.0% N: 0.005-0.40% Mn: 0.1-7.0% Ti: 0-1.0% P: 0.001-0.040% Nb: 0-1.0% S: 0.0003-0.02% Ca: 0-0.01% Cr: 11-40% Zr: 0-0.2% Ni: 5-70% Ce: 0-0.06% Mo: 0- 7.0% Y: 0-0.06% Cu: 0-4.0% Mg: 0-0.06% Al: 0-7.0% B: 0-0.010% The effect of trace impurities along with the main alloy composition is also examined. At the same time, we paid attention to the influence of trace components.

Thus, for the ductility of the alloy from just below the freezing point to a low temperature of 100 ° C. As a result of investigating the influence of the alloy composition, the following was found. A typical example is shown in FIG.

Ingredients that deteriorate ductility: S, B, P, O, N, Ni, Si Ingredients that improve ductility: Y, Ce, Ca, Mg No significant effect: Cr, Mo, Mn, Cu, Ti, C , Al As a result, S, B, P, O, etc. are the most prominent components that deteriorate ductility, but these are all well-studied groups with small equilibrium partition coefficients (Steel Manual, 3rd Edition, Basics). Pp. 217). That is, it was found that the impurity components that are easily segregated during solidification significantly deteriorate the ductility just below the melting point of the alloy. In fact, although cracks just below the melting point pass through the grain boundaries during casting, it was also found that segregation of S and P was extremely remarkable in this portion. Although such a tendency was known for S and P etc. from the past, it was found that B was also harmful this time, and it became clear for the first time that S or more was adversely affected, and the equilibrium distribution coefficient was small ( It was clarified for the first time that the components of the (0.1 or less) group segregated during solidification, and the ductility just below the melting point was greatly deteriorated. In the experiment, it was found that the ductility deteriorates when the amount of Ni increases, and that the smaller the amount of Si is, the more effective it is. However, it is considered that these influence by promoting the above-mentioned impurity segregation.

As a component that improves ductility, Y is particularly remarkable, but Ce, C
It has been found that S and O are clearly fixed with a, Mg, etc. to suppress the segregation tendency of these. Cr, Mo, Mn, Cu, Ti, Nb, etc., which are important alloys of stainless steel as a high alloy, do not have a great influence, and C does not so much.

As a result, S, B, O, P, etc., which have a particularly large segregation tendency and a small equilibrium distribution coefficient, need to be reduced as much as possible or fixed before solidification. S is particularly harmful and needs to be reduced or fixed with Y, Ce, Ca, Mg or the like. B is also harmful, B
It is necessary to reduce the contamination of O can be reduced by utilizing a deoxidizer. P is as described below,
The degree of influence differs depending on the amount of Ni, and it is necessary to reduce it in relation to the amount of Ni.

On the other hand, in terms of alloy composition, Ni and N are components that should be used even if they have a bad influence. In order to ensure sufficient ductility even at the required Ni and N levels, S, P,
It is important to control segregation components such as B and O. Thus, in various alloys, the ductility level (~ 60
% Reduction), the result shows that the amount of Ni and N in the alloy is Ni + 3
It has been found that it is necessary to strictly regulate the amounts of S and P according to the amount of 0 × N. In particular, regarding the S amount, the ΔS amount that is most considered is fixed by the addition of Y, Ce, Ca, Mg, etc. together with the reduction of the S amount (here, the ΔS amount is defined as follows: ΔS = S−0.8. XCa-0.5xY-0.3xMg-
As shown in FIG. 2, the relation with 0.3 × Ce) Ni + 30 × N is required to satisfy ΔS ≦ 0.0141−0.009 log (Ni + 30N). That is, as the amount of Ni + 30 × N in the alloy increases, the amount of S is reduced, and if necessary,
ΔS by adding one or more of Y, Ce, Ca, Mg, etc.
Needs to be small. But Y, Ce, Ca, Mg
Etc. are harmful to the corrosion resistance if added in a too large amount, and Y ≦
0.06%, Ce ≦ 0.02%, Ca ≦ 0.01%, Mg ≦
It must be in the range of 0.02%.

Y is particularly effective, but Y is expensive and the upper limit is 0.0.
It was 6%. A small amount of Ce, Ca, Mg, etc. also has an effect.

Similarly, as shown in FIG. 3, P also needs to be reduced according to Ni + 30 × N so as to satisfy P ≦ 0.060−0.025 log (Ni + 30N). In all cases, B should be 0.0015%, and O should be deoxidized to O0.015%. The reaction of Y, Ce, Ca, etc. is accelerated by the flow at the time of casting, and the amount thereof varies, but the above-mentioned conditions are the component specifications immediately before casting and solidification.

By reducing or fixing the four types of impurities that are particularly prone to segregation during solidification during casting and controlling them within the allowable range according to the amounts of Ni and N, the ductility immediately below the melting point is greatly improved, and the hot rolling process thereafter It becomes steel that is hard to crack even in.

Of course, the Cr amount, Mo amount, etc. also have some influence, but the composition range to be limited next has a smaller influence than the components described above. Therefore, the concept of the present invention can be applied to the following composition ranges. Further, not only thin plates, but also wire rods, steel pipes, and plates can be applied.

C: 0.005 to 0.20% O: ≤ 0.015% Si: 0.05 to 2.0% N: 0.005 to 0.40% Mn: 0.1 to 7.0% Ti: 0 to 1.0% P: ≤ 0.035% Nb: 0 to 1.0% S: ≤ 0.006% B: ≤ 0.0015% Cr: 11 to 40% Y: ≤ 0.06% Ni: 5 to 70% Ce: ≤ 0.02% Mo: 0 to 7.0% Ca: ≤ 0.01 % Cu: 0 to 4.0% Mg: ≤ 0.02% Al: 0 to 7.0% Zr: ≤ 0.2% The reasons for limiting the alloy components of the present invention will be described below.

This time, the high temperature ductility just below the melting point of the alloy is closely related to the segregation tendency of the alloy components. Therefore, the well-known equilibrium distribution coefficient (≦ 0.1), which is a component that easily segregates S, B, O. , P was found to be required to be controlled and quantitatively regulated, and the quantitative regulation was clarified in relation to the amount of Ni and N, which promote the segregation.

S is a component that is extremely prone to segregation.
It is necessary to add and fix components such as Y, Ce, Ca, and Mg that easily form sulfides. In particular, in an alloy containing a large amount of Ni or N, it is necessary to reduce S according to the amount of Ni + 30 × N. Thus ΔS = S−0.8 × Ca−0.
As shown in FIG. 2, the relation between ΔS and the amount of Ni + 30 × N obtained by defining 5 × Y−0.3 × Mg−0.3 × Ce as the weight percentage of each component is ΔS ≦ 0.0141−0.009 log By satisfying (Ni + 30N), cracking can be prevented. The S content was 0.006% or less, but if it exceeds this value, cracking cannot be prevented. Further, Y is most effective because it can be added at 0.06% or less. Ce, Mg 0.02% or less, Ca 0.01%
One kind or two or more kinds are added in the following ranges, if necessary.
However, adding too much deteriorates the corrosion resistance. Y is particularly effective, but it is expensive, and is set to 0.06% or less.
These additive elements have a small amount and a large synergistic effect.

B tends to segregate next to S and promotes cracking. Therefore, it is important to manage the trace amount B. B in casting is 0.0015%
Must be: For this purpose, it is necessary to suppress contamination from raw materials and refractories. Exceeding this will promote cracking.

O is also a component that easily segregates, and segregates during solidification to promote cracking. It is necessary to sufficiently deoxidize it to 0.015% or less. O existing in steel is Al ≦ 0.08%, Si ≦
2.0% or Y ≦ 0.06%, Ce ≦ 0.02%, Mg ≦ 0.02%, Ca ≦
It is sufficient to fix by deoxidation with selective addition of 0.01%.

P also has a large segregation tendency and is preferably as low as possible, but its allowable limit can be determined by P ≦ 0.060−0.025 log (Ni + 30N) as shown in FIG. 3 in relation to the amount of Ni + 30 × N. In particular, it is necessary to reduce P in an alloy containing a large amount of Ni or N. In parallel with the control of the amounts of S, B, and O, as shown in Fig. 3, by controlling P to 0.060-0.025 log (Ni + = 30N), excellent ductility can be obtained from just below the melting point.

Although Ni, N, Si, etc. also deteriorate ductility just below the melting point,
It is an essential component as an alloy composition. Ni is 5% as a necessary lower limit in terms of stabilizing the austenite phase, and a larger amount is more effective in terms of composition stability and corrosion resistance. However, when it exceeds 70%, it becomes expensive and cracking becomes remarkable. . N is effective in stabilizing the phase, enhancing the strength, and improving the corrosion resistance, and the solid solution amount increases together with Cr. The larger the amount, the greater the effect. However, if it exceeds 0.4%, it exceeds the solid solubility limit and bubbles are generated. Si is effective as a deoxidizing agent, from the viewpoint of the flow of molten metal, and is a preferable component from the viewpoint of scale resistance. However, in terms of ductility just below the melting point, it is preferably as small as possible. Therefore, the upper limit of Si is set to 2.0%, and the lower limit is set to 0.05% in terms of economy.

No significant effect was observed for other alloy compositions,
Therefore, it was set as the study range mentioned above.

(Example) As usual, various Cr-Ni-based stainless steels which were melted and secondarily refined were melted. Table 1 shows the components of the molten steel. As described above, these are not only the main components, but especially S, B, P, and O. Further, according to the Ni + 30 × N amount, based on FIGS. Was controlled, and the components were adjusted by the amounts of Y, Ce, Ca, Mg, Al and the like.

Then, after sufficiently controlling the temperature in a ladle, casting was performed by a twin roll casting machine composed of a water-cooled copper mold, and thin cast pieces of 8 mm to 1 mm were cast. The casting width is 600 mm. It was uniformly cooled in the width direction from below the twin rolls with gas and water, and then cooled to 1100 ° C.

The slab was then cooled and wound up, but no cracks occurred in the slab of the steel of the present invention satisfying the regulation of the amounts of S, B, P and O.

Although hot rolling was applied to some of the cast pieces at a surface temperature of 1350 ° C to 1150 ° C at a rolling reduction of 50% or less, cracks did not occur during the hot rolling.

On the other hand, in the comparative alloys shown in Table 1, the contents of S, B, P and O described above are large, and the relation with Ni + 30 × N is not satisfied, and both are mainly in the width direction during casting. A small crack occurred.

[Effects of the Invention] According to the present invention, there is no relative speed difference between the cast piece and the mold, using a so-called synchronous continuous casting method, in the process of producing Cr-Ni stainless steel, continuous casting, the cast piece It is possible to provide a Cr-Ni-based stainless steel that does not crack in the material during the casting process and the hot rolling process when the thickness is close to the product gauge.

[Brief description of drawings]

Figure 1 shows the effect of various alloying elements on the ductility just below the melting point, and Figure 2 shows Ni + 30 × N (%) and ΔS = S- in steel.
0.8 x Ca-0.5 x Y-0.3 x Mg-0.3 x Ce (%)
FIG. 3 is a diagram showing a good ductility region just below the melting point, and FIG. 3 is a diagram showing a good ductility region just below the melting point in relation to Ni + 30 × N (%) and P (%) in the steel.

Claims (4)

[Claims] 1. By weight, Cr: 11-40%, Ni: 5-70
%, Si: 0.05 to 2.0%, Mn ≦ 7.0%, C ≦ 0.
2% and N ≦ 0.4% are included, and the equilibrium distribution coefficient at the time of solidification is small and S ≦ B for S, B, P and O which are particularly prone to segregation.
006%, B ≦ 0.0015%, P ≦ 0.035%, O ≦ 0.015%, and the relationship between Ni + 30 × N amount and ΔS in the alloy (where ΔS = S−0.8 × Ca−0.5 × Y). -0.3 x Mg
−0.3 × Ce) satisfies ΔS ≦ 0.0141−0.009 log (Ni + 30N), and the relationship between the amount of Ni + 30 × N and the amount of P satisfies P ≦ 0.060−0.25 log (Ni + 30N). Cr-Ni stainless steel that is less prone to cracking during the casting process or the subsequent hot rolling process. 2. By weight, Cr: 11-40%, Ni: 5-70
%, Si: 0.05 to 2.0%, Mn ≦ 7.0%, C ≦ 0.
2%, N ≦ 0.4%, Y ≦ 0.06%, Ce
Includes one or more of ≦ 0.02%, Mg ≦ 0.02%, Ca ≦ 0.01%, and has a small equilibrium distribution coefficient during solidification, and S, B, P and O are particularly prone to segregation. S ≦ 0.006
%, B ≦ 0.0015%, P ≦ 0.035%, O ≦ 0.015%, and the relationship between the amount of Ni + 30 × N in the alloy and ΔS (where ΔS = S−0.8 × Ca−0.5 × Y− 0.3 x Mg-
Casting characterized in that 0.3 × Ce) satisfies ΔS ≦ 0.0141−0.009 log (Ni + 30N) and the relationship between Ni + 30 × N amount and P amount satisfies P ≦ 0.060−0.025 log (Ni + 30N). Cr-Ni stainless steel that is less likely to crack during the process or the subsequent hot rolling process. 3. By weight, Cr: 11-40%, Ni: 5-70
%, Si: 0.05 to 2.0%, Mn ≦ 7.0%, C ≦
0.2%, N ≦ 0.4%, Mo ≦ 7%, Cu ≦
4%, Al ≤ 7%, Nb ≤ 1%, Ti ≤ 1%, Zr ≤ 0.2%, and one or more of them, which have a small equilibrium distribution coefficient during solidification and are particularly prone to segregation S, B, S ≦ 0.00 for P and O
6%, B ≦ 0.0015%, P ≦ 0.035%, O ≦ 0.015%, and the relationship between Ni + 30 × N content and ΔS in the alloy (where ΔS = S−0.8 × Ca−0.5 × Y). -0.3 x Mg-0.
3 × Ce) satisfies ΔS ≦ 0.0141−0.009 log (Ni + 30N) and the relationship between the amount of Ni + 30 × N and the amount of P satisfies P ≦ 0.060−0.025 log (Ni + 30N), or Cr-Ni-based stainless steel that does not easily crack during the subsequent hot rolling process. 4. By weight, Cr: 11-40%, Ni: 5-70
%, Si: 0.05 to 2.0%, Mn ≦ 7.0%, C ≦ 0.
2%, N ≦ 0.4%, Y ≦ 0.06%, Ce
≦ 0.02%, Mg ≦ 0.02%, Ca ≦ 0.01%, one or more kinds and Mo ≦ 7%, Cu ≦ 4%, Al ≦ 7%, Nb
≤ 1%, Ti ≤ 1%, Zr ≤ 0.2%, 1 or 2 or more, and has a small equilibrium distribution coefficient during solidification and is particularly prone to segregation S ≤ 0.006% for S, B, P and O , B ≦ 0.0015
%, P ≦ 0.035%, O ≦ 0.015%, and the relationship between the amount of Ni + 30 × N in the alloy and ΔS (where ΔS = S−0.
8 × Ca−0.5 × Y−0.3 × Mg−0.3 × Ce) satisfies ΔS ≦ 0.0141−0.009 log (Ni + 30N), and the relation between the amount of Ni + 30 × N and the amount of P is P ≦ Cr-Ni-based stainless steel that is resistant to cracking during the casting process or the subsequent hot rolling process, which is characterized by satisfying 0.060-0.025 log (Ni + 30N).