KR20110063189A - High heat-resistance cold-rolled steel sheet having excellent formability, heat resistance, surface properties for working and manufacturing method thereof - Google Patents

Abstract

PURPOSE: A high heat-resistance cold-rolled steel sheet with excellent processability, heat-resistance, and discoloration resistance and a manufacturing method thereof are provided to optimize processing conditions by reducing the addition of alloying elements. CONSTITUTION: A high heat-resistance cold-rolled steel sheet with excellent processability, heat-resistance, and discoloration resistance comprises C 0.002~0.005 weight%, Nb 0.02~0.06 weight%, Sn 0.05~0.25 weight%, Mn 0.10~0.35 weight%, Al 0.02~0.08 weight%, P 0.003~0.020 weight%, N 0.002~0.006 weight%, S 0.015 weight%, Fe and inevitable impurities. The value of atomic ratio Nb/C is 0.8~2.0.

Description

HIGH HEAT-RESISTANCE COLD-ROLLED STEEL SHEET HAVING EXCELLENT FORMABILITY, HEAT RESISTANCE, SURFACE PROPERTIES FOR WORKING AND MANUFACTURING METHOD THEREOF

The present invention relates to a high heat resistant cold rolled steel sheet and a method for manufacturing the same for use in automobiles, home appliances, boilers, and the like, and more specifically, for processing, heat resistance and discoloration resistance, which are manufactured by optimizing steel components and process conditions. It relates to a heat resistant cold rolled steel sheet and a method of manufacturing the same.

In the past, cast iron was generally used in parts of products such as automobile exhaust systems, home communication systems, ovens, boilers, etc., but high heat resistance is required because it is continuously exposed to a high temperature environment of several hundred degrees (° C.) or higher. In order to secure an aluminum hot-dip galvanized steel sheet, stainless steel sheet, etc. were processed and used.

The high temperature property is one of the characteristics when the processed product is used in a high temperature environment. The high temperature property, i.e., sag resistance, high temperature strength and discoloration, may be deteriorated due to a local temperature rise when using a product such as an automobile exhaust system. Sex is required. The sag resistance is a sagging phenomenon in which the steel sheet is repeatedly exposed to high temperature to cause a change in the material. When such a phenomenon occurs, it is difficult to maintain the shape of the molded part, and when the thermal stress is concentrated to a specific place, the high temperature strength decreases. As the product shape is deformed or destroyed, it is necessary to satisfy the yield strength of 55MPa or more at a high temperature of around 700 ℃ in order to secure the shape freezing.It prevents the oxidation of the steel sheet at high temperature conditions and secures the adhesion with the plating material during plating. Discoloration resistance, which is a surface property, is required.

Stainless steel sheet has been mainly used for such heat-resistance, but stainless steel sheet is not only expensive to manufacture due to the addition of expensive alloy elements such as Cr and Ni, but also has a high Cr and There is a problem in that corrosion resistance (corrosion resistance) is lowered because grain boundary corrosion occurs in the Cr depleted zone region formed by the precipitation of chromium carbide at the grain boundary by bonding.

Also, in order to secure oxidation resistance at high temperature, an aluminum hot dip galvanized steel sheet may be used. When the aluminum hot dip galvanized sheet is heated to a high temperature of 400 ° C. or higher, an alloy layer of an interface is grown due to the interdiffusion reaction between Fe and Al. There is a problem in that the application can be applied because it loses the gloss of the surface in a short time and the color change is insufficient heat resistance.

In addition, products such as automobile exhaust system, home communication, oven, boiler, etc. are manufactured to be accommodated in a limited space, and formed into a complex shape by various methods, so that the processing process to expand or bend after piping is required, in addition to the above high temperature characteristics Processability is required.

Thus, Japanese Laid-Open Patent Publication No. 9-176816 attempts to improve heat resistance and workability by heat-treating a steel sheet after adjusting aluminum content of Al and solid solution N in steel, but the steel sheet is used at a temperature of 550 ° C. or higher. It is difficult to be applied to a member of, and it is not easy to adjust the amount of the steel component to be added, which may cause workability deterioration and processing defects due to aging.

In addition, Japanese Patent Application Laid-open No. Hei 8-319548 attempts to manufacture a hot-dip aluminum plated steel sheet having excellent high temperature strength by forming a coating layer on the surface of the steel sheet, but suggests a method of improving the plating conditions rather than improving the properties of the steel sheet. Not only is the adjustment difficult when the ingredients are changed, but also there is a problem that it is difficult to obtain target heat resistance.

In order to solve the above problems, the present inventors have repeatedly conducted research and experiments and propose the present invention based on the results, and the present invention has high temperature characteristics and room temperature processability, such as automobile exhaust system, home communication, oven and boiler. At the same time, to provide a high heat-resistant cold rolled steel sheet and a method for manufacturing the same, which can be manufactured at low cost by optimizing steel components and processing conditions while reducing the addition of expensive alloying elements for use in demanding applications. Its purpose is to.

In the present invention, C: 0.002 to 0.005%, Nb: 0.02 to 0.06%, Sn: 0.05 to 0.25%, Mn: 0.10 to 0.35%, Al: 0.02 to 0.08%, P: 0.003 to 0.020%, and N: Provides a high heat resistant cold rolled steel sheet for processing having excellent workability, heat resistance and discoloration resistance, including 0.002% to 0.006%, S: 0.015% or less, balance Fe and other unavoidable impurities.

At this time, the characteristic of the atomic ratio Nb / C of Nb and C is 0.8-2.0, too.

In addition, the cold rolled steel sheet is characterized in that the Nb-based carbide precipitates are formed.

In addition, the cold rolled steel sheet is characterized in that it is made of an equiaxed ferrite and acicular ferrite structure.

Here, the volume fraction of the acicular ferrite structure is also characterized by 5 to 15%.

Furthermore, the Sn-based oxide layer is formed on the surface of the cold rolled steel sheet.

In addition, the Sn-based oxide layer is characterized in that the Sn ₂ O ₃ layer.

In addition, the present invention is C: 0.002 ~ 0.005%, Nb: 0.02 ~ 0.06%, Sn: 0.05 ~ 0.25%, Mn: 0.10 ~ 0.35%, Al: 0.02 ~ 0.08%, P: 0.003 ~ 0.020%, Steel slab containing N: 0.002 ~ 0.006%, S: 0.015% or less, balance Fe and other unavoidable impurities is heated and hot rolled, cold rolled after winding, and then cold rolled steel sheet is annealed at a temperature above 800 ℃ It provides a process for producing a high heat-resistant cold rolled steel sheet for processing, heat resistance and discoloration resistance, characterized in that the treated and annealed steel sheet is cooled at a cooling rate of 30 ° C / sec or more.

At this time, the steel slab is characterized in that the value of the atomic ratio Nb / C of the Nb and C is 0.8 ~ 2.0.

In addition, the hot rolling is also characterized by finish rolling at 900 ~ 950 ℃.

In addition, the hot rolling is characterized in that it comprises the step of cooling the hot rolled hot rolled plate at a cooling rate of 20 ~ 80 ℃ / sec.

The winding is also characterized by being performed at 560 to 680 ° C.

Furthermore, the annealing treatment is also characterized by being performed at 800 to 900 占 폚.

As described above, according to the present invention, it can be manufactured at a lower cost than the conventional stainless steel sheet, and has various processing characteristics of extension flangeability, bending property, and deep drawing property, and thus has excellent room temperature processability, As the precipitation resistance increases the aging resistance, there is no yield point elongation, so it is not only excellent in moldability but also excellent in high temperature strength, ensuring the shape freezing property of high-temperature applications, extending the life of the equipment, and excellent in discoloration resistance at high temperatures. Heat-resistant cold rolled steel sheet can be produced.

Hereinafter, the cold rolled steel sheet of the present invention will be described in detail.

The present inventors have satisfied various processing characteristics such as stretch-flangeability, bendability, deep drawing, etc., anti-aging properties, and corrosion resistance at low cost and 55 MPa at 700 ° C. The present invention was completed by repeating the research and experiment to secure the above yield strength and discoloration resistance at high temperature simultaneously. As a result, the present invention contains a very low carbon content in the steel component and controls the amount of Nb and the atomic ratio of Nb and C to form fine Nb-based carbonized precipitates, and by optimizing the annealing and cooling conditions, the volume fraction of acicular ferrite structure Sn is added to form Sn-based oxide layer on the surface of steel sheet, so it is suitable for product parts of automobile exhaust system, home communication, oven and boiler, etc. because it has excellent heat resistance, corrosion resistance and discoloration at high temperature, and age resistance and workability at room temperature. It is characterized by manufacturing high heat resistant cold rolled steel sheet for processing.

First, the reasons for limiting components of the present invention will be described.

Carbon (C) is an element added for improving the strength of the steel sheet, and in the present invention, carbon is mainly consumed by reaction with Nb to form Nb-based carbide precipitates. As the amount of C added increases, the tensile and yield strength increases, but when excessively added, the workability decreases, so the upper limit is preferably 0.005%. However, if less than 0.002%, the sufficient strengthening effect of carbonized precipitates of Nb-based cannot be obtained, and the grain size is increased so that a sudden change in the material occurs, the content of C is limited to 0.002 to 0.005%.

Manganese (Mn) is a solid solution strengthening element that increases the strength of steel and improves hot workability, but is an element that inhibits ductility and workability by MnS formation. Therefore, when Mn is added excessively, ductility falls and it becomes a factor of economic deterioration and center segregation by addition of a large amount of alloying elements, so an upper limit is preferably 0.35%. However, if less than 0.10% workability is improved, but the target strength is difficult to secure, the Mn content is limited to 0.10 to 0.35%.

Aluminum (Al) is an element added for deoxidation of molten steel and is preferably contained in an amount of 0.02% or more because it is combined with solid solution elements in steel to improve aging characteristics. However, excessive addition of more than 0.08% increases the amount of inclusions in the steel, causing surface defects and lowering the workability, Al content is limited to 0.02 ~ 0.08%.

Phosphorus (P) is an element that improves the strength and corrosion resistance of steel, and it is preferable to contain 0.003% or more in order to secure these properties. However, if the content exceeds 0.020%, it causes central segregation during casting and lowers workability. The content is limited to 0.003 to 0.020%.

Nitrogen (N) exists in solid solution inside the steel and is effective for reinforcing the material. If it contains less than 0.002%, sufficient rigidity cannot be obtained, and the precipitate formation site is reduced. If the content exceeds 0.006%, Since it causes aging and hardening occurs and deteriorates moldability, N content is limited to 0.002% to 0.006%.

Sulfur (S) combines with Mn in the steel to form non-metallic inclusions that serve as the starting point of corrosion and causes red shortness, so it is desirable to reduce the content as much as possible, so the content of S is limited to 0.015% or less. . However, in order to ensure the above effect, it is preferable to manage at 0.010% or less.

Niobium (Nb) is an effective element for increasing the strength of steel sheet and refining grains, and in the present invention, Nb-based carbide precipitates are combined with solid solution dissolved in steel to improve aging and formability, and thus, Nb-based carbide precipitates are formed. It is preferable to contain at least 0.02% because the strength is increased and the grain growth at high temperature is suppressed to provide the effect of refining the ferrite particles. However, when the content exceeds 0.06%, the material is cured and the operability of the continuous annealing treatment is increased. The content of Nb is limited to 0.02 to 0.06% because it lowers the surface properties of the steel sheet.

Starium (Sn) is an element that exists in a solid state inside steel to improve high temperature characteristics and corrosion resistance, and is heated and oxidized by heat treatment to form a Sn-based oxide layer such as Sn ₂ O ₃ on the surface of the steel sheet. To suppress the formation of the alloying layer to improve the corrosion resistance and discoloration resistance, in order to obtain this effect, it is preferable to add 0.05% or more, but if the content exceeds 0.25%, rather than the contribution effect to improving the corrosion resistance or discoloration resistance Since the manufacturing cost increases, the Sn content is limited to 0.05 to 0.25%.

It is also important to manage Nb alone, but to obtain both aging resistance, processability and high temperature at the same time, Nb / C, the atomic ratio of Nb and C, must be maintained within a certain range to ensure solid solution effects and precipitate formation conditions. do.

When the value of Nb / C, which is an atomic ratio of Nb and C, is 0.8 to 2.0, Nb-based carbonized precipitates form solid element C in the steel, thereby ensuring room temperature aging resistance and processability, and appropriately annealing and cooling conditions. By controlling the ferrite microstructure by inhibiting grain growth at high temperature by forming fine Nb-based carbide precipitates, it is possible to secure excellent high temperature characteristics.

However, when the value of Nb / C, which is an atomic ratio of Nb and C, is less than 0.8, there is a problem of deterioration of room temperature aging resistance and processability due to excessive solid solution elements in the steel, and excellent high temperature strength because the amount of Nb-based carbide precipitates is insignificant. It cannot be secured. In addition, when the value exceeds 2.0, the material hardens, the temperature of the recrystallization is rapidly increased, the surface properties deteriorate and the workability of the post-process is lowered. Therefore, the value of Nb / C is 0.8 to 2.0. It is limited to.

The cold rolled steel sheet of the present invention comprises the above components and consists of the remainder Fe and other unavoidable impurities. And alloy elements may be further added to improve the properties of the present cold-rolled steel, if necessary, it is not interpreted to be excluded from the scope of the present invention because the alloy element is not added in the embodiment of the present invention.

On the other hand, the cold-rolled steel sheet of the present invention is characterized by consisting of an equiaxed ferrite (polygonal ferrite) and acicular ferrite (acicular ferrite) tissue, the needle-like ferrite tissue is a kind of bainite grown by nucleation in the mouth of austenite before transformation As it grows by nucleation from fine non-metallic inclusions dispersed in steel, ferrite laths are relatively excellent in ductility and toughness due to the disordered structure in which ferrite laths form a high angle boundary with each other. .

Therefore, the present invention by controlling the conditions of the annealing and cooling process appropriately secures the volume fraction of the needle-like ferrite structure 5-15% to form a high-potential-density type microstructure to suppress abnormal growth of grains at high temperature to increase the high temperature strength By securing it, heat resistance can be improved. If the volume fraction of the acicular ferrite structure is less than 5%, it is difficult to secure the high temperature strength, so that the target heat resistance is difficult to obtain. If the volume fraction of the acicular ferrite structure is more than 15%, the workability is deteriorated by hardening of the material. There is a problem, and the volume fraction of the needle ferrite is limited to 5 to 15%.

Hereinafter, the manufacturing method of the high heat resistant cold rolled steel sheet for processing excellent in workability, heat resistance, and discoloration resistance of this invention is demonstrated in detail.

After reheating the steel slab having the above composition, it is hot rolled, cold rolled after winding, and cooled at a cooling rate of 30 ° C./sec or higher on an annealing steel sheet at a temperature of 800 ° C. or higher to provide excellent workability, heat resistance, and discoloration resistance. High heat resistant cold rolled steel sheet for processing can be produced.

After reheating the steel slab formed as the above-described component system at a normal temperature, the finish rolling temperature during hot rolling is 900 to 950 ° C., and when the finish rolling temperature is less than 900 ° C., the hot rolling is completed in a relatively low temperature region. Due to the occurrence of hybridization of the finally formed crystal grains, the workability and rolling properties are lowered, and if the finish rolling temperature exceeds 950 ° C, uniform hot rolling is not performed throughout the thickness, resulting in insufficient grain refinement, resulting in grain coarsening. Since impact toughness falls, finish rolling temperature is restrict | limited to 900-950 degreeC.

After the hot finish rolling, the hot rolled steel sheet is cooled at a run-out table at a cooling rate of 20 to 80 ° C./sec. If the cooling rate is less than 20 ° C./sec, the grain growth is promoted. This is because coarse grains are formed, which may be a cause of deterioration in strength and workability, and when the cooling rate exceeds 80 ° C / sec, it acts as a cause of variation in materials due to widthwise cooling unevenness.

After cooling in the runout table, the hot rolled steel sheet is wound at a temperature of 560 ~ 680 ℃. If the coiling temperature is less than 560 ℃, the material of the hot rolled material is somewhat hardened to increase the load in the cold rolling process, which is the next process, and thus it is difficult to secure the rolling property. Due to the material deviation caused by the workability is lowered, there is a problem that the high temperature characteristics deteriorate. In addition, when the coiling temperature exceeds 680 ℃, there is a problem that the structure of the final product is produced coarse, deterioration of workability and corrosion resistance, the coiling temperature is limited to 560 ~ 680 ℃.

After the wound steel sheet is subjected to pickling treatment and cold rolling to a target thickness, the steel sheet undergoes a continuous annealing process at a temperature of 800 ° C. or higher for recrystallization and microstructure control. The annealing temperature of 800 ° C. or more corresponds to a temperature for sufficiently securing the transformation driving force of the needle-like ferrite structure. If the annealing temperature is less than 800 ° C., there is a problem that it is difficult to obtain a volume fraction of the acicular ferrite structure present in the microstructure of the target steel sheet, and thus it is difficult to secure excellent high temperature characteristics. However, since the surface defects of the steel sheet may increase during high temperature annealing, the annealing temperature is preferably managed at 900 ° C. or lower.

The annealed steel sheet can secure a volume fraction of the target acicular ferrite structure through a cooling process, for which the cooling rate is maintained at 30 ℃ / sec or more. This is because when the cooling rate is less than 30 ° C./sec, it is difficult to obtain a volume fraction of the target acicular ferrite structure due to slow cooling.

Hereinafter, the present invention will be described in more detail with reference to Examples.

[Example]

Invented steels 1 and 2 and Comparative steels 1 to 5 prepared by melting the composition shown in Table 1 below under the process conditions as shown in Table 2 to produce cold rolled steel invention materials 1 to 5 and comparative materials 1 to 10 After that, the volume fraction of the acicular ferrite structure and the characteristics at room temperature and high temperature were evaluated for each of the prepared cold rolled steel sheets.

Yield elongation phenomenon of the characteristics shown in Table 3 was measured when the yield point elongation was measured and occurred when the elongation occurred, and not occurred when the elongation did not occur, and the bending resistance test was the surface bending after the steel sheet processing. According to the degree of occurrence, the bending index representing this was divided into 5 stages, and 1 to 2 stages with relatively small bending were good, and 3 to 5 stages where the bending occurred to the extent that visual observation can be judged as bad. .

In addition, the sag resistance test was determined to be defective when the sagging of the steel sheet after measuring the sagging of the steel plate after heating the material of 250mm in length, 30mm in width for 100 hours at 700 ℃ using a heat treatment equipment, The high temperature yield strength test was judged to be bad if the yield strength was less than 55MPa at 700 ° C, and higher than that. The high temperature discoloration resistance test showed that the surface glossiness was lowered by more than 30% after maintaining the steel plate at 500 ° C for 48 hours. It was judged to be defective.

In addition, the workability test was judged to be defective when a work crack occurred during normal temperature processing.

At this time, in Table 1, the value of the atomic ratio Nb / C of Nb and C refers to the ratio of the value obtained by dividing the weight percent of each element component by its atomic weight, respectively.

Table 1 Components of Inventive and Comparative Steels

[Table 2] Condition of Manufacturing Process by Steel Plate

[Table 3] Evaluation of properties by steel plate

As shown in Table 3, Inventive Materials 1 to 5 in which the steel components and the process conditions satisfy the scope of the present invention did not occur in the yield point elongation and good bending resistance was excellent in aging resistance, Nb-based carbide precipitates The yield strength at high temperature and the sag resistance after heat treatment (sag resistance) were good due to the formation of and the optimization of the volume fraction of the needle-like ferrite structure, and the Sn-based oxide layer was formed on the surface of the steel sheet, so that the high temperature discoloration resistance was good. No defects occurred during processing, so the processability at room temperature was also excellent.

On the other hand, although the steel components of Table 1 and the like are the invention steels satisfying the scope of the present invention, Comparative Materials 1 to 5, in which some of the process conditions of Table 2 deviate from the scope of the present invention, are mostly excellent in low volume fraction of acicular ferrite structure. It did not have high temperature characteristics, and workability and aging resistance were also poor in many cases.

In addition, although the process conditions of Table 2 satisfy the scope of the present invention, Comparative Materials 6 to 10 in which the steel components C, Nb, Sn, or the atomic ratio of Nb and C of Table 1, etc., are outside the scope of the present invention, acicular ferrite structure In many cases, the volume fraction was low and the room temperature and high temperature characteristics were poor.

Among them, Comparative Material 7 had no yield point stretching phenomenon and good bending resistance, so that aging resistance and workability were good, but sag resistance, high temperature yield strength and discoloration resistance corresponding to high temperature characteristics were poor. This is because the high value of deteriorates the surface characteristics and no Sn-based oxide layer is formed on the surface of the steel sheet due to the absence of Sn. In addition, Comparative Materials 8 to 10 had a high amount of solid solution carbon in steel, which was not only poor in workability and aging resistance, but also had a low Nb / C value, resulting in an insignificant amount of Nb-based carbide precipitates, and a low volume fraction of acicular ferrite structure. This defect was difficult to satisfy the normal temperature workability and the high temperature characteristics at the same time.

As a result, it is possible to optimize the compositional conditions of the steel and the conditions of the manufacturing process (especially annealing and cooling conditions) to form fine Nb-based carbide precipitates, to control the volume fraction of the acicular ferrite structure, and to add Sn to the surface of the steel sheet. _By forming a Sn-based oxide layer such as ₂ O ₃ , it was possible to manufacture a high heat resistant cold rolled steel sheet for processing that satisfies workability, heat resistance, and discoloration resistance at low cost.

The above embodiment is only one example, and the present invention is not limited thereto. Anything that has substantially the same configuration as the technical idea described in the claims of the present invention and achieves the same effect is included in the technical scope of the present invention.

Claims (13)

By weight% C: 0.002 ~ 0.005%, Nb: 0.02 ~ 0.06%, Sn: 0.05 ~ 0.25%, Mn: 0.10 ~ 0.35%, Al: 0.02 ~ 0.08%, P: 0.003 ~ 0.020%, N: 0.002 ~ 0.006 High heat resistant cold rolled steel sheet for processing, excellent in workability, heat resistance and discoloration, including%, S: 0.015% or less, balance Fe and other unavoidable impurities. The method of claim 1, A high heat resistant cold rolled steel sheet having excellent workability, heat resistance, and discoloration resistance, wherein the atomic ratio Nb / C of Nb and C is 0.8 to 2.0. The method of claim 1, The cold rolled steel sheet is a high heat resistant cold rolled steel sheet for processing, excellent heat resistance and discoloration resistance, characterized in that the Nb-based carbide precipitates are formed. The method of claim 1, The cold rolled steel sheet is a high heat-resistant cold-rolled steel sheet for processing, heat resistance and discoloration resistance, characterized in that consisting of an isometric ferrite and acicular ferrite structure. 5. The method of claim 4, A high heat resistant cold rolled steel sheet for processing, heat resistance and discoloration resistance, characterized in that the volume fraction of the acicular ferrite structure is 5 ~ 15%. The method according to any one of claims 1 to 5, A high heat resistant cold rolled steel sheet for processing having excellent workability, heat resistance, and discoloration resistance, wherein a Sn-based oxide layer is formed on a surface of the cold rolled steel sheet. The method of claim 6, The Sn-based oxide layer is a high heat resistant cold rolled steel sheet having excellent workability, heat resistance and discoloration resistance, characterized in that the Sn ₂ O ₃ layer. By weight% C: 0.002 ~ 0.005%, Nb: 0.02 ~ 0.06%, Sn: 0.05 ~ 0.25%, Mn: 0.10 ~ 0.35%, Al: 0.02 ~ 0.08%, P: 0.003 ~ 0.020%, N: 0.002 ~ 0.006 Steel slab containing%, S: 0.015% or less, balance Fe and other unavoidable impurities is heated and hot rolled, cold rolled after winding, and then the cold rolled steel sheet is annealed at a temperature of 800 ° C. or higher, and annealed. Process for producing a high heat-resistant cold rolled steel sheet for processing, excellent in workability, heat resistance and discoloration resistance, characterized in that cooling to a steel sheet at a cooling rate of 30 ℃ / sec or more. The method of claim 8, The steel slab is a method of manufacturing a high heat-resistant cold rolled steel sheet having excellent workability, heat resistance and discoloration resistance, characterized in that the value of the atomic ratio Nb / C of Nb and C is 0.8 ~ 2.0. 10. The method according to claim 8 or 9, The hot rolling is a method of manufacturing a high heat resistant cold rolled steel sheet for processing, excellent heat resistance and discoloration resistance, characterized in that the finish rolling at 900 ~ 950 ℃. 10. The method according to claim 8 or 9, The hot rolling is a method of manufacturing a high heat resistance cold rolled steel sheet having excellent workability, heat resistance and discoloration, characterized in that it comprises the step of cooling the hot rolled hot rolled sheet at a cooling rate of 20 ~ 80 ℃ / sec. 10. The method according to claim 8 or 9, The winding is carried out at 560 ~ 680 ° C, characterized in that the workability, heat resistance and discoloration resistance, excellent manufacturing method for high temperature cold rolled steel sheet for processing. 10. The method according to claim 8 or 9, The annealing treatment is carried out at 800 ~ 900 ° C characterized in that the workability, heat resistance and discoloration resistance excellent processing method for manufacturing a high heat-resistant cold rolled steel sheet.