KR101308717B1 - High heat-resistance cold-rolled steel sheet having excellent formability, heat resistance, surface properties for working and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a high-temperature cold-rolled steel sheet for processing and a method of manufacturing the same having excellent workability, heat resistance, and discoloration resistance, and are C: 0.002 to 0.005%, Sn: 0.05 to 0.25%, and B: 0.001 to 0.003%, Ti, by weight. : 0.03 ~ 0.08%, N: 0.002 ~ 0.006%, Mn: 0.10 ~ 0.35%, Al: 0.02 ~ 0.08%, P: 0.003 ~ 0.020%, S: 0.015% or less, processability including residual Fe and other unavoidable impurities The high heat resistant cold rolled steel for processing and its manufacturing method which are excellent in heat resistance and discoloration resistance are made into a technical summary. According to the present invention, it can be manufactured at low cost compared to the existing stainless steel sheet, has various processing characteristics of elongation flangeability, bending property and deep drawing (excellent room temperature workability), and age-resistant by solid element precipitation This increase in yield point does not occur, not only excellent formability, but also excellent in high temperature strength to ensure the shape freezing properties of high-temperature applications, the equipment life is extended, and high heat resistance cold rolled steel sheet It can manufacture.

Cold Rolled Steel, Needle Ferrite, Heat Resistance, Processability, Discoloration Resistance, Aging Resistance

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%, Sn: 0.05 to 0.25%, B: 0.001 to 0.003%, Ti: 0.03 to 0.08%, N: 0.002 to 0.006%, Mn: 0.10 to 0.35%, Al: Provides a high heat resistant cold rolled steel sheet having excellent workability, heat resistance and discoloration resistance, including 0.02% to 0.08%, P: 0.003% to 0.020%, S: 0.015% or less, balance Fe and other unavoidable impurities.

At this time, the characteristic of the atomic ratio Ti / C of Ti and C is 1.4 to 3.0.

In addition, the cold rolled steel sheet is characterized in that the Ti-based carbonitride precipitate is formed.

Here, the characteristic is that the value of the atomic ratio B / N of B and N is 0.5 to 1.5.

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

In addition, the cold-rolled steel sheet is also characterized by being composed of an equiaxed ferrite and acicular ferrite structure.

At this time, the volume fraction of the needle-like ferrite tissue 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 in the weight% C: 0.002 ~ 0.005%, Sn: 0.05 ~ 0.25%, B: 0.001 ~ 0.003%, Ti: 0.03 ~ 0.08%, N: 0.002 ~ 0.006%, Mn: 0.10 ~ 0.35%, Steel slab containing Al: 0.02 ~ 0.08%, P: 0.003 ~ 0.020%, S: 0.015% or less, balance Fe and other unavoidable impurities is heated, hot rolled, cold rolled, and then cold rolled steel sheet Annealing is carried out at a temperature of 800 ℃ or more, and provides a method for producing a high heat-resistant cold rolled steel sheet for processing, excellent in workability, heat resistance and discoloration resistance to the annealing steel sheet at a cooling rate of 30 ℃ / sec or more. .

At this time, the steel slab is characterized in that the value of the atomic ratio Ti / C of the Ti and C is 1.4 ~ 3.0.

In addition, the steel slab is characterized in that the value of the atomic ratio B / N of the B and N is 0.5 ~ 1.5.

In addition, the hot rolling is characterized in that the 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.

Furthermore, the said winding is also characterized by what is performed at 560-680 degreeC.

In addition, the annealing treatment is also characterized by being performed at 830 to 900 ° C.

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 formability, but also excellent in high temperature strength, which prolongs the life of the facility by securing the shape freezing property of high-temperature applications, and is excellent in processing 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 components, and control the addition amount and the atomic ratio of Ti, C, B and N to form fine Ti-based carbonitride precipitate and B-based nitride precipitate, annealing and cooling By optimizing the condition to secure the fraction of acicular ferrite structure, and by adding Sn to form Sn-based oxide layer on the surface of the steel sheet by heat treatment, it is excellent in heat resistance, corrosion resistance and discoloration at high temperature, aging resistance at room temperature, and workability. It is characterized by manufacturing high heat resistant cold rolled steel sheet suitable for product parts such as home appliances and boilers.

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 is mainly consumed by the reaction with Ti to form Ti-based carbide precipitates in the present invention. 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%. If less than 0.002%, however, sufficient Ti-based precipitates may not be strengthened, and grain size may increase, causing a sharp change in material, so that the C content 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%, the workability is improved, but it is difficult to secure the target high strength, Mn content is limited to 0.10 ~ 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 in order to secure these properties, it is preferable to contain 0.003% or more. 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%.

Boron (B) is dissolved in steel to increase strength and toughness, improve aging resistance and workability by forming boron nitride precipitates such as BN, and are effective for suppressing grain growth at high temperatures. It is preferable to add more than 0.001%, but if the content exceeds 0.003%, material variation is caused, and retardation of recrystallization at a high temperature is a factor that degrades workability, so the content of B is limited to 0.001 to 0.003%.

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. .

Titanium (Ti) combines with solid solution in the steel to form Ti-based carbonitride precipitates to improve aging resistance and processability, and to increase the strength of steel sheet and to suppress grain growth at high temperatures by forming Ti-based carbonitride precipitates. It is desirable to contain 0.03% or more because it provides an effect of miniaturizing the ferrite particles, but if the content exceeds 0.08%, the material is hardened, bringing down the operability of the continuous annealing treatment and deteriorate the surface properties of the steel sheet, Ti The content of is limited to 0.03 ~ 0.08%.

Tin (Sn) is an element that exists in a solid state inside the 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 form an alloying layer on the surface of the steel sheet. It is preferable to add more than 0.05% to achieve this effect, but to suppress the formation and to improve the corrosion resistance and discoloration resistance at high temperature, but if the content exceeds 0.25%, the production cost rather than the contribution to the improvement of corrosion resistance or discoloration resistance Since the cause of the increase, the Sn content is limited to 0.05 ~ 0.25%.

In the case of Ti and B alone, it is important to manage alone, but in order to secure the high temperature and room temperature characteristics targeted by the present invention, it is necessary to consider the effects of precipitate formation and solid solution elements in the steel. To this end, it is also important to maintain room temperature aging resistance, processability and high temperature strength simultaneously by maintaining the atomic ratio Ti / C of Ti and C and the atomic ratio B / N of B and N in a certain range.

When the Ti / C atomic ratio of Ti / C is 1.4-3.0, Ti-based carbonitride precipitates are formed to solidify solid elements in steel to ensure room temperature aging resistance and processability, and to properly control annealing and cooling conditions. By forming a fine Ti-based precipitates to suppress the grain growth at high temperatures to control the ferrite microstructure can ensure excellent high temperature characteristics.

However, when the value of Ti / C is less than 1.4, there is a problem that the room temperature aging resistance and workability deteriorate due to excessive elemental solids in the steel, and the precipitation amount of Ti-based precipitates is insignificant, and thus excellent high temperature strength cannot be obtained. In addition, when the value exceeds 3.0, 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 Ti / C value is 1.4 to 3.0. It is limited to.

In addition, in order to optimize the aging resistance at room temperature, workability, and the effect of suppressing grain growth at high temperature, it is necessary to keep the values of the atomic ratio B / N of B and N at 0.5 to 1.5. When the B / N value is less than 0.5, there is a problem that the room temperature resistance is degraded due to excessive solid solution in steel, the grain suppression effect is insufficient at high temperature, and when the B / N value exceeds 1.5, the ductility is lowered and the workability is decreased. , The value of B / N is limited to 0.5 to 1.5.

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 the nucleation grows from the fine non-metallic inclusions dispersed in the steel, the ferrite laths are relatively superior in ductility or toughness due to the disordered structure in which the ferrite laths form a high angle boundary with each other.

The present invention secures the volume fraction of the needle-like ferrite structure by 5-15% by appropriately controlling the conditions of the annealing and cooling process to form a high-potential-density type microstructure, thereby inhibiting abnormal growth of grains at high temperature to secure high temperature strength. By doing so, 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 target heat resistance is difficult to be obtained. 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.

The present invention is a steel slab having the above composition after reheating, hot rolling, cold rolling after winding, and cold-treated at a cooling rate of 30 ℃ / sec or more for annealing steel sheet at a temperature of 800 ℃ or more workability, heat resistance and discoloration It is possible to manufacture a high heat resistant cold rolled steel sheet for processing excellent.

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 annually 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 rolling property, and the nonuniformity of the widthwise temperature increases, resulting in a difference in the production behavior of low temperature precipitates. Due to this material variation is caused workability is lowered, there is a problem that the high temperature characteristics are deteriorated. 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 winding 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., the volume fraction of the needle-like ferrite structure present in the microstructure of the target steel sheet cannot be obtained, thereby making it difficult to secure excellent room temperature and high temperature strength. 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 is indicated when the yield point elongation is measured and not occurred when elongation has occurred, and not occurred when the elongation has not occurred, and the bending resistance test is performed to the extent that surface bending occurs after steel sheet processing. By dividing the bending index that expresses this into five stages, one to two stages, which are relatively insignificant, are considered good, and three to five stages where the bending phenomenon occurs to the extent that visual observation can be judged as defective.

In addition, the sag resistance test was measured for 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, was determined to be defective when the degree of deflection is 5mm or more. In the high temperature yield strength test, the yield strength was less than 55MPa at 700 ℃, and it was judged as good if it was higher than that.The high temperature discoloration resistance test showed that the surface glossiness was reduced more than 30% after maintaining the steel plate at 500 ℃ for 48 hours If it was determined to be defective.

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

In this case, in Table 1, the values of Ti / C and B / N are atomic ratios, and the weight ratios of respective components divided by their atomic weights refer to ratios.

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 component and the process conditions satisfy the scope of the present invention had no yield point stretching phenomenon, good bending resistance and excellent aging resistance, and Ti-based carbonitride The yield strength at high temperatures and the sag resistance after heat treatment (sag resistance) were good due to the formation of precipitates and B-based nitride precipitates and the optimization of the volume fraction of acicular ferrite structure, and the decrease in surface glossiness at high temperatures was less than 30%. The discoloration property was good, and the processing crack did not occur during the normal temperature processing, so the normal temperature processability was also excellent.

On the other hand, although the steel component of Table 1 is an invention steel that satisfies the scope of the present invention, Comparative Materials 1 to 5, in which some of the process conditions of Table 2 are out of the scope of the present invention, mostly have a low fraction of acicular ferrite structure, and thus have excellent high temperature characteristics. It did not have (sag resistance, high temperature strength, discoloration resistance), and workability and aging resistance (yielding point stretching phenomenon, bending resistance) were also poor.

In addition, although the process conditions of Table 2 satisfy the scope of the present invention, the steel component of Table 1 and the like after evaluation of the manufacturing properties of the comparative material 6 to 10 degrees outside the scope of the present invention, the fraction of the needle-like ferrite structure is low , The room temperature and high temperature characteristics were often poor. Among them, the comparative material 7 had no yield point stretching phenomenon and good bending resistance and workability, but poor sag resistance, high temperature strength and discoloration resistance corresponding to high temperature characteristics. This is because the precipitates are insignificant and Sn-based oxide layers such as Sn ₂ O ₃ are not formed on the surface of the steel sheet due to the absence of the Sn component. In addition, Comparative Materials 8 to 10 had a high amount of solid carbon in steel, which was poor in workability and aging resistance. The high temperature strength was poor, the amount of Sn added was low, and the high temperature discoloration resistance was also poor, and it was difficult to satisfy both workability and high temperature characteristics at the same time.

As a result, Ti-based carbonitride precipitates and B-nitride precipitates can be formed by optimizing the compositional conditions of the steel and the conditions of the manufacturing process (particularly, annealing and cooling conditions), and the volume fraction of the acicular ferrite structure can be controlled. By forming a Sn-based oxide such as Sn ₂ O ₃ on the surface of the steel sheet by heat treatment, it is 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 present invention is not limited to the above-described embodiments. Anything having substantially the same constitution as the technical idea described in the claims of the present invention and achieving the same operational effect is included in the technical scope of the present invention.

Claims (16)

By weight% C: 0.002 ~ 0.005%, Sn: 0.05 ~ 0.25%, B: 0.001 ~ 0.003%, Ti: 0.03 ~ 0.08%, N: 0.002 ~ 0.006%, Mn: 0.10 ~ 0.35%, Al: 0.02 ~ 0.08 %, P: 0.003 ~ 0.020%, S: 0.015% or less, residual Fe and other unavoidable impurities, and workability, heat resistance and discoloration resistance characterized by the formation of Sn ₂ O ₃ layer, Sn-based oxide layer on the surface High heat resistant cold rolled steel for excellent processing. The method of claim 1, The high heat-resistant cold rolled steel sheet for processing, excellent heat resistance and discoloration resistance, characterized in that the value of the Ti and C atomic ratio Ti / C is 1.4 ~ 3.0. 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 the Ti-based carbonitride precipitate is formed. The method of claim 1, The high heat resistance cold rolled steel sheet for processing, excellent heat resistance and discoloration resistance, characterized in that the value of the atomic ratio B / N of the B and N is 0.5 ~ 1.5. The method of claim 1, The cold rolled steel sheet is a high heat resistance cold rolled steel sheet for processing, heat resistance and discoloration resistance, characterized in that the B-based nitride precipitates are formed. By weight% C: 0.002 ~ 0.005%, Sn: 0.05 ~ 0.25%, B: 0.001 ~ 0.003%, Ti: 0.03 ~ 0.08%, N: 0.002 ~ 0.006%, Mn: 0.10 ~ 0.35%, Al: 0.02 ~ 0.08 %, P: 0.003 ~ 0.020%, S: 0.015% or less, high heat for processing, including balance Fe and other unavoidable impurities, characterized by being composed of an equiaxed ferrite and acicular ferrite structure Cold rolled steel sheet. The method according to claim 6, A high heat resistant cold rolled steel sheet for processing having excellent processability, heat resistance, and discoloration resistance, wherein the acicular ferrite structure has a volume fraction of 5 to 15%. delete delete By weight% C: 0.002 ~ 0.005%, Sn: 0.05 ~ 0.25%, B: 0.001 ~ 0.003%, Ti: 0.03 ~ 0.08%, N: 0.002 ~ 0.006%, Mn: 0.10 ~ 0.35%, Al: 0.02 ~ 0.08 %, P: 0.003 ~ 0.020%, S: 0.015% or less, steel slab containing residual Fe and other unavoidable impurities is heated and hot rolled, cold rolled after winding, and then cold rolled steel sheet at a temperature above 800 ° C. Annealing treatment and cooling to annealing steel sheet at a cooling rate of 30 ℃ / sec or more, the surface of the cooled steel sheet formed Sn2O3 layer of Sn-based oxide for processing, excellent heat resistance and discoloration resistance Manufacturing method of high heat resistant cold rolled steel sheet. The method of claim 10, 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 Ti / C atomic ratio Ti / C value of 1.4 ~ 3.0. The method of claim 10, The steel slab is a method of manufacturing a high heat resistance cold rolled steel sheet for processing, heat resistance and discoloration resistance, characterized in that the value of the B / N atomic ratio B / N is 0.5 ~ 1.5. The method according to any one of claims 10 to 12, 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 ℃. The method according to any one of claims 10 to 12, 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. The method according to any one of claims 10 to 12, 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. The method according to any one of claims 10 to 12, The annealing treatment is carried out at 830 ~ 900 ℃ manufacturing method, high heat resistance cold rolled steel sheet excellent in workability, heat resistance and discoloration resistance.