ES2674255T3 - Stainless steel for use in oil well tube - Google Patents

Abstract

Stainless steel used for tubular products for oil producing countries, consisting of, as a percentage by mass, 0.001% to 0.05% C, 0.05% to 1% Si, maximum 2% Mn, maximum 0.03% P, less than 0.002% S, 16% to 18% Cr, 3.5% to 7% Ni, more than 2% and at most 4% Mo, 1.5% to 4 % Cu, 0.001% to 0.3% rare earth metal, 0.001% to 0.1% Al sol., 0.0001% to 0.01% Ca, maximum 0.05% O , and not more than 0.05% N, and one or more selected from the group consisting of not more than 0.5% Ti, not more than 0.5% Zr, not more than 0.5% Hf, not more 0.5% V and at most 0.5% Nb, the rest consisting of Fe and impurities, in which the steel has a structure that includes, in percentage by volume, 10% to 60% of ferrite phase and 2% to 10% residual austenite phase and has a tensile strength of at least 654 MPa.

Description

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DESCRIPTION

Stainless steel for use in oil well pipe Technical field

The present invention relates to stainless steel and more specifically to stainless steel used for tubular products for oil producing countries for use in gas wells or oil wells.

Prior art

The oil or natural gas produced from oil wells or gas wells contains associated corrosive gas such as carbon dioxide gas and hydrogen sulfide. Therefore, tubular products for oil producing countries used to produce oil or natural gas need high corrosion resistance.

Carbon steel or low alloy steel have been used as steel for tubular products for oil producing countries. Since the products have come to be used in a stronger corrosive environment in an oil well or gas well, SUS420 martensitic stainless steel (13% Cr based steel) has been used that has a Cr content of approximately 13 % or stainless steel that has high corrosion resistance as steel based on 13% of improved Cr produced by adding Ni to steel based on 13% Cr.

Recently, drilling of deep oil or gas wells has created a demand for tubular products for oil producing countries that have higher resistance for such deep oil or gas wells. In addition, in an oil or deep gas well, an environment of high temperature aqueous chloride solution of up to 150 ° C or more is created that includes hydrogen sulfide gas and carbon dioxide, and even corrosion resistance is required. higher than the tubular product for conventional oil producing countries. In an environment of high temperature aqueous chloride solution such that it includes hydrogen sulfide gas and carbon dioxide, biphasic stainless steel having superior corrosion resistance and resistance to conventional stainless steel can be used. Biphasic stainless steel, however, contains a large number of alloy elements and, therefore, the manufacturing cost is high.

JP 2005-336595 A (hereinafter referred to as "Patent Document 1"), JP 2006-16637 A (hereinafter referred to as "Patent Document 2") and JP 2007-332442 A (hereinafter referred to as "Document Patent 3 ") propose the use of stainless steel pipes that contain fewer alloy elements than biphasic stainless steel and that have high resistance and high corrosion resistance in an environment of high temperature chloride aqueous solution that includes dioxide gas carbon The stainless steel pipes disclosed by these patent documents each have a higher Cr content than steel based on conventional 13% Cr, so that corrosion resistance can be improved.

More specifically, in the disclosure of Patent Document 1, the Cr content of the stainless steel pipe is 15.5% to 18%, which is greater than that of steel based on conventional 13% Cr. In addition, when Cr + Mo + 0.3Si-43.5C-0.4Mn-Ni-0: 3Cu-9N> 11.5 is established, the steel has a two-phase structure that includes a ferrite phase and a martensite phase , so that it improves the ability to be hot worked of the tubular product for oil producing countries. The biphasic structure could reduce the corrosion resistance, while when Ni, Mo and Cu are added that improve the corrosion resistance so that Cr + 0.65Ni + 0.6Mo + 0.55Cu-20C> 19 is established , 5, the reduction in corrosion resistance of the tubular product for oil producing countries is prevented.

Similarly, according to the disclosure of Patent Document 2, the Cr content of stainless steel is 15.5% to 18% and is contained Ni that improves corrosion resistance. The chemical composition of stainless steel disclosed by the document is similar to that in Patent Document 1, but Mo is not an essential element, and therefore a less expensive alloy design is proposed. In addition, Cu is also an optional element.

The stainless steel disclosed by Patent Document 3 contains 14% to 18% Cr, in addition to Ni, Mo and Cu, so that high corrosion resistance is obtained. In addition, the steel includes a martensite phase and 3% to 15% austenite phase in volume, and therefore improves hardness.

The types of stainless steel disclosed by Patent Documents 1 to 3 undoubtedly contain a greater amount of Cr than steel based on conventional 13% Cr and alloy elements such as Ni, Mo and Cu are added, so that the corrosion rate is reduced in a high temperature corrosive environment. For example, in one embodiment in Patent Document 1, using a 20% by weight aqueous solution of NaCl at 230 ° C in a 100 atm CO2 atmosphere, the corrosion rate (mm / year) was examined and established that the corrosion rate was reduced (see Table 2 in Patent Document 1).

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However, based on the inventors' research, it was found that the use of stainless steel having a high Cr content in an environment of high temperature aqueous chloride solution containing carbon dioxide gas reduces the corrosion rate, but it is more likely to occur SCC (stress corrosion cracking).

In conventional stainless steel such as 13% Cr steel, the corrosion rate is extremely high in an environment of high temperature chloride aqueous solution. Therefore, while general corrosion is generated, SCC is not generated which is local cracking. On the other hand, when the Cr content is greater than that of conventional stainless steel, the corrosion rate is reduced as disclosed by Patent Documents 1 to 3. The reduction in the corrosion rate is produced by a passive film It is formed on the surface of stainless steel. However, the passive film is locally weakened and destroyed in a high temperature environment. The destroyed part is more likely to dissolve, and this dissolution is likely to be the cause of SCC.

Therefore, in the stainless steel used in an environment of high temperature aqueous chloride solution containing carbon dioxide gas, it is necessary not only to reduce the corrosion rate, but also to improve the resistance of SCC.

EP-A1-1.683.885 discloses a highly resistant corrosion resistant stainless steel pipe for line pipe, which has a composition containing 0.001 to 0.015% of C, 0.01 to 0.5% of Yes, 0.1 to 1.8% of Mn, 0.03% or less P, 0.005% or less S, 15 to 18% of Cr, 0.5% or more and less than 5.5% of Ni, 0.5 to 3.5% of Mo, 0.02 to 0.2% of V, 0.001 to 0.015% of N and 0.006% or less of O, by mass, so that it meets [Cr + 0.65Ni + 0.6Mo + 0.55Cu - 20C ^ 18.5], [Cr + Mo + 0.3Si - 43.5C - 0.4Mn - Ni - 0.3Cu - 9N ^ 11.5] and [C + N ^ 0.025].

Summary of the invention

It is an object of the present invention to provide stainless steel for tubular products for oil producing countries having high corrosion resistance in an environment of high temperature chloride aqueous solution containing carbon dioxide gas at 150 ° C or higher. More specifically, it is to provide stainless steel for tubular products for oil producing countries that has a reduced corrosion rate and high resistance of SCC in an environment of high temperature chloride aqueous solution containing carbon dioxide gas.

The inventors considered that it would be necessary to add at least 16% by mass of Cr and a small amount of Mo to the steel in order to reduce the corrosion rate in an environment of high temperature aqueous chloride solution containing carbon dioxide gas at 150 ° C or higher. However, Cr and Mo are ferrite forming elements and, therefore, if at least 16% by mass of Cr and a small amount of Mo are contained, an important part of the steel structure becomes a phase of ferrite and, therefore, high strength cannot be obtained.

On the other hand, an austenite phase is stabilized at high temperatures by adding Ni which is an austenite forming element, so that a hardening martensite phase is formed and a high strength steel structure is obtained. However, if the amount of Ni is too large, the starting temperature for the martensite transformation (Ms point) is reduced and, therefore, the martensite transformation is not generated even at room temperature, so that it is not provided high strength Therefore, when the Ni content is properly adjusted, a structure is formed that mainly includes a martensite phase and approximately at least 10% ferrite phase in volume and high strength can be provided.

Copper (Cu) effectively potentiates a ferrite phase and, therefore, a high strength structure can be provided by adding Cu. In addition, Cu reduces the rate of corrosion in an environment of high temperature aqueous chloride solution and improves the resistance of SCC.

Based on the above findings, the inventors concluded that stainless steel having prescribed strength and reduced corrosion rate can be provided when the steel contains 16% to 18% Cr, more than 2% and no more than 4% of Mo, 3.5% to 7% Ni, and 1.5% to 4% Cu.

The inventors also found that adding at least a prescribed amount of a rare earth metal (REM) in the chemical composition described above results in high SCC resistance even in an environment of high temperature aqueous chloride solution containing carbon dioxide gas. . Now, this will be described in detail.

The inventors prepared stainless steel having the chemical compositions in Table 1 and these types of stainless steel were evaluated for their SCC resistance.

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Table 1

 Acer

   Chemical composition (unit: mass%, the rest consisting of Fe and impurities)

 or No.

 C Yes Mn P S Cu Cr Ni M Al Ca N O REM

 or sun

 A1

 0.01 0.31 0.5 0.01 0.000 1, 17, 3, 2, 0.02 0.001 0.02 0.00 0.000

 9 1 1 6 9 9 1 9 4 9 0 0 3 1

 A2

 0.01 0.30 0.5 0.01 0.001 2, 17, 4, 2, 0.03 0.000 0.01 0.00 0.000

 8 5 5 0 0 2 2 5 0 8 8 5 2

 A3

 0.02 0.29 0.5 0.01 0.001 2, 16, 4, 2, 0.02 0.001 0.01 0.00 0.000

 1 2 7 0 1 9 1 5 9 3 6 6 5

 A4

 0.02 0.29 0.4 0.01 0.000 2, 17, 4, 2, 0.02 0.001 0.01 0.00 0.001

 0 9 6 8 0 0 0 6 8 6 9 3 1

 TO 5

 0.01 0.31 0.5 0.01 0.001 1, 17, 4, 2, 0.03 0.001 0.02 0.00 0.002

 9 1 5 0 9 2 1 4 2 1 2 5 8

 A6

 0.01 0.31 0.5 0.01 0.000 1, 17, 4, 2, 0.02 0.000 0.01 0.00 0.03

 9 0 6 9 9 1 1 4 9 9 8 3

With reference to Table 1, in stainless steel grades with No. A1 to A6, the chemical compositions are the same, except for REM. The REM content is different among the numbered stainless steel grades in the range of 0.0001% to 0.03%. In addition, these numbered stainless steel grades were quenched-tempered so that the tensile strength of each type of stainless steel was adjusted in the range of 860 MPa to 900 MPa. The structures of these numbered stainless steel grades include, in volume percentage, 60% martensite phase, 30% ferrite phase and 10% austenite phase.

A specimen for the four-point bending test having a length of 75 mm, a width of 10 mm and a thickness of 2 mm of each of the numbered stainless steel grades was sampled. Sampled specimens were subjected to a flexural load by four-point flexion. At the time, the amount of bending of each specimen was determined according to ASTM G39 so that the tension applied on each specimen was equal to the tensile strength of each specimen.

Each bending specimen was immersed for 25 months in a 25% by weight aqueous NaCl solution in an autoclave at 204 ° C (400F) that contained CO2 inside it under a pressure of 30 atm. After immersion for a month, each specimen was examined for the presence of SCC. More specifically, a longitudinal section of each specimen was observed with a 100x magnification optical microscope and the presence / absence of SCC was determined by visual inspection.

The test result is given in Fig. 1. In Fig. 1, the abscissa represents the REM content (mass%) and the ordinate represents the presence / absence of SCC. In Fig. 1, "•" in "SCC present" in the ordinate indicates the presence of SCC, while "•" in "no SCC" indicates the absence of SCC. As can be clearly seen from Fig. 1, when the REM content was not less than 0.001%, no SCC was generated even in an environment of high temperature aqueous chloride solution containing carbon dioxide. Although it is not clear how REM improves SCC resistance, this may be for the following reason.

As a result of the microscopic observation of stainless steel specimens that had SCC in the tests described above, it was found that SCC originated from a hole and propagated along a previous austenite grain boundary in a predominant structure in martensite This may suggest that the behaviors of accumulation of dislocations towards the limit of previous austenite under tension and propagation of figures are somewhat correlated.

Then, REM probably has some effect on the behaviors of accumulation of dislocations towards the previous austenite limit and the SCC resistance of stainless steel containing at least 0.001% of REM can be improved. Note that the grades of stainless steel with No. A1 to A3 contained 0.0008% to 0.0013% of Ca, but their REM contents were less than 0.001% and therefore SCC was generated. Therefore, at least 0.001% of REM content contributed to the improvement of SCC resistance more than Ca.

The inventors have completed the following invention based on the previous findings.

The stainless steel used for tubular products for oil producing countries according to the invention consists of, in mass percentage, 0.001% to 0.05% of C, 0.05% to 1% of Si, at most 2% of Mn , at most 0.03% of P, less than 0.002% of S, 16% at 18% of Cr, 3.5% at 7% of Ni, more than 2% and at most 4% of Mo, 1.5 % to 4% of Cu, 0.001% to 0.3% of earth metal, 0.001% to 0.1% of Al sol., 0.0001% to 0.01% of Ca, at most 0.05% of O, at most 0.05% of N, and one or more selected from the group consisting of at most 0.5% of Ti, at most 0.5% of Zr, at most 0.5% of Hf, as maximum 0.5% of V and at most 0.5% of Nb, the rest consists of Fe and impurities, in which the steel has a structure that includes, in percentage by volume, 10% to 60% ferrite phase and 2% to 10% residual austenite phase and has a tensile strength of at least 654 MPa.

The stainless steel according to the invention preferably further includes at least one selected from the group consisting of 0.005% to 0.5% Ti, 0.005% to 0.5% Zr, 0.005% to 0.5% Hf, 0, 0055 at 0.5% V and 0.005% at 0.5% Nb.

In this way, the generation of an attributable hole of a depleted layer in Cr can be reduced.

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Brief description of the drawings

Fig. 1 is a graph showing the relationship between the content of rare earth metals in stainless steel and SCC.

Best way to carry out the invention

Now, embodiments of the invention will be described in detail. The stainless steel according to the invention is applicable to tubular products for oil-producing countries for use in an environment of high temperature aqueous chloride solution containing carbon dioxide gas at 150 ° C or more. Hereinafter, this high temperature chloride aqueous solution environment containing carbon dioxide gas at 150 ° C or more will simply be referred to as "high temperature aqueous chloride solution environment".

1. Chemical composition

The stainless steel according to the invention has the following chemical composition. Hereinafter, "%" related to elements means "% by mass."

C: 0.001% to 0.05%

Carbon (C) forms carbide with Cr and reduces the corrosion resistance of steel in an environment of high temperature chloride aqueous solution. Therefore, the C content is preferably as small as possible. Therefore, the upper limit for the C content is 0.05%. Note that the lower limit for the content of C that can be substantially controlled is 0.001%.

Yes: 0.05% to 1%.

Silicon (Si) deoxidizes steel in the refining process. To obtain the effect, the lower limit for the Si content is 0.05%. On the other hand, an excessive Si content not only saturates the deoxidizing effect, but also reduces the ability to heat the steel. Therefore, the upper limit for the Si content is 1%.

Mn: 2% or less

Manganese (Mn) improves the strength of steel. However, excessive Mn content is more likely to produce segregation in the steel. Segregation in steel reduces the toughness of steel and also reduces the resistance of SCC in an environment of high temperature aqueous chloride solution. Therefore, the content of Mn is not more than 2%. The content of Mn is preferably not less than 0.2% in order to improve the resistance. However, if the content of Mn is less than 0.2%, the strength of the steel improves somewhat.

P: 0.03% or less

Phosphorus (P) is an impurity and reduces the resistance of SSC (sulphide stressing) and the resistance of SCC in an environment of high temperature chloride aqueous solution. Therefore, the content of P is preferably as small as possible. The content of P is therefore not more than 0.03%.

S: less than 0.002%

Sulfur (S) combines with Mn or the like and forms an inclusion. The inclusion formed becomes an origin for a hole or SCC and reduces the corrosion resistance of steel. In addition, the S reduces the ability to be hot worked steel. Therefore, the content of S is preferably as small as possible. Therefore, the content of S is less than 0.002%.

Cr: 16% to 18%

Chromium (Cr) is an essential element that improves corrosion resistance in an environment of high temperature chloride aqueous solution. In order to achieve high SCC resistance in the environment of high temperature chloride aqueous solution, the lower limit for Cr content is 16%. On the other hand, since Cr is a ferrite forming element, excessive Cr content increases the ratio of a ferrite phase in the steel structure and reduces the strength of the steel. In addition, it reduces the ratio of a phase of residual austenite, which reduces the toughness of the steel. Therefore, the upper limit for Cr content is 18%. The Cr content is preferably from 16.5% to 17.5%.

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Ni: 3.5% to 7%

Nickel (Ni) improves corrosion resistance in an environment of high temperature chloride aqueous solution and also improves the toughness of steel. In order to obtain these effects, the lower limit for Ni content is 3.5%. On the other hand, Ni is an austenite-forming element and excessive Ni content increases the ratio of a residual austenite phase in the steel structure, which reduces the strength of the steel. Therefore, the upper limit for Ni content is 7%. The Ni content is preferably 3.5% to 6.5%, more preferably 3.8% to 5.8%.

Cu: 1.5% to 4%

Copper (Cu) reduces the speed of solution of the steel in an environment of high-temperature chloride aqueous solution and also improves the SCC resistance of the steel. In addition, the Cu strengthens a ferrite phase in the steel structure. In order to obtain these effects, the lower limit for the Cu content is 1.5%. On the other hand, excessive Cu content reduces the ability to be hot worked steel. Therefore, the upper limit for the Cu content is 4%. The Cu content is preferably 1.5% to 3.0%, more preferably 1.5% to 2.5%.

Mo: greater than 2% and not greater than 4%

Molybdenum (Mo) improves the pitting corrosion resistance and SCC resistance of steel when it coexists with Cr. In order to obtain the effects, the Mo content is greater than 2%. On the other hand, Mo is a ferrite forming element and, therefore, an excessive Mo content increases the ratio of a ferrite phase in the steel structure, which reduces resistance. Therefore, Mo content is not more than 4%. The Mo content is preferably 2.1% to 3.3%, more preferably 2.3% to 3.0%.

In the sun: 0.001% to 0.1%

Aluminum (Al) deoxidizes steel in the refining process. In order to obtain the effect, the lower limit for the Al content is 0.001%. On the other hand, an excessive Al content produces a large amount of an alumina inclusion that will be generated in the steel, which reduces the toughness of the steel. Therefore, the upper limit for the Al content is 0.1%. Note that the Al content in the specification means the acid soluble aluminum content (Al sol.).

Ca: 0.0001% to 0.01%

Calcium (Ca) deoxidizes steel in the refining process. In addition, Ca improves the ability to be hot processed. In order to obtain these effects, the lower limit for Ca content is 0.0001%. On the other hand, an excessive Ca content produces a large amount of an inclusion such as CaO that is to be generated in the steel, which reduces the toughness of the steel. In addition, inclusion such as CaO forms an origin for a hole. Therefore, the upper limit for the Ca content is 0.01%.

N: 0.05% or less

Nitrogen (N) stabilizes an austenite phase and also improves resistance to pitting corrosion. On the other hand, an excessive N content causes various nitrides to form in the steel, which reduces the toughness of the steel. Therefore, the content of N is not more than 0.05%. In order to effectively obtain the effect, the lower limit for the N content is preferably 0.005%.

O: 0.05% or less

Oxygen (O) is an impurity and is combined with another element to form rust, which reduces the toughness and corrosion resistance of steel. Therefore, the O content is preferably as small as possible. Therefore, the O content is not more than 0.05%.

Rare earth metals: 0.001% to 0.3%

Rare earth metals (REM) are important elements according to the invention. REMs improve the resistance of SCC in an environment of high temperature aqueous chloride solution as described above. In order to obtain the effect, the lower limit for REM content is 0.001%. On the other hand, excessive REM content saturates the effect. Therefore, the upper limit for REM content is 0.3%. The content of REM is preferably from 0.001% to 0.1%, more preferably from 0.001% to 0.01%.

Note that REM according to the invention refers to yttrium (Y) with atomic number 39 and lanthanum lanthanoids (La) with atomic number 57 to lutetium (Lu) with atomic number 71.

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The stainless steel according to the invention contains at least one of the previous REMs. Thus, the REM content means the total content of at least one selected from the plurality of REM described above.

The balance of the chemical composition consists of Fe and impurities.

The stainless steel according to the invention contains at least one selected from the group consisting of Ti, Zr, Hf, V and Nb instead of a part of Fe if necessary.

Ti: 0.5% or less Zr: 0.5% or less Hf: 0.5% or less V: 0.5% or less Nb: 0.5% or less

Titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V) and niobium (Nb) are not essential elements and are added as optional elements. These elements each fix the C and reduce the generation of Cr carbide. Therefore, the generation of a hole attributable to a depleted Cr layer formed around the Cr carbide is reduced and the sensitivity of SCC is reduced. However, excessive content of any of these elements reduces the toughness of the steel. Therefore, the upper limits for the content of these elements are each 0.5%. In order to effectively obtain the effect described above, the lower limits for the content of these elements are each preferably 0.005%. Note, however, that if the content of these elements is lower than the preferable lower limit, the effect described above is obtained in some way.

2. Manufacturing method

The stainless steel according to the invention can have the following structure carrying out quenching-tempering as a heat treatment, so that the corrosion resistance can be provided as intended and the necessary strength when used as tubular products for oil producing countries. Now, a method of manufacturing a stainless steel pipe according to the invention will be described by way of example.

The steel having the chemical composition described above is melted and manufactured in a billet. The billet produced is subjected to hot work and manufactured in a stainless steel pipe. A Mannesmann method is used, for example, such as hot work to make a seamless steel pipe. Note that hot work can be hot extrusion or hot forged.

The stainless steel pipe produced is quenched and tempered. At the moment, the preferable tempering temperature is 900 ° C to 1200 ° C, and the preferable tempering temperature is 450 ° C to 650 ° C.

3. Structure

The stainless steel structure produced by the method described above includes, in percentage by volume, 10% to 60% ferrite phase and 2% to 10% residual austenite phase.

Now, the volume percentage of the ferrite phase is obtained by the following method. A specimen that has its polished surface is etched using a mixed solution of royal water and glycerin. Using the engraved specimen, the area ratio of the ferrite phase on the surface of the specimen is measured by a point counting method according to JISG0555. The measured area ratio is used as a percentage by volume. The volume percentage of the residual austenite phase is measured by X-ray diffraction.

Note that in the stainless steel structure, the distinct portion of the ferrite phase and the residual austenite phase is primarily a reverted martensite phase. Carbide, nitride, boride and a Cu phase other than the martensite phase may be included.

The stainless steel according to the invention has the structure described above, so that the tensile strength is not less than 654 MPa (corresponding to 95 ksi). Stretch strength can be adjusted to 758 MPa (corresponding to 110 ksi) or more and additionally to 862 MPa (corresponding to 125 ksi) or more. Stretch resistance in this specification refers to 0.2% stretch resistance at the creep point based on the ASTM standard.

The stainless steel according to the invention has high tenacity since it contains the residual austenite phase equal to the volume percentage described above in the structure.

Examples

A plurality of types of stainless steel were produced and examined that had various chemical compositions for their resistance to SCC in an environment of high temperature aqueous chloride solution.

Specimen Manufacturing

A plurality of types of stainless steel having the chemical compositions in Table 2 were melted.

Claims (2)

1. Stainless steel used for tubular products for oil producing countries, consisting of, in mass percentage, 0.001% to 0.05% of C, 0.05% to 1% of Si, at most 2% of Mn, 5 maximum 0.03% of P, less than 0.002% of S, 16% to 18% of Cr, 3.5% to 7% of Ni, more than 2% and a maximum of 4% of Mo, 1.5% to 4% of Cu, 0.001% to 0.3% of rare earth metal, 0.001% to 0.1% of Al sol., 0.0001% to 0.01% of Ca, at most 0.05% of O, and at most 0.05% of N, and one or more selected from the group consisting of a maximum of 0.5% of Ti, a maximum of 0.5% of Zr, a maximum of 0.5% of Hf, a maximum of 0.5% of V and a maximum of 0.5% of Nb, consisting of 10 rest in Fe and impurities, in which the steel has a structure that includes, in percentage by volume, 10% at 60% ferrite phase and 2% to 10% residual austenite phase and has a tensile strength of at minus 654 MPa. 2. The stainless steel according to claim 1, further comprising at least one selected from the group consisting of 0.005% to 0.5% Ti, 0.005% to 0.5% Zr, 0.005% to 0.5% of Hf, 0.005% to 0.5% of V and 0.005% to 0.5% of Nb. PRESENCE / ABSENCE OF SCC image 1